工业废渣复合再生胶凝材料稳定粉砂土路用性能及机理

Road Performance and Mechanism of Composite Reclaimed Cementitious Material from Industrial Waste Residue Stabilized Silty

为促进工业废渣资源化循环利用,制备工业废渣复合再生胶凝材料(RCI)并稳定路基粉砂土,对比RCI稳定土和水泥稳定土不同性能.通过抗压强度和弯拉强度试验分析稳定土力学性能,通过干缩、温缩、冻融循环和疲劳试验评价稳定土耐久性,借助XRD和SEM分析稳定土成分和微观形貌.结果表明:两种稳定土初期抗压强度和弯拉强度相当,随着养护时间增加,RCI稳定土强度显著高于水泥稳定土;RCI稳定土干缩、温缩和抗冻融性能优于水泥稳定土;在0.5和0.6应力强度比下,RCI稳定土的疲劳寿命高于水泥稳定土,在0.7应力强度比下两者疲劳寿命基本相当;RCI水化产物中增加了钙矾石,且水化硅酸钙含量高于水泥水化产物;RCI稳定土微观形貌更加密实均匀,整体性较好;水泥稳定土微观形貌相对松散,含有较多微空隙.

In order to promote the recycling of industrial waste residue,the composite reclaimed cementitious material from industrial waste residue(RCI)was prepared to stabilize subgrade silty soil,and the different properties of RCI stabilized soil and cement stabilized soil were compared.The mechanical properties of stabilized soil were analyzed by compressive strength and flexural strength tests.The durability of stabilized soil was evaluated by drying shrinkage,temperature shrinkage,freeze-thaw cycles and fatigue tests.The composition and micro morphology of stabilized soil were analyzed by XRD and SEM.The results show that the initial compressive strength and flexural tensile strength of the two stabilized soils are similar,and with the increase of curing time,the strength of RCI stabilized soil is significantly higher than that of cement stabilized soil.The dry shrinkage,temperature shrinkage and freeze-thaw resistance of RCI stabilized soil are better than that of cement stabilized soil.The fatigue life of RCI stabilized soil is higher than that of cement stabilized soil at 0.5 and 0.6 stress intensity ratio,and the fatigue life of RCI stabilized soil is almost the same at 0.7 stress intensity ratio.Ettringite is added to the hydration products of RCI,and the content of calcium silicate hydrate is higher than that of cement hydration products.The micro morphology of RCI stabilized soil is more dense and uniform,and the integrity is better.The micro morphology of cement stabilized soil is relatively loose and contains more micro voids.