水泥基渗透结晶型防水材料对硫铝酸盐水泥固化土性能影响及机制分析

水泥土固化过程中Ca2+浓度会随水化反应的进行而逐步降低，导致水泥颗粒未完全水化，固化土强度增长受限，而水泥基渗透结晶型防水材料（CCCW）中活性物质能催化未水化水泥颗粒反应。选择硫铝酸盐水泥（SAC）为胶凝材料、CCCW为添加剂，通过单掺与复掺的方式，结合X射线衍射（XRD）、电镜扫描（SEM）表征，分析了固化土的无侧限抗压强度、水稳定性、耐干湿循环性能及微观结构。结果表明，复掺16%混合料（4%CCCW+12%SAC）的固化土强度是同掺量下单掺SAC固化土强度的1.5倍，且比单掺20%SAC的固化土强度高1.41 MPa；复掺16%混合料（4%CCCW+12%SAC）的固化土泡水2～8 d软化系数平均达0.97，而同掺量下SAC固化土平均仅为0.73；单掺的固化土强度随干湿循环次数增加逐级降低，而复掺混合料的固化土强度呈波浪式发展；CCCW中活性物质能增加固化土中钙矾石生成量并修复微裂缝，钙矾石长径比显著增大，可直接连接两个甚至多个土颗粒，形成三维网状结构，显著提高结晶体的微观加筋、骨架及填充作用，改善SAC固化土强度、水稳定性及耐干湿循环性能。

Mechanism analysis and effect of cementitious capillary crystalline waterproofing materials on sulfur aluminate cement solidified soil

The strength development of solidified soil would be limited by the incompletely hydrated cement particles for the gradually reduced Ca2+ concentrations as the hydration reaction proceeds. Theoretically the unhydrated cement particles would be catalyzed by the active substances in cementitious capillary crystalline waterproofing (CCCW) materials. Using sulfur aluminate cement (SAC) as cementitious material, CCCW as additive, a series of experiments was conducted in a single-mixed or admixed way. The properties of solidified soil including unconfined compressive strength (UCS), water stability, the ability resisting wetting-drying cycles and microstructure were analyzed with X-ray diffraction (XRD) and scanning electron microscope (SEM) characterization. The results show that the UCS of soil solidified by 16% mixture (4% CCCW+12% SAC) is 1.5 times the soil solidified by the same content of SAC and 1.41 MPa higher than the soil solidified by 20% SAC. The average softening coefficient of the soil solidified by 16% mixture (4% CCCW+12% SAC) reaches 0.97 after 2-8 days soaking in water while only 0.73 of the soil solidified by SAC. The UCS of soil solidified with single-mixed gradually decreases with the increase of wetting-drying cycles while wavy development of solidified soil with admixed. The generation amount of AFt increases and the microfractures are repaired in solidified soil by the active substances in CCCW. Two or more soil particles are connected by AFt and a three-dimensional net structure is formed with a significantly increased aspect ratio. It is shown that the properties of soil solidified by SAC including the UCS, water stability, ability resisting wetting and drying cycles are improved due to the application of CCCW.