Study the Behavior of High Performance Concrete Circular Short Columns Confined by CFRP

Abstract

This paper presents the results of experimental study on reinforced concrete columns rehabilitation with carbon fiber reinforced polymer (CFRP) under concentrated load. Twelve short circular reinforced concrete columns (150 mm diameter and 600 mm height) were tested. Three specimens were unstrengthening and tested until failure as control specimens. Nine specimens were rehabilitation by carbon fiber reinforced polymer after loading about 75% from ultimate axial load capacity of control specimens. The test parameters were the type of concrete are normal strength concrete (NSC), high performance concrete (HPC) and high performance concrete containing engine oil (HPCEO) in additional to effective the ratio CFRP confining (fall wrap (100%strengthening), 50mm strips wrap 50mm spacing (50%strengthening)and 40mm strips wrap-60mm spacing(40%strengthening)). Test results showed that Adding used engine oil to concrete have significantly effect on workability of concrete where work as plasticizer. HPCEO mix showed lower strength (compressive, splitting tensile and flexural) and ultimate axial load of column than those HPC mix but greater than NSC mix. Where the compressive strength of concrete was (27.3 MPa, 45.8 MPa and 69.7 MPa) for NSC, HPCEO and HPC respectively. The ultimate axial load capacity of unconfined reinforced concrete columns was (52 ton, 78 ton and 117 ton) for NSC, HPCEO and HPC respectively. Reducing efficiency of rehabilitation by CFRP with increasing in compressive strength of concrete. The ratios of increasing in ultimate axial load capacity of rehabilitation RC columns with 100% and 50% wrapping in comparison with 40%wrapping are 20% and 4% respectively for NSC, while these ratios become 15% and 5% respectively for HPCEO and for HPC , these ratios are 10%and 3% respectively.

Keywords

• rc columns
• carbon fiber reinforced polymeric composites (cfrp)
• strengthening systems
• type of material