Early-Age Properties of of Sorghum Husk Ash and Calcium Carbide Waste Binder in Mortar

Abstract

Portland cement is a binder that is most commonly used as construction material in the production of mortar in masonry and concrete. The manufacturing of cement during clinker production is however noted to contribute to CO2 emmisiion which makes it non-environmental friendly material. Nothwithstanding, report on total replecement of PC are scarce in literature. Sorghum husk ash (SHA) which is an incinerated ash from agricultural by-product consisting majorly of amorphous silica (SiO2) when combined with calcium carbide waste (CCW), an industrial by-product generated from an acetylene gas production process with major component of lime (CaO) in the presence of water forms compounds possessing cementitious properties. This paper reports on early-age properties of SHA (as SiO2 source) and CCW (as CaO source) binder in mortar. Paste from different binder combinations of SHA/CCW were studied for setting time while the mortar samples were tested to study the rate of hydration and strength development. The study revealed the SHA sample to be of high SiO2 (84%) and CCW which is majorly CaO (66% content).The result obtained shows improvement in the performance of the binders with superplastizer formulated from 70/30, 60/40 and 50/50 SHA/CCW respectively, having 28days compressive strength of 7.6N/mm2 [MPa], 7.0 N/mm2 [Mpa] and 5.3 N/mm2 [MPa] representing 36%, 34% and 28% of cement type I (CEM I) strength. The study showed that addition of Sperplasticizer reduced the water demand and improved the rate of hydration.The binder combination of 70/30, 60/40, and 50/50 SHA/CCW with water reducing agents can be adopted for used in masonry works as it comforms to type N of ASTM C270 mortar.