Feasibility of Design One-Part Sodium Silicate Activated Metamontmorillonite-Limestone Cements

Abstract

In this study, the potential of calcined montmorillonite as a primary precursor for one-part alkali-activated cement incorporated with high percentage of limestone, is evaluated. Comparative studies on the properties of the sodium silicate activated metakaolin-limestone and metamontmorillonite-limestone fresh and hardened cement pastes depending on several formulation and processing parameters (precursor nature, dosages of limestone and alkali reactant, curing conditions) showed that metamontmorillonite exhibits reactivity comparable to that of metakaolin in the studied cement systems. The mechanical performance of optimal alkali-activated cement formulations consisted of 20-30% of metamontmorillonite and 70-80% of limestone is provided by both reactivity of metamontmorillomite under sodium silicate activation and the filler, nucleation, and chemical effects of the raw limestone. The reaction products and microstructures of alkali-activated metamontmorillonite-limestone cement-based hardened pastes were investigated using thermal, XRD, and SEM/EDS analyses.

Keywords

• metakaolin
• metamontmorillonite
• alkali
• cement