Effect of High Strength Concrete Prepared from Recycled Aggregates on the Behavior of Reinforced Concrete Beams Under Flexure

Abstract

Experimental study of the flexural implementation of high-strength reinforced recycled aggregate mixture is investigated for 100 × 150 × 1000 mm beams of reinforced concrete with different coarse recycled aggregate ratios plus three steel reinforcement ratio (ρ) casting and testing at 28 days. The aim of this research is to use coarse recycled aggregate ratios as a natural coarse aggregate replacement by (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100%) in high strength concrete. Former investigations experiments have been carried out and provided on the characteristics of the mixture prepared with recycled aggregates, such as strength in compressive, workability, flexural tensile strength, and splitting tensile strength. Prism and cylinders have been prepared, and specimens have been tested at ages 7, 14, 28 days of curing. This investigation considers the flexural efficiency of reinforced recycled aggregate mixture beams in describe as cracking and ultimate flexural strength, and load-deflection correlation, the moment at mid-span, and ductility and failure modes. Results show that 100% recycled coarse aggregate degrades the concrete strength relevant to 18.0, 18.9, and 19.3%, 16.2, 16.6, and 19.4% and 16.0, 16.2, and 18.2% in expression of compressive, splitting and flexural strength with tensile for 7, 14 and 28 days, reduces the workability by 33.3% and decreases the cracking and ultimate load with the improved rate of recycled coarse aggregate regarding of 39.4 and 45.1% and 10.9% for ductility for the beams with ratio of reinforcement of ρ=0.0157%. Decreasing the reinforcement ratios with ρ=0.0105 and 0.0067% while keeping the strength of concrete constant 100% recycled coarse aggregate decreases the cracking and ultimate load of about 11.3 and 20.8% and 15.6 and 24.4% respectively and 2.0 and 4.3% for ductility.