Experimental Research On Carbonation Resistance Of Basalt Fiber And Shrinkage Compensating Concrete With Chloride Salt

With the wide use of concrete,concrete durability problems have become increasingly prominent.In order to improve the durability of concrete,the basalt fiber and HCSA expansive agent were added into the concrete,and the chloride salt was used to simulate the corrosion of the concrete in the seaside.In the test,the chloride salt content was 1kg/m3,2 kg/m3,3 kg/m3 and 4 kg/m3,respectively.The amount of HCSA expansive agent was 8%,10%and 12%,respectively.The basalt fiber content was 0 and 3 kg/m3,respectively.There were 56 groups of compressive and tensile strength test in total.The parameters of carbonation test of concrete were selected according to the results of compressive and tensile strength,and five groups of carbonation tests were designed.The test results of basalt fiber and shrinkage compensating concrete with chloride salt on compressive and tensile strength showed that the compressive and tensile strength of concrete increased with the increase of the amount of chloride under the same content of basalt fiber and expansion agent.Compared with plain concrete,when the chloride dosage is 4kg/m3,the concrete compressive strength values in the chlorine salt concrete,shrinkage compensating concrete containing chloride salt,basalt fiber shrinkage compensating concrete containing chloride salt were increased to 23.6%,25.1%and 26.4%respectively,the splitting tensile strength values were increased to 4.8%,8.8%and 31.3%respectively,so it can be seen that the addition of basalt fibers,the improvement of the splitting tensile strength of concrete is greater than its compressive strength-In addition,when the expansive agent content is 8%,the compressive strength of concrete is best,mainly because the content of 8%expansion agent can effectively improve the micro cracks of internal concrete,so as to improve the compactness of concrete,which can enhance the value of the compressive strength of concrete.The test results of basalt fiber and shrinkage compensating concrete with chloride salt on carbonation test results showed that compared with plain concrete,when the chloride salt content and expansive agent content and basalt fiber content were 4 kg/m3,29.6 kg/m3 and 3 kg/m3 respectively,not only the compression-tension strength character of concrete,but also the anti carbonation ability all achieved the best condition.At the same time,when the concrete carbonation age was 3 d,7 d,14 d and 28 d respectively,the carbonation resistance of the test block was increased by 12.9%,19.7%,7.2%,and 5.8%respectively,compared with the plain concrete.When the carbonating period was 28 d,the minimum carbonation depth is 8.46 mm.Early carbonation rate of concrete is higher than the latter carbonation rate,because early concrete carbonation reaction can generate a large number of carbonized products of CaCO3,which will be attached to the concrete hydration products of Ca(OH)2 surface,thereby reducing the concrete carbonization rate.