鋼渣土混拌基層材料試驗研究及微觀機理分析

黃偉 邱鵬 趙魯卿 唐鋼 王宗森

摘要：針對鋼渣用于基層材料易發生膨脹的問題，采用鋼渣、高爐礦渣微粉、土混拌并結合土體固化技術，制備道路基層材料鋼渣混合土。對16組不同配比土樣開展了擊實、膨脹率、無側限抗壓強度試驗。研究表明：鋼渣混合土最佳含水率受配比影響較小，均維持在12%～14%;最大干密度隨鋼渣摻量的減少而降低，隨高爐礦渣微粉摻量的增加而降低;高爐礦渣微粉的摻入可顯著降低鋼渣混合土膨脹率，提高其無側限抗壓強度;7、14、28、90 d無側限抗壓強度均隨鋼渣占比增加呈先增后減趨勢，配比為50%鋼渣、50%土時達到最大。微觀結構分析表明：土顆粒表面電荷的改變使得鋼渣混合土體結構在成型時更易受壓密實，鋼渣中游離氧化鈣（fCaO）在固化過程中的水化反應受到明顯抑制，主要與礦渣中二氧化硅（SiO2）發生消解反應生成水化硅酸鈣凝膠（C—S—H）;與此同時，鋼渣、土相互包裹的顆粒間堆疊效應及C—S—H凝膠填充混合料縫隙產生的自密實效應進一步提高了土體強度，從而制備出強度高、安定性好的鋼渣混合土。

關鍵詞：道路工程;鋼渣混合土;抗壓強度;膨脹抑制;最優配比

中圖分類號：TU411.3;U416.1 文獻標志碼：A 文章編號：20966717（2020）04004409

收稿日期：20191020

基金項目：安徽省高校自然科學研究重大項目（KJ2018ZD006）;安徽省住房城鄉建設科學技術計劃（2018YF007）

作者簡介：黃偉（1963 ），男，教授，主要從事道路材料研究，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試驗結果及討論

3.1擊實試驗

圖2是4組16個鋼渣混合土試件擊實試驗干密度含水率曲線測試結果。由……