掺加黏土的固废基泡沫轻质土强度和耐久性研究

Preparation and properties of solid waste foam lightweight soil containing clay

为减小工程造价和环境污染等问题,采用电石渣、石膏和矿渣固废全部替代水泥制备了泡沫轻质土,研究黏土掺量对固废泡沫轻质土耐久性的影响。研究结果表明:当黏土掺量由0%提高到45%时,试样7 d的抗压强度由2.16 MPa降至0.58 MPa,28 d劈裂抗拉强度由0.73 MPa降至0.18 MPa;干湿循环10次后,当黏土掺量分别为0%、25%和35%时,试样抗压强度分别为2.06、1.28和0.62 MPa;当黏土掺量为45%时,冻融循环10次后的试样被完全破坏。养护前7 d,所有试样收缩应变增幅较大,应变范围为1523×10^(-6)~1932×10^(-6)。黏土掺量为25%~35%时,相较于黏土掺量为45%的泡沫轻质土收缩性的改善更明显。该研究建议泡沫轻质土作为路床填料时,黏土掺量小于25%,路堤填料黏土掺量小于35%。

To reduce the project cost and alleviate the environmental pollution problems,the foam lightweight soil was prepared by replacing cement with calcium carbide slag,gypsum and slag solid waste in this study,and the influences of clay content on durability of solid waste foam lightweight soil were investigated.The results show that when the clay content increased from 0 to 45%,the compressive strength of samples at 7 d varied from 2.16 to 0.58 MPa,and the 28 d splitting tensile strength decreased from 0.73 MPa to 0.18 MPa.After 10 of wetting-drying cycles,When the clay content was 0%,25%and 35%,the compressive strengths of the specimens were 2.06,1.28 and 0.62 MPa respectively.At a clay content of 45%,the samples were completely destroyed after 10 freeze-thaw cycles.In addition,the shrinkage strain of all samples increased rapidly at 7 d before curingThe strain range was from 1523×10^(-6)to 1932×10^(-6).The improvement in shrinkage is more evident at a clay content of 25%~35%than at a clay content of 45%of the foamed lightweight soil.It is recommended that the clay content of foamed lightweight soil used as a fill for a road bed should be less than 25%and that of a fill for an embankment should be less than 35%.