DAODU, Hannah Omokhowa

This project work was created in order to highlight and present the findings froma studyon the "EFFECT OF IMPROPER CURING ON THE STRENGTH ANDTRANSPORTPROPERTIES OF LOW GRADE RICE HUSK ASH (RHA) CONCRETE" withthegoal of understanding how various curing techniques for 3, 7, 14 and 28 days affect theachievable compressive strength and other structural properties of a lowgrade concretesuch as 20MPA having Ordinary Portland Cement (OPC) (an agriculturally basedpozzolanic material, lying in abundance around the globe most times as waste, foundsuitable by researchers to partially replace OPC in the production of concrete). After designing a low grade concrete mix with a goal mean strength of 20N/mm2, anumber of concrete mixtures cast into 100mm metallic cubes were made in the labusingOPC as the binder (partially substituted with RHA at various percentages). Inafog/curing room with ambient temperatures between 30 and 20 °C and lowrelativehumidity (RH), three different types of "curing methods" (a moisture management balancing act) were used for these samples. The first series of cubes cast after demoulding were fully submerged in water and cured at 100% RH for the durationof itscuring period (signifying wet curing). The final set of cubes cast were completelycuredout in open air without any water submerging after demoulding (signifying dry/air curing), while the other set of cubes stayed in water for 3 days after demouldingas well and then continued to cure for the remaining curing period at a relatively lowhumidity. Therefore, performance was assessed in terms of compressive strength, transport properties, and other tests conducted. It was found that while the strength of RHAconcrete continued to decline after the addition of 15% RHA, the replacement level of 5% RHA gave the strongest results overall and demonstrated the greatest potential tobeused as a useful material for various building materials. The partial replacement of RHAwith OPC can be seen to have a positive impact on the environment by reducingtheamount of agricultural waste produced, which results in more cost-effective andenvironmentally friendly concretes than those currently used in the industry.