Constitutive Relationship Of Hybrid Fiber Reinforced Cement-based Composites

In modern society,with the development of economy and the progress of science and technology,the world construction industry has made continuous development and innovation,many new techniques have been applied to the construction industry,people pay more attention to building life cycle,strengthen technology development and innovation,promotion and application of new technology,new materials,new equipment,new technology,to maximize resource conservation to reduce energy consumption,energy saving,water saving,material saving and environmental protection.This requires the emergence of excellent new building materials to meet the needs of the actual project,so as to achieve the durability of buildings and low-carbon environmental protection.Therefore,the research of new materials is very important,and fiber reinforced cement based composites will emerge as the times require.Fiber reinforced cement based composite is a kind of hardened water formed by hydration and hardening of cement and water A composite material made of a mixture of fibers or hybrid fibers as reinforcing material.It is in the ordinary cement-based materials mixed with randomly uniform fibers,after adding fiber,fiber and prevents the inhibitory effect on the propagation of micro cracks;improve the composite tensile strength,crack resistance,impermeability and frost resistance,impact resistance and other mechanical properties.This also means that it can be applied to practical engineering in a variety of complex environments.In this paper,the influence of blending of three element copolymer fiber and PVA fiber on the properties of cement-based composites is studied.Two different water binder ratios were designed and the water binder ratio was 0.42 and 0.37 respectively.At the same time,12 different fiber contents were designed to make hybrid fiber cement matrix composites.The experimental results show that the incorporation of hybrid fiber can significantly improve the mechanical properties of cement based composites,improve the axial compressive strength of cement-based composite materials,and enhance the ductility of cement-based composites.Through the analysis of the test data of the cylinder of different water binder ratio,content and different fibers and different fiber types of these three factors,the compressive strength of cement composites under epitaxial compression peak stress peak strain.Through the analysis of stress strain curves of uneasily compression,hybrid fiber reinforced cementations composites can be seen in comparison with the cement based composite materials and the incorporation of a fiber cement composites,hybrid fiber reinforced cementations composites stress-strain curve of the descending stage shows better ductility.Through the test data of stress-strain curve,data fitting effect of different fiber content on the compressive strength and peak strain,referring to non linear elastic theory of concrete epitaxial compression constitutive model,fitting stress-strain curve of ascending and descending segment expressions given compressive strength and the change of fiber volume fraction of hybrid fiber reinforced cementations composites under uneasily compression based on stress strain constitutive model.The research results provide some reference value for the theoretical study of hybrid fiber reinforced cement-based composites in the future.