大型混凝土渡槽早期抗裂性研究

Early Cracking Resistance of Large Concrete Aqueduct

制作掺人膨胀剂的混凝土试块，并将试块在20℃和60℃水中进行养护，研究和观察不同龄期的混凝土自由膨胀及水泥浆体孔结构和微观结构。研究结果表明：混凝土的膨胀随膨胀剂掺量和养护龄期增加而增加，养护温度从20％增大到60℃，混凝土膨胀率增加约80％～100％。掺入新型膨胀剂可以补偿和抑制混凝土收缩，优化水泥浆体孔结构的分布，提高其密实度，有效控制大型混凝土渡槽开裂。

The concrete specimen mixed with different expansive agent are cured in 20℃ and 60℃ water to study the free expansion of concrete under different ages and the pore size distribution and micro-structure of concrete paste. The results show that the expansion increases with the content of expansive agent and curing period, and the expansion increases by 80% to 100% when the curing temperature is increased from 20℃ to 60℃. The new expansive agents can compensate and inhibit concrete shrinkage, optimize pore structure of concrete paste and improve concrete density. This will contribute to control the cracking of large concrete aqueducts effectively.