龙湖公路隧道混凝土早期收缩性能研究

Study on the early shrinkage performance of concrete of the Long-lake road tunnel

龙湖公路隧道是郑东新区的重要交通枢纽,建成通车后,将在郑州市交通体系中发挥至关重要的作用。采用国内先进的非接触法混凝土收缩变形测定仪,开展了试验室和施工现场混凝土收缩试验,深入研究了膨胀剂掺量、养护条件对混凝土早期收缩性能的影响。结果表明:随着膨胀剂掺量的增加,混凝土早期收缩率减小;随着养护湿度的降低,混凝土收缩率增大;膨胀剂掺量为6%和8%时,混凝土28d抗拉强度基本相同;膨胀剂掺量达到10%时,混凝土28d抗拉强度明显降低。随着养护相对湿度的降低,相同膨胀剂掺量的混凝土28d抗拉强度亦降低。混凝土收缩率在混凝土浇筑成型后的12 h内增长极为显著,之后混凝土收缩率趋于平稳。

The Long-lake road tunnel is an important traffic hub in Zheng-dong New District.And the tunnel will play a vital role in the transportation system of Zhengzhou City.The early-age shrinkage experiment in laboratory and construction site was carried out with Non-contact method of concrete shrinkage deformation-measuring instrument in order to study the impacts of expander and curing condition on early age shrinkage performance of concrete.Results show that the early shrinkage of concrete decreased with the increase of the expander , and the early shrinkage of concrete increased with the decrease of the curing humidity.when the amount of expander is 6%or 8%,the ten-sile strength of concrete was basically the same.When the amount of expander was 10%,the tensile strength of concrete declined obvious-ly.The tensile strength of concrete declined with the decrease of the curing humidity.The shrinkage ratio of concrete grown significantly within 12 h after the pouring of concrete,then the shrinkage ratio of concrete was levelling off.