Sulfate Dry-wet Circulation Basalt-Polypropylene Fiber Reinforced Concrete Beams Under Flexural Performance Study

The basalt and polypropylene fibers were mixed into C40 concrete with different volume ratios(0.05%,0.1%,0.2%)and different mixing ratios(1:1,1:2,2:1)to make a total of 14 test pieces and accompanying test blocks.Among them,10 samples and accompanying test blocks were subjected to 10 times of sulfate dry-wet cycle erosion.The influence of fiber content and hybrid ratio on concrete resistance to sulfate attack is analyzed from two aspects of basic mechanical properties of materials and flexural properties of components.Material aspects of the standard cube compressive strength,splitting tensile strength,axial compressive strength and elastic modulus of four aspects carries on the analysis,The results show that the properties of concrete are improved by adding fiber in the natural state,but the improvement effect is not as significant as that after sulfate corrosion.After 10 times of sulfate dry and wet cycles,the maximum standard cube compressive strength was increased by about 24%,64% for splitting tensile strength,and about 14% for axial compressive strength and elastic modulus.Therefore,adding proper amount of fiber into concrete can improve its resistance to sulfate attack.Component of 14 root bending performance test specimens,from the failure characteristics,the cracking moment,ultimate bending moment,steel bar strain,deflection and deformation characteristics of six aspects,The influence of different fiber content and hybrid ratio on sulfate resistance was compared between the natural environment and the wet and dry cycle of sulfate.The results show that the failure characteristics of the specimens are basically the same before and after corrosion.In the natural environment,the cracking bending moment of the fiber is increased by 20% at the highest,the ultimate bending moment by about 8%,and the displacement ductility coefficient by 3%.So adding appropriate fiber concrete specimen to improve its resistance to sulfate erosion ability.By conducting bending tests on fiber reinforced concrete beams under different environments,the influences of fiber content,hybrid ratio and sulfate dry-wet cycle erosion on cracking moment values of specimens were analyzed,The cracking moment calculation models of basalt-polypropylene hybrid fiber concrete beams under different conditions are established.The results show that the maximum relative error between the calculated value and the test value is only 8.8%,so the calculated model results are reliable.