Experimental Investigation on Engineering Properties of Concrete Incorporating Reclaimed Asphalt Pavement and Rice Husk Ash

Transcription

1 buildings Artile Experimental Investigation on Engineering Properties of Conrete Inorporating Relaimed Asphalt Pavement and Rie Husk Ash Mulusew Aderaw Getahun 1,2, * ID, Stanley Muse Shitote 3 and Zahary C. Abiero Gariy 4 1 Civil Engineering Department, Pan Afrian University Institute for Basi Sienes, Tehnology and Innovation (PAUSTI), Nairobi, Kenya 2 Ethiopian Roads Authority, Addis Ababa 1770, Ethiopia 3 Civil Engineering Department, Rongo University, Rongo , Kenya; sshitote@rongovarsity.a.ke 4 Civil Engineering Department, Jomo Kenyatta University of Agriulture and Tehnology (JKUAT), Nairobi 5505, 00100, Kenya; zagariy@eng.jkuat.a.ke * Correspondene: mulusew06@gmail.om; Tel.: Reeived: 11 June 2018; Aepted: 9 July 2018; Published: 23 August 2018 Abstrat: Waste generation from agriultural and onstrution industries is growing at an upsetting rate that auses a heavy burden on landfill failities. On the other hand, the onstrution industry is exhausting natural resoures thereby posing environmental problems. This study investigates the potential use of agro-industrial waste suh as rie husk ash (RHA) and onstrution waste like relaimed asphalt pavement (RAP) as promising onstrution materials. The durability and physial and mehanial properties of onrete were assessed by partially replaing ement and virgin aggregates with RHA and RAP, up to 20% and 50%, respetively. A total of 22 mixes were studied, twelve of whih were devoted to studying the olletive effets of RHA and RAP on the engineering properties of onrete. Based on experimental results, RHA and RAP dereased slump, ompating fator, density, water absorption and sorptivity. RHA inreased ompressive and tensile splitting strength, whereas RAP dereased ompressive and tensile splitting strength. Comparable strength and favorable sorptivity values were obtained when 15% RHA was ombined with up to 20% RAP in the onrete mix. Thus, utilizing RHA and RAP as onrete ingredients an ontribute to solid waste management, engineering and eonomi benefits. Keywords: slump; ompating fator; density; water absorption; sorptivity; durability; ompressive strength; tensile splitting strength; volumes of permeable void spaes 1. Introdution The onstrution industry onsumes about 40% of the global energy; is the largest global onsumer of raw materials; and is responsible for 25 40% of the world s total CO 2 emissions and 28% of solid waste in the form of onstrution debris [1]. Over 10 billion tons of Portland ement onrete (PCC) is produed annually worldwide due to its versatility, durability and sustainability [2,3]. However, its prodution onsumes a substantial amount of energy and raw materials. The ement prodution alone is both energy and resoure intensive. It was attested that every ton of ement prodution onsumes about 4 GJ of energy and 1.7 tons of raw materials and releases approximately ton of CO 2 [2,4 7]. Moreover, PCC prodution onsumes more than 8 billion tons of aggregates eah year [6]. Consequently, an inreasing demand for onrete will ontinue reduing natural stone deposits signifiantly thereby poses a threat on the environment [7 9]. Conurrently, a substantial quantity of onstrution and agro-industrial solid wastes disposal is posing a huge threat to the environment [10 12]. For example, road maintenane and rehabilitation Buildings 2018, 8, 115; doi: /buildings

2 Buildings 2018, 8, of 24 ativities have been generating a large amount of valuable asphalt pavement materials that are either disarded along the generation point or hauled off to the disposal site [13 15]. Similarly, aording to the FAO 2017 [16] report, the global paddy prodution in 2017 was foreasted to amount to million tons. Assuming annual rie prodution remains the same, million tons of rie husks is available for disposal every year worldwide. Thus, agro-industrial solid waste disposal is another serious onern unless we find a preferred alternative use. In order to urb these onerns, the ement and onrete industry ould be an ideal home for onstrution and industrial wastes. Reently, waste materials suh as rushed onrete, asphalt pavement and rushed glasses are some of the reyled materials whih have been used as a oarse and/or fine aggregate in onrete prodution [17,18]. In addition, numerous researhes devoted to find alternatives for ement replaement [19 23]. Thus, utilizing RAP and rie RHA as aggregate and ement partial replaements, respetively, is in harmony with this approah. The onern on how to use RAP has gained a remarkable uriosity in the United States due to the inreasing demand for sustainable onstrution materials use [24]. But, in underdeveloped and developing ountries where reyling materials is not a ulture, a tremendous amount of RAP and RHA materials are usually disarded in landfills [13]. Previous studies [25 28] revealed and onsistently reported that utilizing RAP in PCC aused redutions in ompressive, flexural, and tensile splitting strength ompared to PCC ontaining virgin aggregates. The findings from past studies showed that the derease in strength of PCC ontaining RAP was largely instigated by the effets of porosity in the interfaial transition zone (ITZ) and preferential asphalt ohesion failure [29 31] However, previous studies [27 30] exhibited that onrete ontaining RAP had better dutility, toughness and frature properties ompared to normal onrete. Huang et al. [26] reported that RAP ould initiate rak propagation and lead to the formation of a prolonged rak pattern allied to the higher dissipation of energy. Hene, there is a need to improve the strength of onrete ontaining RAP in order to maximize the utilization of RAP materials in onstrution appliations. RHA was found to enhane the onrete properties by filler and pozzolani effets [12,32]. The enhanement in strength is believed to be an advantage from the high silia ontent of RHA, whih, in itself, possesses little ementitious value, but when alium hydroxide reats with RHA in the presene of water, a ementitious omplex is formed [33]. The hydration of trialium siliate (C 3 S) gives 61% alium-siliate-hydrate (C-S-H) and 39% alium hydroxide; the hydration of dialium siliate (C 2 S) results in 82% C-S-H and 18% alium hydroxide, where up to 15% of the weight of Portland ement is hydrated lime [34]. Calium hydroxide has no ontribution to onrete strength, but rather has detrimental effets on the durability of onrete. Thus, RHA an provide an opportunity to alter the free lime (Calium hydroxide) to a C-S-H gel that makes the onrete strong [35]. Therefore, the main objetive of this study was to investigate the olletive effets of RHA and RAP on the physial and mehanial properties of onrete. The engineering properties of RHA-inlusive onrete were assessed in the first phase. Then, the effets of RAP on wet and hardened onrete properties were investigated. Finally, the ombined effets of RHA and RAP on engineering properties of onrete were assessed. Thus, utilizing RAP in ombination with RHA for onrete prodution an ontribute to engineering benefits, eonomi savings, solid waste management and environmental protetion. 2. Material and Methods 2.1. Materials Materials used for this study were fine relaimed asphalt pavement (FRAP), ourse relaimed asphalt pavement (CRAP), fine virgin aggregate (FVA), ourse virgin aggregate (CVA), ordinary Portland ement (OPC) type I, rie husk ash (RHA), water, Sika VisoCrete 3088 superplastiizer (SVCSP) and Sikament NNG superplastiizer (SNNGSP). Figure 1 depits aggregates (CRAP, CVA,

3 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 3 of 24 FRAP, and FVA) and ementitious materials (ement and RHA). All materials were obtained from different parts of Kenya. FVA (river sand) and VCA were purhased from Masinga and Molongo distrits of Kenya respetively. The RAP was obtained from an old distressed flexible pavement, Ruaka-Banana-Limuru Road (D407), sampled at atthe setion near Tigoni, Kiambu County of ofkenya. The road was onstruted about 21 years ago without major rehabilitation. RHA was olleted from the dump site site of of Mwea Mwea Rie Rie Milling Milling Fatory. Fatory. Cement Cement and superplastiizers and superplastiizers were bought were from bought Bamburi from Bamburi Cement and Cement Sika Kenya and Sika Limited Kenya respetively. Limited respetively. Tap watertap waswater used was for mixing. used for mixing. Figure 1. Materials. Figure 1. Materials Methods 2.2. Methods The methods adopted and followed for this study are disussed in the subsequent setion. The The methods adopted and followed for this study are disussed in the subsequent setion. most important test methods are summarized in Table 1. The most important test methods are summarized in Table 1. Table 1. Test methods adopted. Table 1. Test methods adopted. Test on Constituent Materials Tests on Fresh and Hardened Conrete Test on Constituent Materials Tests on Fresh and Hardened Conrete Test Performed Standard Used Performed Standard Used Test Performed Standard Used Test Performed Standard Used Sieve analysis BS EN Slump BS EN Aggregate Sieve speifi analysis gravity (SG) BS EN Compating Slump fator BS EN BS Aggregate speifi gravity (SG) BS EN Compating fator BS Fineness modulus modulus ASTM ASTM C136 C136 Fresh Fresh density density BS BS EN EN ement and RHA SG SG ASTM C188 C188 Compressive strength BS BS EN EN Aggregate water absorption BS EN Tensile strength BS EN BS EN strength BS EN Aggregates density ASTM C29 Water absorption ASTM C642 Aggregates Voids in aggregates density ASTM C29 C29 Water Sorptivity absorption ASTM ASTM C1585 C642 Voids in ACV aggregates IS ASTM 2386-IVC29 Permeable Sorptivity voids ASTM C642 C1585 AIV IS 2386-IV Hardened density ASTM C642 ACV IS 2386-IV Permeable voids ASTM C642 AIV IS 2386-IV Hardened density ASTM C Test Methods for Material Charaterization Aggregate Test Methods sampling for Material was arried Charaterization out in aordane with BS EN (1997) [36] requirements to get representative Aggregate sampling sampleswas for the arried bath. out Grading aordane of the aggregates with BS EN was determined (1997) [36] inrequirements line with BS EN to get representative (2012) [37] proedures samples for using the bath. test sieves Grading of the of sizes the aggregates omplyingwas withdetermined BS ISO in line (2013) with [38]. BS The EN RAP (2012) material [37] was proedures obtainedusing through test ripping sieves of and the milling sizes omplying of old existing with BS pavement, ISO and(2013) then [38]. rushed The manually RAP material andwas finally obtained sievedthrough using 5ripping mm sieve and inmilling orderof toold separate existing into pavement, FRAP (grain and then size rushed less thanmanually 5 mm) and and CRAP finally (grain sieved size using greater 5 mm than sieve 5 in mm). order RHA to separate was sieved into using FRAP 0.10 (grain mm size sieve. less The than speifi 5 mm) gravity and CRAP and water (grain absorption size greater ofthan oarse 5 mm). and fine RHA aggregates was sieved wereusing determined 0.10 mm as sieve. per BSThe EN speifi (2013) gravity [39]. and Bulk water density absorption and voids of oarse in aggregates and fine were aggregates determined were indetermined line with the as proedures per BS EN defined(2013) ASTM [39].(2003) Bulk density [40]. Aggregate and voids rushing aggregates and impat were determined tests were performed in line with aording the proedures to the proedures defined in ASTM speified (2003) in IS[40]. 2386: Aggregate Part IV (2002) rushing [41]. and impat tests were performed aording to the proedures speified in IS 2386: Part IV (2002) [41] Mix Design and Mixing Proedures The Mix mix Design design and for Mixing 25 MPa Proedures Portland ement onrete (PCC) was done in aordane with BS EN 206 (2014) [42] and BS EN (2012) [43]. A total of 22 mixtures were prepared. Table 2 portrays The mix design for 25 MPa Portland ement onrete (PCC) was done in aordane with BS EN the partiulars of studied mixture proportions. In all the mixtures, 254 kg/m 206 (2014) [42] and BS EN (2012) [43]. A total of 22 mixtures were prepared. 3 of water and water Table 2 portrays the partiulars of studied mixture proportions. In all the mixtures, 254 kg/m 3 of water and water to ementitious material ratio of 0.65 were kept onstant. The first phase of the study was replaing ement by 5, 10, 15 and 20% RHA (by weight of ement) to assess the effet of RHA on wet and

4 Buildings 2018, 8, of 24 to ementitious material ratio of 0.65 were kept onstant. The first phase of the study was replaing ement by 5, 10, 15 and 20% RHA (by weight of ement) to assess the effet of RHA on wet and hardened properties of onrete. In the seond phase, FVA and CVA were replaed by 10, 20, 30, 40, and 50% FRAP and CRAP (by weights of FVA and CVA) respetively to asertain the influene of RAP on the properties of onrete. The third phase was to asertain the olletive effets of RHA and RAP on engineering properties of onrete. SNNGSP was used at 0.5, 0.85, 2, and 2.75% (by weight of ementitious material) for 5, 10, 15, and 20% RHA ontent respetively. SVCSP (more powerful than SNNGSP) was used at 0.5, 0.7, 0.9, and 1.1% (by weight of ementitious material) for RHA and RAP ombined mixtures. Manual mixing was performed as per BS EN (2013) [44] with a ontrol mehanism to prevent the loss of ementitious materials and water quantified during mixture proportioning. The hemial analysis of ement and RHA were onduted as per BS EN (2013) [45] test method. The speifi gravities of ement and RHA were done in aordane with ASTM C188 (2016) [46]. Table 2. Mix proportions for 25 MPa onrete omprising RHA and RAP. Mix Desription Cement (kg/m 3 ) RHA (kg/m 3 ) FVA (kg/m 3 ) FRAP (kg/m 3 ) CVA (kg/m 3 ) CRAP (kg/m 3 ) Control (5 20)% RHA ( ) (20 78) (10 50)% RAP ( ) (71 356) ( ) ( ) 5% RHA + (10 30)% RAP ( ) (71 214) ( ) ( ) 10% RHA + (10 30)% RAP ( ) (71 214) ( ) ( ) 15% RHA + (10 30)% RAP ( ) (71 214) ( ) ( ) 20% RHA + (10 30)% RAP ( ) (71 214) ( ) ( ) Test Methods for Fresh Conrete Properties Fresh onrete properties were assessed by onduting slump, ompating fator, and fresh density tests. Three repliate speimens were prepared for eah test. Sampling for testing was done in aordane with proedures stipulated in BS EN (2009) [47]. Slump, ompating fator and fresh density was determined in aordane the proedures speified in BS EN (2009) [48], BS (1993) [49], and BS EN (2009) [50] respetively Test Methods for Hardened Conrete Properties Cubes of dimensions 100 mm 100 mm 100 mm and ylinders with a diameter of 100 mm and 200 mm long onforming to BS EN (2012) [51] requirements were used to make onrete speimens for ompressive and tensile splitting strength test respetively. A total of 132 ube and 66 ylinder speimens were made and ured in aordane with the methods speified in BS EN (2009) [52] for 7 and 28 days ompressive and 28 days tensile splitting strength test respetively. Three repliate speimens were prepared for eah test. Compressive and tensile splitting strength of onrete were determined aording to BS EN (2009) [53] and BS EN (2009) [54] test method respetively. Speimens were loaded to failure in automati omputerized testing mahine onforming to BS EN (2000) [55]. Density, water absorption and void spaes in onrete were determined onsistent with ASTM C642 (2013) [56]. Three repliate speimens were prepared for eah test. A total of 66 ubes of dimensions 100 mm 100 mm 100 mm were made and ured for 28 days. The samples were dried in an oven for 72 h at a temperature of 105 C until the hange in mass was less than 0.5%. Then, the samples were put in the water at an average temperature of 21.5 C for about 72 h until the inrease in saturated surfae dried mass was less than 0.5%. Finally, the speimens were plaed in a reeptale, overed with tap water, and boiled for 5 h and then ooled by natural loss of heat for 15 h to a final average temperature of 22.5 C.

5 Buildings 2018, 8, of 24 Sorptivity by the onrete speimens was determined in aordane with ASTM C1585 (2013) [57] test methods. Three repliate speimens were prepared for eah test. A total of 66 ubes of dimensions 100 mm 100 mm 100 mm were made and ured for 28 days for the sorptivity test. The speimens Buildings 2018, 8, x FOR PEER REVIEW were dried in an oven at of 24 C temperature for 24 h and then remained in an oven at a temperature of 50 dimensions C for 3 days. 100 After mm 3100 days, mm eah 100 speimen mm were made was and plaed ured inside for 28 adays ontainer for the sorptivity and stored test. atthe an average temperature speimens of were 22 dried C for in 15 an days oven before at 110 C the temperature start of the for absorption 24 h and then proedure. remained in The an oven speimens at a were removed temperature from of the 50 storage C for 3 days. ontainer After 3 and days, the eah 5 faes speimen of the was speimens plaed inside were a ontainer sealed and properly stored to deter at an average temperature of 22 C for 15 days before the start of the absorption proedure. The entrane of moisture while the opposite fae left open and exposed to water. The initial weight of the speimens were removed from the storage ontainer and the 5 faes of the speimens were sealed speimens was reorded after sealing and submerged in water about 3.5 mm above the bottom fae. properly to deter entrane of moisture while the opposite fae left open and exposed to water. The Theinitial weight weight gainof was the determined speimens was forreorded eah test after speimens sealing and at interval submerged of time in water 5, 10, about 30 min, 3.5 mm 1, 2, 3, 4, 5, andabove 6 h. the bottom fae. The weight gain was determined for eah test speimens at interval of time 5, 10, 30 min, 1, 2, 3, 4, 5, and 6 h. 3. Results and Disussion 3. Results and Disussion 3.1. Material Charaterization 3.1. Material Charaterization Virgin aggregates (VA) and RAP materials were haraterized in terms of gradation, fineness modulus, Virgin water aggregates absorption, (VA) speifi and RAP gravity, materials bulk were density, haraterized void ontent, in terms ACV, of gradation, and AIV. fineness modulus, water absorption, speifi gravity, bulk density, void ontent, ACV, and AIV. Physial and Mehanial Properties of Materials Physial and Mehanial Properties of Materials The speifi gravity, water absorption, bulk density, aggregate rushing value (ACV), aggregate The speifi gravity, water absorption, bulk density, aggregate rushing value (ACV), aggregate impat impat value value (AIV) (AIV) of of aggregates, among others, others, are are tabulated tabulated in Table in Table Table 3. Physial and mehanial properties of materials. of materials. Property OPC RHA FVA FRAP CVA CRAP Property OPC RHA FVA FRAP CVA CRAP Fineness modulus Fineness modulus Silt Content [%] Silt Content (%) Bulk speifi Bulk gravity speifi gravity Bulk speifi Bulk gravity, speifi SSD gravity, basis SSD basis Apparent Apparent speifi gravity speifi gravity Water Absorption Water Absorption (%) [%] Loose bulk density (kg/m 3 ) Loose bulk density Rodded bulk density (kg/m 3 [kg/m 3 ] ) Voids in Rodded loose aggregates bulk density (%) [kg/m 3 ] Voids in Rodded Voids in aggregates loose aggregates (%) [%] Maximum Voids partile in Rodded size (mm) aggregates 0.09 [%] Aggregate Maximum rushing values partile (%) size (mm) Aggregate Impat values (%) Aggregate rushing values [%] Aggregate Impat values [%] Gradation results of oarse and fine aggregates are depited in Figures 2 and 3 respetively. Gradation results of oarse and fine aggregates are depited in Figures 2 and 3 respetively. As As an be seen from the figures, the grading of CVA and FVA met the grading requirements of BS 882 an be seen from the figures, the grading of CVA and FVA met the grading requirements of BS 882 (1992) [58]. (1992) [58]. 100 Perent Pass CVA Lower Limit Upper Limit CRAP Sieve Size (mm) Figure 2. Coarse aggregate partile size distribution as per BS 882 speifiations. Figure 2. Coarse aggregate partile size distribution as per BS 882 speifiations.

6 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 6 of Perent Pass FVA 40 Lower Limit 20 Upper Limit 0 FRAP Sieve Size (mm) Figure 3. Fine aggregate partile size distribution as per BS 882 speifiations. Figure 3. Fine aggregate partile size distribution as per BS 882 speifiations. The grading of CRAP was slightly outside the limits and while that of FRAP was within the limits speified in BS 882. It is apparent from the figure that CRAP was finer than CVA whereas, FRAP was oarser than FVA. Similar findings were reported by previous study [28]. The fineness of CRAP and oarseness of FRA might be attributed to the fragmentation of CRAP materials during rushing and agglomeration of partiles respetively and their soures as well. All oarse aggregates used in this study had 19.1 mm nominal maximum aggregate sizes. The fine aggregates partile sizes were between 0.15 and 5 mm. FVA and FRAP had fineness modulus of 2.65 and 3.61 respetively. RAP materials had lower speifi gravity than that of virgin aggregates. This is onsistent with the findings by [25]. The lower speifi gravity of RAP may be attributed to the substantial amounts of low-density asphalt-mortar oatings on the RAP surfaes and its soure as well. The water absorption of RAP was found to be lower than that of VA. The reason might be attributed to the asphalt oating around both oarse and fine RAP that ould hinder the maximum possible amount of water whih ould have been absorbed by the aggregates. RAP materials had lower loose and rodded bulk density than that of virgin aggregates. RAP materials also showed higher void spae than that of virgin aggregates whih may demand a higher amount of ement paste to fill the total surfae area in order to produe quality onrete [35]. The ACV test done on the CRAP exhibited the abnormal result. The test speimen ompressed into a single solid mass under loading. This might be due to the presene of asphalt film around RAP might bind the rushed aggregates into a single solid dense mass. The ACV and AIV values of CVA and CRAP were below the maximum limit stipulated in IS 383 (2002) [59]. CRAP had lower ACV and AIV value than that of CVA. The speifi gravity of RHA was less than that of OPC by 35%. The bulk density of RHA was also about 33% of that of OPC. The lower the speifi gravity and bulk density of RHA may result in a redution of onrete density. The maximum partile size of OPC and RHA were 90 and 100 µm respetively. Table 4 depits the hemial omposition of OPC, RHA, FRAP, and FVA. The grading of CRAP was slightly outside the limits and while that of FRAP was within the limits speified in BS 882. It is apparent from the figure that CRAP was finer than CVA whereas, FRAP was oarser than FVA. Similar findings were reported by previous study [28]. The fineness of CRAP and oarseness of FRA might be attributed to the fragmentation of CRAP materials during rushing and agglomeration of partiles respetively and their soures as well. All oarse aggregates used in this study had 19.1 mm nominal maximum aggregate sizes. The fine aggregates partile sizes were between 0.15 and 5 mm. FVA and FRAP had fineness modulus of 2.65 and 3.61 respetively. RAP materials had lower speifi gravity than that of virgin aggregates. This is onsistent with the findings by [25]. The lower speifi gravity of RAP may be attributed to the substantial amounts of low-density asphalt-mortar oatings on the RAP surfaes and its soure as well. The water absorption of RAP was found to be lower than that of VA. The reason might be attributed to the asphalt oating around both oarse and fine RAP that ould hinder the maximum possible amount of water whih ould have been absorbed by the aggregates. RAP materials had lower loose and rodded bulk density than that of virgin aggregates. RAP materials also showed higher void spae than that of virgin aggregates whih may demand a higher amount of ement paste to fill the total surfae area in order to produe quality onrete [35]. The ACV test done on the CRAP exhibited the abnormal result. The test speimen ompressed into a single solid mass under loading. This might be due to the presene of asphalt film around RAP might bind the rushed aggregates into a single solid dense mass. The ACV and AIV values of CVA and CRAP were below the maximum limit stipulated in IS 383 (2002) [59]. CRAP had lower ACV and AIV value than that of CVA. The speifi gravity of RHA was less than that of OPC by 35%. The bulk density of RHA was also about 33% of that oftable OPC. 4. The Chemial lower omposition the speifi of ement, gravity RHA, and FRAP, bulk and density FVA. of RHA may result in a redution of onrete density. The maximum partile size of OPC and RHA were 90 and 100 µm respetively. Table 4 depits the hemial omposition of OPC, RHA, FRAP, and FVA. Chemial Composition (%) Cement RHA FRAP FVA CaO SiO Al2O Table 4. Chemial omposition of ement, RHA, FRAP, and FVA. MgO Na2O Chemial Compound K2O (%) Cement 0.53 RHA FRAP 2.50 FVA CaO TiO SiO 2 MnO Al 2 O Fe2O MgO Na 2 O C3A K 2 O SO TiO Loss 2 on ignition (LOI) MnO Fe 2 O C 3 A SO Loss on ignition (LOI)

7 Buildings 2018, 8, of 24 The sum of the silion dioxide (SiO 2 ), aluminium oxide (Al 2 O 3 ) and iron oxide (Fe 2 O 3 ) ontents of RHA was 94.8%; as a result, RHA fulfilled the 70% minimum requirement of BS EN (2012) [60] to be used as a good pozzolana. The free alium oxide (CaO) ontent was less than the upper bound (1.5%) speified in BS EN (2012). This indiates the ability of the RHA to onvert the free lime (Calium hydroxide) to a C-S-H gel [60] that makes the onrete strong. The loss on ignition (LOI) of RHA was greater than that of ement but satisfied the limits speified in BS EN (2012) [60]. LOI denotes the amount of unburnt arbon residue in the RHA that is responsible for an inrease in water demand [32] whih may have an influene on the properties of fresh onrete i.e., ould result in low workability. The physial and hemial properties of superplastiizers used in the study are presented in Table 5. Table 5. Properties of superplastiizers. Property Superplastiizer Sikament NNG Sika VisoCrete 3088 Appearane/olor Dark brown liquid Yellowish liquid Density (kg/l) ph value Chemial base Naphthalene formaldehyde Aqueous solution of modified sulphonate polyarboxylate Dosage % by weight of ement 0.2 2% by weight of ement 3.2. Fresh and Hardened Properties of Conrete Fresh Properties of Conrete Tables 6 8 show slump, ompation fator (CF) and density of fresh onrete. Slump From trial mixes, it was observed that RHA aused a dramati derease in slump as ompared to the ontrol mix. When Sikament NNG SP was added, the slump inreased by 23.33% from 60 to 74 mm at 5% RHA and 0.5% SP ontent. Surprisingly, it was also disovered that as the ontent of RHA inreased, the slump dereased onsiderably despite inreasing the dosages of SP. The slump dereased by 20, 33.33, and 75% from 60 mm to 48, 40, and 15 mm at 10, 15, and 20% RHA ontent with the addition of 0.85, 2, and 2.75% SP respetively. The high demand for water and the resulted lower slump might be attributed to the large speifi surfae area and high unburnt arbon ontent of RHA. Like that of RHA, the partial replaement of virgin aggregate by RAP resulted in a substantial derease of slump as ompared to the ontrol mix. The slump dereased by 33, 47, 62, 67, and 78% from 60 mm to 40, 32, 23, 20, and 13 mm at 10, 20, 30, 40, and 50% RAP ontent respetively. The redution in slump might be attributed to absorption of the mixing water by the fine dust layers around the RAP periphery and water might also be ontrolled by RAP partile and was not able to move freely and thus, play no role to workability. The inlusion of both RHA and RAP in the mix found to derease the slump signifiantly as expeted. However, there was a slight (3%) improvement in the slump when 0.5% Sika VisoCrete 3088 SP was added to the onrete mix ontaining (5RHA + 10RAP) % as shown in Table 8. The slump dereased steadily as the RHA and RAP ontent inreased regardless of inreasing the SP dosages. This may be attributed to the ombined effets of RHA and RAP as already disussed.

8 Buildings 2018, 8, of 24 Table 6. Fresh properties of RHA onrete mixes. Fresh Properties Mix Designation (RHA)% Control (5) (10) (15) (20) Slump (mm) Compation Fator (CF) Fresh Density (g/m 3 ) Buildings 2018, 8, x FOR PEER REVIEW 8 of 24 Table Table Fresh properties of ofrha RAPonrete mixes. mixes. Mix Designation [RHA]% Fresh Properties Control Mix [5] Designation [10] (RAP)% [15] [20] Fresh Properties Slump (mm) Control 60 (10) 74 (20) 48 (30) 40 (40) 15 (50) Compation Fator (CF) Slump Fresh (mm) Density (g/m ) Compation Fator (CF) Fresh Density (g/m Table 3 ) 7. Fresh properties of RAP onrete mixes Mix Designation [RAP]% Table Fresh 8. Properties Fresh properties of both RHA and RAP onrete mixes. Control [10] [20] [30] [40] [50] Slump (mm) Compation Fator (CF) Mix0.931 Designation (RHA RAP) % Fresh Properties Fresh Density (5(g/m + 10) 3 ) ( ) ( ) ( ) ( ) ( ) Slump (mm) Table 8. Fresh properties of both RHA and RAP onrete mixes. Compation Fator (CF) Fresh Density (g/m 3 ) Mix Designation (RHA + RAP) % Fresh Properties [5 + 10] [5 + 20] [5 + 30] [ ] [ ] [ ] Fresh Properties ( ) ( ) ( ) ( ) ( ) ( ) Slump [mm] Slump Compation (mm) Fator (CF) Compation Fresh Fator Density (CF) [g/m 3 ] Fresh Density Fresh (g/m Properties 3 ) [ ] [ ] [ ] [ ] [ ] [ ] Slump [mm] Compation Fator (CF) Compation Fator (CF) Fresh Density [g/m 3 ] The CF values of the onrete ranged from to as shown in Tables 6 8; these values are Compation Fator (CF) within the ranges speified in BS [49]. The CF of RHA-inlusive onrete inreased by 1% at 5% RHA ontent, The CF whereas values of CF the dereased onrete ranged by 19% from as theto RHA ontent as shown inreased Tables 6 8; to these 20%. values Figure 4a and are within the ranges speified in BS [49]. The CF of RHA-inlusive onrete inreased by Equation (1) (obtained by regression) show the relationship between slump and ompation fator. R 2 1% at 5% RHA ontent, whereas CF dereased by 19% as the RHA ontent inreased to 20%. Figure and standard 4a and Equation error (1) of estimate (obtained by (SEE) regression) of the show model the were relationship and between slump respetively. and ompation Similarly, fator. Rthe 2 and CF standard values error of RAP-inlusive of estimate (SEE) of onrete the model dereased were by and 5% from respetively to at 50% RAP ontentsimilarly, relative the to the CF values ontrol of mix. RAP-inlusive Figure 4b onrete and Equation dereased (2) by 5% (obtained from byto regression) at 50% illustrate the relationship RAP ontent between relative to slump the ontrol andmix. ompation Figure 4b and fator. Equation R 2 (2) and (obtained SEE of by the regression) modelillustrate were and the relationship between slump and ompation fator. R respetively. 2 and SEE of the model were and respetively. Compation fator (Cf) (a) RHA onrete C f = S R² = Slump, S [mm] Compation fator (Cf) C f = 0.82S R² = Slump, S [mm] (b) RAP onrete Figure 4. Relationship between slump and ompation fator for RHA and RAP onrete. Figure 4. Relationship between slump and ompation fator for RHA and RAP onrete.

9 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 9 of 24 Buildings 2018, 8, x FOR PEER REVIEW 9 of 24 C f = 0.52 S (1) where: C f is ompating fator; and S is the Cslump f = 0.52in mm S 0.143for fresh RHA onrete (1) C f = 0.52 (1) where: Cf is ompating fator; and S is the slump in mm C f = 0.82 S for fresh RHA onrete where: Cf is ompating fator; and S is the slump in mm for fresh RHA onrete (2) C f = f S (2) (2) where: C f is the ompating fator; and S is the slump in mm for fresh RAP onrete where: Cf Awhere: slight is the Cf inrease is the ompating ompating was observed fator; fator; and and in S S CF is is the the values slump at in 5% mm RHA for for fresh fresh + (10 30)% RAP RAP onrete onrete RAP ontent, whereas A slight CF dereased A slight inrease marginally inrease was was observed for in the remaining CF CF values at mixes. 5% Figure RHA 5 + [10 30]% (obtained RAP RAP byontent, ontent, regression) whereas whereas depits CF CF the dereased dereased marginally for for the the remaining mixes. Figure 5 (obtained by by regression) depits depits relationship between slump and ompation fator for RHA- and RAP-inlusive onrete. R 2 the the and SEE relationship between slump and and ompation fator for RHA- and RAP-inlusive onrete. R of the model were and respetively. 2 Rand 2 and SEE SEE of the of model the model were were and and respetively. Density [g/m 3 ] Compation fator (Cf) Compation fator (Cf) Density = 2.480(RHA) R² = f S S C f = S R² = S R² = Slump, 45S [mm] Slump, S [mm] Figure 5. Relationship between slump and ompation fator. Figure 5. Relationship between slump and ompation fator. Figure 5. Relationship between slump and ompation fator. Fresh Density Fresh Fresh Density The Density fresh density of RHA-inlusive PCC dereased by 3.8% from 2480 to 2386 kg/m 3 as the RHA The ontent in the mix inreased from 0 to 20%. The redution in fresh density might be due to the fat The fresh density of RHA-inlusive PCC PCCdereased by 3.8% by 3.8% from from to 2386 tokg/m 2386 as kg/m the RHA 3 as the that the partile density of RHA (2.03) was lower than that of ement partile density (3.12). The RHA ontent ontent in the inmix theinreased mix inreased from 0 from to 20%. 0 tothe 20%. redution The redution in fresh density in freshmight density be due might to the be due fat to relationship between fresh density and RHA ontent (obtained by regression) is depited in Figure the that fat the that partile the partile density density of RHA of(2.03) RHA was (2.03) lower wasthan lower that than of that ement of ement partile partile density density (3.12). The (3.12). 6a. R 2 and SEE of the model were and respetively. The relationship The mix between between ontaining fresh fresh RAP density exhibited density and RHA relatively and ontent RHA lower ontent (obtained fresh density (obtained by regression) ompared by regression) to is the depited mix ontaining is in depited Figure in Figure 6a. Rvirgin 2 6a. and Raggregates. SEE 2 andof SEE the The model of the fresh model were density were of and RAP-inlusive and respetively mix dereased respetively. by 5.7% from 2480 to 2339 kg/m 3 The as The the mix mix RAP ontaining ontent RAP the mix exhibited inreased relatively from 0 to lower 50%. fresh The redution density ompared in density might to to the the be mix attributed mix ontaining ontaining virgin virgin to aggregates. the fat that The The speifi fresh fresh gravities density of of both RAP-inlusive FRAP and CRAP mix dereased were lower by bythan 5.7% 5.7% those from fromof both to to FVA and kg/m kg/m 3 as as the the CVA RAP RAP respetively. ontent ontent in in the Figure the mix mix 6b inreased inreased (obtained from from by regression) 00 to to 50%. 50%. The gives The redution the relationship in in density between might fresh be bedensity attributed to and RAP Content. R 2 and SEE of the model were and respetively. the to fat the that fat that speifi speifi gravities gravities of both of both FRAP FRAP and and CRAP CRAP were were lower lower than than those those of of both both FVA FVA and and CVA CVA respetively. Figure 6b (obtained by regression) gives the relationship between fresh density respetively. Figure 6b (obtained by regression) gives the relationship between fresh density and RAP and RAP Content. R Content. R and SEE of and SEE of the model were and respetively. the model were and respetively. Density = (RAP) R² = Density [g/m 3 ] Density = 2.480(RHA) Density Density [g/m 3 ] [g/m 3 ] RHA Content [%] 2.30 RAP Content [%] (a) RHA onrete 2.25 (b) RAP onrete Figure 6. Fresh density for RHA and RAP onrete. RHA Content [%] RAP Content [%] (a) RHA onrete R² = (b) RAP onrete Figure 6. Fresh density for RHA and RAP onrete. Figure 6. Fresh density for RHA and RAP onrete. Density = (RAP) R² = 0.993

10 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 10 of 24 The fresh density for mixes ontaining both RHA and RAP is graphially depited in Figure 7. The fresh density for mixes ontaining both RHA and RAP is graphially depited in Figure 7. It was observed that the mixes ontaining both RHA and RAP had lower fresh density ompared to It was observed that the mixes ontaining both RHA and RAP had lower fresh density ompared to the ontrol mix. The mix inorporating 20% RHA 30% RAP showed 3.6% redution in fresh density the ontrol mix. The mix inorporating 20% RHA + 30% RAP showed 3.6% redution in fresh density relative to that of the ontrol mix. The redution in fresh density might be attributed to the olletive relative to that of the ontrol mix. The redution in fresh density might be attributed to the olletive effets pertaining to RHA and RAP as has been explained. effets pertaining to RHA and RAP as has been explained. Density [g/m 3 ] RHA and RAP Content [%] Figure 7. Fresh density for both RHA- and RAP-inlusive onrete. Figure 7. Fresh density for both RHA- and RAP-inlusive onrete Hardened Properties of Conrete Hardened Properties of Conrete Table 9 shows the ompressive strength (CS), tensile splitting strength (TSS), bulk dry density, water Table absorption 9 shows (w), the ompressive permeable void strength spaes (CS), (v), and tensile sorptivity splitting (k) of strength the onrete. (TSS), bulk dry density, water absorption (w), permeable void spaes (v), and sorptivity (k) of the onrete. Table 9. Hardened properties of onrete. Table 9. Hardened properties of onrete. CS (MPa) TSS (MPa) Mix Desription 7 Days 28 Days 28 Days w [%] v [%] K [mm/h 1/2 ] CS (MPa) TSS (MPa) Control Mix Desription (0.41) (0.42) 2.13 (0.13) 7.24 w (%) (0.18) v (%)(0.01) K (mm/h /2 (0.02) ) RHA5% (0.61) 7 Days (0.75) Days Days (0.20) 7.19 (0.30) (0.29) 1.92 (0.06) RHA10% Control (0.71) (0.41) (0.73) (0.42) (0.06) (0.13) (0.18) (0.01) (0.60) (0.02)(0.25) RHA15% RHA5% (0.41) (0.61) (0.79) (0.75) (0.01) (0.20) (0.30) (0.11) (0.29) (0.40) (0.06)(0.78) RHA10% (0.71) (0.73) 2.26 (0.06) 7.16 (0.18) (0.60) 1.90 (0.25) RHA20% (0.80) (0.32) 2.25 (0.09) 7.15 (0.01) (0.03) 1.75 (0.11) RHA15% (0.41) (0.79) 2.29 (0.01) 7.15 (0.11) (0.40) 1.80 (0.78) RAP10% RHA20% (0.20) (0.80) (0.90) (0.32) (0.06) (0.09) (0.01) (0.30) (0.03) (0.18) (0.11)(0.20) RAP20% RAP10% (0.40) (0.20) (0.0.5) (0.90) (0.07) (0.06) (0.30) (0.09) (0.18) (0.08) (0.20)(0.02) RAP30% RAP20% (0.40) (0.40) (0.08) (0.0.5) (0.01) (0.07) (0.09) (0.19) (0.08) (0.64) (0.02)(0.13) RAP40% RAP30% (0.60) (0.40) (0.07) (0.08) (0.10) (0.01) (0.19) (0.20) (0.64) (0.47) (0.13)(0.03) RAP50% RAP40% (0.30) (0.60) (0.12) (0.07) (0.04) (0.10) (0.20) (0.30) (0.47) (0.65) (0.03) (0.01) RAP50% (0.30) (0.12) 1.26 (0.04) 6.45 (0.30) (0.65) 0.69 (0.01) [5RHA + 10RAP]% (0.75) (0.68) 2.05 (0.03) 6.69 (0.15) (0.16) 1.88 (0.27) [5RHA + 10RAP]% (0.75) (0.68) 2.05 (0.03) 6.69 (0.15) (0.16) 1.88 (0.27) [5RHA + 20RAP]% (0.38) (0.47) 1.85 (0.10) 6.65 (0.04) (0.05) 1.81 (0.08) [5RHA + 20RAP]% (0.38) (0.47) 1.85 (0.10) 6.65 (0.04) (0.05) 1.81 (0.08) [5RHA [5RHA + 30RAP]% + 30RAP]% (0.84) (0.84) (0.54) (0.54) (0.04) 6.62 (0.08) (0.08) (0.08) (0.08) (0.05) (0.05) [10RHA [10RHA + 10RAP]% + 10RAP]% (0.84) (0.84) (0.66) 2.12 (0.06) 6.68 (0.01) (0.11) (0.11) (0.55) (0.55) [10RHA [10RHA + 20RAP]% + 20RAP]% (0.97) (0.97) (0.07) (0.07) 2.09 (0.01) 6.49 (0.18) (0.24) (0.24) (0.18) (0.18) [10RHA + 30RAP]% (0.38) (0.61) 1.80 (0.03) 6.20 (0.10) (0.06) 1.41 (0.17) [10RHA + 30RAP]% (0.38) (0.61) 1.80 (0.03) 6.20 (0.10) (0.06) 1.41 (0.17) [15RHA + 10RAP]% (0.55) (0.54) 2.22 (0.25) 6.33 (0.06) (0.02) 1.87 (0.35) [15RHA [15RHA + 10RAP]% + 20RAP]% (0.55) (0.24) (0.54) (0.56) (0.03) (0.25) (0.05) (0.06) (0.10) (0.02) (0.07)(0.35) [15RHA [15RHA + 20RAP]% + 30RAP]% (0.24) (0.13) (0.56) (0.12) 2.10(0.03) 1.89 (0.01) (0.07) (0.05) (0.17) (0.10) (0.29)(0.07) [15RHA [20RHA + 30RAP]% + 10RAP]% (0.13) (0.50) (0.12) (0.14) (0.01) (0.05) 6.30 (0.13) (0.07) (0.45) (0.17) (0.46)(0.29) [20RHA + 20RAP]% (1.04) (0.92) 1.99 (0.01) 6.25 (0.08) (0.52) 1.89 (0.04) [20RHA + 10RAP]% (0.50) (0.14) 2.15 (0.05) 6.30 (0.13) (0.45) 1.92 (0.46) [20RHA + 30RAP]% (0.43) (0.93) 1.79 (0.06) 6.25 (0.11) (0.03) 1.65 (0.06) [20RHA + 20RAP]% (1.04) (0.92) 1.99 (0.01) 6.25 (0.08) (0.52) 1.89 (0.04) [20RHA + 30RAP]% Average value for(0.43) three repliate speimens (0.93) 1.79 and(0.06) standard 6.25 deviation (0.11) (in parentheses) (0.03) 1.65 (0.06) Average value for three repliate speimens and standard deviation (in parentheses). Compressive Strength (CS) (CS) CS CS test test results of of PCC mixtures ontaining RHA are depited in Figure8a. 8a. RHA enhaned the the 7-days 7-days CS CS by by 12.0, 12.0, 16.1, 22.4, and 20.5% at 5, 10, 15, and 20% RHA ontent respetively relative to to the the ontrol ontrol mix. mix. Similarly, the the 28-days CS was also enhaned by 4.4, 10.8, 12.5, 12.5, and and9.0%. 9.0%. In In this this study, study, the the highest highest 7 and 7 and 28-days CS CS gain gain was was observed at 15% RHA ontent. The The 7 and 7 and days days CS CS test test results of of RAP inlusive onreteare are depitedin infigure Figure8b. 8b. A Adramati redution redution in in CS CS was was observed observed with with an an inrement inrement of of RAP ontent ontent in in the the onrete onrete mixtures. mixtures. The The 7 and 7 and

11 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 11 of days CS dereased by 36.1 and 44.3%, relative to the ontrol mix, respetively, at 50% RAP ontent. This is28-days onsistent CS dereased with the by results 36.1 and found 44.3%, inrelative previous to the studies ontrol [23,28,29]. mix, respetively, The redution at 50% RAP inontent. CS might be Buildings 2018, 8, x FOR PEER REVIEW 11 of 24 This is onsistent with the results found in previous studies [23,28,29]. The redution in CS might be attributed to the olletive effet of higher porosity and asphalt ohesion failure, whih ours instead attributed to the olletive effet of higher porosity and asphalt ohesion failure, whih ours instead of the28-days adhesive CS dereased failure ofby the 36.1 ement-asphalt and 44.3%, relative interfae to the ontrol or ohesive mix, respetively, failure of the at 50% ITZ RAP [26,27]. ontent. of the adhesive failure of the ement-asphalt interfae or ohesive failure of the ITZ [26,27]. This is onsistent with the results found in previous studies [23,28,29]. The redution in CS might be attributed 35 to the olletive effet of higher porosity and asphalt 30 ohesion failure, whih ours instead of the adhesive failure 7-day of the ement-asphalt 28-day interfae or ohesive failure of the 7-day ITZ [26,27]. 28-day day 28-day 7-day 28-day RHA [%] RAP Content [%] (a) RHA onrete 0 (b) 10 RAP onrete RHA Figure [%] 8. Compressive strength for RHA and RAP onrete. RAP Content [%] Figure 8. Compressive strength for RHA and RAP onrete. (a) RHA onrete (b) RAP onrete The relationship between RHA ontent and the 28-days CS given in Figure 9a (obtained by The regression). relationship The regression between Figure model 8. RHA Compressive had ontent R 2 and strength and SEE the for values RHA 28-days of and RAP CSand onrete. given inrespetively. Figure 9a The (obtained CS by regression). dereased The linearly regression with RAP model ontent had as R shown 2 and in SEE Figure values 9b. A of similar trend and was found respetively. by previous The CS study The [61]. relationship From the regression between analysis, RHA ontent linear and form the relationship, 28-days CS Equation given in (3) Figure was found. 9a (obtained R 2 and SEE by dereased linearly with RAP ontent as shown in Figure 9b. A similar trend was found by previous regression). values of the The model regression were model and had Rrespetively. 2 and SEE values of and respetively. The study [61]. From the regression analysis, linear form relationship, Equation (3) was found. R 2 CS dereased linearly with RAP ontent as shown in Figure 9b. A similar trend was found by previous and SEE values of the model were and 1.476frespetively. = f o 0.21 RAP (3) study [61]. From the regression analysis, linear form relationship, Equation (3) was found. R 2 and SEE values where: of f the is model the 28-days were CS of and the RAP-inlusive respetively. onrete in MPa; f o is the 28-days CS of the mix f = f o 0.21 RAP (3) with no RAP ontent in MPa; and RAP fis the = frelaimed 0.21 asphalt pavement ontent in %. (3) CS [MPa] CS [MPa] where: f is the 28-days CS of the RAP-inlusive onrete in MPa; f o is the 28-days CS of the mix with no RAP ontent in MPa; and RAP is the relaimed asphalt pavement ontent in %. where: f f = (RHA) RHA + 30 is the 28-days CS of the RAP-inlusive onrete in MPa; f o is the 28-days CS of the mix f = f o -0.21(RAP) with no 35RAP ontent in MPa; and RAP is the relaimed 25 asphalt pavement ontent in %. R² = R² = f = (RHA) RHA f = f o -0.21(RAP) R² = R² = RHA Content [%] 10 RAP Content [%] (a) RHA onrete (b) RAP onrete Figure 9. Relationship 20 between 30 RHA and RAP 0 ontent and 20 CS RHA Content [%] RAP Content [%] Figure 10 portrays (a) RHA the onrete ompressive strength of both RHA- and (b) RAP-inlusive onrete onrete at 7 and 28-days. The partial replaement of ement by RHA improved the CS of RAP-inlusive onrete Figure 9. Relationship between RHA and RAP ontent and CS. moderately. This might Figurebe 9. redited Relationship to the between development RHA and of RAP additional ontent C-S-H and CS. gel due to the high reative silia ontent of RHA and/or filler effet. Mixtures inorporating (10RHA + 10RAP)%, Figure 10 portrays the ompressive strength of both RHA- and RAP-inlusive onrete at 7 and (15RHA + 10RAP)%, (15RHA + 20RAP)% and (20RHA + 10RAP)% showed omparable strength. The 28-days. The partial replaement of ement by RHA improved the CS of RAP-inlusive onrete maximum strength (27.62 MPa) obtained at 15% RHA and 10% RAP ombination. Thus, it is evident moderately. This might be redited to the development of additional C-S-H gel due to the high that treatment of RAP by RHA possibly will be an effetive way to enhane the mehanial properties reative silia ontent of RHA and/or filler effet. Mixtures inorporating (10RHA + 10RAP)%, of RAP inorporating onrete. (15RHA + 10RAP)%, (15RHA + 20RAP)% and (20RHA + 10RAP)% showed omparable strength. The maximum strength (27.62 MPa) obtained at 15% RHA and 10% RAP ombination. Thus, it is evident that treatment of RAP by RHA possibly will be an effetive way to enhane the mehanial properties of RAP inorporating onrete. CS, f [MPa] CS, f [MPa] CS [MPa] CS [MPa] o RAP CS, f [MPa] CS, f [MPa] Figure 10 portrays the ompressive strength of both RHA- and RAP-inlusive onrete at 7 and 28-days. The partial replaement of ement by RHA improved the CS of RAP-inlusive onrete moderately. This might be redited to the development of additional C-S-H gel due to the high reative silia ontent of RHA and/or filler effet. Mixtures inorporating (10RHA + 10RAP)%, (15RHA + 10RAP)%, (15RHA + 20RAP)% and (20RHA + 10RAP)% showed omparable strength. The maximum strength (27.62 MPa) obtained at 15% RHA and 10% RAP ombination. Thus, it is evident that treatment of RAP by RHA possibly will be an effetive way to enhane the mehanial properties of RAP inorporating onrete.

12 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 12 of 24 Buildings 2018, 8, x FOR PEER REVIEW 12 of 24 CS [MPa] CS [MPa] day 28-day 7-day 28-day RAH and RAP Content [%] RAH and RAP Content [%] Figure Compressive strength strength for both for RHA both and RHARAP andinlusive RAP inlusive onrete. onrete. Tensile Splitting Strength (TSS) Tensile SplittingFigure Strength 10. Compressive (TSS) strength for both RHA and RAP inlusive onrete. The 28-days TSS of the mixtures ontaining RHA is represented in Figure 11a. There was a gradual TheTensile 28-days inrement Splitting TSS of in TSS Strength the mixtures with inreasing (TSS) ontaining RHA is represented in Figure 11a. There was a gradual the RHA ontent up to 15%. The TSS peaked at 15% RHA inrement and then dereased in TSS with beyond inreasing 15% RHA. the RHA However, ontent still up 20% torha 15%. inlusive The TSSonrete peakedshowed at 15% better RHA and then The 28-days TSS of the mixtures ontaining RHA is represented in Figure 11a. There was a dereased strength gradual than beyond inrement the ontrol 15% in RHA. TSS mix. with The However, inreasing inrement still in the 20% strength RHA RHA ontent was inlusive 2.8, up 6.1, to onrete 7.5, 15%. and The 5.6% showed TSS at peaked 5, 10, better 15, at 15% and strength RHA than the 20% and ontrol RHA then mix. ontent dereased The respetively, inrement beyond 15% inrelative strength RHA. to However, was the 2.8, ontrol 6.1, still 7.5, mix. 20% and TSS RHA 5.6% inreased inlusive at 5, 10, in onrete 15, a seond-order andshowed 20% RHA better ontent respetively, polynomial strength than with relative the RHA ontrol toontent the ontrol mix. as depited The mix. inrement TSS Figure inreased 11a strength (Rin 2 = a0.96 was seond-order and 2.8, SEE 6.1, = 7.5, 0.018). polynomial and The 5.6% trend at with 5, for 10, TSS RHA 15, and ontent aswas depited 20% similar RHA in to ontent that Figure of CS. 11a respetively, The (Rinrement 2 = 0.96relative and in TSS SEE to might = the 0.018). be ontrol asribed The mix. to trend the TSS development for inreased TSS was extra in similar a of seond-order C-S-H to that of CS. gel due to the ative silia ontent of RHA. Thepolynomial inrement with in TSS RHA might ontent be asribed depited to the in Figure development 11a (R 2 = 0.96 extrand of SEE C-S-H = 0.018). gel due The totrend the ative for TSS silia TSS dereased linearly with inreasing the RAP ontent as an be seen in Figure 11b (R 2 = 0.98 ontent was similar of RHA. to that of CS. The inrement in TSS might be asribed to the development extra of C-S-H and SEE = 0.052). TSS dereased by 12.2, 20.7, 29.6, 34.7, and 40.8% for 10, 20, 30, 40, and 50% RAP gel respetively. TSS due dereased to the ative The derement linearly silia ontent pattern with inreasing of RHA. for TSS was thesimilar RAP ontent to that of asthe ancs. behowever, seen in Figure the rate 11b of (R 2 = 0.98 and strength SEE TSS = redution 0.052). dereased TSSlinearly the dereased with TSS mixtures by inreasing 12.2, was 20.7, the lower 29.6, RAP ompared 34.7, ontent andas to the 40.8% an be CS s. for seen This 10, in is 20, Figure onsistent 30, 40, 11b with and (R 2 = 50% 0.98 RAP and SEE = 0.052). TSS dereased by 12.2, 20.7, 29.6, 34.7, and 40.8% for 10, 20, 30, 40, and 50% RAP respetively. previous study The[26]. derement pattern for TSS was similar to that of the CS. However, the rate of strength respetively. The derement pattern for TSS was similar to that of the CS. However, the rate of redution in the TSS mixtures was lower ompared to the CS s. This is onsistent with previous strength 2.3 f redution t = (RHA) in the 2 + TSS 0.14(RHA) mixtures was lower 2.2 ompared to the study [26]. f t = CS s (RAP) This is onsistent with previous study [26] R² = 0.96 R² = 0.98 f t = (RHA) (RHA) f t = -0.17(RAP) R² = 0.96 R² = RHA Content [%] 1.3 RAP Content [%] STS [MPa] STS [MPa] 2.0 (a) RHA onrete 1.0 (b) RAP onrete RHA Figure Content 11. Splitting [%] strength for RHA and RAP onrete. RAP Content [%] (a) RHA onrete (b) RAP onrete From regression analysis, a power form relationship was found between the 28 days TSS and CS of RHA inlusive onrete as shown in Equation (4) and Figure 12a (R 2 =0.99 and SEE= 0.004). Figure 11. Splitting strength for RHA and RAP onrete. f TSS [MPa] TSS [MPa] = 0.28 (4) From regression analysis, a power form t relationship was found between the 28 days TSS and CS From regression analysis, a power form relationship was found between the 28 days TSS and CS where: of RHA f inlusive and ft are onrete the 28-days as shown CS and in TSS Equation of the RHA (4) and inlusive Figure onrete 12a (R 2 =0.99 respetively, and SEE= in MPa 0.004). of RHA inlusive onrete as shown in Equation (4) and Figure 12a (R 2 =0.99 and SEE= 0.004). 0.6 The exponential form relationship was found between 0.28 the 28 days TSS and CS of RAP inlusive = (4) onrete as presented in Figure 12b (R 2 = 0.97 and t SEE = ). f t = 0.28 f 0.6 Equations (5) and (6) were obtained (4) by regression. where: f and ft are the 28-days CS and TSS of the RHA inlusive onrete respetively, in MPa where: f and f The exponential t are the 28-days CS and TSS of the RHA inlusive onrete respetively, in MPa. form relationship was found between the 28 days TSS and CS of RAP inlusive onrete The exponential as presented form in Figure relationship 12b (R was 2 = 0.97 found and SEE between = ). the Equations 28 days TSS (5) and and (6) CS were of RAP obtained inlusive onrete by regression. as presented in Figure 12b (R 2 = 0.97 and SEE = ). Equations (5) and (6) were obtained by regression. f t = 0.17 RAP (5) f 0.6

13 TSS, f t (MPa) TSS, f t (MPa) Buildings 2018, 8, x FOR PEER REVIEW 13 of 24 Buildings 2018, 8, of 24 f t = 0.17 RAP (5) Buildings 2018, 8, x FOR PEER REVIEW 13 of 24 f t f = (6) t f (6) f where: where: f andf f t and are the f 28-days are the 28-days CS andcs t = 0.17 RAP TSS and oftss theof RAP the RAP inlusive inlusive onrete respetively, in in MPa. (5) t 0.93 f = t f (6) where: f and f are the 28-days CS and TSS of the RAP inlusive onrete respetively, in MPa f t = t 0.28f 0.6 f t = 0.105f R² = R² = f t = 0.28f 0.6 f 1.6 t = 0.105f R² = R² = CS, f [MPa] CS, f [MPa] (a) RHA onrete (b) RAP onrete Figure 12. Relationship between CS and TSS for RHA and RAP onrete. Figure 12. CS, Relationship f [MPa] CS, f [MPa] between CS and TSS for RHA and RAP onrete. (a) RHA onrete (b) RAP onrete The experimental results of TSS of both RHA and RAP inlusive PCC and its relationship with The CS are experimental depited in Figures results 12. Relationship 13 of and TSS14 of respetively. both between RHACS and TSS RAP TSS was for improved inlusive RHA and by PCC RAP 4.7% onrete. andat its 15% relationship RHA and 10% with CS are depited RAP ontent in Figures ompared 13 and to the 14ontrol respetively. speimen s TSSresult was improved whih was similar by 4.7% to at the 15% CS results. RHA and TSS 10% and RAP ontent CS were The ompared positively experimental to the orrelated results ontrol (Rof speimen s 2 = TSS of and both SEE RHA result = 0.065) and RAP whih with inlusive was a power similar funtion PCC and to theas its CS shown relationship results. in Equation with TSS and CS were(7). CS are depited in Figures positively orrelated (R 2 13 and 14 respetively. TSS was improved by 4.7% at 15% RHA and 10% = and SEE = 0.065) with a power funtion as shown in Equation (7). RAP ontent ompared to the ontrol speimen s result whih was similar to the CS results. TSS and 0.68 CS were positively orrelated (R 2 = and f = t SEE = 0.065) f (7) f t = f 0.68 with a power funtion as shown in Equation (7) (7). STS, f t [MPa] STS, f t [MPa] Buildings 2018, 8, x FOR PEER REVIEW of 24 f = t f (7) RHA and RAP Content (%) TSS (MPa) TSS (MPa) Figure 13. Tensile splitting RHA strength and RAP for RHA Content and RAP (%) inlusive onrete. RHA and RAP Content (%) Figure Tensile splitting strength for RHA- and RAP-inlusive onrete. Figure 13. Tensile splitting strength for RHA and RAP inlusive onrete. Figure 13. Tensile splitting ft strength = 0.235ffor RHA and RAP inlusive onrete R² = f t = 0.235f ft = R²= 0.235f R² = CS, f (MPa) Figure 14. Relationship between 19 TSS CS, and 21 f CS (MPa) for 23 RHA and 25 RAP inlusive 27 onrete. 29 CS, f Figure. 14. Relationship between TSS and (MPa) CS for RHA- and RAP-inlusive onrete. Figure 14. Relationship between TSS and CS for RHA and RAP inlusive onrete. Water Figure Absorption 14. Relationship between TSS and CS for RHA and RAP inlusive onrete. TSS, f t (MPa) TSS, f t (MPa) The water absorption after immersion (wi) and after immersion and boiling (wi&b) dereased with inreasing RHA ontent as shown in Figure 15a. The minimum relative perentage of redution in water absorption were 0.7 and 1.2% for wi and wi&b respetively at 5% RHA ontent whereas, the maximum relative perentage of redution in water absorption were 1.3, and 2.0% for wi, and wi&b respetively at 20% RHA ontent. This redution ould be due to the fat that the finer HHA partiles might have filled the pore spaes in the onrete. The water absorption is orrelated to RHA ontent in a power funtion as shown in Equations (8) and (9). The wi&b values are slightly higher than those TSS, f t [MPa] TSS, f t [MPa]

14 Buildings 2018, 8, of 24 Water Absorption Buildings 2018, 8, x FOR PEER REVIEW 14 of 24 The water absorption after immersion (w i ) and after immersion and boiling (w i&b ) dereased with inreasing Water Absorption RHA ontent as shown in Figure 15a. The minimum relative perentage of redution in water absorptions The water absorption were 0.7 and after 1.2% immersion for w i (wi) and and w i&b after respetively immersion at and 5% boiling RHA(wi&b) ontent, dereased whereas the maximum with inreasing relative perentage RHA ontent of as redution shown in Figure in water 15a. The absorption minimum were relative 1.3, perentage and 2.0% of for redution w i, and w i&b respetively in water at absorptions 20% RHAwere ontent. 0.7 and This 1.2% redution for wi and ould wi&b respetively be due to the at 5% fat RHA thatontent, the finer whereas HHAthe partiles mightmaximum have filledrelative the pore perentage spaes of the redution onrete. in water The absorption water absorption were 1.3, isand orrelated 2.0% for towi, RHA and wi&b ontent in a power respetively funtionat as 20% shown RHA ontent. in Equations This redution (8) and ould (9). The be due w to the i&b values fat that arethe slightly finer HHA higher partiles than those might have filled the pore spaes of the onrete. The water absorption is orrelated to RHA ontent of w i. in a power funtion as shown in Equations (8) and (9). The wi&b values are slightly higher than those The water absorption of RAP inlusive onrete dereased with inreasing RAP ontent, as an of wi. be seen from The water Figureabsorption 15b. Theof minimum RAP inlusive w i onrete and w i&b dereased were 6.4, with and inreasing 6.9%, with RAP relative ontent, as perentage an redution be seen of from Figure and 6.20% 15b. The respetively minimum wi at 50% and wi&b RAPwere ontent. 6.4, and The 6.9%, redutions with relative in water perentage absorption mightredution be due tof the lower and 6.20% waterrespetively absorptionat of50% RAP RAP aggregates ontent. The ompared redutions to in that water of virgin absorption aggregate. The other might possible be due to reason the lower might water be absorption due to the of RAP melted aggregates asphalt ompared and dust to that layer of virgin engulfed aggregate. around the aggregate The other ouldpossible fill voidreason spaes might in the be onrete due to the [62]. melted Theasphalt water and absorption dust layer is related engulfed toaround RAP ontent the in aggregate ould fill void spaes in the onrete [62]. The water absorption is related to RAP ontent a power funtion as shown in Equations (10) and (11). The w i&b values were somewhat higher than in a power funtion as shown in Equations (10) and (11). The wi&b values were somewhat higher than those of w i. those of wi. Water absorption, w [%] w i = 7.36(RHA) R² = w i&b = 7.24(RHA) R² = RHA Content [%] (a) RHA inlusive onrete Water absoption, w [%] w i = 7.38(RAP) R² = w i&b = 7.214(RAP) R² = RAP Content [%] (b) RAP inlusive onrete Figure 15. Water absorption by RHA and RAP onrete. Figure 15. Water absorption by RHA and RAP onrete i = (8) w 7.36 RHA w i = 7.36 RHA (8) wi&b= 7.24 RHA (9) w i&b = 7.24 RHA (9) w i= 7.38 RAP (10) w i = 7.38 RAP (10) w i&b = RAP (11) w i&b = RAP (11) where: w i is the water absorption after immersion in %; wi&b is the water absorption after where: immersion w i is theand water boiling; absorption RHA and after is the immersion rie husk in ash %; ontent w i&b isin the %; water and RAP absorption is relaimed after asphalt immersion and boiling; pavement RHA ontent andin is %. the rie husk ash ontent in %; and RAP is relaimed asphalt pavement ontent in The %. water absorption of RHA and RAP inlusive onrete at 28 days are depited in Figure 16. Both w i and wi&b dereased as RHA and RAP ontent inreased. The relative perentage redution The water absorption of RHA and RAP inlusive onrete at 28 days are depited in Figure 16. of wi&b (13.7%) was lower than both that of RHA inlusive onrete (1.30%) and RAP inlusive Both w i and w i&b dereased as RHA and RAP ontent inreased. The relative perentage redution of onrete (10.94%). The least wi, and wi&b found were 6.25, and 7.06% respetively at 20% RHA and w i&b (13.7%) was lower than both that of RHA inlusive onrete (1.30%) and RAP inlusive onrete 30% RAP ombination. The maximum relative perentage of redution in absorption were 13.7 and (10.94%). 4.2% The for the least respetive w i, and least w i&b absorptions. found werethe 6.25, redution and 7.06% of water respetively absorption at might 20% RHA be due and to 30% the RAP ombination. olletive The effet maximum of RHA and relative RAP disussed perentage above. of redution in absorption were 13.7 and 4.2% for the respetive least absorptions. The redution of water absorption might be due to the olletive effet of RHA and RAP disussed above.

15 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 15 of 24 Water absoption Water absoption [%] [%] 7.5 Buildings 2018, 8, x FOR PEER REVIEW 15 of RHA and RAP Content [%] Figure 16. Water absorption by both RHA- and RAP-inlusive onrete. Figure 16. Water absorption by both RHA- and RAP-inlusive onrete. Volume of Permeable Void Spaes in RHA Hardened and RAP Conrete Content [%] Volume The ofvolume Permeable Figure of permeable Void 16. Water Spaes void absorption in spaes Hardened by in both hardened RHA- Conrete and RHA RAP-inlusive onrete. dereased slightly with inrement of RHA. The voids dereased by 3.22% from to 16.77% as the RHA ontent The inreased Volume volume from of of Permeable permeable 0 to 20%. Void void The redution Spaes spaes in in Hardened hardened in void spae Conrete RHA inlusive onrete dereased slightly with might be attributed to the finer silieous inrement of RHA. The voids dereased by 3.22% from to 16.77% as the RHA ontent inreased partiles The volume whih ould of permeable fill a portion void of spaes void in spaes hardened that exist RHA in inlusive the onrete onrete matrix. dereased As an slightly be seen from 0 to 20%. The redution in void spae might be attributed to the finer silieous partiles whih with from inrement Figure 17a of and RHA. Equation The voids (12), a dereased power funtion by 3.22% was from found as a to good 16.77% fit (R as 2 = the RHA and ontent SEE = ould0.026) fill a to portion orrelate of void RHA spaes ontent that with exist the voids. in the onrete matrix. As an be seen from Figure 17a and inreased from 0 to 20%. The redution in void spae might Equation (12), Figure a power 17b depits funtion the volume was found of permeable as a goodvoid fit (R spaes 2 be attributed to the finer silieous partiles whih ould fill a portion of void spaes that exist = in the in RAP onrete andinlusive SEE matrix. = 0.026) onrete. As to an orrelate It be is seen lear RHA ontent from with Figure the the figure 17a voids. and that Equation voids dereased (12), a power exponentially funtion with was found an inrement as a good of fit RAP (R 2 ontent. = and The SEE voids = 0.026) Figure dereased to 17b orrelate by depits 9.47% RHA from theontent volume to with of 15.68% permeable the voids. as the RAP voidontent spaes inreased RAP inlusive from 0 to onrete. 50%. The It redution is lear from the figure in void that Figure spae voids 17b ould depits dereased be due the to volume exponentially the lower of permeable water withabsorption an void inrement spaes of RAP of RAP RAP aggregates inlusive ontent. ompared onrete. The voids It to is that dereased lear of by 9.47% from virgin from the aggregates figure 17.32that toand 15.68% voids oozed dereased out theasphalt RAPexponentially ontent film whih inreased with ould an fill from inrement a portion 0 to 50%. of RAP voids The redution ontent. spaes in The onrete. in voids spae oulddereased As be an due be to by seen the 9.47% from lower from Equation water (13), absorption to 15.68% an exponential as of the RAP RAP funtion aggregates ontent was inreased obtained ompared from from to 0 to that regression 50%. ofthe virgin analysis redution aggregates to orrelate RAP ontent with the voids (R 2 = and SEE = 0.024). and oozed in void out spae asphalt ould film be due whih to the ould lower fill water a portion absorption of voids of RAP spaes aggregates in onrete. ompared As an to be that seen of from virgin aggregates and oozed out asphalt film whih ould fill a portion of voids spaes in onrete. Equation (13), an exponential funtion was obtained from17.5 regression analysis to orrelate v = 17.6e RAP RAP ontent As an be seen with the voids (R 2 from Equation (13), an exponential funtion was obtained from regression analysis to = and v = SEE = (RAP) 0.024). orrelate RAP ontent with the voids = and SEE 17.0 = 0.024). R² = R² = v = 17.6e RAP v = (RAP) R² = R² = RHA Content [%] RAP Content [%] (a) RHA inlusive onrete (b) 0RAP 10 inlusive 20 onrete RHA Content Figure [%] 17. Voids in RHA and RAP onrete. RAP Content [%] Voids, v Voids, [%] v [%] Wi Voids, v Voids, [%] v [%] Wi&b (a) RHA inlusive onrete (b) RAP inlusive onrete v = RHA (12) Figure 17. Voids in RHA and RAP onrete. Figure 17. Voids in RHA RAP v = e and RAP onrete. (13) where: v is the volume of permeable void v = spaes RHA in %; and RHA is the rie husk ash ontent (12) in %; v = RHA (12) and RAP is the relaimed asphalt pavement ontent in %. RAP v = A relationship between voids and water absorption (13) v = e RAP for RHA onrete was determined as shown (13) where: in Figure v is 18a the and volume Equations of permeable (14) and void (15). spaes Aording %; and to the RHA orrelation is the rie found, husk ash water ontent absorption in %; where:v dereased is the volume exponentially of permeable and RAP is the relaimed asphalt the void void pavement in spaes onrete in ontent dereased. %; and RHA in %. Water is absorption the rie husk by RAP ash ontent onrete in %; and RAP dereased A isrelationship theexponentially relaimed between asphalt with voids voids pavement and in water onrete ontent absorption as shown in %. for in RHA Figure onrete 18b, and was Equations determined (16) as and shown (17). in A relationship Figure 18a and between Equations voids (14) and and water (15). absorption Aording to for the RHA orrelation onrete found, was determined water absorption as shown in Figure dereased 18a and exponentially Equations as (14) the and void (15). in onrete Aording dereased. to thewater orrelation absorption found, by RAP water onrete absorption dereased exponentially with voids in onrete as shown in Figure 18b, and Equations (16) and (17). Wi Wi&b

16 Buildings 2018, 8, of 24 dereased exponentially as the void in onrete dereased. Water absorption by RAP onrete dereased exponentially with voids in onrete as shown in Figure 18b, and Equations (16) and (17). Buildings 2018, 8, x FOR PEER REVIEW 16 of 24 Buildings , 8, x FOR wpeer i&b = REVIEW 3.87e 0.037v of R² = 0.93 w i&b = 3.89e 0.037v 7.40 w i&b = 3.87e 0.037v R² = R² = 0.93 w i&b = 3.89e 0.037v R² = wi = 2.25e wi = 4.79e 0.024v v 7.15 R² = R² = wi = 4.79e 0.024v wi = 2.25e 0.067v 7.15 R² = R² = Permiable Voids,v [%] Permeable Voids, v [%] (a) RHA inlusive onrete (b) RAP inlusive onrete Permiable Voids,v [%] Permeable Voids, v [%] Figure 18. Relationship between water absorption and voids for RHA and RAP onrete. Figure(a) 18. RHA Relationship inlusive between onrete water absorption and voids (b) RAP for inlusive RHA andonrete RAP onrete. Water Water absorption absorption [%] [%] Figure 18. Relationship between water absorption and voids for RHA and RAP onrete v wi = 4.79 w i = 4.79 e v (14) (14) i&b 3.87 w i&b 3.87 e v v wi = 4.79 e (15) (14) (15) v i = 2.25 w i = 2.25 e v v wi&b = 3.87 e (16) (15) (16) v i&b 3.89 w i&b 3.89 e v v wi = 2.25 e (17) (16) (17) where: w i is absorption after immersion in %; wi&b is absorption v w after immersion and boiling; and v i&b = 3.89 e (17) where:w is the i is absorption after immersion in %; w volume of permeable void spaes in %. i&b is absorption after immersion and boiling; and v is the volume where: The of w volume ipermeable is absorption of permeable void after spaes immersion void in spaes %. in %; wi&b is absorption after immersion and boiling; and v in both RHA and RAP inlusive PCC is portrayed in The Figure is the volume 19. As expeted, of permeable the relative void void spaes perentage spaes in %. in of both redution RHA of and voids RAP (4.86%) inlusive both PCC RHA isand portrayed RAP in Figureinlusive 19. The As expeted, PCC volume is higher of the permeable than relative that void of perentage RHA spaes inlusive of both redution PCC RHA (3.22%) and of but RAP voids lower inlusive (4.86%) than that PCC inof both is RAP portrayed RHA inlusive and in RAP inlusive PCC Figure PCC (9.47) 19. As isby higher 1.64 expeted, and than 4.61% the relative that respetively. perentage of redution of voids (4.86%) in both RHA and RAP of RHA inlusive PCC (3.22%) but lower than that of RAP inlusive inlusive PCC is higher than that of RHA inlusive PCC (3.22%) but lower than that of RAP inlusive PCC (9.47) by 1.64 and 4.61% respetively. PCC (9.47) by and 4.61% respetively. Voids Voids [%] [%] Figure 19. Void spaes RHA in both and RHA- RAP Content and RAP-inlusive [%] onrete. Sorptivity Figure 19. Void spaes in both RHA- and RAP-inlusive onrete. Figure 19. Void spaes in both RHA- and RAP-inlusive onrete. The Sorptivity sorptivity by RHA onrete, shown in Table 10, was obtained from the slope of the line that is the best fit to the umulative amount of water absorption (I) plotted against the square root of time Sorptivity (t 1/2 ), The depited sorptivity in Figures by RHA A1 onrete, and A2 shows shown the in umulative Table 10, was amount obtained of water from the absorption slope of from the line whih that the is the best fit to of the RAP umulative inlusive amount onrete of was water determined absorption and (I) tabulated plotted against Table the 11. square root of time The sorptivity by RHA onrete, shown in Table 10, was obtained from the slope of the line that is (t 1/2 ), depited in Figures A1 and A2 shows the umulative amount of water absorption from whih the best fit to the umulative amount of water absorption (I) plotted against the square root of time the sorptivity of RAP inlusive onrete was determined and tabulated in Table 11. (t 1/2 ), depited in Figures A1 and A2 shows the umulative amount of water absorption from whih the sorptivity of RAP inlusive onrete was determined and tabulated in Table 11. Water Water absorpition absorpition [%] [%] RHA and RAP Content [%]

17 Buildings 2018, 8, of 24 Table 10. Sorptivity by RHA inlusive onrete. RHA Content (%) (0) (5) (10) (15) (20) Buildings 2018, 8, x FOR PEER REVIEW Sorptivity, K (mm/h 1/2 17 of 24 ) Determination Coeffiient (R Table 2 ) 10. Sorptivity by RHA inlusive onrete Correlation Coeffiient (R) RHA Content [%] [0] [5] [10] [15] [20] Sorptivity, K [mm/h Table 11. Sorptivity 1/2 ] by RAP inlusive onrete. Determination Coeffiient [R 2 ] Correlation Coeffiient [R] RAP Content (%) (0) (10) (20) (30) (40) (50) Sorptivity (mm/h 1/2 ) Table 11. Sorptivity by RAP inlusive onrete Determination Coeffiient (R 2 ) RAP Content [%] [0] [10] [20] [30] [40] [50] Correlation Coeffiient (R) Sorptivity (mm/h 1/2 ) Determination Coeffiient [R 2 ] The effet of RHA Correlation ontent Coeffiient on the sorptivity [R] of onrete is depited in0.993 Figure a. As an be seen from Equation (18), the sorptivity dereased linearly as the RHA ontent inreased. The sorptivity dereasedthe byeffet 11.1% of RHA fromontent on to the sorptivity mm/hof 1/2 onrete whenis RHA depited ontent in Figure inreased 20a. As an from be seen 0 to 20%. from Equation (18), the sorptivity dereased linearly as the RHA ontent inreased. The sorptivity The redution in sorptivity might be due to the fat that finer RHA partiles filled up air voids dereased by 11.1% from to mm/h exist in the onrete matrix, as a result of whih the 1/2 when RHA ontent inreased from 0 to 20%. The rate of ingress of water was inhibited. The influene redution in sorptivity might be due to the fat that finer RHA partiles filled up air voids exist in the of RAP onrete ontent matrix, on the as a sorptivity result of whih of onrete the rate of isingress also portrayed of water was ininhibited. Figure 20b. The influene Sorptivity of RAP dereased signifiantly ontent on as the sorptivity ontent of onrete RAP inreased. is also portrayed A linear Figure relationship 20b. Sorptivity was found dereased between signifiantly RAP ontent and sorptivity, as the ontent andof Equation RAP inreased. (19) represents A linear relationship the same. was Similar found between findingsrap were ontent reported and sorptivity, in the previous studies and [13,27]. Equation The(19) main represents reasonthe being same. given Similar for findings the redution were reported in sorptivity in the was previous the melted studies [13,27]. asphalt layer surrounding The main the reason RAPbeing aggregates. given for In the addition, redution the in sorptivity authorswas of this the melted paper believed asphalt layer that surrounding the redution in the RAP aggregates. In addition, the authors of this paper believed that the redution in sorptivity sorptivity might also be asribed to the lower water absorption by the RAP aggregates ompared to might also be asribed to the lower water absorption by the RAP aggregates ompared to that of the that of the virgin aggregates. virgin aggregates. Sorptivity, K [mm/h 1/2 ] k =k o (RHA) R² = Sorptivity, k [mm/h 1/2 ] k =k o (RAP) R² = RHA ontent [%] (a) RHA inlusive onrete RAP Content [%] (b) RAP inlusive onrete Figure 20. Relationship between sorptivity and RHA, and RAP ontents. Figure 20. Relationship between sorptivity and RHA, and RAP ontents. k = k o RHA (18) k = k o RHA (18) where: k and ko are the sorptivity by RHA inlusive onrete and onrete without RHA respetively where: in kmm/h and k 1/2 o ; are and the RHA sorptivity is the rie by husk RHA ash ontent inlusive %. onrete and onrete without RHA respetively in mm/h 1/2 ; and RHA is the rie husk ash ontent in %. k = k o RAP (19) where: k and ko are the sorptivity by RAP k = inlusive k o onrete RAP and onrete without RAP, respetively, (19) in mm/h 1/2 ; and RAP is the relaimed asphalt pavement ontent, in %. where: k and Figures k o are A3 A6 the sorptivity depit the umulative by RAP inlusive amount of onrete water absorption and onrete (I) plotted without against RAP, the square respetively, in mm/h root 1/2 of time ; and(trap 1/2 ), from is the whih relaimed the sorptivity asphalt by both pavement RHA and ontent, RAP inlusive %. onrete was determined and tabulated in Table 12.

18 Buildings 2018, 8, of 24 Figures A3 A6 depit the umulative amount of water absorption (I) plotted against the square root of time (t 1/2 ), from whih the sorptivity by both RHA and RAP inlusive onrete was determined and tabulated in Table 12. Table 12. Sorptivity by both RHA- and RAP-inlusive onrete. RHA and RAP Content Sorptivity (mm/h 1/2 ) Determination Coeffiient (R 2 ) Correlation Coeffiient (R) Control % RHA + 10% RAP % RHA+ 20% RAP % RHA+ 30% RAP % RHA+ 10% RAP % RHA+ 20% RAP % RHA+ 30% RAP % RHA+ 10% RAP % RHA+ 20% RAP % RHA+ 30% RAP % RHA+ 10% RAP % RHA+ 20% RAP % RHA+ 30% RAP It is evident from experimental results that the sorptivity by RHA and RAP inlusive onrete was dereased as expeted. The redution in sorptivity ranged from 2.29 to 28.16% relative to the ontrol speimens. The redution in sorptivity ould be due to the ombined influenes of RHA and RAP as already disussed. Although sorptivity value alone does not suffie to envisage the servie life of a struture [63], aording to the researh onduted by Hinzak, Conroy, and Lewis, ited in the study [64], a onrete is said to be durable if sorptivity is less than 6 mm/h 1/2. The experimental results of this study revealed that all onrete speimens had sorptivity values under the limit speified i.e., onsidered as durable onrete holding other fators onstant. 4. Conlusions The effets of RHA and RAP on the engineering properties of onrete were studied. Based on the experimental results obtained and the analysis and disussion made, the following onlusions an be drawn: 1. The water demand of the mix inreased as the RHA and RAP ontent inreased; as a result, the slump and ompation fator of the fresh onrete dereased signifiantly. 2. The density of onrete dereased with inreasing RHA and RAP ontent in the onrete mix. 3. RHA-inlusive onrete exhibited an inrease in both ompressive and tensile splitting strength. The maximum possible strength was obtained when ement was replaed by 15% RHA. 4. Compressive and tensile splitting strength dereased drastially as the RAP ontent inreased beyond 20%. 5. Comparable strength and favorable sorptivity values were obtained when 15% RHA was ombined with up to 20% RAP in the onrete mix. 6. Speimens ontaining both RHA and RAP exhibited lower water absorption, permeable void spae and sorptivity values ompared to that of the ontrol speimens. This indiates that RHA and RAP inlusive onrete might perform better when subjeted to aggressive environment. Author Contributions: S.M.S., M.A.G. and Z.C.A.G. designed the experiments; M.A.G. performed the experiment and olleted data; S.M.S. and M.A.G. analyzed the data; Z.C.A.G. failitated resoures; M.A.G., S.M.S. and Z.C.A.G. wrote the paper. Funding: The authors wish to thank the Afrian Union Commission (AUC) and Japan International Cooperation Ageny (JICA) for funding this researh. Conflits of Interest: The authors onfirm that there are no known onflits of interest.

19 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 19 of 24 Buildings 2018, 8, x FOR PEER REVIEW 19 of 24 Appendix Cumulative Water Absorption Appendix A. Cumulative Water Absorption Appendix A. Cumulative Water Absorption Figure A1. Cumulative water absorption by RHA Conrete. Figure Figure A1. A1. Cumulative water absorption by byrha RHAConrete. Figure A2. Cumulative water absorption by RAP Conrete. Figure Figure A2. A2. Cumulative water absorption by by RAP RAP Conrete. Conrete.

20 Buildings 2018, 8, of 24 Buildings 2018, 8, x FOR PEER REVIEW 20 of 24 Buildings 2018, 8, x FOR PEER REVIEW 20 of 24 Figure A3. Cumulative water absorption by 5% RHA and (10 30) % RAP-inlusive onrete. Figure Figure A3. A3. Cumulative Cumulative water water absorption by 5% RHA RHAand and (10 30) (10 30) % RAP-inlusive % RAP-inlusive onrete. onrete. Figure A4. Cumulative water absorption by 10% RHA and (10 30) % RAP-inlusive onrete. Figure A4. Cumulative water absorption by 10% RHA and (10 30) % RAP-inlusive onrete. Figure A4. Cumulative water absorption by 10% RHA and (10 30) % RAP-inlusive onrete.

21 Buildings 2018, 8, of 24 Buildings 2018, 8, FOR PEER REVIEW Buildings 2018, 8, x FOR PEER REVIEW 21 of of 24 Figure Figure A5. A5. Cumulative Cumulative water water and and (10 30) (10 30) % RAP-inlusive RAP-inlusive onrete. Figure A5. Cumulative water absorption by 15% RHA and (10 30) % RAP-inlusive onrete. onrete. Figure A6. Cumulative water absorption by 20% RHA and (10 30) RAP-inlusive onrete. Figure Figure A6. A6. Cumulative Cumulative water water absorption absorption by by 20% RHA RHA and and (10 30) (10 30) % % RAP-inlusive RAP-inlusive onrete. onrete. Referenes Referenes Referenes 1. World Eonomi Forum. Shaping the Future of Constrution: Breakthrough in Mindset and Tehnology; World 1. World Eonomi Forum. Shaping the Future of Constrution: A Breakthrough in Mindset and Tehnology; World Eonomi Forum: Cologny, Switzerland, World Eonomi Forum: Forum. Cologny, Shaping Switzerland, the Future of Constrution: A Breakthrough in Mindset and Tehnology; 2. Meyer, C. The greening of the onrete industry. Cem. Conr. Compos. 2009, 31, World 2. Meyer, 3. Kosmatka, Eonomi C. The greening of the onrete industry. Cem. Conr. Compos. 2009, 31, A.W. Forum: Design Cologny, and Control Switzerland, of Conrete Mixtures, th ed.; Portland Cement Assoiation: New York, 2. Meyer, 3. Kosmatka, A.W. Design and Control of Conrete Mixtures, 5th ed.; Portland Cement Assoiation: New York, NY, C. USA, The greening of the onrete industry. Cem. Conr. Compos. 2009, 31, [CrossRef] NY, USA, Kosmatka, 4. Suhendro, A.W. B. Design Toward and green Control onrete of Conrete for better Mixtures, sustainable 5th environment. ed.; Portland Proedia Cement Eng. Assoiation: 2014, 95, New York, 4. Suhendro, B. Toward green onrete for better sustainable environment. Proedia Eng. 2014, 95, NY, USA, Suhendro, B. Toward green onrete for better sustainable environment. Proedia Eng. 2014, 95, [CrossRef]

22 Buildings 2018, 8, of Benhelal, E.; Zahedi, G.; Shamsaei, E.; Bahadori, A. Global strategies and potentials to urb CO 2 emissions in ement industry. J. Clean. Prod. 2013, 51, [CrossRef] 6. Khan, R.; Jabbar, A.; Ahmad, I.; Khan, W.; Naeem, A.; Mirza, J. Redution in environmental problems using rie-husk ash in onrete. Constr. Build. Mater. 2012, 30, [CrossRef] 7. Pin, K.; Behnood, A.; Ash, F. Effets of deiers on the performane of onrete pavements ontaining air-ooled blast furnae slag and supplementary ementitious materials. Cem. Conr. Compos. 2018, 90, Adom-Asamoah, M. Comparative Study of the Physial Properties of Palm Kernel Shell Conrete and Normal Conrete in Ghana; University of Johannesburg: Johannesburg, South Afria, Lun, L.T. Effets of Rie Husk Ash Produed from Different Temperatures on the Performane of Conrete; Faulty of Engineering and Green Tehnology Universiti Tunku Abdul Rahman: Petaling Jaya, Malaysia, Ismail, S.; Wai, K.; Ramli, M. Sustainable aggregates: The potential and hallenge for natural resoures onservation. Proedia So. Behav. Si. 2013, 101, [CrossRef] 11. Aprianti, E.; Shafigh, P.; Bahri, S.; Nodeh, J. Supplementary ementitious materials origin from agriultural wastes A review. Constr. Build. Mater. 2015, 74, [CrossRef] 12. Alex, J.; Dhanalakshmi, J.; Ambedkar, B. Experimental investigation on rie husk ash as ement replaement on onrete prodution. Constr. Build. Mater. 2016, 127, [CrossRef] 13. Bida, S.M.; Danraka, M.N.; Ma ali, J.M. Performane of Relaimed Asphalt Pavement (RAP) as a Replaement of Fine Aggregate in Conrete. Int. J. Si. Res. 2016, 5, Singh, S.; Ransinhung, G.D.R.N.; Debbarma, S.; Kumar, P. Utilization of relaimed asphalt pavement aggregates ontaining waste from Sugarane Mill for prodution of onrete mixes. J. Clean. Prod. 2018, 174, [CrossRef] 15. Behnood, A.; Modiri, M.; Gozali, F.; Ameri, M. Effets of opper slag and reyled onrete aggregate on the properties of CIR mixes with bitumen emulsion, rie husk ash, Portland ement and fly ash. Constr. Build. Mater. 2015, 96, [CrossRef] 16. Food and Agriulture Organization. FAO Rie Market Monitor; FAO: Rome, Italy, Tuaum, W.O.A.; Shitote, S. Inorporating Reyled Glass Aggregate. Buildings 2018, unpublished. 18. Szilagyi, F.H.; Dio, C. Conrete prodution with reyled materials in the sustainable development ontext. J. Environ. Res. Prot. 2016, 13, Amerian Soiety of Civil Engineers. Sustainable Constrution Materials; Amerian Soiety of Civil Engineers: Reston, VA, USA, Modarres, A.; Hosseini, Z. Mehanial properties of roller ompated onrete ontaining rie husk ash with original and reyled asphalt pavement material. J. Mater. Des. 2014, 64, [CrossRef] 21. Johari, M.A.M.; Brooks, J.J.; Kabir, S.; Rivard, P. Influene of supplementary ementitious materials on engineering properties of high strength onrete. Constr. Build. Mater. 2011, 25, [CrossRef] 22. Elahi, A.; Basheer, P.A.M.; Nanukuttan, S.V.; Khan, Q.U.Z. Mehanial and durability properties of high performane onretes ontaining supplementary ementitious materials. Constr. Build. Mater. 2010, 24, [CrossRef] 23. Snellings, R.; Salze, A.; Srivener, K.L. Cement and Conrete Researh Use of X-ray diffration to quantify amorphous supplementary ementitious materials in anhydrous and hydrated blended ements. Cem. Conr. Res. 2014, 64, [CrossRef] 24. Lothenbah, B.; Srivener, K.; Hooton, R.D. Cement and Conrete Researh Supplementary ementitious materials. Cem. Conr. Res. 2011, 41, [CrossRef] 25. Shi, X.; Mukhopadhyay, A.; Liu, K.W. Mix design formulation and evaluation of portland ement onrete paving mixtures ontaining relaimed asphalt pavement. Constr. Build. Mater. 2017, 152, [CrossRef] 26. Huang, B.; Shu, X.; Li, G. Laboratory investigation of portland ement onrete ontaining reyled asphalt pavements. Cem. Conr. Res. 2013, 35, [CrossRef] 27. Ibrahim, A.; Mahmoud, E.; Khodair, Y.; Patibandla, V.C. Fresh, Mehanial, and Durability Charateristis of Self-Consolidating Conrete Inorporating Reyled Asphalt Pavements. J. Mater. Civ. Eng. 2014, 26, [CrossRef] 28. Abraham, S.M.; Ransinhung, G.D.R.N. Strength and permeation harateristis of ement mortar with Relaimed Asphalt Pavement Aggregates. Constr. Build. Mater. 2018, 167, [CrossRef] 29. Brand, A.S.; Roesler, J.R. Bonding in ementitious materials with asphalt-oated partiles: Part I The interfaial transition zone. Constr. Build. Mater. 2017, 130, [CrossRef]

23 Buildings 2018, 8, of Brand, A.S.; Roesler, J.R. Bonding in ementitious materials with asphalt-oated partiles: Part II Cement-asphalt hemial interations. Constr. Build. Mater. 2017, 130, [CrossRef] 31. Berry, M.; Stephens, J.; Bermel, B.; Hagel, A.; Shroeder, D. Feasibility of Relaimed Asphalt Pavement as Aggregate in Portland Cement Conrete; Montana Department of Transportation: Helena, MT, USA, Chao-lung, H.; le Anh-tuan, B.; Chun-tsun, C. Effet of rie husk ash on the strength and durability harateristis of onrete. Constr. Build. Mater. 2011, 25, [CrossRef] 33. ASTM C595. Standard Speifiation for Blended Hydrauli Cements 14; ASTM International: West Conshohoken, PA, USA, Mamlouk, M.S.; Zaniewski, J.P. Materials for Civil and Constrution Engineers, 3rd ed.; Pearson Eduation Ltd.: Hoboken, NJ, USA, Jamil, M.; Kaish, A.B.M.A.; Raman, S.N.; Zain, M.F.M. Pozzolani ontribution of rie husk ash in ementitious system. Constr. Build. Mater. 2013, 47, [CrossRef] 36. BS EN Tests for General Properties of Aggregates: Part 1. Methods for Sampling; Conrete Soiety: Farmington Hills, MI, USA, BS EN Tests for Geometrial Properties of Aggregates Part 1: Determination of Partile Size Distribution Sieving Method; Conrete Soiety: Farmington Hills, MI, USA, BS ISO Test Sieves Tehnial Requirements and Testing Part 2: Test Sieves of Perforated Metal Plate; ISO: Geneva, Switzerland, BS EN Tests for Mehanial and Physial Properties of Aggregates Part 6: Determination of Partile Density and Water Absorption; BSI Standards Ltd.: Brussels, Belgium, ASTM C29/C29M. Standard Test Method for Bulk Density ( Unit Weight ) and Voids in Aggregate; ASTM International: West Conshohoken, PA, USA, IS 2386: Part IV. Methods of Test for Aggregates for Conrete: Part IV Mehanial Properties; Conrete Soiety: Farmington Hills, MI, USA, BS EN 206. Conrete Speifiation, Performane, Prodution and Conformity; British Standards Institution: London, UK, BS Conrete Complementary British Standard to BS EN 206: Constituent Materials and Conrete; BSI Standards Ltd.: London, UK, BS Testing Conrete Part 125: Methods for Mixing and Sampling Fresh Conrete; British Standards Institution: London, UK, BS EN Method of Testing Cement, Part 2: Chemial Analysis of Cement; BSI Standards Ltd.: London, UK, ASTM C188. Standard Test Method for Density of Hydrauli Cement; ASTM International: West Conshohoken, PA, USA, 2016; Volume I, pp BS EN Testing fresh onrete, Part 1: Sampling Fresh Conrete; BSI Standards Ltd.: London, UK, BS EN Testing Fresh Conrete, Part 2: Slump Test; BSI Standards Ltd.: London, UK, BS Testing Conrete, Part 103: Method for Determination of Compating Fator; BSI Standards Ltd.: London, UK, BS EN Testing Fresh Conrete, Part 6: Fresh Density; BSI Standards Ltd.: London, UK, BS EN Conrete Complementary British Standard to BS EN Guidane for the Speifier; BSI Standards Ltd.: London, UK, BS EN Testing Hardened Conrete, Part 2: Making and Curing Speimens for Strength Tests; BSI Standards Ltd.: London, UK, BS EN Testing Hardened Conrete, Part3: Compressive Strength of Test Speimens; BSI Standards Ltd.: London, UK, BS EN Testing Hardened Conrete, Part 6: Tensile Splitting Strength of Test Speimens; BSI Standards Ltd.: London, UK, BS EN Testing Hardened Conrete, Part 4: Speifiation for Compressive Strength Testing Mahines; BSI Standards Ltd.: London, UK, ASTM C642. Standard Test Method for Density, Absorption, and Voids in Hardened Conrete; ASTM International: West Conshohoken, PA, USA, ASTM C1585. Standard Test Method for Measurement of Rate of Absorption of Water by Hydrauli Cement Conretes; ASTM International: West Conshohoken, PA, USA, 2013.

24 Buildings 2018, 8, of BS 882. Speifiation for Aggregates from Natural Soures For Conrete; BSI Standards Ltd.: London, UK, IS 383. Speifiation for Coarse and Fine Aggregates from Natural Soures for Conrete; BSI Standards Ltd.: London, UK, BS EN Fly Ash for Conrete, Part 1: Definition, Speifiations and Conformity Criteria; BSI Standards Ltd.: London, UK, El, S.; Ben, E.; El, S.; Khay, E.; Ahour, T.; Loulizi, A. Modelling of the adhesion between relaimed asphalt pavement aggregates and hydrated ement paste. Constr. Build. Mater. 2017, 152, Singh, S.; Ransinhung, G.D.; Kumar, P. An eonomial proessing tehnique to improve RAP inlusive onrete properties. Constr. Build. Mater. 2017, 148, [CrossRef] 63. Martys, N.S.; Ferraris, C.E. Pii sooos-8846(97) apillary transport in mortars and onrete. Cem. Conr. Res. 1997, 27, [CrossRef] 64. Menéndez, G.; Irassar, V.L.B.E.F. Hormigones on ementos ompuestos ternarios. Parte II: Meanismos de transporte Ternary blend ements onrete. Part II: Transport mehanism. Constr. Build. Mater. 2007, 57, by the authors. Liensee MDPI, Basel, Switzerland. This artile is an open aess artile distributed under the terms and onditions of the Creative Commons Attribution (CC BY) liense (