卤水侵蚀下高延性混凝土力学性能试验及强度衰减模型研究

Experimental study on mechanical properties and strength degradation model of high ductile concrete under brine erosion

为了研究高延性混凝土(HDC)在卤水侵蚀作用下的基本力学性能变化规律,以3种氯盐溶液(5%,10%和15%NaCl溶液)和3种卤水溶液(5%NaCl+5%Na_(2)SO_(4),5%NaCl+10%Na_(2)SO_(4)和10%NaCl+5%Na_(2)SO_(4)溶液)为侵蚀介质,对HDC试件进行卤水长期浸泡(共360d)试验,分析了不同浓度的卤水溶液长期浸泡下HDC试件抗压和抗折强度随浸泡时间的变化规律。试验结果表明:卤水溶液的侵蚀现象较单一氯离子溶液明显,其中5%NaCl+10%Na_(2)SO_(4)卤水溶液的侵蚀最严重;在整个浸泡过程中,HDC试件质量均出现先降低后上升的变化趋势;单一侵蚀溶液中HDC试件的抗压及抗折强度均出现先增长后降低趋势,卤水溶液中则无侵蚀前期的强度上升阶段,随着硫酸盐浓度的增加,HDC试件损伤劣化速度变快,且氯离子浓度越高,延缓越明显。通过回归分析建立了卤水长期侵蚀HDC试件强度衰减模型。

In order to study the basic mechanical properties of high ductility concrete(HDC) under brine erosion, three chloride solutions(5%, 10% and 15% NaCl solution) and three brine solutions(5%NaCl +5%Na_(2)SO_(4),5%NaCl+10%Na_(2)SO_(4) and 10% NaCl + 5% Na_(2)SO_(4) solution) were used as corrosive media. The HDC specimen was subjected to long-term immersion in brine test(360 d). The variation of HDC specimens compressive strength and flexural strength with soaking time under different long-term immersion of brine solution were analyzed. The test results show that: the erosion phenomenon of brine solution is more obvious than that of single chloride solution, and the erosion of(5% NaCl + 10% Na_(2)SO_(4)) brine solution is the most serious. During the whole soaking process, the quality of HDC specimens decreased first and then increased. The compressive strength and flexural strength of HDC specimens in single etching solution increased first and then decreased. In the brine solution, there was no intensity rising stage in the early stage of erosion. With the increase of sulfate concentration, the degradation rate of HDC specimens damage became faster, and the higher the ion concentration, the more pronounced the delay. Through regression analysis, a long-term erosion HDC intensity attenuation model of brine was established.