80℃加速养护评定外掺MgO膨胀剂混凝土的安定性

Soundness evaluation of concrete containing MgO-based expansive agent in accelerated curing of 80℃ water

本文采用80℃水养护与实际工程用混凝土配合比相同的外掺MgO膨胀剂的混凝土试件,通过考察试件膨胀、劈拉强度和微观结构的变化,综合评估外掺MgO膨胀剂的混凝土的体积安定性。结果表明,80℃水养护能够有效加速MgO膨胀的水化,使其膨胀在90d内趋于稳定。掺5%和8%MgO膨胀剂的混凝土试件的劈拉强度比未掺膨胀剂的混凝土高,且微观结构完好,表明掺MgO膨胀剂的混凝土体积安定。

MgO concrete specimens with the same mix proportion of field concrete were cured in 80℃ water,and the expansion,splitting-tensile strength and microstructures of concrete specimens were investigated.Results showed that the hydration of MgO-based expansive agent was accelerated effectively,and the expansion curves of MgO concrete leveling off within 90d.When added with 5% and 8% of MgO-based expansive agent,the splitting-tensile strengths were increased,and on destructions in microstructure were caused,which indicated that the concrete specimens added with MgO-based expansive agent were sound.