石油焦灰渣-矿粉用作泥浆固化剂的试验研究

Experiment study on petroleum coke desulfurization slag and mineral powder as mud solidifying agent

以石油焦灰渣、矿粉复合用作泥浆固化剂制备固化土,对固化土的浆液工作性能、力学强度以及抗冲刷性能进行了试验研究,对比了石油焦灰渣-矿粉和水泥、石灰的固化效果,分析了石油焦灰渣-矿粉的固化机理。结果表明,石油焦灰渣-矿粉的固化效果弱于水泥,但明显强于石灰;其固化土浆液的扩展度随着石油焦灰渣掺量的增加而增大,当石油焦灰渣掺量为20%时,浆液凝结时间最短,初、终凝时间分别为6.3、9.9 h,固化土的28 d无侧限抗压强度达到1.98 MPa,冲刷14 d后的质量损失率与强度损失率也最低,分别为2.57%和4.07%;其固化机理在于固化剂自身水化反应、固化剂与土粒之间的离子交换反应和火山灰反应复合协同作用可生成C-S-H凝胶和钙矾石(AFt),两者相互搭接形成致密结构,促进土体强度提高。

A composite of petroleum coke desulfurization slag and mineral powder was used as a mud solidification agent to prepare solidified soil.Experimental studies were conducted on the slurry workability,mechanical strength,and erosion resistance of the solidified soil.The solidification effects of petroleum coke desulfurization slag and mineral powder,cement,and lime were compared,and the solidification mechanism of petroleum coke desulfurization slag and mineral powder was analyzed.The results show that the solidification effect of petroleum coke desulfurization slag and mineral powder is weaker than that of cement,but significantly stronger than that of lime.The expansion degree of its solidified soil slurry increases with the increase of petroleum coke desulfurization slag content.When the petroleum coke desulfurization slag content is 20%,the slurry has the shortest setting time,with initial and final setting times of 6.3 h and 9.9 h,respectively.The unconfined compressive strength of solidified soil is the highest,reaching 1.98 MPa at 28 days.The quality loss rate and strength loss rate after 14 days of erosion are also the lowest,with 2.57%and 4.07%respectively.The curing mechanism is that the hydration reaction of the curing agent itself,the ion exchange reaction between the curing agent and soil particles,and the pozzolanic reaction can generate C-S-H gel and ettringite(AFt),which are overlapped to form a dense structure and promote the strength of soil.