Stress-stain behavior, elastic modulus, and toughness of the soilcrete modified with powder polymers

Abstract

This article discusses the effect of two types of polymer on the stress–strain (σ–ε) behavior, elastic modulus and total toughness of soilcrete. Soilcrete properties modified with two types of polymer content up to 0.20% (% wt.) were tested. The σ–ε behavior of modified soilcrete with polymeric admixtures was examined for curing periods up to 28 days. Additional polymer content maintains the flowability of soilcrete with the range of 105 to 110% as recommended by ASTM C109, and the water/cement ratio (w/c) decreased by 14.5 to 25.5% with the addition of polymer. The compression strength of soilcrete increased by 72 to 153% when 0.20% of the polymer was added to the soilcrete, and therefore the compression toughness was increased with increasing polymer content. Modifying the soilcrete with polymer content increased the initial elastic modulus (Ei) of soilcrete by 55% to 195% according to polymeric admixture types, curing age (t), w/c, and polymeric admixture percent. With increasing polymer content, the soilcrete samples become brittle, and the strain at failure is reduced. Adding polymeric admixture creates an amorphous gel that fills the spaces between cement particles with working fibers net or meshes covering the sand particles, which cause a reduction in the voids, porosity and increasing the density of the soilcrete; subsequently, the mechanical properties significantly increased. The nonlinear Vipulanandan p-q model was employed to predict the σ–ε relationship of the modified soilcrete with polymer and was compared with the β model prediction. Statistical assessment tools were used to evaluate the compressive stress–strain models and nonlinear approaches to predict the compressive strength and the modulus of elasticity as a function of water/cement ratio, curing age, and amount of the polymers.