硫酸盐-干湿循环侵蚀环境下纤维沥青混合料低温抗裂性研究

Low-temperature Crack Resistance of Fiber Reinforced Asphalt Mixture Under Sulfate and Dry-wet Circle Corrosion Environment

基于国内外对硫酸盐腐蚀环境下纤维沥青混合料的低温抗裂性鲜有研究的现状,采用干湿循环作用下不同浓度(5%、10%)Na2SO4溶液加速劣化试验,研究了水镁石纤维沥青混合料在Na2SO4腐蚀介质中的低温抗裂性变化规律,并与聚酯纤维和玄武岩纤维沥青混合料进行对比;探索了沥青混合料硫酸盐腐蚀损伤机理及纤维在混合料中的阻裂作用。研究结果表明:与纯净水环境相比,沥青混合料在盐蚀环境下的低温抗裂性能劣化程度更为严重;Na2SO4溶液渗入沥青混合料空隙和裂缝中发生的结晶型侵蚀是导致沥青混合料低温抗裂性劣化的主要诱因;水镁石纤维具有优良的增强增韧效应,可以有效提高沥青混合料在硫酸盐腐蚀环境下的低温抗裂性。研究成果可为硫酸盐富集地区沥青混合料材料组成设计提供参考。

In order to investigate the regularity of the low-temperature crack resistance of brucite fiber asphalt mixture under the action of sulfate corrosive medium, a series of accelerated deterioration tests through dry-wet cycles were con- ducted in Naz SO4 solution with different concentrations including 5 % and 10%,along with the eomparsion of polyester fi- ber asphalt mixture and basalt fiber asphalt mixture. Then the sulfate corrosion damage mechanism of asphalt mixture and the role of fiber＇s crack resistance in asphalt mixture were discussed. The experimental results indicate that the attenua- tion of low-temperature crack resistance of asphalt mixture in sulfate solution is more severe than that of being in purified water. The attenuation of the low-temperature crack resistance of asphalt mixture is mainly caused by the Na2SO4 crystal corrosion after the solution permeates the voids and cracks in the asphalt mixture. The brucite fiber has good reinforcing and toughening effect, which can improve effectively the low-temperature crack resistance of asphalt mixture in sulfate corrosion environment. It can be referred to the material component design of asphalt mixture in sulfate enrichment re- gions.