Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite

The cement industry plays a significant role in contributing to global carbon dioxide emissions, representing a considerable portion of the total environmental impact. In response to growing environmental concerns, supplementary cementitious materials such as calcined clay and limestone have gained prominence due to their abundance and reduced carbon footprint. Among these, Limestone Calcined Clay Cement (LC3) has emerged as a promising sustainable alternative to ordinary Portland cement (OPC). This study investigates the feasibility of utilizing locally available non-kaolinitic clayey soil in the development of LC3-based binders. The research was conducted in two phases: initially, the optimum calcination temperature, substitution level of calcined clay, and calcined clay-to-limestone ratio (CC:LS) were determined, yielding optimal values of 650°C, 30%, and 2:1, respectively. Subsequently, the optimal binder compositions were reinforced with recycled sheep wool (Wl) and polypropylene (PP) fibers at varying dosages of 0%, 0.5%, 1%, and 1.5% by binder weight. Fresh mortar flowability was assessed, followed by evaluation of mechanical properties including compressive strength, flexural strength, and splitting tensile strength. Durability parameters such as fire resistance, water absorption, water sorptivity, and porosity were also examined. The results indicated that fiber additions of 1.5% Wl and 1% PP offered the best balance of mechanical performance and durability. However, increasing fiber content consistently reduced flowability. Overall, the findings demonstrate the viability of using locally sourced clayey soil as a pozzolanic material in LC3 production and highlight LC3 potential as a sustainable structural material.