为探究掺入农业固废青稞秸秆灰(HBSA)对氯氧镁水泥(MOC)冻融循环侵蚀后损伤劣化与细微观结构的影响,制备了HBSA改性MOC砂浆(MOCM)。通过对不同HBSA掺量下MOCM在冻融侵蚀环境下的宏观性能试验、表观形貌分析、细微观结构测试,采用抗冻性能评价参数表征HBSA改性MOCM的冻融损伤劣化规律。结合细观孔隙结构测试与微观结构表征,揭示HBSA影响MOCM抗冻性能的内在原因。基于可靠性理论,采用一元Wiener随机分布函数对HBSA改性MOCM的抗冻性能退化过程进行数值分析。研究结果表明,MOCM经过60次冻融侵蚀后,HBSA掺量为10 wt%时MOCM的损伤劣化程度最轻,抗冻性能比未掺HBSA时提高了23.48 %。掺入10wt%HBSA的MOCM的细观孔隙结构得到优化,开口孔隙率比为未掺HBSA时减小了5.04 %,最可几孔径显著减小,内部的微小孔隙数量增加。掺入10%wtHBSA的MOCM的水化产物中生成了水化硅酸镁(M-S-H)凝胶,增加了微观结构的密实性与5相晶体在水中的稳定性。一元Wiener随机分布函数可以较好用于HBSA改性MOCM的抗冻性能劣化过程分析,掺入10wt%HBSA的MOCM的冻融损伤可靠性更高,抗冻性能更优。

To investigate the effect of adding highland barley straw ash (HBSA) of agricultural solid waste on the damage deterioration and microstructure of magnesium oxychloride cement (MOC) after freeze-thaw cycle erosion, MOC mortar (MOCM) modified by HBSA was prepared. By conducting macro performance tests, apparent morphology analysis, and microscopic structure testing of MOCM under freeze-thaw erosion environments with different HBSA dosages, the frost resistance evaluation parameter was used to characterize the freeze-thaw damage degradation law of MOCM modified by HBSA. Combining microscopic pore structure testing and microstructure characterization, the intrinsic reasons why HBSA affects the frost resistance of MOCM was revealed. Based on reliability theory, a one-dimensional Wiener random distribution function was used to numerically analyze the degradation process of frost resistance of HBSA modified MOCM. The research results show that after 60 cycles of freeze-thaw erosion, the degree of damage deterioration of MOCM is the lightest when the HBSA content is 10 wt%, and the frost resistance is improved by 23.48% compared to without HBSA. The micro pore structure of MOCM added with 10wt% HBSA was optimized, and the open porosity ratio decreased by 5.04% compared to without HBSA. The most probable pore size significantly decreased, and the number of internal micro pores increased. The hydration product of MOCM added with 10%wt HBSA generates hydrated magnesium silicate hydrate (M-S-H) gel, which increases the compactness of microstructure and the stability of five phase crystals in water. The one-dimensional Wiener random distribution function can be well used for analyzing the degradation process of frost resistance in HBSA modified MOCM. MOCM added with 10wt% HBSA has higher reliability in freeze-thaw damage and better frost resistance.

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国家自然科学基金(No. 52178216);青海省重点研发与转化计划项目(No. 2022-QY-222); 青海民族大学理工类科学研究项目(No. 2024XJMA03);青海民族大学研究生创新项目(No. 66M2024030)