Diagnosis and reinforcement of alkali-aggregate reaction of prefabricated frame
In this paper,the long-term cracking and detection process of engineering example structure are described.The macroscopic characteristics of the in-situ failure of prefabricated frames concrete are investigated,and the coarse aggregate is classified.Based on the energy spectrum analysis,the MgO content in cement paste is not the main cause of concrete cracking of prefabricated frames.Type I aggregate-cement transition zone Basic oxide(K,Na ions)produce osmotic reaction,which is diagnosed as alkali-silicic acid reaction.According to the test results,the average expansion rate of core samples is more than 0.04%,which proves that the expansion failure of concrete is caused by alkali aggregate reaction.According to the test results,the alkali-aggregate reaction of the original prefabricated frames was treated by sealing joint with glue and adding isolation sandwich,and the equivalent displacement bearing capacity of the new box-section frames was adopted for strengthening.
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