PROPERTIES OF QUANTENARY BLENDED CEMENT MORTAR CONTAINING RICE HUSK ASH, CALCIUM CARBIDE WASTE AND METAKAOLIN

Abstract

ABSTRACT In order to reduce carbon dioxide (CO2) emissions and increase the strength and durability of mortars/concrete in the cement industry, the use of pozzolanic materials has received increased interests in the last decades. Hence, with a view to producing a PC blended mortar with low carbon foot-print and also cut cost, this study presents three supplementary cementitious materials (SCMs), that were used to produce quaternary binders; Rice Husk Ash (RHA), Calcium Carbide Waste (CCW) and Metakaolin (MK) as partial replacement of Portland Cement (PC). To investigate and evaluate the combinations of the (SCMs) for optimal level of replacement as blending agent in cement, the materials were blended together in a varied combinations proportion of 5 %, 10 %, 15%,20 %, 25% and 30% of PC. RHA were employed for the blended mortar mix in all the mixes prepared. The properties of cements was investigated, their effects on standard consistency, setting times (initial and final), compressive strength and splitting tensile was evaluated. At the fresh state, the flow (workability) and the consistency of mortar mixtures were determined, while at the hardened state, the compressive strength and splitting tensile at the ages of 7, 21, 28, 56 and 90 days were evaluated. Test results showed that RHA significantly influenced the standard consistency of the quaternary binders as compared with CCW and MK. Water demand in the paste increases with increase in RHA content within the paste due to its porous nature as both the initial and final setting time was increased due to their combinations than in Portland cement mortar mix. The compressive and the splitting tensile strength properties of the mortar comparatively improved with rice hush ash, metakaolin and calcium carbide waste. The effect of the SCMs on consistency and setting times in quaternary binder is retardation of the setting time which can be overcome by activation. With the combined use of MK, RHA and CCW results revealed improvement in low early compressive strength development was overcome. Test results also revealed that the compressive strength of mortar cubes also increased as the RHA increased relative to the other pozzolan percentage in the mixes. Therefore, the combination of RHA, CCW and MK could be used as a supplementary cementitious material at 15% percentage replacement to produce cement-based material of higher quality of low carbon foot print.