Study on rheological property, volumetric deformation, mechanical strength and microstructure of mortar incorporated with waste glass powder (WGP)

Abstract

To achieve a much better utilization the medium and small particle size of WGP, this study investigated the effect of WGP with different particle sizes (6.63 μm, 18.33 μm, 30.15 μm and 49.38 μm) and replacement ratios (3.0 %, 6.0 %, 9.0 %, 12.0 % and 15.0 %), as the supplementary cementitious materials, on the performance of the mortar. First, the rheological properties of the fresh mortar was evaluated by using Bingham model, Modified Bingham model, and H-B model; Second, the autogenous shrinkage and dry-wet cycling deformation of the hardened mortar were monitored; Finally, the micromorphology, weight loss and crystalline structure of hydration products were analyzed by SEM, TG and XRD. The results show that, for the fresh mortar with WGP, Modified Bingham model is more suitable for estimating the yield stress (τ0) and H-B model is more appropriated to interpret the plastic viscosity. As the averaged diameter of WGP increased, the yield stress (τ0) emerged a reversed S-shaped variation tendency; the flow index (n) remains relatively minor scatter and change slightly, ranging from 0.6 to 0.88; the plastic viscosity varied with a little fluctuation with the scope of 4.0 Pa·s to 5.94 Pa·s. The contents of the WGP had great influences on the autogenous shrinkage of the mortar, the tremendously change mainly taken placed in the rapidly increase stage; with the condition of same WGP content, the particle size of the WGP has a minimal impact on the autogenous shrinkage; under the drying and wetting cycle environment from 28 days to 140 days, the deformation rate changed in a way of sinusoidal wave. The addition of WGP can further reduce the heat of hydration of the hardened cement paste, and the rate of hydration heat peaked at about 20 h, there is no reaction occurred for 49.38 μm WGP with calcium hydroxide (CH).