关键词: 膨胀特征;RC梁;约束机制;长期监测试验;ASR反应;

Abstract: Alkali-silica reaction(ASR) can produce expansion stress, causing concrete expansion, cracking and even damage, while steel bars can inhibit the expansion caused by ASR reaction.However, at present single material tests cannot evaluate the restraint effect of steel bars.Based on the restraint effect of steel bars, the expansion characteristics of reinforced concrete(RC) beams under different alkali solution immersion areas and immersion depths within 34 months were studied by an accelerated ASR reaction experiment.The results showed that when the immersion position and immersion depth were different, the RC beam structure exhibited different expansion characteristics.The expansion rate of the part directly immersed in the alkali solution was larger, and the expansion rate around the steel bar was significantly reduced.Furthermore, the constraint mechanism of steel bars on the expansion of concrete ASR reaction was analyzed.The results showed that steel bars can produce direct and indirect constraints on expansion.The research results can provide reference for the evaluation of structural mechanical properties of reinforced concrete after ASR reaction damage.

Key words: expansion characteristic; reinforced concrete beam; restraint effect; long-term monitoring test; ASR reaction;