Effect of recycled aggregates and steel fibers on flexural and shear behavior of reinforced normal concrete beams

Abstract EN

Concrete wastes are generally delivered to the landfill sites for disposal.

Due to increase charges of landfill and shortage of natural coarse aggregate (NA), recycled coarse aggregate (RA) (resulting from concrete wastes) is growing interest in Building Engineering.

It is sustainable to use recycled construction materials to preserve the natural resources and maintain the environmental of cities.

In the present study, RA was used as a full replacement of NA in some specimens of beams to produce normal concrete (NC).

The experimental work consists of casting and testing eight rectangular simply supported reinforced concrete beams of (1200*180*250) mm with concentric point load as well as tests for control specimens to determine the mechanical properties of NC.

Four of each eight beams for flexural and the other four beams for shear behavior.

The present research also includes the following main variables: transverse reinforcement (stirrups spacing, 50 mm and 100 mm), coarse aggregate (RA and NA) and steel fibers of (Vf = 0.5%).

All beams have constant longitudinal steel reinforcement ratio=0.008.

Experimental results have generally showed that ultimate loads (Pu) of beams made with RA are approximately close to the results of beams made with NA by percentages (6.2% and 10.1%) for flexural and shear behavior respectively.

RA can be used as a full replacement in the future construction industry.

The presence of steel fibers increases the maximum deflection of beams by 38.55% for flexural and 31.70% for shear