矿渣改性淤泥用于管沟回填的工程特性研究

Engineering Characteristics Research of Slag-Modified Dredged Sediment for Pipe Trench Backfill

矿渣、淤泥是典型固废材料,为拓展资源化利用途径,以矿渣、硫铝酸盐水泥为固化剂,将淤泥改性为早强流动化土,并用于市政管沟回填工程。采用室内试验方法研究矿渣替代部分水泥后,流动化土在不同含水率、矿渣替代率下的施工和易性与力学特性。结果表明:当含水率增大时流动度会随之增大而密度将随之减小,矿渣替代率的改变对流动度、密度影响有限;流动化土的无侧限抗压强度随着龄期的增加而增加,但随含水率和矿渣替代率的增加而减小,当矿渣替代率小于42.9%时,养护1天后强度可达100 kPa以上,流动化土的抗干湿循环能力随矿渣替代率的增加而降低;流动度与填充性呈正相关,当流动度>200 mm时,流动化土的填充率可达97%以上,能较好为工程所用。

Slag and dredged sediment are typical solid waste.In order to expand the utilization of resources,the dredged sediment was modified into early strength flowable soil by using slag and sulfoaluminate cement as curing agent,and it was used for backfilling in municipal pipe ditch engineering.The workability and mechanical properties of flowable soil with different water content and slag replacement ratio were studied after slag partly replaced sulfoaluminate cement.The results show that when the moisture content increases,the fluidity increases and the density decreases,and the change of slag replacement ratio has limited influence on the fluidity and density.The unconfined compressive strength of flowable soil increases with the increase of curing age,but decreases with the increase of moisture content and slag replacement ratio.When the slag replacement ratio is less than 42.9%,the strength can reach more than 100 kPa after curing for 1 day,and the drying-wetting cycle resistance of flowable soil decreases with the increase of slag replacement ratio.When the fluidity is greater than 200 mm,the filling rate of the flowable soil can reach more than 97%,which can be better used for engineering.