Study of the use of LC3 cements containing different calcined clays and fillers

Abstract

To mitigate CO₂ emissions from cement production, supplementary cementitious materials (SCMs) are increasingly being explored as substitutes for Portland Cement (PC), such as calcined clay, a key component of LC³ (calcined limestone clay cement). This study evaluates the properties of LC³ mortars, in fresh and hardened state, using three types of calcined clays with different kaolinite contents and replacing the limestone filler with ornamental stone residues (OSW) to improve workability and eco-efficiency. The mortars were mechanically tested in both states and their eco-efficiency was evaluated. The compressive strength of calcined clay mortars decreased from 10% to 55% compared to the reference, except for the clay mixture with 72% kaolinite. The flexural strength decreased from 8% to 28%. Blends with OSW showed better results than those with limestone, improving compressive strength by up to 36% and reducing porosity through pore refinement. LC³ demonstrates greater eco-efficiency than traditional cement, despite slight reductions in mechanical strength.