Performance of Carbide Lime Waste Mortar via 24 Hours Accelerated CO2 Curing

Abstract

This paper examined the use of Calcium Lime Waste (CLW) as a cementitious material for early CO₂ capture. CLW is mostly Calcium Hydroxide (Ca(OH)₂) with high CaO concentration, excellent for CO₂ capture. Ordinary Portland Cement (OPC) mortar contained CLW (0-40%) direct substitutions were investigated under physical properties (workability and density), mechanical properties (compressive strength) and CO₂ capturing properties (carbonation thickness and CO₂ uptake by Thermogravimetric Analysis (TGA)) and porosity properties (Mercury Intrusion Porosimetry (MIP)) within the first 24 hours of accelerated carbonation curing, compared to control sample. Results indicated that 30% was the optimum mix based on the workability, CO₂ capture and strength. TGA showed the carbonation converted Ca(OH)₂ to CaCO₃. MIP indicated that CLW increased mortar porosity and reduced pore size relative to the control mortar. The study shows CLW can act as an effective CO₂ absorbent towards sustainable development of the construction industry by reusing industrial waste and sequestering CO_2.