Effect of calcium chloride on the hydration characteristics of ground clay bricks cement pastes

Effect of CaCl2 on the hydration characteristics of the different cement pastes using ordinary Portland cement (OPC) and blended Portland cement with ground clay bricks (GCB) was studied. Various mixes were prepared using a water/solid ratio (W/S) of 0.25 (by weight). Three percentages of CaCl2 (0.25, 0.5 and 0.75%) are used; the CaCl2 used was dissolved in the mixing water. The hydration characteristics were tested via the determination of the combined water content, phase composition, compressive strength, total porosity (P%) and X-ray diffraction analysis (XRD) at different time intervals up to 180 days. The results showed that calcium chloride accelerates cement hydration in all systems studied. Ten % GCB in the presence of 0.50% CaCl2 is the optimum ratio which has the higher compressive strength.