某湖底隧道混凝土的干缩体积稳定性及其控制

文章针对于某明挖施工的湖底隧道,研究分析了水泥品种、单位用水量、减水剂以及减缩剂对混凝土长期的干缩试验影响规律。试验结果表明:水泥的粒度大小直接影响着混凝土各龄期的干缩值,水泥粒度越小,其相应混凝土的干缩值越大;随着单位用水量的增加,混凝土的干缩增加;普通聚羧酸减水剂对减小混凝土干缩效果不明显,应用减缩型减水剂或将其与普通减水剂复掺,能有效地减小混凝土的干缩,前者达到16%,后者达到12%。在混凝土中掺加减缩剂,减小干缩的效果更显著,能减小27%。通过研究和试验,为该隧道原材料优选和配合比的确定提供了参考。

Study on the drying shrinkage volume stability of concrete and its controlfor an under-lake tunnel

Long-term drying shrinkage performance of concrete adopted in an under-lake tunnel has been studied respectively by applying different types of cement,water consumption,types of water reducing agents and shrinkage reducing agent.Results indicated that the sizes of cement particles can influence concrete's drying shrinkage in all ages.Drying shrinkage of concrete increases with the decrease of the size of cement particles and also increases with the increase of water consumption.Adding ordinary poly-carboxylate water-reducing agents into concrete can rarely alleviate dry shrinkage of concrete,while shrinkage-reducing poly-carboxylate water-reducing agent can be applied alone or mixed with ordinary poly-carboxylate water-reducing agents to reduce the drying shrinkage effectively to 16% and 12% respectively.Adding shrinkage-reducing agent into concrete can more effectively alleviate dry shrinkage of concrete to 27%.The studies of this paper can offer the basis for the selection of raw materials and the conformation of mixing ratios of the concrete to be used in the tunnel.