工业及建筑废弃物固化盐渍土的力学性能和路用性能影响

Experimental Study on the Influence of Road Performance of Saline Soil Solidified by Industrial and Construction Waste Materials

为探讨各试验因素及固化剂种类对固化盐渍土的力学性能和路用性能影响,采用单掺与双掺水泥窑粉尘、废弃混凝土再生微粉等工业及建筑废弃物作为固化方案,以初始含水率、养护龄期、固化剂掺量为试验因素,通过无侧限抗压试验研究固化盐渍土力学性能,并进行干湿与冻融耐久性试验、承载比试验,以评估固化盐渍土路用性能,采用扫描电镜试验对固化盐渍土进行微观结构分析,揭露其固化机理。结果表明:初始含水率、养护龄期、固化剂掺量、固化剂种类是影响固化盐渍土的力学性能和路用性能主要因素;养护28 d,初始含水率为9.9%、单掺30%废弃混凝土再生微粉固化盐渍土的力学性能与路用性能最佳,抗压强度达到3227.40 kPa,干湿、冻融循环后残余强度分别达到2924.60、2243.49 kPa;从微观分析可知,废弃混凝土再生微粉固化盐渍土的土体结构变得密实且稳定。可见,初始含水率为9.9%、单掺30%废弃混凝土再生微粉固化盐渍土用作于盐渍土地区公路路基与路面基层的建设,具有一定的工程意义与经济价值。

In order to explore the effects of various test factors and curing agents on the mechanical and road properties of solidified saline soil,industrial and construction wastes such as cement kiln dust and recycled fine powder of waste concrete were used as solidification schemes.With the initial moisture content,curing age and curing agent content as the test factors,the mechanical properties of solidified saline soil were studied by unconfined compression test.The dry-wet and freeze-thaw durability test and bearing ratio test were carried out to evaluate the road performance of solidified saline soil.Scanning electron microscope test was used to analyze the microstructure of solidified saline soil and reveal its curing mechanism.The results show that initial moisture content,curing age,curing agent content and curing agent type are the main factors affecting the mechanical properties and road performance of solidified saline soil.After 28 days of curing,the mechanical properties and road performance of saline soil cured with 30%recycled fine powder of waste concrete are the best,the compressive strength reaches 3227.40 kPa,and the residual strength after dry-wet and freeze-thaw cycles reaches 2924.60 kPa and 2243.49 kPa,respectively.From the microscopic analysis,it can be seen that the soil structure of saline soil solidified by recycled micro-powder of waste concrete becomes dense and stable.It can be seen that the saline soil solidified with 30%recycled fine powder of waste concrete with an initial moisture content of 9.9%has certain engineering significance and economic value to be used in the construction of highway roadbed and pavement base in saline land area.