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碳化固化技术是一种利用二氧化碳对搅拌有活性氧化镁的土体进行碳化,以达到快速提高强度的低碳搅拌处理软土的创新技术。通过室内试验研究干湿循环对碳化固化土物理力学特性的影响,并与相同掺量下水泥固化土进行对比。结果表明:活性Mg O固化粉土碳化3 h试样的无侧限抗压强度可达5 MPa,粉质黏土碳化24 h试样可达2.6 MPa;干湿循环后碳化固化土的干密度降低,而水泥土干密度基本不变;6次干湿循环后粉土碳化试样的无侧限抗压强度仍然能达到4 MPa以上,为水泥固化粉土强度的2倍,具有较好的抗干湿循环性能;经过6次干湿循环后,粉质黏土碳化试样的残余强度仅为35%,而水泥固化粉质黏土降到65%,表明固化粉质黏土的抗干湿循环性能均较差,且粉质黏土碳化试样的抗干湿循环能力不及水泥固化粉质黏土试样。通过X射线衍射(XRD)、电镜扫描(SEM)及压汞试验(MIP)测试表明干湿循环对粉土碳化试样的累计孔隙影响不大,因此粉土试样仍然具有比较大的密实度来保证试样强度;粉质黏土碳化试样因孔隙增加明显而变得疏松,因此强度显著降低。
Carbonization Curing is an innovative technology that uses carbon dioxide to carbonize a soil that has been activated with activated magnesia to achieve a fast, low-carbon, enhanced-strength soft clay treatment. The effects of the wetting and drying cycles on the physical and mechanical properties of carbonized solidified soil were studied through laboratory tests and compared with the same amount of cement stabilized soil. The results show that the unconfined compressive strength of activated MgO solidified silt for 3 h can reach 5 MPa, that for silty clay can reach 2.6 MPa for 24 h, and the dry density of carbonized solidified soil decreases after wet-dry cycle , While the dry density of cement soil remained unchanged. The unconfined compressive strength of soil carbonized specimens after 6 wet-dry cycles could still reach 4 MPa or more, which was twice that of cement-cured silt and had good resistance After six times of drying and wetting cycles, the residual strength of the silty clay samples was only 35%, while that of the cement-cured silty clay was reduced to 65%, indicating that both the wetting and drying cycles of the cured silty clay Poor, and silty clay carbonization of the sample wetting and drying capacity is less than the cement-cured silty clay samples. X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests show that the wetting and drying cycles have little effect on the cumulative pore size of the carbonized silt samples, so the silt samples still have a relatively large solidity To ensure the strength of the sample; silty clay carbonized samples due to significant increase in porosity and become loose, so significantly reduced strength.