Research On Constitutive Relation Of Micro Steel Fiber Reinforced Cement-Based Composite Materials

With the rapid development of modern science and technology, construction industry around the world has also been a huge leap forward. Because of its national conditions, China is still a country in the primary stage of socialism. In such an environment, the construction of a large number of national infrastructure and a wide range of urbanization are the inevitable demand of the whole country and society. The contradiction between increasingly urgent need of excellent engineering materials and ordinary building materials cannot meet the actual working conditions is becoming more and more prominent so that the research of new building materials is imminent. Due to the involvement of the fibers of random distribution, cement-based composite materials arises at the historic moment. Compared with the ordinary cement-based materials, the strength of the cement-based composite materials did not decrease when the ductility of the material and other mechanical properties greatly improve. This means that it will be applicable to various complex conditions of the construction conditions, especially in the seismic performance. At present, many experts and scholars have already conducted the research on it. This paper will on the basis of previous studies and choose a different ratio of length to diameter of the micro steel fiber composite so that the further research on the mechanical properties of steel fiber cement matrix composites and constitutive relations can be get. In this paper, the diameter of two kinds of micro steel fiber is 0.2mm and their length are 13mm (ratio of length to diameter is 65) and 6mm (ratio of length to diameter is 30). By designing 3 different water binder ratio (0.39,0.35,0.23) and 4 different fiber content (0,1%,2%, 3%) to make different blocks which test cubic compressive strength, splitting tensile strength, peak stress, peak strain and constitutive relations. Through the block performance test, it is concluded that the relation between cubic compressive strength and fiber content, the relation between cubic compressive strength and the ratio of length to diameter, the relation between the improve rate of cubic compressive strength and water-binder ratio; the relation between splitting tensile strength and fiber content, the relation between splitting tensile strength and ratio of length to diameter, the relation between the improve rate of splitting tensile strength and the water-binder ratio; the relation between peak stress and fiber content, the relation between peak stress and ratio of length to diameter; the relation between peak strain and fiber content, the relation between peak strain and the ratio of length to diameter.In the end constitutive relation can be get.