Cementitious composites with glass waste from recycling of cathode ray tubes

Cathode ray tubes (CRTs) glass waste with a high lead concentration can be used as supplementary cementitious material in mortars based on portland cement and slag cement, as well as for the partial replacement of the solid component in alkali activated slag/fly ash binders. The values of cumulative lead released at 64 days, assessed by monolith leaching test NEN 7345, were below the emission limit stipulated in current legislation and consequently the mortars can be used without environmental restriction. The substitution of the active binding component (cement, slag or fly ash) with CRT glass waste decreases the rate of hardening processes, but due to its high fineness, the CRT glass waste powder exerts also a filler effect which can compensate the compressive strength reduction. Compressive strengths of mortar specimens cured in different conditions (air or water with different pH values) were assessed in order to evaluate their possible use as building materials.