ABSTRACT
Recycled aggregate concrete is a kind of concrete which uses recycled materials, usually referred to aggregate from demolished buildings, to replace natural aggregate for cost effectiveness and environment sustainability. Recycled concrete aggregate is a construction material produced by demolishing and crushing previously cast concrete.
This study aimed at evaluating the effect on the strength and water absorption of pre-treating recycled concrete aggregates with sulfuric acid and water. The study was carried out in the Civil Engineering Laboratory facility in University of Benin. Ordinary Portland cement with a specific gravity of 3.15 and surface area of 23540 cm/g was used, crushed granite from local quarry, coarse aggregates were also used. The second type of aggregate was obtained by treating the sieved recycled aggregates with sulfuric acid and water. After the concrete materials were mixed properly with concrete mixer and poured into a mould, a total of 75 concrete cubes were casted.
Laboratory tests such as compression test, sieve analysis, slump test and water absorption test were conducted on the samples. The average compression strength for each duration of curing (7, 14, and 28 days) were recorded. Water absorption test was conducted for 3 samples of each mix and the cubes were dried in the oven for six hours. The result of the experiment showed that maximum compressive strength of the samples decreased on increase in partial replacement of natural aggregates, but water absorption of the pre-treated recycled concrete aggregates with sulfuric acid reduced.
