黄伟 邱鹏 赵鲁卿 唐钢 王宗森

摘要：針对钢渣用于基层材料易发生膨胀的问题，采用钢渣、高炉矿渣微粉、土混拌并结合土体固化技术，制备道路基层材料钢渣混合土。对16组不同配比土样开展了击实、膨胀率、无侧限抗压强度试验。研究表明：钢渣混合土最佳含水率受配比影响较小，均维持在12%～14%;最大干密度随钢渣掺量的减少而降低，随高炉矿渣微粉掺量的增加而降低;高炉矿渣微粉的掺入可显著降低钢渣混合土膨胀率，提高其无侧限抗压强度;7、14、28、90 d无侧限抗压强度均随钢渣占比增加呈先增后减趋势，配比为50%钢渣、50%土时达到最大。微观结构分析表明：土颗粒表面电荷的改变使得钢渣混合土体结构在成型时更易受压密实，钢渣中游离氧化钙（fCaO）在固化过程中的水化反应受到明显抑制，主要与矿渣中二氧化硅（SiO2）发生消解反应生成水化硅酸钙凝胶（C—S—H）;与此同时，钢渣、土相互包裹的颗粒间堆叠效应及C—S—H凝胶填充混合料缝隙产生的自密实效应进一步提高了土体强度，从而制备出强度高、安定性好的钢渣混合土。

关键词：道路工程;钢渣混合土;抗压强度;膨胀抑制;最优配比

中图分类号：TU411.3;U416.1 文献标志码：A 文章编号：20966717（2020）04004409

收稿日期：20191020

基金项目：安徽省高校自然科学研究重大项目（KJ2018ZD006）;安徽省住房城乡建设科学技术计划（2018YF007）

作者简介：黄伟（1963 ），男，教授，主要从事道路材料研究，Email：hwpsagd@163.com。

Received：20191020

Foundation items：Major Projects of Natural Science Research of Anhui Universities （No. KJ2018ZD006）; Anhui Housing Urban and Rural Construction Science and Technology Program Project （No. 2018YF007）

Author brief：Huang Wei （1963 ）， professor， main research interest： road materials， Email： hwpsagd@163.com.

Experimental study and micromechanism analysis of steel slagsoil mixed road base material

Huang Wei1， Qiu Peng1， Zhao Luqing2， Tang Gang1，Wang Zongsen2

（1.School of Architectural Engineering， Anhui University of Technology， Maanshan 243002， Anhui， P. R. China;2.Anhui Magang Jiahua New Building Materials Co.， Ltd.， Maanshan 243000， Anhui， P. R. China）

Abstract： In view of the problem that steel slag is prone to expand in base material， steel slag， blast furnace slag micropowder and soil were mixed to prepare a road base materialsteel slag mixed soil using soil solidification technology. The compaction， expansion rate and unconfined compressive strength tests were carried out on 16 soil samples with different mixture ratios. The results show that the optimum moisture content of the steel slag mixed soil is little affected by the mixture ratio， which maintained at 12～14%. The maximal dry density decreases with steel slag content， and decreases as the content of blast furnace slag micropowder rises. Blast furnace slag micropowder could significantly reduce the expansion rate of steel slag mixed soil and increase its unconfined compressive strength. The 7 d， 14 d， 28 d and 90 d unconfined compressive strength of steel slag mixed soil are firstly increase then decrease with steel slag content， and the strength reaches the maximum value when the mixture ratio is 50% steel slag and 50% soil. Microstructural analysis shows that the change of surface charge of soil particle enhance the compactness of steel slag mixed soil in molding process. The hydration reaction of fCaO in the steel slag was inhibited during solidification， and which conduct digestion reaction with SiO2 in the mineral slag to form hydrated calcium silicate gel （C—S—H）. At the same time， interparticle stacking effect between steel slag and soil and selfcompacting effect produced by C—S—H gel could enhance strength of steel slag mixed soil， and thus steel slag mixed soil with high strength and stability is prepared.

3试验结果及讨论

3.1击实试验

图2是4组16个钢渣混合土试件击实试验干密度含水率曲线测试结果。由……