Preparation and mechanical properties of polypropylene fiber reinforced calcined kaolin-fly ash based geopolymer

Abstract

To improve the environmental benefits and solve the problems of large shrinkage and high brittleness, the partial replacement of calcined kaolin by fly ash as a raw material for geopolymer synthesis and the influences of polypropylene (PP) fiber on the mechanical properties and volume stability were investigated. The results show that compressive strength of the geopolymer containing 33.3%(mass fraction) fly ash by steam curing at 80 °C for 6 d is improved by 35.5%. The 3-day compressive strength, flexural strength and impacting energy of geopolymers containing 0.05%PP fiber increase by 67.8%, 36.1% and 6.25%, while the shrinkage and modulus of compressibility decrease by 38.6% and 31.3%, respectively. The results of scanning electron microscopy (SEM) and the appearances of crack growths confirm that PP fiber can offer a bridging effect over the harmful pores and defects and change the expanding ways of cracks, resulting in a great improvement of strength and toughness.

Keywords

polypropylene fiber / calcined kaolin / fly ash / geopolymer / preparation / mechanical properties

References

[1] ProvisJ. L., LukeyG. C., van DeventerJ. S. J.. Do geopolymer actually contain nanocrystalline zeolites? A reexamination of existing results [J]. Chem Mater, 2005, 17: 3075-3085

[2] SwanepoelJ. C., StrydomC. A.. Utilisation of fly ash in a geopolymeric material [J]. Applied Geochemistry, 2002, 17: 1143-1148

[3] DivyaK., RubinaC.. Mechanism of geopolymerization and factors influencing its development: A review [J]. J Mater Sci, 2007, 42: 729-746

[4] RahierH., WastielsJ., BiesemansM., WillemR., van AsscheG., van MeleB.. Reaction mechanism, kinetics and high temperature transformations of geopolymers [J]. J Mater Sci, 2007, 42(9): 2982-2996

[5] YangN.-r., ZengY.-wei.. Research and development of chemically-activated cementing materials, necessity and feasibility [C]. Research Progress in Chemically-Activated Cementing Materials, 2005, Nanjing, Southeast University Press: 1-14

[6] DuxsonP., Fernández-JiménezA., ProvisJ. L., LukeyG. C., PalomoA., van DeventerJ. S. J.. Geopolymer technology: the current state of the art [J]. J Mater Sci, 2007, 42: 2917-2933

[7] PhairJ. W., van DeventerJ. S. J., SmithJ. D.. Effect of Al source and alkali activation on Pb and Cu immobilisation in fly-ash based “geopolymers” [J]. Applied Geochemistry, 2004, 19(3): 423-434

[8] SumajouwD. M. J., HardjitoD., WallahS. E., RanganB. V.. Fly ash-based geopolymer concrete: Study of slender reinforced columns [J]. J Mater Sci, 2007, 42: 3124-3130

[9] ZhangY.-s., SunW., LiZ.-jin.. Impact behavior and microstructure characteristics of PVA fiber reinforced fly ash-geopolymer boards prepared by extrusion technique [J]. J Mater Sci, 2006, 41: 2787-2794

[10] DiasD. P., ThaumaturgoC.. Fracture toughness of geopolymeric concretes reinforced with basalt fibers [J]. Cement and Concrete Composites, 2005, 27: 49-54

[11] ZhaoQ., NairB., Rahimian, BalaguruP.. Novel geopolymer based composites with enhanced ductility [J]. J Mater Sci, 2007, 42: 3131-3137

[12] ZhuH.-j., YaoX., ZhangZ.-hua.. Optimum activated temperature of kaolin [J]. J Cent South Univ Technol, 2007, 14(S2): 131-134

[13] DavidK., JijiB., Martinau, et al.. Preparation, structure and hydrothermal stability of alternative (sodium silicate-free) geopolymers [J]. J Mater Sci, 2007, 42: 9267-9275

[14] BrandtA. M.. Fibre reinforced cement-based (FRC) composites after over 40 years of development in building and civil engineering [J]. Composite Structures, 2008, 86: 3-9

[15] PereraD., UchidaO., VanceE., FinnieK. S.. Influence of curing schedule on the integrity of geopolymers [J]. J Mater Sci, 2007, 42: 3099-3106