使用水泥、赤泥与钢渣综合处治软土的试验研究

Experimental Study on Comprehensive Treatment of Soft Soil with Cement,Red Mud and Steel Slag

赤泥与钢渣是冶金工业中大量产生的固体废弃物,如无法高效利用,会造成环境问题和土地问题。提出一种由水泥、赤泥和钢渣组成的复合软土固化剂,该固化剂利用赤泥的高碱性和水泥水化产生的碱性环境激发钢渣的活性,并利用赤泥增补体系中的活性铝酸盐成分。通过无侧限抗压强度试验发现,当固化剂中的水泥、赤泥和钢渣比例为50∶25∶25时,经该复合固化剂固化的软土强度达到了水泥固化土的88.8%。通过压汞试验研究固化土微观性质发现,随着水泥、赤泥和钢渣比例的变化,固化土中的孔隙分布也发生了变化:水泥固化土中的大孔隙、中孔隙相对含量最少;当固化剂中水泥、赤泥和钢渣比例为50∶25∶25时,经其固化的固化土比固化剂中水泥、赤泥和钢渣比例为50∶15∶35时的固化土中的大孔隙、中孔隙相对含量少,因而导致了固化土强度的变化。通过XRD(X射线衍射)谱图发现∶固化剂中水泥、赤泥和钢渣比例为50∶25∶25时,水化反应最为彻底。将这种固化剂应用于地基加固中,既实现了废弃物的再利用,又可以减少地基加固中水泥的用量,节约成本,具有良好的经济效益和环境效益。

Red mud and steel slag are the solid waste massively produced in metallurgical industry.Their low utilization has caused serious environmental and land problems.A composite curing agent composed of cement,red mud and steel slag are proposed.The activation of steel slag is excited by the alkali environment produced by red mud and cement hydration.Meanwhile,activated aluminate is provided by red mud.According to unconfined compression test,when the ratio of cement,red mud and steel slag is 50∶25∶25,the strength of the composite curing agent to solidify soft soil reaches 88%of that of cement stabilized soil.According to mercury injection test,the pore size distribution varied with the proportion of cement,red mud and steel slag.The solidified soil with cement,red mud and steel slag ratio of 50∶25∶25 contains less large and middle pores than that with cement,red mud and steel slag ratio of 50∶15∶35,which leads to the change of strength.XRD(X-ray diffraction)spectrum shows that when the proportion of cement,red mud and steel slag in the curing agent is 50∶25∶25,the hydration reaction is the most through.The application of the curing agent realizes the recycling of waste and decreases the cement used in ground improvement,save costs,leading to a positive economic and environmental effect.