Abstract:

Conservation of natural resources and rapid urbanization has prompted growing demand for natural aggregate by construction industry. This demand is compounded by considerable decline in the availability of good quality natural aggregate and enormous increase in quantities of demolished concrete. This report presents a study of mechanical properties of concrete made by using the demolished concrete as coarse aggregate in addition to steel fibers.. In the concrete mixes the ratios of concrete aggregate range from 0% to 100% with the increment of 25% the ratio of steel fiber was 6% of whole mix volume. Three concrete mixes have been prepared with proportion of 1:2:4, the water cement ratio was 0.5. The essential mix was control mix without steel fiber for comparison, the other mixes with or without steel fibers with different proportion of recycle concrete aggregate. The mixes were casted in standard specimens, cylinders and cubes and tested under static loading The specimens were tested for compression strength and splitting tensile strength. This research shows that increasing recycle concrete aggregate will decrease the compressive strength and splitting tensile strength but adding steel fibers will increase these strengths. The recycled concrete aggregate with steel fiber are found to make a good quality concrete therefore recycle concrete aggregate can be used successfully for structural concrete instead of natural aggregate .

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