Transformation and utilization of agricultural waste as component of green concrete for rural housing and development schemes

Abstract: Several researchers have outlined cost saving and cement blending merits without compromising standards. As such, utilizing artificial pozzolana as supplementary cementitious materials (SCMs) in concrete engineering is well known. However, there is continual search for substitute materials. The use of Rice Husk Ash (RHA) as cementitious constituent in green concrete was studied. Its abundance paved way for the study to look into the compressive strength of the concrete type formed by partly substituting Ordinary Portland Cement (OPC) with RHA under short curing series. Analysis on RHA revealed significant properties of pozzolanic hardening. 60 cubes of 100 mm dimensions were cast with cement replacement by RHA ranging from 0-40% while adopting a 28 day targeted strength of 25 MPa as control. The cubes were cured at relative humidity (RH) of 95-100% and temperature (T) of 22-250C in a chamber for periods of 7, 14, 21 and 28 days. The outcomes displayed trends of strength gain, reduced density and compressive strength with increase in RHA. The 28 days density and strength of the normal concrete was 2465 kg/m3 and 28.57 MPa while the 10% RHA sample (i.e. best substitute matrix) had 2398 kg/m3 and 25.97 MPa respectively. The strength of 10% RHA/OPC concrete (25.97 MPa) was slightly higher than the adopted strength (25 MPa) at 28 days. This signifies its suitability as concrete constituents and can be a major cost reduction factor in rural shelter projects where less structural complexities are required. Hence, it can be employed in the construction of simple foundations and concrete composites