Experimental Study On Durability Of B-PP HFRC And Analysis Of Durability Evaluation Method

In this paper, This set of experiments include five kinds of series of21experimentalgroups of fiber reinforced concrete，through mixing in the basalt fibers and polypropylenefibers with a single blending and the different ratio of blending ways and0.3%,0.6%,0.9%,1.2%volume mixing ratio in the ordinary C30concrete matrix. the experimental research andmechanism analysis have been done, which are about basic mechanical properties, resistanceto water permeability, frost resistance, corrosion resistance to sulfates and so on. The resultsshowed that:Basalt fibers, polypropylene fibers and the series hybrid fibers reduce the compressivestrength of the concrete base in different degree, but greatly improve the splitting tensilestrength and flexural strength of the concrete base. Among them, the hybrid fiber series isbetter than single-doped fiber series.Impermeability of the concrete can be greatly enhanced after the fibers are mixed in theconcrete base. the single-doped Polypropylene fibers series has greatly improvedimpermeability of the concrete base, so that resistance to water penetration properties of thebasic concrete is improved by14.6%when the single-doped Polypropylene fibers is about0.6%, which is the best. Besides, resistance to water penetration properties of the concretebase is improved by25%when the2:1series hybrid fiber is about0.3%Basalt fibers, polypropylene fibers and their hybrid Fiber Series have significantlyenhance the effect of the mass loss and strength loss of the concrete base, in the process of50times,100times,150freeze-thaw cycles. In the process, the best experiment series about theimprovement of the strength loss are ratio of0.3%of1:1fiber hybrid fiber series,0.3%of2:1fiber hybrid fiber series,0.6%of2:1fiber hybrid fiber series. What,s more, in the process, thebest experiment series about the improvement of the mass loss is ratio of about0.6%ofPolypropylene Series single-doped fiber reinforced concrete,0.9%of1:1hybrid fiberseries,0.3%of1:1hybrid fiber series. From the overall analysis: hybrid fiber series are betterthan the single-doped fiber series in the improvement of the mass loss and strength loss in theprocess of concrete anti-freeze-thaw cycles. Basalt fibers, polypropylene fibers and theirhybrid fiber series have greatly enhance corrosion resistance to sulfate in the different instarsof the concrete matrix. The most significant experiments of improving compressive strengthcorrosion factor are ratio of0.6%of1:1hybrid fiber series in the7d and14d of the concreteinstars, and0.3%of1:2hybrid fiber series in the28d of the concrete instars. Consequently,Basalt-polypropylene fiber concrete is better than single-doped fiber reinforced concrete inaspects of sulfate resistant to corrosion.Through researching and analyzing the concrete durability and evaluation methods athome and abroad, based on the "durability of concrete evaluation system," advocated byProfessor Yi cheng, China University of Mining, contacting real environment coupling factors in the affecting of the durability of concrete, in view of a certain relationship between thedurability of concrete and the concrete permeability, the new evaluation system has beenbuilt,which is named for "the comprehensive evaluation system with the concreteimpermeability evaluating the durability.". In this paper, combining with the research resultsof the basalt-polypropylene fiber concrete durability, the functional relationship have beenfitted out, which is about the compressive strength corrosion factor of the basalt-polypropylene fiber reinforced concrete in the process of100freeze-thaw cycle strength lossand7d sulfate corrosion resistant. On this basis, the specific function formula has beenestablished through evaluating the durability of basalt-polypropylene fiber concrete from theperspective of impermeability.