现浇应力吸收层湿接缝混凝土性能研究

Research on the performance of cast-in-situ concrete in wet-joint of stress absorbing layer

结合工程实践,采用密实骨架堆积法设计应力吸收层湿接缝混凝土配合比,从而达到了减少胶凝材料用量、提高混凝土体积稳定性和耐久性的目的。配制出了现浇应力吸收层湿接缝混凝土,并对其力学性能、抗裂性能、体积稳定性以及抗冲击性能进行研究。试验结果表明:混凝土7 d强度到达56.3 MPa,28 d强度到达63.4 MPa,满足7 d张拉施工。混凝土28 d自由膨胀率为2.0×10-4,28 d之后,膨胀率趋于稳定。聚丙烯腈纤维和钢纤维会明显提高混凝土的劈裂抗拉强度,属于防裂等级的一级,并具有优良的体积稳定性和抗冲击性能。

Based on engineering practice,the study adopted the method of dense proportion design to design the mixture proportion of concrete in wet-joint of stress absorbing layer,to reduce the amount of cementitious materials and enhance the volume stability and durability performance.The series of experiments on cast-in-situ concrete in wet-joint of stress absorbing layer was studied,such as the mechanical property,cracking resistance performance,volume stability and shock resistance performance.The results indicated that the compressive strengths of concrete at 7 d had 56.3 MPa and reached 63.4 MPa at 28 d,which met the requirement of tensioning construction.The polyacrylonitrile fiber and steel fiber could improve the tensile splitting strength apparently,which proved the excellent volume stability and shock resistance performance of cast-in-situ concrete in wet-joint of stress absorbing layer.