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 investigate 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 load 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.
