Compressive Strength of RAC Cylinders Cast with Recycled Aggregates from Different Structural Members

Abstract

In this research study, the effect on the compressive strength of recycled aggregate members is presented. Demolished waste was collected from five different structural members. Hammering was used to reduce the aggregate size to a maximum of 1 inch. Using a 1:2:4 mix and 0.5 w/c ratio, 55 cylinders in 11 batches were prepared for each source of coarse aggregates. Additionally, one batch of cylinders was prepared with conventional concrete and its results were compared with the others. Altogether, 280 cylinders of standard size were prepared and cured for 28 days. The compressive strength of all specimens was determined in a universal testing machine. The optimum replacement percentage with the least reduction in compressive strength was found to be 35%. Column concrete contributed most to compressive strength with a reduction equal to 6.23%, whereas beam concrete caused a 6.9% reduction. Further, a comparison for mixed aggregates by taking the average of all sources was conducted. It showed that 35% replacement was also the optimum with a reduction in strength equal to 8.63%.

Keywords

• recycled aggregates
• demolishing waste
• parent concrete strength
• structural members
• compressive strength
• green concrete