Properties of mortar prepared with recycled cathode ray tube funnel glass sand at different mineral admixture

With rapid advances in the electronic industry, the management of cathode ray tube (CRT) glass waste has become a major environmental problem. In this study, 25% Ordinary Portland cement was replaced by Fly ash (FA) or Ground granulated blast-furnace slag (GGBFS), the crushed CRT funnel glass sand untreated with nitric acid (n-TFG) was used to replace river sand fine aggregate of 0%, 25%, 50%, 75% in the mortar. The fresh, mechanical properties of the mortar were studied, the alkali-silica reaction (ASR) expansion, drying shrinkage and leaching of lead from mortar were evaluated. The test results showed, the use of n-TFG glass sand improves fresh properties of the mortar. The mortar with n-TFG glass sand has higher mechanical properties than control mortar. At the drying shrinkage period of 56 days, drying shrinkage of nearly all the mortar with n-TFG glass sand are higher than the limit of 0.075%. ASR expansion of the mortar are found to be below 0.1% at 14 days tested age, except the mortar with GGBFS and 75% n-TFG glass sand. The lead leaching from mortar with n-TFG glass sand was reduced comparing the content of the leachable lead from n-TFG glass sand. Moreover, at a given replacement level of n-TFG glass sand, FA series mortar has better fresh properties, a lower wet density, mechanical properties, drying shrinkage, ASR expansion and the leaching of lead than GGBFS series mortar.