USING RICE HUSK ASH AND CDW IN STANDARD CONCRET

In major Indian cities there is a surge in construction and demolition waste (CDW) quantities causing an adverse effect on the environment. The use of such waste as recycled aggregate in concrete can be useful for both environmental and economic aspects in the construction industry. This study discusses the possibility to replace natural coarse aggregate (NA) with recycled concrete aggregate (RCA) in structural concrete. An investigation into the properties of RCA is made using crushing and grading of concrete rubble collected from different demolition sites and under construction roads locations around Neelbad Bhopal. Aggregates used in the study were: natural sand, dolomite and crushed concretes obtained from different sources. Groups were designed to study the effect of recycled coarse aggregates quality/content, cement dosage, use of superplasticizer. Tests were carried out for: compressive strength, flexural strength and workability. The results showed that the cement in concrete can be replaced by cow dung ash up to 10%. Concrete rubble could be transformed into useful recycled aggregate and used in concrete production with properties suitable for most structural concrete applications. A significant reduction in the properties of recycled aggregate concrete (RAC) made of higher percentage RCA was seen when compared to natural aggregate concrete (NAC), while the properties of RAC made of a blend of 60% NA and 40% RCA showed not much significant change in concrete properties.