Effect of Mixing Process on Polypropylene Modified Bituminous Concrete Mix Properties

Authors: Noor Zainab Habib, Ibrahim Kamaruddin, Madzalan Napiah, Isa Mohd Tan

Abstract:

This paper presents a research conducted to investigate the effect of mixing process on polypropylene (PP) modified bitumen mixed with well graded aggregate to form modified bituminous concrete mix. Two mode of mixing, namely dry and wet with different concentration of polymer polypropylene was used with 80/100 pen bitumen, to evaluate the bituminous concrete mix properties. Three percentages of polymer varying from 1-3% by the weight of bitumen was used in this study. Three mixes namely control mix, wet mix and dry mix were prepared. Optimum binder content was calculated considering Marshall Stability, flow, air voids and Marshall Quotient at different bitumen content varying from 4% - 6.5% for control, dry and wet mix. Engineering properties thus obtained at the calculated optimum bitumen content revealed that wet mixing process is advantageous in comparison to dry mixing as it increases the stiffness of the mixture with the increase in polymer content in bitumen. Stiffness value for wet mix increases with the increase in polymer content which is beneficial in terms of rutting. 1% PP dry mix also shows enhanced stiffness, with the air void content limited to 4%.The flow behaviour of dry mix doesn't indicate any major difference with the increase in polymer content revealing that polymer acting as an aggregate only without affecting the viscosity of the binder in the mix. Polypropylene (PP) when interacted with 80 pen base bitumen enhances its performance characteristics which were brought about by altered rheological properties of the modified bitumen. The decrease in flow with the increase in binder content reflects the increase in viscosity of binder which induces the plastic flow in the mix. Workability index indicates that wet mix were easy to compact up to desired void ratio in comparison to dry mix samples.

Keywords: Marshall Flow, Marshall Stability, Polymer modified bitumen, Polypropylene, Stiffness.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1071764

References:

[1] Whiteoak C.D The shell bitumen hand book. Surrey, UK. 2003.
[2] Didier Lesueur "The colloidal structure of bitumen: Consequences on the rheology and on the mechanism of bitumen modification". Advances in colloid and Interface Science, vol. 145, pp. 42-82, 2009.
[3] Gonzalez et al "Rheology and stability of bitumen/EVA blends" European Polymer Journal, vol.40, pp. 2365-2372, 2004.
[4] Airey, G.D. "Fundamental binder and Practical mixture evaluation of polymer modified bituminous" The International Journal of Pavement Engineering, vol 5(3), pp 137-151, 2004.
[5] Bardesi A, et al. "Use of modified bituminous binders, special bitumens with bitumen additives in pavement applications". Technical Committee Flexible Roads (C8) World Road Association (PIARC), 1999.
[6] Tapkin et al., "Polypropylene fiber modification of asphalt using mechanical and optical means" Advanced Testing and characterization of Bituminous Materials Loizos, Partl, Scarpas & Al-Qadi (eds), chapter 47, pp 487- 496,2009 Taylor & Francis Group, London, UK..
[7] Hadidy Al, Qui Tan Yi " Effect of polyethylene on life of flexible pavements" Construction and Building Materials vol. 23 pp. 1456- 146,2009.
[8] J.Stastna et al. "Viscosity functions in polymer modified asphalts" Journal of Colloid and Interface Science, vol. 259, pp.200-209, 2002.
[9] Lu.X and Isacsson "Compatibility and storage stavbility of styrene- butadiene-styrene copolymer modified bitumens" Journal of Materials and Structure, vol.30, pp.618-626, 1997.
[10] Drozdov Aleksey. D, Yuan Q "The viscoelastic and Viscoplastic behavior of low density polyethylene" International Journal Of Solid and Structure, vol. 40, pp2321-2342, 2003.
[11] Chen Jian-Shiuh et al. "Asphalt Modified by Styrene-Butadiene Styrene Triblock Copolymer: Morphology and Modal" Journal of Materials in Civil Engineering May/June, pp. 224-229, 2002
[12] Yousefi AA, Kadi A AIT "Composite asphalt binders: Effects of modified RPE on asphalt" Journal of Materials in civil Engineering, May, pp.113-123, 2000.
[13] Wekumbura et al., "Destruction and Recovery of Internal Structure in Polymer-Modified Asphalts" Journal of Materials Civil Engineering, pp. 227-232, 2007.
[14] Bhattacharya Sati N "Rheology Fundamentals and Measurement" chapter 1, Royal Melbourne Institute of Technology. Australia.1997.
[15] Guler M. "Effects of mix design variables on mechnaical properties of hot mix asphalt" Journal of Transportation Engineering March, pp 128-136, 2008.
[16] Huang Shin- Che "Rubber Concentrations on Rheology of Aged Asphat Binders" Journal of Materials in Civil Engineering March, pp 221-229, 2008.
[17] Yilmaz M. et al., "Effects of using asphaltite as filter on mechanical properties of hot mix" Construction and Building Materials, April, pp 1- 8, 2011.
[18] Cabrera,J.G and Dixon, J.R. "Performance of durability of bituminous material" Proceeding of Symposium, University of Leeds, March,1994.2