| 司政*,杨正午,张朝森.低压环境下混凝土抗冻耐久性试验及损伤模型研究[J].实验力学,2025,40(1):91~100 |
| 低压环境下混凝土抗冻耐久性试验及损伤模型研究 |
| Frost durability test and damage model study of concrete under low pressure environment |
| 投稿时间：2023-12-28 修订日期：2024-03-21 |
| DOI：10.7520/1001-4888-23-274 |
| 中文关键词: 高原地区 气压条件 气孔结构 抗冻性能 冻融损伤模型 |
| 英文关键词:highland area barometric pressure conditions stomatal structure frost resistance freeze-thaw damage model |
| 基金项目:国家自然科学基金项目(51879217) |
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| 摘要点击次数: 222 |
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| 中文摘要: |
| 为研究高原地区不同气压条件对混凝土抗冻性能的影响，对60 kPa、80 kPa、100 kPa气压养护条件下的混凝土进行冻融循环试验，分析不同气压对混凝土抗冻性能和硬化混凝土气孔结构的影响规律，并建立了以相对动弹性模量为基础的混凝土冻融损伤模型和混凝土抗压强度预测模型。试验结果表明：100 kPa气压条件下混凝土抗冻耐久性最佳，80 kPa气压条件下抗冻耐久性次之，60 kPa气压条件下抗冻耐久性最差。由硬化混凝土气孔结构分析可知，在环境气压降低的情况下引气剂的引气能力会受到影响，降低了混凝土内部的含气量，致使气孔结构参数整体变差，从而导致低压环境下的混凝土抗冻性能下降。基于相对动弹性模量建立的混凝土冻融损伤模型和抗压强度预测方程拟合精度较高，可以反映不同气压条件下混凝土的冻融损伤变化过程。本文研究可为高原地区水利工程冻融耐久性能研究提供参考。 |
| 英文摘要: |
| In order to study the influence of different air pressure conditions on the frost resistance of concrete in the plateau area, freeze-thaw cycle tests were carried out on concrete under the conditions of 60 kPa, 80 kPa and 100 kPa air pressure curing, and an analysis was conducted on the effects of various air pressures on the frost resistance and pore structure of hardened concrete. Subsequently, a freeze-thaw damage model for concrete was established based on the relative dynamic elastic modulus, along with a predictive equation for concrete compressive strength utilizing this modulus. The test results show that the frost resistance durability of concrete under 100 kPa air pressure is the best, followed by 80 kPa frost resistance durability, and 60 kPa frost resistance durability is the worst. The analysis of the porosity structure of hardened concrete shows that the air-entraining capacity of the air-entraining agent will be affected when the ambient air pressure is reduced, reduces the air content inside the concrete and leads to an overall deterioration of the pore structure parameters, resulting in the decrease of the frost resistance of concrete in the low-pressure environment. The freeze-thaw damage model, along with the compressive strength prediction equation, both formulated using the relative dynamic elastic modulus, exhibit a high degree of fitting accuracy, which can reflect the freeze-thaw damage process of concrete under different air pressure conditions. This study can provide a reference for the freeze-thaw durability of water conservancy projects in plateau areas. |
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