EFFECT OF SILICA NANOPARTICLES ON THE PERFORMANCE OF SORGHUM HUSK ASH AND CALCIUM CARBIDE WASTE BINDER BASED MORTAR

ABSTRACT

Research trends in the construction industry is toward the application of nano materials in mortar/concrete which could act as set accelerator due to the ultrafine nature of silica nano_particles (SNPs). The study is aimed at investigating the effect of SNPs on the performance of Sorghum Husk Ash (SHA) and Calcium Carbide Waste (CCW) binder based mortar with a view to establishing its suitability. SHA was an incinerated ash from agro-by-product of sorghum husk with major component of amorphous silica (SiO2) when combined with calcium carbide waste (CCW) an industrial by-product from an acetylene gas production process with major component of lime (CaO) in the presence of water to forms compounds possessing cementitious properties. Assessment of mortar in fresh state, early-age strength development and hardened properties were carried out. Pastes from different binder 70/30 (SHA_CCW) containing 0.5% to 5% at 0.5 step interval of SNPs. The water-to-binder ratio (w/b) and High Range Water Reducer Admixture (HRWRA) was optimized at 0.5 and 1.5% respectively by mass of binder. With a normal mix of 1:3 binder/sand, samples were studied for flowbility, air content, setting times, degree of hydration, water absorption, abrasion resistance and compressive strength was also determined at ages (3, 7, 14, 28, 56 and 90 days). Mortar samples with 3.0% (SNPs), exhibited better performance at 28 days with compressive strength value of 7.45 N/mm2 representing 137% of 70/30 (SHA_CCW) strength and 90 days with compressive strength value of 9.01 N/mm2 representing 134% of 70/30 (SHA_CCW) strength. SNPs (3.0%) and SHA_CCW (70/30) in 1:3 binder/sand mortar at 0.5 w/b with 1.5% water-reducing admixture is recommended for use in masonry work as it conforms to class N mortar of ASTM C270.