The impact of red clay brick and perlite wastes on the reusability of katoite-based binder after exposure to elevated temperatures.

• Katoite (KT) binder is fabricated by mixing dolomite powder with sodium aluminate. • Both KT and unreacted dolomite powder completely decomposed at 1000 °C. • Thermally-exposed KT powder can be rehydrate to yield layered-double hydroxide. • Using silicate waste powder enhanced firing resistance but inhibit the rehydration. This study investigated the effect of red-clay brick and perlite wastes (RCBW and PW) on the performance and rehydration of katoite-based binder after exposure to elevated temperatures. The KT-binder was produced by combining dolomite waste with sodium aluminate. The exposure of KT binder to temperatures up to 1000 °C (CA-1000) caused a significant compressive strength loss associated with the decomposition of KTand other phases into mayenite, sodium aluminate, and lime. The CA-1000 acts as a one-part alkali-activated binder, as it can re-interact with water to yield a layered double hydroxide-based binder with 1-day compressive strength of 9.7 MPa and volume expansion of 160%. The individual inclusion of 50 wt% RCBW and PW improved the thermal resistance of the CA-binder but decreased its ability to rehydrate, as they hindered the reformation of sodium aluminate and mayenite through the formation of lower hydraulic calcium/sodium aluminosilicates. [ABSTRACT FROM AUTHOR]