论文部分内容阅读
采用冻融循环试验评价水泥黄土的耐久性。冻融循环试验之后,试样切成片状,测定含水量和拍摄扫描电镜照片。对比研究循环试验前后水分分布及微结构变化,揭示水泥黄土的强度衰减机理。显微照片表明,掺加到黄土中的水泥水化并在土粒间产生大量的针状、纤维状结晶体。这种三维结晶网络提高了水泥黄土的强度。冻结期间发现试样中的水分或从外界补给的水分向冻结锋面逐渐迁移,并结晶形成连续冰层。在此过程中,冰层附近的水泥水化结晶网络被拉断,其结果,融化后试样中出现弱面。
The freeze-thaw cycle test was used to evaluate the durability of cement loess. After the freeze-thaw cycle test, the sample was cut into sheets, the moisture content was measured, and photographs were taken with a scanning electron microscope. The moisture distribution and microstructural changes before and after the cyclic test were compared to reveal the strength attenuation mechanism of cement loess. Micrographs show that the cement incorporated into the loess hydrates and produces a large number of acicular, fibrous crystals between the soil particles. This three-dimensional crystalline network increases the strength of cement loess. During freezing, it was found that the water in the sample or the moisture supplied from the outside gradually migrated to the freezing front and crystallized to form a continuous ice layer. During this process, the cement hydration crystal network near the ice layer was broken. As a result, a weak surface appeared in the sample after melting.