Road Performance Of Composite Fiber Cement Concrete Experimental Research

Cement concrete pavement is one of the most important pavement structure,In the research of composite fiber cement concrete,fiber can be divided into high elastic modulus fiber and low elastic modulus fiber.At present,there are many research results on the composite of low modulus chemical fiber,high modulus metal fiber and chemical fiber,but the composite effect of high modulus metal fiber and cellulose is rarely studied.In this paper,the composite fiber cement concrete were prepared by C50 concrete,steel fiber and cellulose fiber.And study the performance and mix design by used the composite fiber cement concrete.The mechanical properties such as compressive/flexural strength,splitting tensile strength,compressive modulus of elasticity and so on were tested and verified by SEM scanning.The durability tests such as impermeability,wear resistance,frost resistance and fatigue performance tests were carried out,and the following results were obtained:1)SEM scanning shows that cellulose fiber and steel fiber are distributed in the concrete,which can combine with the matrix well.According to their different properties,different fibers can improve the performance of cement concrete from different levels.2)In the basic mechanical properties:the addition of fibers makes the mechanical strength of concrete to a certain extent,and the compressive strength increase is not very obvious.The composite effect of composite fiber can be better reflected in the mechanical test,and the improvement of the mechanical strength index is better than that of the single-mixed fiber.Among them,S-UF3 composite fiber concrete has the most superior mechanical properties.In addition,UF fiber(Cellulose fiber)has more effect on the strength of concrete than SF fiber(Steel fiber)in the later stage,which can promote the hydration of cement concrete in the later stage.3)In terms of durability,the average seepage height of S-UF composite fiber concrete is lower than that of single fiber concrete,and the impermeability of concrete is improved by the composite effect of fiber.UF fiber is better than SF fiber in improving the wear resistance of concrete,and S-UF4 has the best wear resistance.After 100 cycles of freeze-thaw,the relative dynamic modulus of elasticity and mass of S-UF3 composite fiber concrete decrease the least,and the composite fiber can improve the freeze-thaw damage of concrete.4)In terms of fatigue life,under the stress ratio of 0.6,both S-UF3 and SF2 have reached 2 million times of fatigue strength life.But at the stress ratio of 0.7 and 0.8,the fatigue strength of S-UF3 is increased by 12.59%and 14.45%respectively compared with SF2.It can be seen that the composite fiber has a better effect on inproving the fatigue strength of concrete.