高原地区抗冻引气混凝土含气量设计方法研究

Design of Air Content of Frost Resistance Air-Entrained Concrete in Plateau Area

对高原与平原地区不同水胶比引气混凝土的含气量、气泡间距系数及抗冻耐久性指数进行测试,同时搜集整理国内外相关研究成果,研究分析了高原低气压环境对引气混凝土含气量损失、气泡间距系数变化及临界抗冻耐久性指数的影响。结果表明:相较于平原地区,高原低气压环境下引气混凝土含气量损失增大,硬化后混凝土含气量损失约1.0%~1.5%;硬化混凝土含气量与气泡间距系数的对数间存在良好的线性关系,但高原低气压环境可能劣化引气混凝土的气孔结构;硬化混凝土气泡间距系数与抗冻耐久性指数间也具有良好的线性关系,且不受环境气压影响;以引气混凝土气泡间距系数为桥梁,提出一种基于混凝土抗冻耐久性要求的高原地区引气混凝土含气量设计方法。

The effect of low atmospheric pressure environment of plateau on air content loss,the change of bubble spacing coefficient and the critical value of frost resistance durability index were studied through testing the air content,bubble spacing coefficient and frost resistance durability index of air-entrained concrete with different water-binder ratios in plateau and plain areas,and collecting correlative results of domestic and foreign researches.The results show that compared with the plain area,the air content loss of air-entrained concrete increases under low-pressure environment in the plateau,and the air content loss is about 1.0%~1.5%during the hardening process.There is a good linear relationship between the air content of hardened concrete and the logarithm of the bubble spacing coefficient,but the bubble structure of air-entrained concrete may be degraded in the environment of low atmospheric pressure on the plateau.There is also a good linear relationship between the bubble spacing coefficient and frost resistance durability index,and it is not affected by atmospheric pressure.An air content design method of air-entrained concrete in plateau area based on the objective of frost resistance durability of concrete is proposed by taking bubble spacing coefficient as the link.