浸烘与加载耦合作用下混凝土的损伤失效研究

Stress Corrosion of Concrete Exposed to Immersion-dry and Loading Conditions

研究了水灰比分别为0.53、0.35和0.27的普通混凝土(OPC)、高性能混凝土(HPC)和高强混凝土(HSC)在盐湖卤水浸烘、浸烘+30%荷载和盐湖现场暴露环境下盐应力腐蚀行为。试验结果表明:在不同环境作用下,混凝土在应力腐蚀作用下的相对动弹性模量要经历强化和劣化2个发展阶段,强化和劣化阶段的时间与试验环境和混凝土类型密切相关。水灰比越大,劣化速率越大强化时间越短。浸烘循环+30%荷载作用显著加速了混凝土应力腐蚀破坏进程。OPC应力腐蚀的强化段在浸烘循环+30%荷载时间与长度暴露环境条件的相应时间长度分别压缩了67%。在浸烘+30%荷载循环作用下,在强化阶段HSC发生应力腐蚀的干湿循环次数分别比OPC和HPC延长了1.8倍,因此,在中国盐湖地区,HSC表现出更强的抗应力腐蚀能力。

The considered concretes include ordinary portland cement （OPC）, High Strength Concrete （HSC） and High performance Concrete （HPC） with the water to binder 0. 53, 0. 35and 0. 27 under three different conditions. This study revealed that the relative dynamic elastic modulus of concrete went through of time strength of these water to binder, Immersing- en and deterioration stages subjected to stress corrosion under three conditions, the length stages are closely related with test environment and concrete type. With the increase of the ratio of deterioration was increased, and the length of strength stages was decreased. drying ＋ 30% loading action significantly accelerated the process of stress corrosion damage Under the action of Immersing-drying ＋ 30% load, strengthen section of the length of OPC shorter 67%, compared with the length of time at exposure salt lake. The effect of immersing and drying, HSC Immer- sing-drying cycles when the stress strength occurred were longer 1.8 times than the OPC and HPC. HSC showed more resistance to stress corrosion in the salt lake regions of china.