Analysis And Application And Anti-deformation Performation Of Fiber Reinforced Cement Concrete

Concrete is brittle and its compressive strength is much higher than its bending strength.In order to increase its toughness,polypropylene fiber and steel fiber are added in order to increase its bending strength,increase its durability,reduce the thickness of road surface and save resources.The basic mechanical properties of polypropylene concrete and steel fiber concrete were studied.The suitable content of polypropylene fiber and steel fiber were determined by considering the reinforcement coefficient and mixing coefficient.The flexural strength of polypropylene concrete,steel fiber concrete and plain concrete,as well as the increase of flexural strength of different steel fiber contents were compared,and the strengthening mechanism was analyzed.At the same time,the fatigue performance of concrete was studied and the fatigue equation was formulated.The correlation and significance with stress level were tested.Finally,the structural combination of different types of concrete pavement is designed to check and test the stress in the limit state,and the results are analyzed.The results show that the toughening effect of steel fiber is more obvious than that of polypropylene,and the toughening effect tends to decrease with the increase of fiber content,and the optimum steel fiber content is about 0.7%.Among them,the most obvious increase of index I5 is SS-7 concrete(211.71%),while the most obvious increase of index I10 and I20 is LS-7 concrete(291.89% and 415.32%,respectively).And the frost resistance of steel fiber concrete is improved obviously.Macroscopically speaking,the fatigue failure process of fiber rein forced concrete starts from the generation of cracks,then widens until the complete failure;plain concrete,on the other hand,is brittle.The fatigue life of plain concrete,polypropylene fiber concrete and steel fiber concrete is steel fiber concrete > polypropylene fiber concrete > prime concrete.When the load stress level is 0.8,the fatigue life of LS-7 concrete is 17.6 times longer than that of plain concrete.The intercept and slope of fatigue equation of LS-10 concrete are higher than that of plain concrete.By comparing the frost resistance,it can be found that the flexural strength of LS-7 concrete before and after freezing-thawing decreased by 11.4%,while the flexural strength of LS-7 concrete only decreased by 10.4% before and after freezing-thawing.Compared with plain concrete,LS-7 concrete had better frost resistance.After regression fitting,the correlation coefficient of plain concrete and SS-7 concrete reached above 0.99,showing a strong negative correlation.Except for LS-10,all of them showed a "very negative correlation",while LS-10 showed a strong negative correlation,while the regression effect of fatigue equation of LS-7 was not obvious.