Role of Low-cost Nano RHA on Physico-mechanical Properties of Cement Mortar

THIS WORK compares nano-structured rice husk ash (RHA) before grinding and nano-sized RHA after grinding in terms of the physical properties of cement and mortar performance. Blaine surface area, sieve analysis (45 mu m mesh), water of consistency, expansion, initial and final setting time, and compressive strength (at 2, 7, 28, 60 and 90 d of curing) measurements were performed for 0, 2, 4, 6, 8 and 10% RHA replacement of cement by weight. RHA both before and after grinding enhanced the cement physical and mechanical properties, as well as the mortar performance in terms of the long-term aged strength, at a constant water/cement ratio and without the use of any type of super-plasticizer (SP). The enhancement became stable at all long-term ages for 10% replacement in the case of RHA before grinding and 4% replacement in the case of RHA after grinding. More considerable enhancements were observed with a high replacement percentage up to 10% nano-sized RHA due to the small size of its particles, which increased the pozzolanic reactivity and worked as a filler material to produce a denser mortar.