THE APPLICATION OF ASBUTON AND POLYMER MODIFIED BITUMEN FOR PAVEMENT MIXTURE DESIGN AT HOT AND ARID REGION Mohammed I. D. Matar 1), Ary Setyawan 2), Kusno Adi Sambowo 3) Post Graduate Civil Engineering ProgramsUniversitas Sebelas Maret (2013-2014), Jl. Ir. Sutamai 36A, Surakarta 57126; Telp. 0271-634524. Email: Mater_108@yahoo.com Abstract Many of the studies have been done in finding other alternative material in order to using as polymer modified bitumen in asphalt mixes and Rock Asphalt on improvement its properties, highway quality And increase the ability to withstand changes in temperature in hot and arid regions Current rapid increases in traffic volume and legal weight increased loads on the road structure Different temperatures will make the asphalt less resilient to stresses inflicted It could reduce the service life and increase the cost of maintenance of the road. The mechanical properties of the asphalt paving mixtures were characterized at three testing permanent deformation, fatigue and cracking that is forcing engineers to consider these issue attempts to improve the quality and characteristics of asphalt pavement using additives. Many of the studies have been done in finding other alternative material in order to using as polymer modified bitumen in asphalt mixes and Rock Asphalt on improvement its properties, highway quality And increase the ability to withstand changes in temperature in hot and arid regions. In this study, the laboratory works can be divided into three stages: The First Stage, make tests in the laboratory on the following Aggregate materials, to know the physical properties and the possibilityknow their physical properties and specifications. The Third Stage, a total of 108 samples prepared from Asphalt (60/70 pen), ASBUTON and Polymer Modified Bitumen (Starbit E-55) all of them separately. Including Marshall Stability T of their use in the mixture. The Second Stage, make tests in the laboratory on the following bituminous materials: Asphalt 60/70 pen, ASBUTON and Polymer Modified Bitumen (Starbit E-55) all of them separately, to est (MS) to get OBC, (UCS), (ITS) with at (30ºC, 40ºC, 60ºC) and Permeability Test. The objective of that is a comparing the results of laboratory tests to know the best stable and resilient material at different temperatures. In comparison with the results of Marshall Test, it is noticed that Starbit E-55 mixture was more stable than Asphalt 60/70 pen and ASBUTON mixtures; the density of the Asphalt 60/70 pen mixture was higher than the density of the Starbit E-55 and ASBUTON mixtures respectively. The results of Permeability test shows that the Asphalt 60/70 pen mixture was less permeable than Starbit E-55 and ASBUTON mixtures respectively. The result of ITS and UCS test shows that Asphalt 60/70 pen mixture was higher performance than Starbit E- 55 and ASBUTON mixtures at (30 C). Asphalt 60/70 pen mixture was less sensitive to temperature changes compare with Starbit E-55 and ASBUTON mixtures. Keywords: AC, Asphalt 60/70 pen, ASBUTON, PMB ( Starbit E-55), ITS test & UCS test @ (30 ºC, 40 ºC, 60 ºC), permeability test. I. Introduction Current rapid increases in traffic volume and legal weight increased loads on the road structure Different temperatures will make the asphalt less resilient to stresses inflicted It could reduce the service life and increase the cost of maintenance of the road. The mechanical properties of the asphalt paving mixtures were characterized at three testing permanent deformation, fatigue and cracking that is forcing engineers to consider these issue attempts to improve the quality and characteristics of asphalt pavement using additives. There are about 83,200 km of roads in Libya, 47,590 km of which are surfaced. 234 out of 1000 Libyans have cars, which is the highest rate in Africa. The best roads run along the 52
coast between Tripoli and Tunis in Tunisia; also between Benghazi and Tobruk, connecting with Alexandria in Egypt. There is a high rate of road accidents, Because of the poor conditions of the highways and increase the number of vehicles. Libya has two routes in the Trans-African Highway network, but only one currently functions as such, the Cairo-Dakar Highway. In Libya, rutting is the dominant deterioration problem because of hot climate and dry. The average temperature in Libya is around 30 C. Therefore, the existing pavement should be improved to increase rutting resistance. In order to obtain the better pavement, the bitumen properties as one of the important component in the mixture itself must be enhanced. To improve the performance of bitumen blends used in the course floating on the surface of the pavement. There are many of the rates that can be added, including, thermal polymers, thermoplastics, and natural rubber, chemical fiber, adhesion improvers, antioxidants, natural asphalt, and carbon black fillers (Telford, 2003). The pavement using modifier in asphalt mixtures is to increase the resistance of asphalt to permanent deformation at high temperatures of the road without adversely affecting on the properties of asphalt (Yen and Chilingraian, 1994). The use of modified bituminous offers a solution to reduce the frequency of maintenance required at particular locations and provides a much longer service life for maintenance treatments at difficult sites (Telford, 2003). Polymers and the main are used to modify bitumen properties in some way to effect a perceived improvement in asphalt performance. Improvements in the mechanical or structural properties of asphalt.and can often result in reduced stiffness, though some improvement in deformation resistance and cohesive strength can be obtained and used to Reducing rutting i.e., permanent deformation, Improve asphalt cohesive strength and Reduce risk of lowtemperature thermal cracking by reducing the temperature susceptibility the bitumen (Robinson, 2004). Problem in Libya is rutting the dominant deterioration problem because of hot climate and dry. The average temperature in Libya is around 30 C. Therefore, the existing pavement should be improved to increase rutting resistance. In order to obtain the better pavement, the bitumen properties as one of the important component in the mixture itself must be enhanced. There are three asphalt materials: Asphalt 60/70 pen, ASBUTON, Polymer Modified Bitumen. The research is carried out to compare and determine the mechanical properties of the paving mixture include permanent deformation of the paving mix. The primary objectives of this study are: 1. To verify the feasibility of the use of ASBUTON as a binder for alternative industrial asphalt in flexible pavement at hot and arid region; 2. To verify the feasibility of the use of Polymer Modified Bitumen as a binder for alternative industrial asphalt in flexible pavement at hot and arid region; 3. To determine the performance characteristics of asphalt mixture to each of the three materials, using the following tests: Marshall Stability Test (MS), Unconfined Compressive Strength Test (UCS), Indirect Tensile Strength Test (ITS) and Permeability Test. Comparison between the results of the tests three different asphalt mixtures with different temperatures (30ºC, 40ºC, 60ºC). II. The Method In this study, the laboratory works can be divided into three stages: The First Stage: make tests in the laboratory on the following Aggregate materials, to know the physical properties and the possibility of their use in the mixture. The Second Stage: make tests in the laboratory on the following bituminous materials: Asphalt 60/70 pen, ASBUTON and Polymer Modified Bitumen (Starbit E-55) all of them separately, to know their physical properties and specifications. The Third Stage: a total of 108 samples prepared from Asphalt (60/70 pen), ASBUTON and Polymer Modified Bitumen 53
(Starbit E-55) all of them separately. Including Marshall Stability Test (MS) to get OBC, (UCS), (ITS) with at (30ºC, 40ºC, 60ºC) and Permeability Test. The objective of that is a comparing the results of laboratory tests to know the best stable and resilient material at different temperatures. a) Sample preparation (for 1st stage): Preparing the Aggregate Samples: Aggregates used in this study consist of coarse aggregate, fine aggregate and filler. Coarse aggregate is defined as the aggregate retains on sieve size 4.75 mm (No.4) while fine aggregate is defined as the aggregate passing sieve size 4.75 mm (No.4) and retains on sieve size 75 μm (No.200). 1) 2 sample of Aggregate (Impact test); 2) 2 sample of Aggregate Specific Gravity and Absorption of Aggregates. 3) Aggregate Gradation The percentages of aggregates required for every sieve size were determined according to the Indonesian standards. Then the samples retained were calculated using the percent passing for every sample size. Table 1 below summaries the upper and lower limit According to Indonesian standards. Table: 3.1: Gradation limits for Wearing Course in Sieve size mm Upper Limit specs. Lower Limit specs. 3/4" 19.1 100 100 1/2" 12.5 90 100 3/8" 9.5 72 90 #4 4.76 43 63 #8 2.38 28 39.1 #16 1.18 19 25.6 #30 0.59 13 19.1 #50 0.279 9 15.5 #100 0.149 6 13 #200 0.074 4 10 Pan (Source: Indonesian standards, 2012) b) Sample preparation (for 2nd stage): Preparing the Bitumen Samples: In this study will use three types of bitumen: Asphalt 60/70 pen, ASBUTON and Polymer modified bitumen (Starbit E-55). The bitumen contents for these samples were ranged as (5 to 7) % of the total weight according to ASTM 3515-96. It has been made the tests for bitumen to know the physical properties of bitumen. c) Sample preparation (for 3rd stage): 1- Samples for Marshall Stability Test (M.S) The numbers of samples required are: 3 Samples for each Percentage of bitumen and 15 samples for each type of bitumen: Asphalt 60/70 pen, ASBUTON and According to Table 3.3. Table 3.3: Shows the distribution and number of samples of Marshall testing for each type of bitumen. Total of samples =15 x 3= 45. 2- Sample Testing for Unconfined Compressive Strength (UCS) at OBC. The numbers of sample required are: 3 samples of each type of bitumen: Asphalt 60/70 pen, ASBUTON and at each different temperature (30 C, 40 C, 60 C) at OBC. Total of samples = 3 x 3 x 3 = 27. 3- Sample Testing For Indirect Tensile Strength (ITS) at OBC. The numbers of sample required are: 3 samples of each type of bitumen: Asphalt 60/70 pen, ASBUTON and at each different temperature (30 C, 40 C, 60 C) at OBC; Total of samples = 3 x 3 x 3 = 27. 54
4- Sample Testing For Permeability At OBC The numbers of samples required are: 3 samples of each type of bitumen: Asphalt 60/70 pen, ASBUTON and at OBC. III. Results and Discussions The aim of this study was to achieve the viability of using Asphalt 60/70 pen, ASBUTON and Polymer Modified Bitumen (Starbit E-55) as a binder for alternative industrial asphalt in flexible pavement at hot and arid region. All of the Asphalt concrete mixtures (AC) were prepared based on Marshall Mix design. The Asphalt concrete mixtures (AC) were between normal aggregate and (Asphalt pen 60/70, ASBUTON and Starbit E-55). In comparison between the three types of Asphalt concrete mixtures (AC) properties in terms of Marshall Stability Test (MS) to get optimum bitumen content, "Unconfined Compressive Strength Test (UCS) and Indirect Tensile Strength Test (ITS) in different temperatures (30ºC, 40ºC, 60ºC)" and Permeability Test. A- Aggregate Tests 1- Sieve Analysis and Aggregates Distribution. In this study, sieve analysis was conducted to separate the aggregate according to the sieve size. Asphalt Concrete mixtures specifications require aggregate particles to be within a certain range of sizes and for each size of particle to be presented in a certain proportion. Based on the Indonesian National Standards, the aggregates were blended as in Figure 1 and sieved. The aggregate samples passing from each sieve size were collected based on the percentage of the weigh Figure 1: Gradation limit for Asphalt Concrete 2- Aggregate Impact Value Impact test was conducted to determine the validity of the use of aggregates in asphalt concrete mixture, the asphalt concrete mixture has been designed according to Indonesian national standards for the paving wearing course. the result was indicated to the good quality of strength of Aggregate Impact Value is 26%, where the Aggregate impact value must be Less than 30% (according to ASTM D5874-95 Standard Test Method for Determination of the Impact Value). 3- Specific Gravity and Water Absorption. Aggregate size above 4.75 mm is defined as coarse aggregate and the specific gravity and absorption were analyzed according to AASHTO T 85. The results shown in Table 2 were indicated to the good quality of strength of aggregate. Table 2: Specific Gravity of aggregate. Size of Aggrega te Coarse Aggrega te Fine Aggrega te )%( % 66.45 % 33.55 B- Asphalt Tests Bul k 2.56 8 2.69 5 Specific Gravity gr/cmᶾ Appare nt Absorpti on % 2.763 2.749 % 2.885 2.444 % 1- Result of Penetration & Softening Point Tests. The penetration test is an empirical test that measures the consistency (hardness) of asphalt. This test was conducted according to international standards ASTM D5-97 (ASTM, 2001). Softening point test measures the temperature in which the asphalt reaches certain softness at the softening point temperature of asphalt. This test was conducted according to international standards (ASTM D36-95), where table 3 presents the results of penetration test & softening point value for each type of Asphalt Cement. Table 3: Results of penetration & softening point. 55
2- Result of Specific Gravity & Ductility Tests. The Specific Gravity Test was conducted to measure the mass and volume of the asphalt sample and to determine its maximum specific gravity. This test was conducted according to international standards (AASHTO T 209), The ductility test measures the maximum distance for the bitumen ductility without breaking. This test was conducted according to international standards (ASTM D113), where Table 4 presents the results of Specific Gravity & ductility values for asphalt cement for each type of asphalt. Result was indicated to the high quality for all type of asphalt. Table 4: Results of Specific Gravity & ductility. 3- Affinity between bitumen and aggregate The affinity test between bitumen and aggregate was for assessing the degree of coating for each type of Asphalt and the adhesion property is characterized by the coating index. This test was conducted according to European standard (EN 12697-11:2005), Table 5 presents the results of Affinity value for asphalt cement for each type of asphalt. Table 5: Results of Affinity. using Figure 2 from (The Shell Bitumen Handbook, Fifth Edition), Depending on the penetration and softening point value and Table 6 Shows the values of the temperature of the asphalt mixture for each type of asphalt concrete. Table 6: Temperature of the Asphalt Concert. Figure 2: Determines the value of the dynamic viscosity and temperature (mixing and compaction) depending on the value of the penetration and softening point. 5- Maximum Specific Gravity of AC (Gmm) Maximum Specific Gravity of AC (Gmm) was important to use in Marshall Mix design control and carried out using 5.78% of bitumen by weight of sample. This test was conducted according to (ASTM D2041), to estimate the bitumen ratio (Pb) depending on the aggregate gradation in the Table 1 before by the following equation Pb = 0.035 A + 0.045 B + 0.18 C + K Where: A = Aggregate passed of Sieve 3/4 "and reserved on sieve 8 #. B = Aggregate passed of Sieve 8 # and reserved on sieve 200 #. C = Aggregate passed of Sieve 200 #. K = constant (0.5 to 1). Pb=0.035 66.45+0.045 26.55+0.18 7+1=5.78 %. Table 7 shows the result of the Maximum Specific Gravity test of Asphalt concrete. Table 7: Maximum Specific Gravity of AC C- Asphalt Mixtures Tests 4- Temperature of Mixing and Compaction The temperature of mixing and compaction for asphalt concrete have been identified 1- Marshall Mix Design Three types of blends were prepared for each type of asphalt cement mixture: Asphalt 60/70 pen, ASBUTON, Starbit E-55, and Marshall Specimens were conducted 56
according to (ASTM D 1559); specimens were prepared for each bitumen contents within the range given (5%, 5.5%, 6%, 6.5% and 7%). The optimum bitumen content has been determined in this study based on the maximum Stability according to the Marshall Stability (MS). Table 4.12 shows some properties of OBC that obtained from mix design. The results of Marshall mix design shows that the values of optimum bitumen content equal for all asphalt concrete mixtures, because it has been using the same aggregate gradation in this study. The results of Marshall Test have been collected in Table 8. Table 8: Results of Marshall test 2- Indirect Tensile Strength Test (ITS) This test was conducted under hot and dry conditions; it was determined by measuring the ultimate load to failure of a specimen that is subjected to a constant deformation rate of 50.8 mm/minute on its diametrical axis according to (ASTM D6931). It is the measure of pavement response in terms of stresses. Three samples for each type of asphalt cement were tested at temperatures (30 C, 40 C, and 60 C). Figure 3 and Table 9 shows the summarized results for the resilient modulus test for each type of Asphalt cement mix specimens with OBC. Table 9: Results of ITS Test at OBC. Figure 3: ITS results for each type of Asphalt cement mixes. Through a review of the results ITS test in Table 9 and Figure 3 were obtained the observations following: At a Temperature of 30 C: The ITS value of normal mixture (Asphalt 60/70 pen) is higher than ASBUTON mixture by 6.2% and Higher than polymer modified bitumen (Starbit E-55) mixture by 7.44%. At a Temperature of 40 C: The ITS value of normal mixture (Asphalt 60 /70 pen) is Higher than polymer modified bitumen (Starbit E-55) mixture by 17% and higher than ASBUTON mixture by 24.56%. At a Temperature of 60 C: The ITS value of normal mixture (Asphalt 60/70 pen) is Higher than polymer modified bitumen (Starbit E-55) mixture by 23.1% and higher than ASBUTON mix by 41.1%. Through the above observation, the normal asphalt (Asphalt 60 /70 pen) is less sensitive to temperature changes by using ITS test compared with polymer-modified bitumen (Starbit E-55) and ASBUTON mixtures. 3- Unconfined Compressive Strength Test (UCS) Unconfined Compressive Strength Test (UCS) used to determine the resistance to permanent deformation of bituminous mixtures at temperatures (30 C, 40 C, and 60 C) and loads. It is conducted by applying a static load to a specimen using OBC and then measuring the maximum load. This test used to determine the permanent deformation of normal and modified asphalt mixtures. It noticed that the permanent deformation of the asphalt mixtures correlated with the rutting potential. Figure 4 and Table 10 shows the summarized results for the Unconfined Compressive Strength Test (UCS) for each type of asphalt cement at OBC. Table 10: Results of UCS Test at OBC. Figure 4: Results of UCS test for each type of asphalt cement mixers at OBC. Through the review of the results of UCS test in Table 10 and Figure 4 were obtained the following observations: 57
At temperature 30 C: The UCS value of ASBUTON mixture is higher than polymer modified bitumen (Starbit E-55) mixture by 4% and higher than normal mixture (Asphalt 60 /70 pen) by 19.1%. At temperature 40 C: The UCS value of ASBUTON mixture is higher than normal mixture (Asphalt 60 /70 pen) by 6.6%, and higher than polymer modified bitumen (Starbit E-55) mixture by 15.77%. At temperature 60 C: The UCS value of normal mixture (Asphalt 60/70 pen) is higher than ASBUTON mixture by 7.26% and higher than polymer modified bitumen (Starbit E-55) mixture by 11.54%. The UCS value of ASBUTON mixture is higher than polymer modified bitumen mixture and higher than normal mixture at normal temperatures. However, normal mixture is higher than ASBUTON mixture and higher than polymer modified bitumen mixture at 60 C temperatures. Through the study of the relationship between the value of UCS and temperature changes, find that normal bitumen lower sensitive to heat than polymer modified Bitumen and ASBUTON mixtures. 4- Permeability Test Permeability testing is important because one of the primary assumptions in structural pavement design for conventional pavements is flexible (Asphalt Concrete) and the pavement must be impermeable. The basis for this design approach is to minimize moisture infiltration and thus maintain adequate support from the underlying unbound materials. Figure 5 and Table 11 shows the summarized results for the Test for each type of asphalt cement at OBC. Through the review of the Permeability test results in Table 11 and Figure 5 were obtained the following observations: A. The Coefficient of Permeability (K) value of ASBUTON mixture is higher than mixture by 8.8% at water pressure 5 Kg/cm² and by 13.22% at water pressure 10 Kg/cm². B. The Coefficient of Permeability (K) value of ASBUTON mixture is higher than normal asphalt (Asphalt 60/70 pen) mixture by 25.43% at water pressure 5 Kg/cm² and by 31.05% at water pressure 10 Kg/cm². The results of Permeability test Shows that normal asphalt (Asphalt 60/70 pen) mixture lower than polymer modified bitumen (Starbit E-55) Firstly and lower than ASBUTON mixture Secondly. Since the mixture has the lowest coefficient of permeability is the higher quality, because, when water leaks into the soil layer (Base Course), causing deformities, cracks and holes. Observe that the relationship between the coefficient of permeability and water pressure to be an inverse relationship, because the increase of water pressure leads to a decrease in permeability coefficient. IV. 1- Conclusion CONCLUSIONS a) ASBUTON could not be used as a binder for alternative industrial asphalt in flexible pavement at hot and arid region. Because it is because it is the highest sensitivity to temperature changes as the results of ITS and UCS test. b) Polymer Modified Bitumen (Starbit E-55) could be used as a binder for alternative industrial asphalt in flexible pavement at hot and arid region. Because it is less sensitive to temperature change. According to the results of ITS and UCS test. c) In comparison with the results of Marshall Test, it is noticed that Starbit E- 55 mixture was more stable than Asphalt 60/70 pen and ASBUTON mixtures; the density of the Asphalt 60/70 pen mixture was higher than the density of the Starbit E-55 and ASBUTON mixtures 58
respectively. The results of Permeability test shows that the Asphalt 60/70 pen mixture was less permeable than Starbit E-55 and ASBUTON mixtures respectively. The result of ITS and UCS test shows that Asphalt 60/70 pen mixture was higher performance than Starbit E-55 and ASBUTON mixtures at (30 C). Asphalt 60/70 pen mixture was less sensitive to temperature changes compare with Starbit E-55 and ASBUTON mixtures respectively. V. REFERENCES Brown & Cross, 1992. A National Study of Rutting in Hot Mix (HMA) Pavements. Paper presented at the 1992 Annual Meeting of the Association of Asphalt Paving Technologists held in Charleston, SC (February/1992). EN 12697-11: 2005/AC 2007 Bituminous mixtures - Test methods for hot mix asphalt Part 11: Determination of the affinity between aggregate and bitumen. Indonesian standards, 2012: General specification of bina marga, 2012. Revision. Richard & Bent, 2004. Road Engineering for Development. London. 2nd ed: Spon Press. Robinson, 2004. Polymers in Asphalt. Rapra Technology Limited. Vol 15, pp. 15-17-29. Teong, 2007. Evaluating Rutting on Porous Asphalt Mixes Comparison between Marshall and Superpave Method In Terms of Volumetric Properties. Universiti Teknologi Malaysia. Telford, 2003. The Shell Bitumen Handbook, published for shell bitumen by Thomas Telford publishing. pp. 61-65- 125. 59