新型富水热半导体材料耐久性与稳定性试验研究
发布时间：2019-05-21 16:54
【摘要】：青藏高原高海拔的多年冻土区岩土工程，都面临着高温、高含冰冻土以及全球气候变暖的难题。工程修建带来的人工热扰动必将导致下部多年冻土融化沉降，尤其对于未来黑色路面的高速公路更为严重。这样给维持多年冻土区工程长期安全增加了难度，随之而来的还有病害治理问题。本文在课题组前期相关富水热半导体材料研究成果基础上，新研制一种既可以在新建路基中应用，又可治理既有路基工程的新型高效、施工方便、经济环保热半导体材料。此种新型富水材料基于冰、水相变后的4倍导热系数差异，水化反应形成的网状结构可短时间固结大量自由水，，冻融状态下导热系数比在2.9倍以上，并形成较高的强度。 本文以室内试验为主，选用硫铝酸盐水泥熟料为基料，天然硬石膏和生石灰为辅料，考虑多种添加剂同时作用的复杂性和搅拌工艺的影响，通过正交优化，最终确定新型富水热半导体材料的制浆工艺为：基料浆液和辅料浆液分别搅拌5min后混合浇筑；各组分配比范围为：以硫铝酸盐水泥熟料为基料，缓凝剂R1和缓凝剂R2（0.4%~0.6%，与基料的质量比，下同）、基料膨润土（2%~4%）、天然硬石膏（40%~60%）、生石灰（15%~25%）、氢氧化锂（2%~4%）、促凝剂C（2%~4%）、辅料膨润土（5%~7%）。获得研制的新型热半导体材料性质如下： (1)新型富水材料在水灰比为2.0~3.0条件下，含水率达到140%以上，冻融状态下导热系数比分别为2.9倍以上，养护28d抗压强度大于1.7MPa，并且其冻胀率和渗透系数分别低于3.9%和9.6E-6cm/s。 (2)对新型富水材料试样进行25次冻融循环测试，得出水灰比2.0、2.5和3.0试样的保水率和抗压强度分别在97%和1.3MPa以上，水灰比2.0试样的强度高达2.94MPa。在经历多次冻融后，保水率较高，具有良好的热半导体性，抗压强度保持在峰值强度的80%以上，新型富水材料具有良好的抗冻融性。 (3)在不改变材料热半导体性的同时，利用其重结晶性质，确定了材料的预压荷载为对应临期峰值强度的80%，将三种水灰比试样养护3d后进行预压处理，其后续强度均有所增大，水灰比3.0试样强度可提高近10%，且水灰比越大预压时间越早，后续强度增长越大。因此，工程应用时合理利用材料的重结晶性，能有效提高材料的抗压强度，加强工程的力学稳定性。 综合试验结果，新型富水热半导体材料具有富水、高热半导体性、高强、低冻胀和低渗五大特性，并具有良好的抗冻融循环特性，是一种针对多年冻土区岩土工程理想的热半导体浆液材料。
[Abstract]:Geotechnical engineering in permafrost areas of Qinghai-Xizang Plateau is faced with the problems of high temperature, high ice content, frozen soil and global warming. The artificial thermal disturbance caused by engineering construction will lead to the melting and settlement of permafrost in the lower part, especially for the highway with black pavement in the future. This makes it more difficult to maintain the long-term safety of permafrost engineering, followed by the problem of disease control. On the basis of the research results of hydrothermal semiconductor materials in the early stage of the research group, a new type of high efficiency, convenient construction and economic and environmental protection thermal semiconductor materials can be developed, which can not only be used in the new roadbed, but also can be used in the treatment of the existing subgrade engineering. Based on the difference of thermal conductivity of ice and water phase transformation, the reticular structure formed by hydration reaction can consolidate a large amount of free water in a short time, and the thermal conductivity ratio is more than 2.9 times in freeze-thaw state, and the strength is higher. In this paper, based on laboratory test, sulphoaluminate cement clinker is selected as base material, natural anhydrite and quicklime as auxiliary materials, considering the complexity of simultaneous action of various additives and the influence of mixing process, through orthogonal optimization, Finally, the pulping process of the new hydrothermal semiconductor material is determined as follows: the base slurry and auxiliary slurry are mixed and poured with 5min respectively; The distribution ratio of each group is as follows: using sulphoaluminate cement clinker as base material, retarder R1 and retarder R2 (0.4% 鈮
本文编号：2482243
[Abstract]:Geotechnical engineering in permafrost areas of Qinghai-Xizang Plateau is faced with the problems of high temperature, high ice content, frozen soil and global warming. The artificial thermal disturbance caused by engineering construction will lead to the melting and settlement of permafrost in the lower part, especially for the highway with black pavement in the future. This makes it more difficult to maintain the long-term safety of permafrost engineering, followed by the problem of disease control. On the basis of the research results of hydrothermal semiconductor materials in the early stage of the research group, a new type of high efficiency, convenient construction and economic and environmental protection thermal semiconductor materials can be developed, which can not only be used in the new roadbed, but also can be used in the treatment of the existing subgrade engineering. Based on the difference of thermal conductivity of ice and water phase transformation, the reticular structure formed by hydration reaction can consolidate a large amount of free water in a short time, and the thermal conductivity ratio is more than 2.9 times in freeze-thaw state, and the strength is higher. In this paper, based on laboratory test, sulphoaluminate cement clinker is selected as base material, natural anhydrite and quicklime as auxiliary materials, considering the complexity of simultaneous action of various additives and the influence of mixing process, through orthogonal optimization, Finally, the pulping process of the new hydrothermal semiconductor material is determined as follows: the base slurry and auxiliary slurry are mixed and poured with 5min respectively; The distribution ratio of each group is as follows: using sulphoaluminate cement clinker as base material, retarder R1 and retarder R2 (0.4% 鈮
本文编号：2482243
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