Feng Wei
Institute of Architecture and Civil Engineering, Yulin University, Chongwen West Road 4, Yulin, 719000, China.
Sci Rep. 2022 Mar 10;12(1):3976. doi: 10.1038/s41598-022-07418-7.
Current researches on the mechanical properties of concrete are mainly concentrated on the aggressiveness of sulfate, chloride ion, acid and freeze-thaw cycles. However, the evolution of concrete mechanical properties aggressived by landfill leachate remains to be revealed. As the micro-nano indentation test is a new method to measure the fine/micro mechanical behavior of materials, it is used in this research to evaluate the micro-mechanics of the landfill leachate of the concrete sample surface and different aggressived depths. In addition, the evolution of the macro-mechanical properties of concrete aggressived by the landfill leachate was studied through uniaxial compression tests. The results show that the hydration products with high elastic modulus are consumed by the aggressiveness of landfill leachate, which results in a large number of microscopic cracks on the surface of the concrete. Moreover, the longer the aggressive time, the shallower the aggressive depth, and the more severe the deterioration of the micromechanical properties of the sample surface. It is also notable that the uniaxial compressive strength of the concrete samples aggressived by landfill leachate showed a linear increase and then gradually decrease. Comparing with the sodium chloride and sodium sulfate solutions, the landfill leachate has the most significant weakening effect on the elastic modulus of concrete.
目前关于混凝土力学性能的研究主要集中在硫酸盐、氯离子、酸和冻融循环的侵蚀性方面。然而，受垃圾渗滤液侵蚀的混凝土力学性能演变仍有待揭示。由于微纳压痕试验是一种测量材料细观/微观力学行为的新方法，本研究利用该方法评估混凝土试样表面及不同侵蚀深度处垃圾渗滤液的微观力学性能。此外，通过单轴压缩试验研究了受垃圾渗滤液侵蚀的混凝土宏观力学性能的演变。结果表明，高弹性模量的水化产物被垃圾渗滤液侵蚀消耗，导致混凝土表面出现大量微观裂缝。而且，侵蚀时间越长，侵蚀深度越浅，试样表面微观力学性能劣化越严重。还值得注意的是，受垃圾渗滤液侵蚀的混凝土试样的单轴抗压强度呈先线性增加后逐渐降低的趋势。与氯化钠和硫酸钠溶液相比，垃圾渗滤液对混凝土弹性模量的削弱作用最为显著。
