Experimental Study On The Resistance To Chloride Ion Permeability Of Basalt Fiber Reinforced Concrete

As a new kind of fiber reinforced concrete,compared with normal concrete,basalt fiber reinforced concrete shows good performances in aspects such as impact resistance and fracture energy.However,nowadays most studies are mainly on its mechanical properties,researches on its chloride penetration property are few,in this case,focus on the property of resistance to chloride ion permeability of BFRC,some experimental studies were operated in this paper.In this thesis,3 different types of BFRC were defined by using different concrete matrix.For type I,the binding material is common Portland cement while in type II,30% of cement was replaced with fly ash.In type III,based on the type II,5 percent of cement was replaced with silica fume.In each kind of BFRC,5 different basalt fiber volumes were used,which were 0.00%,0.15%,0.30%,0.45%,0.60%.Two different curing periods were set in all mixes.Cube compressive strength test,electric flux test,NEL test,micro-test(SEM experiment and Mercury injection experiment)were operated in this thesis.The Cube Compressive Strength Test results showed that with the increase of basalt fiber addition,the compressive strength of BFRC increased at first and then decreased.The compressive strength reached the maximum value when the basalt fiber volume content was 0.15%.The compressive strength of basalt fiber reinforced concrete was lower when fly ash was used,but with the increase of curing time,BFRC with fly ash showed a faster growth in compressive strength than normal BFRC.When fly ash and silica fume were compound added,BFRC showed obvious improvements in compressive strength and resistance to chloride ion permeability etc.Electric flus test results showed that with the increase of basalt fiber addition,the charge passed showed a uptrend.For the concrete with same basalt fiber volume content,the addition of fly ash and silica fume can reduce the charge passed obviously,when fly ash and silica fume were compound added the charge passed reached the lowest value.With the increase of curing time,BFRC with mineral admixtures(FA&SF)showed a faster decrease in charge passed than normal BFRC.The NEL method to measure the coefficient of chloride ion penetration of BFRC test results showed an excellent correlation with the electric flus test results.The micro-test(SEM experiment and Mercury injection experiment)results showed that the pore volume of BFRC was increased with the increment of basalt fiber volume addition,theaddition of fly ash and silica fume can improve the density degree of BFRC.