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国内外对冻融循环与硫酸盐腐蚀耦合作用下沥青混凝土的性能鲜有研究。鉴于此,在10%Na2SO4溶液加速劣化条件下采用真空饱水冻融劈裂试验,以冻融腐蚀因子评价沥青混凝土在冻融与腐蚀耦合作用下的性能变化规律。试验结果表明硫酸盐腐蚀加剧了冻融循环对沥青混凝土的破坏作用。SEM微观分析表明硫酸盐溶液较水溶液更易于侵入沥青膜与集料界面及沥青混凝土空隙中,并在冻融条件下发生结冰膨胀导致界面强度降低和裂缝的产生与扩展是沥青混凝土性能衰减的主要原因。水镁石纤维具有优良的稳定效应、界面增强效应和加筋桥接效应,掺加水镁石纤维可以有效提高沥青混凝土抗冻融腐蚀性能。
Domestic and international research on the performance of asphalt concrete under the coupling of freeze-thaw cycle and sulfate corrosion. In view of this, the vacuum saturated freezing-thawing splitting test under the condition of accelerated degradation of 10% Na2SO4 solution was used to evaluate the variation of performance of asphalt concrete under the action of freeze-thaw and corrosion by the freeze-thaw corrosion factor. The test results show that sulfate corrosion aggravates the destructive effect of freeze-thaw cycles on asphalt concrete. SEM microscopic analysis shows that the sulphate solution is easier to invade into the bitumen membrane and aggregate interface and asphalt concrete voids than the aqueous solution, and the icing expansion under freeze-thaw condition leads to the decrease of interface strength and the generation and propagation of cracks, which is the attenuation of asphalt concrete performance main reason. Brucite fiber has excellent stability effect, interface enhancement effect and reinforced bridging effect. Adding brucite fiber can effectively improve the freeze-thaw corrosion resistance of asphalt concrete.