Experimental Study on the Dynamic Mechanical Properties of Fiber-Reinforced Concrete
|School||Harbin Institute of Technology|
|Keywords||PFRC SFRC strain rate dynamic increase factor damage constitutive model|
Fiber-reinforced concrete is a sort of composite material based on concrete, which uses the fiber as the reinforce material. Nowadays, the fiber-reinforced concrete becomes one of the research focuses for its superior mechanical properties. The research on fiber-reinforce concrete are carried out both at home and abroad. Compared with research on the static mechanical properties, there are fewer studies on the dynamic mechanical properties. In this paper, the dynamic mechanical properties of two kinds of fiber reinforced concrete-Steel Fiber Reinforced Concrete (SFRC) and Polypropylene Fiber Reinforced Concrete (PFRC) were studied by the tests of 105 cylindrical specimens using MTS Electro-hydraulic Servo System. The PFRC with different polypropylene fiber content volume rate(0.067%, 0.1%, 0.133%) and the SFRC with different steel fiber content volume rate (0.75%, 1.0%, 1.33%) were tested and analyzed under the 0.000145 s-1~ 0.1 s-1 strain rate. The result shows that the fiber-reinforce concrete is very sensitive to the strain rate. The conclusions are described as follows:The strength and toughness of concrete can be improved to some extent with polypropylene fiber or steel fiber, and increase with the fiber content increasing. The peak stress, peak strain and toughness of concrete increase along with strain rate increasing, and the sensitivity of strain rate of fiber-reinforced concrete is more obvious than plain concrete. The strain-rate effect of PFRC and SFRC were studied systematically, the functional relationships among dynamic growth factor, peak strain and toughness with stain rate were set up under the uniaxial compression experiments of two kinds of fiber-reinforced concrete.In order to analyze fiber-reinforcement-effect on elastic modulus of concrete , 21 prism specimen’s elastic modulus were tested in this paper, it was found that the concrete’s elastic modulus could be enhanced a small amount by polypropylene or steel fiber, and raise along with the fiber content increasing.Based on damage theory, the stress-strain curve got from experiment is analyzed in order to study the effect of material strength and mechanical properties by fiber content. Further more, a damage softening constitutive model is set up in which the effect of fiber reinforcing and strain-rate hardening are considered.