Replacing Coarse Aggregate by Ethiopian Rift Valley Scoria Aggregate in Structural Concrete; A Case study in Wolaita sodo

Abstract

Although scoria is found abundantly in Ethiopian rift valley, its use so far has been limited to highway construction as base course and mortal aggregate in masonry constructing and for the production of hallow concrete blocks. Scoria, which can replace aggregate, has not been used in reinforced concrete constructions. This may be attributed to lack of sufficient technical data necessary for structural design. The availability of scoria in large quantities where aggregate is scarce and expensive can have significant reduction in cost in concrete construction. The main objective of this study was to i nvestigate the benefits and effects of structural concrete using scoria aggregate in structural concrete. Five different types of mixes were used for compressive strength , flexural strength and dry unit weight of C- 25 grade concrete tests by mixing 100%, 75%, 50%, and 25% ratios of scoria as coarse aggregate and 100% basaltic aggregate. The results of this investigation indicated that the required compressive strength was achieved by replacing 100% scoria aggregate as normal basaltic aggregate for C- 25 grade of concrete. It is advisable to use scoria aggregate in order to reduce the dead lo ad of the structure since concrete produced by scoria was light - weight. Further the use scoria as coarse aggregate in the study area will reduce the construction cost significantly.