养护方式对宁波通途路综合管廊混凝土抗裂性能的影响

Influence of Curing Methods on Concrete Crack Resistance of Tongtu Road Utility Tunnel in Ningbo

为提高综合管廊混凝土的抗裂性能,开展椭圆环法及实体模型试验,对胶砂或混凝土初始开裂时间、裂缝宽度、总开裂面积进行统计与分析,以研究减缩剂养护、混凝土养护剂养护和土工布养护3种养护方式对综合管廊混凝土抗裂性能的影响。由试验结果得出:1)减缩剂养护使混凝土初始开裂时间相比土工布养护推迟了约6.65%,裂缝宽度降低了约70.67%;养护剂养护下混凝土初始开裂时间相比土工布养护提前了约0.77%,裂缝宽度增加了约11.20%。2)减缩剂养护使平板总开裂面积相对于土工布养护减少了46.97%;养护剂养护使平板总开裂面积相对于土工布养护增加了约7.15%。研究表明:减缩剂养护可以明显改善综合管廊混凝土的抗裂性能,而当混凝土养护剂养护方法不当时对提高混凝土抗裂性能的效果不明显。

In order to improve the crack resistance of concrete for utility tunnel,the elliptical ring method and solid model test are carried out.The initial cracking time,crack width and total cracking area of concrete are statistically analyzed to study the influence of shrinkage reducing agent,concrete curing agent and geotextile on the crack resistance of concrete of utility tunnel.The experimental results show that:(1)Compared with geotextile curing,the initial cracking time of concrete cured by shrinkage reducing agent is delayed by about 6.65%and the crack width is reduced by 70.67%,and that cured by curing agent is advanced by 0.77%and the crack width is increased by 11.20%.(2)Compared with geotextile curing,the total cracking area of the slab cured by shrinkage reducing agent is decreased by 46.97%,and that cured by curing agent is increased by 7.15%.The results show that the shrinkage reducing agent can significantly improve the crack resistance of the concrete in the utility tunnel,but the effect of the concrete curing agent on improving the crack resistance of the concrete is not obvious.