甘肃省戈壁地区养护方式对预制混凝土箱梁抗裂性及强度的影响

Effects of Curing Methods on Crack Resistance and Strength of Precast Concrete Box Girder in Gobi,Gansu

为研究甘肃省戈壁地区养护方式对预制混凝土箱梁抗裂性及强度的影响,首先勘测了现场气候条件,选择了三种养护方案。然后测试和分析了不同养护方式下试验箱梁强度及裂缝的发展规律,结果表明:按照蒸汽养护、土工布包裹养护、薄膜包裹养护的顺序混凝土强度及拉压比逐渐减小,抗裂性逐渐减弱;蒸汽养护为戈壁地区最佳的养护方式;戈壁地区出现的裂缝宽度主要分布在0.00~0.02 mm及0.03~0.04 mm两个区间;在戈壁地区混凝土箱梁的养护不仅要注重保湿养护,更应该加强保温养护。最后结合试验和现场施工情况,对大温差、干寒、强风地区预制混凝土箱梁裂缝的预防和控制提出一些针对性的建议。

In order to study the effect of curing methods on crack resistance and strength of precast concrete box girder in Gobi, Gansu Province, firstly, we surveyed the weather conditions at the site and selected three maintenance schemes. Then we tested and analyzed the strength of the box girder and the development of the crack under different curing methods, the results show ： the concrete strength and the ratio of tensile and compressive strength of the concrete are gradually reduced, and the cracking resistance is gradually weakened ; steam curing is the best maintenance method in Gobi area ; the width of cracks in Gobi area is mainly distributed in 0. 00-0. 02 mm and 0. 03-0. 04 mm two intervals; the maintenance of concrete box girder in Gobi area should not only pay attention to moisture conservation, but also strengthen the insulation. Final ly, this paper puts forward some suggestions on the prevention and control of cracks in precast concrete box girder in large temperature difference, dry and strong wind area combined with the test and field construction.