干湿交替机制下PVA纤维增强混凝土抗硫酸盐侵蚀性能试验研究

Experimental study on sulfate corrosion resistance of PVA fiber reinforced concrete under alternate wetting and drying mechanism

为增强混凝土抗硫酸盐侵蚀性能,对PVA纤维混凝土进行干湿交替作用下硫酸盐侵蚀试验,选择浓度为5%的硫酸盐溶液,并采用干湿交替机制侵蚀PVA纤维混凝土,每15次干湿交替测试试件质量、抗压强度、劈裂抗拉强度、相对动弹性模量,最后运用SEM扫描微观结构分析了侵蚀机理。结果表明:各组试件的试件质量、抗压强度、劈裂抗拉强度、相对动弹性模量均随干湿交替的进行呈现先增长后降低的趋势;PVA纤维能够在一定程度上提升混凝土的抗硫酸盐侵蚀性能,延缓硫酸根离子对混凝土的侵蚀,提高混凝土的承载力和变形能力,改善其内部结构;适量的纤维掺入混凝土对其在硫酸盐侵蚀环境中干湿交替作用下的力学性能有一定的提升,劣化程度有所降低,但过量纤维掺入反而有不利影响;PVA纤维最佳掺量为2.0 kg/m^(3)。

In order to enhance the concrete sulfate attack resistance,dry wet alternation of PVA fiber concrete under the action of sulfate erosion test,select a concentration of 5%sulfate solution and USES the erosion of PVA fiber concrete dry-wet alternate mechanism,each 15 dry-wet alternate test specimen quality,compressive strength,splitting tensile strength,relative dynamic elastic modulus.Finally,the mechanism of erosion was analyzed by SEM scanning microstructure.The results show that the mass,compressive strength,splitting tensile strength and relative dynamic modulus of each group increase first and then decrease with the alternation of wetting and drying.PVA fiber can improve the sulfate corrosion resistance of concrete to a certain extent,delay the sulfate ion erosion of concrete,improve the bearing capacity and deformation capacity of concrete,improve its internal structure;an appropriate amount of fiber incorporation in concrete can improve the mechanical properties of concrete under the action of wetting and drying alternately in the sulfate erosion environment,and the deterioration degree is reduced to a certain extent.However,excessive fiber incorporation in concrete has adverse effects.The optimal content of PVA fiber is 2.0 kg/m^(3).