Improvement on the properties of waste glass mortar with nanomaterials

Nowadays, nano materials were proved to be able to improve the properties of mortar, especially for recycled mortar with poor properties. In this study, nano-silica (nS) and nano-clay (nC) were used in waste glass mortar, with an additional amount of nS or nC varied from 0% to 6% of binder content by weight. Waste glass cullet was used as fine aggregate to fully replace natural sand in waste glass mortar. The properties of fresh and hardened waste glass mortar with or without nS/nC, including the early stiffening, flowability, density, compressive and flexural strength, shrinkage and alkali-silica reaction, were experimentally examined in this study. In addition, the pore size distribution of waste glass mortar was studied by using the mercury intrusion porosimetry test to build the relationship between microstructure and macro properties. The results show that nC has a greater effect on the early stiffening and flowability of mortar than nS. The defining pore structure and denser microstructure lead to the higher density and mechanical properties of mortar with nS/nC. nC is more beneficial for improving the 28-day compressive strength of glass mortar at a very small amount, whereas, the effect of nS on the strength at early ages of glass mortar is clearer. The incorporating use of 1% nS/nC have similar effect on suppressing the drying shrinkage but quite different influence on the ASR expansion. The additional use of 1% nS can increase the ASR expansion of glass mortar while 1% nC suppressed the expansion by 43.6% at 28-day. (C) 2020 Published by Elsevier Ltd.