基于固弃物的固化土路用性能及固化机理研究

为探索矿渣、粉煤灰和脱硫石膏等固体废弃物应用于黄泛区道路工程建设的可行性，基于粉煤灰、矿渣、脱硫石膏、普通硅酸盐水泥和固废基硫铝酸盐水泥制备了粉土固化剂。研究了固化剂掺量（4%、6%、8%、10%）对固化土无侧限抗压强度、劈裂强度、加州承载比（CBR）、水稳性能及抗干湿循环性能的影响。结果表明：使用固废基硫铝酸盐水泥和普通硅酸盐水泥与其他固弃物协同制备的固化剂固化效果最优；固化剂掺量不低于8%时，固化土强度满足JTG D50-2017要求；固化土CBR值高于75%，满足JTG D30-2015中路基填料承载比要求；基于X射线衍射分析和二次电子成像技术，发现固化土中存在水化硅酸钙凝胶（CSH）和钙矾石晶体（AFt）；这些物质通过填充缝隙、挤密、黏结土颗粒，增强土体性能。

Study on Pavement Performance and Solidified Mechanism of Solidified Soil Based on Solid Waste

In order to study the feasibility of applying solid waste to road engineering in Yellow River flooded areas, stabilized agents were prepared base on fly ash, slag, desulfurized gypsum, Ordinary Portland Cement and Solid-waste base Sulphoaluminate Cement. The influence of different stabilized agent inclusions (4%, 6%, 8%, 10%) on unconfined compressive strength, splitting strength, California bearing ratio, water damage resistance and dry-wet cycles resistance of stabilized soil were investigated. The experimental results indicate that the stabilized effect is improved significantly by using Solid-waste base Sulphoaluminate Cement to replace part of ordinary Portland cement. When the content of stabilized agents are not less than 8%, the strength of cured soil meets the requirements of JTG D50-2017. The CBR values of all kinds of stabilized soil are higher than 75%, which meets the requirement of minimum bearing ratio of subgrade filling in JTG D30-2015 (i.e. ≥ 8%). X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) analyses were conducted to study the stabilized mechanism. The experimental results showed that the hydration products mainly contain fibrous and flocculent C-S-H gels and needle-flake shaped AFt crystals, which are able to fill, compact and bond the soil particles. Thus, the properties of soil are enhanced.