Experimental Study of Tensile Properties of Composite System of High Performance Concrete and Reinforcements

Abstract:

Ultra-high-performance concrete （UHPC） is known for its ultra-high strength， engineered cementitious composites （ECC） possesses high tensile strain-hardening characteristic， and fiber reinforced polymer bar （FRP bar） has the advantages of high tensile strength， low density， and good corrosion resistance. It is expected that the combination of high-performance matrix and high-performance reinforcement can solve the durability issue long-existed in civil engineering and maintain high strength simultaneously. In this paper， three kinds of matrix materials （normal concrete， ECC， and UHPC） and two kinds of reinforcements （steel and BFRP bar） were selected for fabricating six different composite systems. Tensile tests were conducted to obtain the tension-strain behaviors of the composite system for comparison. The test results indicate that the tensile properties of the composite system are affected by various factors. High-performance matrix can effectively enhance the tensile strength of the system， but the sustained tensile contribution and the strain-softening behavior after peak strength of high-performance matrix may bring premature failure to the system， thus reducing the ductility eventually. It is preliminarily demonstrated that the ductility of the composite system is determined by the components with a weaker deformability. In the design of the composite structural member made of high-performance materials， it is recommended that the individual properties of materials and the interaction between materials be comprehensively considered.

Key words:ultra-high ductility concrete;fiber reinforced polymer bar;composite system;tensile properties