Energy efficient Cementitious Material : an option for low cost housing schemes

Abstract: Energy efficient and cost saving cement alternatives have been identified for use by researchers without compromising standards. The utilization of artificial pozzolanas as Cementitious Materials (CMs) in cement chemistry and engineering is widely known. Nevertheless, there is continual search for optional and greener substitutes. The use of Rice Husk Ash (RHA) as CM was studied. The abundance of RHA and the need for low cost shelter triggered this investigation looking into chemical composition of the generated ash and the compressive strength of the concrete type produced by partly replacing Ordinary Portland Cement (OPC) with RHA under short hydration periods. 60 cubes of 300 mm dimensions were cast with cement substituted by RHA ranging from 0-40%, adopting 28 day targeted strength of 25 MPa as control. Specimens hydrated at relative humidity (RH) of 95-100% and temperature (T) of 22-25 0 C in a chamber for 7, 14, 21, and 28 days. Results revealed trends of strength gain and reduced density with increase in RHA. The 28 day density and strength of the control specimen was 2465 kg/m3 and 28.6 MPa while the 10% RHA sample (i.e. best replaced matrix) had 2398 kg/m3 and 26.0 MPa respectively. The strength of 10% RHA/OPC product (26.0 MPa) was slightly higher than the adopted strength (25 N/mm2) at 28 days. This can serve as cost saving means in rural housing schemes with less structural demands