Crack resistance of concrete based on temperature-controlled magnesium oxide expansion agent
The effects of temperature-controlled magnesium oxide expansion agent(TME)on workability,setting time,compres-sive strength,limited expansion rate of mortar,heat reduction rate of hydration and cracking resistance of engineering structures were studied.The results show that the addition of TME improves the cohesiveness of concrete,prolongs the setting time of concrete,and the influence on the compressive strength of concrete is concentrated within 7 days,but has no effect on the strength of concrete at 28 days.The effect of TME on the limited expansion rate of water-cured mortar at 40 ℃ was concentrated within 28 days and in-creased with the increase of TME content.TME can obviously reduce the heat release rate of cement hydration and the tempera-ture appreciation of cement mortar.The 6％TME content significantly reduces the number of cracks in concrete,reduces the struc-tural temperature appreciation by 5.0℃,the final value of the 14 day expansion process is 133.9 με,reduces the cracking tempera-ture by 14.4℃,and improves the anti-cracking safety factor by 62％.It also has a significant effect on the early cracks caused by construction discontinuity.
万方数据
维普
