改性钢渣沥青混合料的水稳定性

Water stability of modified steel slag asphalt mixture

针对钢渣遇水膨胀和钢渣沥青混合料(steel slag asphalt mixture,SSAM)水稳定性不足的问题,采用SiO_(2)胶体溶液制备改性钢渣,测试改性钢渣的物理性能、体积膨胀率并研究改性机理;将改性钢渣替代粗集料(4.75~16 mm)制备改性钢渣沥青混合料(modified steel slag asphalt mixture,MSSAM),评价其体积稳定性和水稳定性。结果表明:钢渣经过改性后,各项物理性能均有所改善;SiO_(2)胶体溶液可在钢渣表面形成改性保护层,增强改性钢渣的整体性能,其中质量分数为2%的SiO_(2)胶体溶液改性钢渣可将体积膨胀率降至1.75%,满足规范要求;在浸水120 h后,MSSAM的体积稳定性比SSAM提高了53.9%;冻融循环15次后,相较SSAM,MSSAM的劈裂强度比(tensile strength ratio,TSR)提高了12.67%,具有更优的水稳定性。

In view of the expansion of steel slag in water and the insufficient water stability of steel slag asphalt mixture(SSAM),the modified steel slag was prepared with SiO_(2) colloidal solution,and the physical properties,volume expansion rate and modification mechanism of the modified steel slag were tested.Modified steel slag asphalt mixture(MSSAM)was prepared by replacing coarse aggregates(4.75-16 mm)with modified steel slag.The volumetric stability and water stability were evaluated.The results show that all physical properties of the steel slag are improved after modification.SiO_(2) colloidal solution forms a modified protective layer on the surface of the steel slag to enhance the overall performance of the modified steel slag.The volume expansion rate of the steel slag modified by 2%mass fraction of SiO_(2) is reduced to 1.75%,meeting the specification requirements.The volumetric stability of MSSAM is increased by 53.9%compared to SSAM after 120 h of immersion in water.After 15 freeze-thaw cycles,the tensile strength ratio(TSR)of MSSAM is increased by 12.67%compared to SSAM,providing a better water stability.