掺氧化镁混凝土的膨胀效果分析

Analysis of expansion effect of magnesium oxide(MgO) in mass concrete

本文通过仿真计算,综合分析了混凝土的弹性模量增长、徐变度随龄期的变化和温度对氧化镁膨胀量的影响,同时研究了养护温度及坝体混凝土温度对有效补偿量的影响,以及掺量相同时坝体不同部位掺氧化镁的膨胀补偿效果。结果表明,氧化镁后期膨胀对于补偿温降收缩较为有效,在约束区氧化镁的膨胀可有效补偿温降收缩,从而改善应力状态,但在坝体某些部位,氧化镁膨胀有可能恶化坝体应力分布。

The influence of the growing elastic modulus, time dependent creep and temperature change on the expansion of magnesium oxide (MgO) concrete is studied using simulation analysis. The influence of curing temperature and temperature of concrete on the effective expansion and the compensation effects in different dam areas are also probed. Results show that the expansion of MgO at later age is good for compensating the shrinkage induced by temperature drop and the expansion of MgO can improve the stress status in the restricted zones but may worsen the stress status in other zones.