Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Concrete Pavement Applications

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1 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Dong-Hyun, Kim and Chan-Gi, Park * Rural Construction Engineering, Kongju National University, Yesan, Republic of Korea Received: 14 September 2012, Accepted: 1 February 2013 Summary The objective of this study was to improve the performance of a pavement structure by applying precast concrete to enable rapid repair of the pavement. Latex-modified fibre-reinforced concrete (LMFRC) was used to achieve this objective. This study also determined the type of fibre reinforcement and the amount of added latex that exhibited the best performance. Three types of reinforcing fibres were evaluated: polyvinyl alcohol (PVA), polypropylene (PP), and nylon fibre. Latex was added to the LMFRCs at 0, 5, 10, and 15% of the cement weight. The LMFRC was tested for slump, compressive strength, flexural strength, chloride-ion penetration, abrasion resistance, and impact resistance. Test results showed that increasing latex content improved the flexural strength, permeability resistance, abrasion resistance, and impact resistance. When comparing the types of reinforced fibre, the hydrophilic PVA and nylon fibres showed superior resistance to microcracking and crack propagation due to their stronger bonding with the concrete matrix compared with the non-hydrophilic PP fibre. Consequently, the concrete containing the nylon fibre had the best performance, proving that nylon fibre is the most desirable reinforcing fibre for precast concrete pavement. Keywords: Abrasion, Durability, Latex modified fibre reinforced concrete (LMFRC), Impact resistance, Precast concrete pavement, Permeability, Styrene butadiene latex (latex) *Corresponding Author. Tel.: ; fax: cgpark@kongju.ac.kr Smithers Rapra Technology, 2013 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

2 Dong-Hyun, Kim and Chan-Gi, Park INTRODUCTION Concrete pavement has been widely applied to many structures, including general-use roads, highways, and airport runways [1]. However, concrete pavement is susceptible to rapid deterioration due to scaling, erosion, and/ or abrasion caused by the influx of water and moisture that penetrates through the concrete surface [2-3]. To cope with these problems, a variety of maintenance methods have been applied [1-5]. However, concrete pavement repair requires ~28 days to cure [5]. During this time, traffic must be rerouted, thus introducing significant delays [5-7]. Due to the long curing times, it is not possible to apply ordinary portland cement to the roadway or airport runway in need of urgent rehabilitation [1-3, 5]. Three approaches have been studied for more rapid repair of concrete pavement, i.e., application of fast-setting cement, use of magnesia phosphate cement, and use of precast concrete [1-7]. The durability of precast concrete pavement is excellent; previous studies have shown little evidence of deterioration resulting from the rapidly developing heat of hydration [1-3]. Also, precast concrete pavement is plant-based, and the quality control during manufacturing is excellent [1-3]. In fact, precast concrete structures are more likely to become cracked due to impact during delivery and installation. Most research on precast concrete has focused on pavement design, installation, and the design and analysis of joints [1-3]. There have been few studies on the material itself in terms of defects and cracking that may occur during transportation, installation, and throughout the lifetime of precast concrete pavement. The objective of this study was to improve the performance of a pavement structure by applying precast concrete to enable rapid repair of the pavement. Also, the present study used a material-oriented approach to determine the mix ratio of concrete having excellent durability. This study reasoned that incorporating reinforcing fibres would arrest crack formation and growth and improve resistance to impact load and that admixing latex would improve the long-term durability by reducing permeability [5, 8-10]. In this study, three types of reinforcing fibres were used: polyvinyl alcohol (PVA), polypropylene (PP), and nylon. Latex was added at 0, 5, 10, and 15% with respect to the cement weight of plain concrete (having no fibre reinforcement) and the three types of fibre-reinforced concrete (FRC). 240 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

3 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast MATERIALS AND METHODS Materials Latex from the Dow Chemical Company (Midland, MI, U.S.A.) was used; its properties are listed in Table 1. The physical and chemical characteristics of ASTM Type 1 cement are shown in Table 2. The coarse aggregate had a maximum grain size of 25 mm, and the fine aggregate had a specific gravity of The reinforcing fibres were all 6 mm long but varied in diameter: PP fibres were 0.1 mm, PVA fibres were mm, and nylon fibres were mm in diameter. The aspect ratio (i.e., fibre length/fibre diameter) of reinforcing fibres has a significant effect on the performance of FRCs: the higher the aspect ratio, the better the tensile performance. However, if the aspect ratio is too high, fibre balling may degrade performance. The aspect ratios of the fibres used in this study were 60 (PVA), 400 (PP), and 461 (nylon). The shapes and characteristics of the reinforcing fibres are given in Figure 1 and Table 3. Table 1. Properties of latex Solids content (%) Styrene content (%) Butadiene content (%) ph Density (g/mm 3 ) Surface tension (dyne/cm) Particle size (A) Viscosity (cps) 49 34±1.5 66± Table 2. Properties of cement Physical properties Fineness (cm 2 /g) Density (g/mm 3 ) Stability (%) Initial (min) Setting time Final (min) Compressive strength(mpa) 3 days 7 days 28 days 3, Chemical L.O.I * (%) MgO (%) SO 3 (%) properties * Loss on ignition Table 3. Properties of fibre Properties PVA fibre Nylon fibre PP fibre Elastic modulus (GPa) Density (g/mm 3 ) Fibre length (mm) Fibre diameter (mm) Aspect ratio Tensile strength (MPa) Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

4 Dong-Hyun, Kim and Chan-Gi, Park (a) (b) (c) Figure 1. Shape of reinforcing fibres (a) PP fibre, (b) PVA fibre, (c) Nylon fibre 242 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

5 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Mix Proportions In an attempt to assess the mechanical properties, permeability, impact resistance, and abrasion resistance of latex-modified fibre-reinforced concrete (LMFRC) for precast concrete pavement applications, three different types of reinforcing fibres having different latex contents were studied, i.e., PVA (0.1% vol), PP (0.1% vol), and nylon (0.1% vol). Latex was added to the cement at 0, 5, 10, and 15% of the cement weight. The mix ratios are shown in Table 4. Table 4. Mix proportions of precast concrete pavements No. of mix W/C (%) S/a (%) Unit weight (kg/m 3 ) W C S G Admixture PP fibre Nylon fibre PVA latex No No No No No No No No No No No No No No No No Slump Tests The slump tests were carried out according to the ASTM C 143 standard to determine the effect of the added latex and reinforcing fibres on the workability of the LMFRC [11]. Compressive Strength Tests The compressive strength tests were performed in accordance with the ASTM C 39 standard [12]. Specimens that were mm in size were Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

6 Dong-Hyun, Kim and Chan-Gi, Park initially cured in air for 1 day and then cured in water at 23 ± 2 C. Each test was performed after 28 days of curing. Flexural Tests The flexural tests were conducted in accordance with the ASTM C 78 standard [13]. Specimens that were mm in size were cured in water at 23 ± 2 C. Each test was performed after 28 days of curing. Chloride-ion Penetration Tests The chloride-ion penetration tests were conducted in accordance with the ASTM C 1202 standard [14]. Specimens that were mm in size were tested after 28 days of curing. The test apparatus for the chloride-ion penetration test is shown in Figure 2. Figure 2. Chloride ion penetration test set-up Abrasion Tests The abrasion tests were conducted in accordance with the ASTM C 944 standard [15]. Specimens that were mm in size were tested after 244 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast 28 days of curing. The test apparatus for the abrasion test is shown in Figure 3.

7 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast 28 days of curing. The test apparatus for the abrasion test is shown in Figure 3. Figure 3. Abrasion test set-up Impact Tests The impact tests were conducted in accordance with the specifications of the ACI Committee 544 [16]. Specimens that were mm in size were cured in water at 23 ± 2 C. Each test was performed after 28 days of curing. The setup of the impact test apparatus is shown in Figure 4. RESULTS Slump The results of the slump tests for samples having varying amounts of added latex are shown in Figure 5. The slump value increased as the percentage of latex in the cement increased. The slump value was highest for the plain mix with no reinforcing fibre. When latex was added up to 5%, the slump value of PP-LMFRC was greater than the slump values for the mixes containing PVA and nylon fibres. These Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

8 Dong-Hyun, Kim and Chan-Gi, Park Figure 4. Impact test set-up results suggest that the non-hydrophilic PP-LMFRC did not absorb the mixing water, in contrast to the hydrophilic PVA- and nylon-lmfrcs, which exhibited smaller slump values. However, all three LMFRC mixes (5, 10, and 15% latex) had similar slump values; this suggests that the surfactant interactions, induced by the addition of latex, improved the fluidity of the LMFRC. Compressive Strength Figure 6 shows the compressive strength test results for LMFRCs with different amounts of added latex. The compressive strength decreased as the amount of latex increased. This result was the same for all of the mix ratios. It is well known that the addition of latex is beneficial to tensile strength at the expense of compressive strength. Conventional research explains this in terms of a latex film, which suppresses the hydration reaction and thereby reduces the compressive strength of the cement. For the mixes with no latex added (0%) and 5% latex added, the compressive strength of the FRC was greater than that of the mixes with 10 and 15% latex added. When 10 or 15% latex was added, however, the compressive strength values were very similar. When 0 and 5% latex was added, the reinforcing fibres limited crack formation and growth; when 10 and 15% latex was added, hydration heat generation had a greater effect on compressive strength than did the latex film layer. 246 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

9 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast Figure 5. Slump test results Figure 6. Compressive strength test results Flexural Strength Figure 7 shows the flexural strength test results of the LMFRCs as a function of the amount of latex added and the type of reinforcing fibres. The addition of latex had a greater effect on the tensile strength and flexural strength of Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

10 Dong-Hyun, Kim and Chan-Gi, Park the concrete compared to the compressive strength. This suggests that the latex film enhanced the bond strength between materials when the concrete was subjected to flexural or tensile loading. This study showed that the flexural strength increased for all three types of LMFRCs as the amount of latex additive increased. The test results for flexural strength with different reinforcing fibres showed that the flexural strength was greater in the LMFRCs compared with that obtained with no reinforcing fibre added. This suggests that the reinforcing fibres suppressed crack generation and growth within the concrete. The flexural strengths of the mixes containing PVA and nylon fibres were greater than those of the mixes containing PP fibre. These results were attributed to the non-hydrophilic nature of the PP fibre, which inhibits bonding with concrete, in contrast to the hydrophilic PVA and nylon fibres. The flexural strengths of the PVA LMFRC and nylon-lmfrc were similar. The flexural strength of concrete mixes containing only fibre, i.e., no latex, was slightly greater for the mix containing nylon fibre than that containing PVA fibre. This is because the nylon fibres had a higher aspect ratio (471) than the PVA fibres (400). Figure 7. Flexural strength test results Chloride-ion Penetration Test Results Figure 8 shows the test results of chloride-ion penetrability resistance in the LMFRC as a function of the amount of latex added and the type of reinforcing 248 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

11 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast fibres. Chloride-ion penetration tests are used to indirectly evaluate the permeability of concrete. Our test results showed that the chloride penetration decreased as the amount of latex added increased. This suggests that the latex filled in the voids within the LMFRC; as the latex film thickness increased, the chloride-ion penetration decreased. The resistance to chloride-ion penetration was greatest in the plain concrete (no fibre reinforcement), where penetration was similar for all three LMFRCs. Closer inspection revealed that the degree of penetration for PVA- and nylon-lmfrcs was smaller, compared with that for the PP-LMFRC. The PVA- and nylon-lmfrcs exhibited similar chlorideion penetration. This suggests that the more hydrophilic reinforcing fibres, such as PVA and nylon, are better able to suppress void generation between the fibres and LMFRC matrix. Additionally, the chloride-ion penetration was lower for the nylon fibre-reinforced material because of its higher aspect ratio (471) compared with that for the PVA fibre (400). Figure 8. Chloride ion penetration test results Abrasion Test Results Figure 9 shows the abrasion test results of the LMFRCs as a function of the amount of latex added and the type of reinforcing fibres. The abrasion resistance improved as the amount of latex additive increased. This finding was attributed to latex filling the voids within the LMFRC, resulting in the formation Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

12 Dong-Hyun, Kim and Chan-Gi, Park of a thick latex film. The abrasion resistance of the LMFRC was greater than that in plain concrete. This result was attributed to the reinforcing fibres that restrained the de-bonding of the concrete particles under abrasion stress due to the bridging effect. Hydrophilic PVA- and nylon-lmfrcs demonstrated superior performance in the abrasion test, compared with non-hydrophilic PP-LMFRCs. Also, the abrasion resistance for the mix containing nylon fibre was slightly greater. This is because of the higher aspect ratio of the nylon fibres (471) compared with the PVA fibres (400). Figure 9. Abrasion test results Impact Test Results Figure 10 shows the impact test results with respect to the amount of latex added and the type of reinforcing fibres. The number of impacts for the occurrence of the first crack and the final fracture tended to increase as the amount of latex added increased. The latex film improved the bonding strength between materials, preventing the growth of cracks due to impact. The number of impacts for the occurrence of the first crack and the final fracture increased more for the mixes containing reinforcing fibres. The hydrophilic PVA- and nylon-lmfrcs demonstrated superior performance in the impact test compared with non hydrophilic PP-LMFRC. Also, the impact resistance of the mix containing nylon fibre was slightly greater. This is because of the higher aspect ratio of the nylon fibres (471) compared with the PVA fibres (400). 250 Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

13 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast (a) (b) Figure 10. Impact test results (a) No. of initial crack, (b) No. of fracture CONCLUSIONS The present study evaluated the effects of latex additive and the type of reinforcing fibres on the performance of LMFRC for applications in precast concrete pavement. The results are summarised below. Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

14 Dong-Hyun, Kim and Chan-Gi, Park 1. Slump values tended to increase as more latex was added to the concrete mixture. This result was attributed to the improved fluidity of the LMFRC due to the surfactant interactions of the latex. Additionally, the slump values were greater for the hydrophilic PVA- and nylon-lmfrcs, which absorbed the mixing water, compared with non-hydrophilic PP-LMFRC. 2. Increasing the amount of latex in the cement led to improved bond strength between the LMFRC materials due to the formation of a latex film. This latex film increased the flexural strength of the LMFRC, but had little effect on the compressive strength. The flexural strength of the LMFRC was superior to that of plain concrete (no reinforcing fibres added); moreover, the use of hydrophilic fibres in the LMFRC (PVA and nylon fibres) resulted in better performance in terms of flexural strength. The flexural strength of concrete mixes containing only fibre, i.e., no latex, was slightly greater for the mix containing nylon fibre than that containing PVA fibre. This is because the nylon fibres had a higher aspect ratio (471) than the PVA fibres (400). 3. Increasing the amount of latex in the LMFRC improved the concrete s resistance to chloride-ion penetration, abrasion, and impact. Latex filled the voids and microcracks in the concrete matrix to form a protective latex film. The LMFRC demonstrated superior performance in resistance tests, compared with plain concrete, with hydrophilic PVA- and nylon-lmfrcs providing a higher resistance than the non-hydrophilic PP-LMFRC. Better chloride-ion penetration, abrasion, and impact resistances were obtained when high-aspect-ratio nylon fibres were used than when lowaspect-ratio PVA fibres were employed. acknowledgements This research was supported by a grant (code 11PTSI-B ) from transportation system efficiency program funded by Ministry of Land, Transport, and Maritime Affairs of Korean government. REFERENCES 1. Bull J.W. and Woodford C.H., Design of precast concrete pavement units for rapid maintenance of runways, Computers & Structures, 64(1 4) (1997) Ackroyd R.F. and Bull J.W., The design of precast concrete pavements on low bearing capacity subgrades, Computers and Geotechnics, 1(4) (1985) Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

15 Permeability, Abrasion, and Impact Resistance of Latex-Modified Fibre Reinforced Concrete for Precast 3. Bull J.W. and Clarke J.D., Rapid runway and highway repair using precast concrete raft units, Proc. Int. Conf. on Rapidly Assembled Structure, Bulson, P.S.(Editor), Computational Mechanics Publications, Southampton, UK (1991), Seehra S.S., Gupta S. and Kumar S., Rapid setting magnesium phosphate cement for quick repair of concrete pavements characterisation and durability aspects, Cement and Concrete Research, 23(2) (1993) Won J.P., Kim J.H., Lee S.W. and Park C.G., Durability of Low-Heat, Ultra Rapid-Hardening, Latex Modified Polymer Concrete, Progress in Rubber, Plastics and Recycling Technology, 25(2) (2009) Jean Péra, and Jean Ambroise, Fibre-reinforced magnesia-phosphate cement composites for rapid repair, Cement and Concrete Composites, 20(1) (1998) Fei Qiao, Chau, C.K. and Zongjin Li, Property evaluation of magnesium phosphate cement mortar as patch repair material, Construction and Building Materials, 24(5) (2010) Park C.G. and Lee J.H., Effect of styrene butadiene latex polymer contents on the bond properties of macro polypropylene fiber in polymer-modified cement-based composites, Journal of Applied Polymer Science, 126(S2), (2012) E330 E Zoran J. Grdic, Gordana A. Toplicic Curcic, Nenad S. Ristic, and Iva M. Despotovic, Abrasion resistance of concrete micro-reinforced with polypropylene fibers, Construction and Building Materials, 27(1) (2012) Altoubat S.A., Roesler J.R., Lange D.A. and Rieder K.A., Simplified method for concrete pavement design with discrete structural fibers, Construction and Building Materials, 22(3) (2008) ASTM C143, Standard Test Method for Slump of Hydraulic-Cement Concrete, Philadelphia: American Society for Testing and Materials, ASTM C39, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens, Philadelphia: American Society for Testing and Materials, ASTM C78, Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading), Philadelphia: American Society for Testing and Materials, ASTM C1202, Standard Test Method for Electrical Indication of Concrete s Ability to Resist Chloride Ion Penetration, Philadelphia: American Society for Testing and Materials, Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4,

16 Dong-Hyun, Kim and Chan-Gi, Park 15. ASTM C944, Standard Test Method for Abrasion Resistance of Concrete or Mortar Surfaces by the Rotating-Cutter Method, Philadelphia: American Society for Testing and Materials, ACI Committee 544, Measurement of Properties of Fiber Reinforced Concrete. American Concrete Institute: Detroit, Michigan, Progress in Rubber, Plastics and Recycling Technology, Vol. 29, No. 4, 2013

A STUDY ON THE ENHANCEMENT OF DURABILITY PERFORMANCE OF FACED SLAB CONCRETE IN CFRD

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