Calcined paper mill lime mud as an activator in GGBFS-based cementless UHPC

Abstract

This study investigates the potential use of calcined lime mud as an activator in the development of a sustainable, ground granulated blast furnace slag (GGBFS)-based cementless UHPC. The effects of the calcination temperature (550 °C to 850 °C) of lime mud and its weight percentage in the UHPC mixture were evaluated with various tests, such as compressive strength, isothermal calorimeter, and thermogravimetric analysis. Microstructural changes and pore size distribution were also analyzed using XRD, FTIR, and MIP. The results showed that calcined lime mud can be an effective activator in the UHPC mix, and its mechanical properties are influenced by the calcination temperature and weight percentage. The addition of 10% calcined lime mud enhanced the compressive strength of the UHPC up to 150 MPa without negatively affecting its microstructural and hydration characteristics, suggesting that calcined lime mud has the potential to be used as a sustainable alternative to CaO in GGBFS-based cementless UHPC.