养护方式对C100超高强混凝土抗压强度的影响规律研究

Study on the Influence of Curing Methods on Compressive Strength of C100 Ultra-high Strength Concrete

对比研究了标准养护、同条件养护和80℃蒸汽养护对C100超高强混凝土强度发展的影响规律。结果表明:(1)标养条件下,强度的发展主要集中在7 d内;掺合料能降低胶凝材料体系的水化放热总量,推迟水化放热温峰的出现。(2)同养条件下,混凝土的3 d强度主要受化学反应控制,7 d后的强度主要受扩散控制。(3)采用3 d 80℃蒸养的方式可快速预测混凝土的标养28 d强度。(4)温差应力释放和凝胶结构转变是导致超高强混凝土强度发生倒缩的主要原因;可通过适当增加掺合料的比例、降低入模温度和选用适当的缓凝剂等改善超高强混凝土的倒缩。

The effects of standard curing,equivalent condition curing and 80 ℃ steam curing on the strength development of C100 ultra-high strength concrete were studied. The results show that:( 1)Under the condition of standard curing,the strength is mainly concentrated in 7 d. Mineral admixture can reduce the total amount of hydration heat release in the cementitious material system and delay the emergence of hydration exothermic temperature.( 2) Under the same condition curing,the 3 d intensity of concrete is mainly controlled by chemical reaction,and the intensity after 7 d is mainly controlled by diffusion.( 3) Using 3 d 80 ℃ steam curing method can quickly predict the 28 d strength of concrete.( 4) The temperature difference stress release and gel structure change is the main reason for the strength contraction of the ultra-high strength concrete; increase the proportion of the admixture,reduce the mold temperature and choose the appropriate retarder can reduce the retreat of ultra-high strength concrete.