Systematic characteristic evaluation of clay-based cementitious material derived from calcium carbide residue and...

Clay-based cementitious materials with high performance and low carbon emissions have gained considerable interest in recent years. This study develops a new marine soft clay-based cementitious material derived from calcium carbide residue (CCR) and waste tile powder (WTP). Systematic characterisation is conducted through macro- and micro-scale tests, including unconfined compressive strength (UCS) testing, orthogonal experiments, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The UCS of specimens under varying influence factors (WTP content, temperature, CCR content and curing time) was evaluated. Furthermore, stress-strain behaviour, failure strain, liquid and plastic limits, microstructure and carbon footprint were investigated. Experimental results reveal that CCR and WTP promote strength improvement. When 17% CCR and 15% WTP are mixed with clay, the 28-d strength reaches 2210.19 kPa. The optimal proportions of NaOH, WTP and CCR are 14%, 14% and 0.8%, respectively, as determined by orthogonal experiments. SEM-EDS results indicate that cementitious products are clearly observed with the addition of WTP and CCR. The microscopic mechanism is also discussed. This research demonstrates that the clay-based cementitious system derived from CCR and WTP is an environmentally friendly material with excellent properties, providing a new approach for solid waste recycling.