CRTSⅢ型板式无砟轨道结构底座混凝土收缩开裂性能研究  

Study on Shrinkage and Cracking Performance of Roadbed Concrete Used in CRTSⅢSlab Ballastless Track Structure

作　　者：王栋 WANG Dong(Hefei-Anqing High-speed Railway Co.Ltd.,Hefei 230011,China)

机构地区：[1]合安高铁股份有限公司,合肥230011

出　　处：《铁道建筑》2021年第4期125-128,共4页Railway Engineering

摘　　要：针对CRTSⅢ型板式无砟轨道底座现浇混凝土易开裂问题,对比研究了采用降低胶凝材料总量和用水量、降低坍落度、提高含气量、掺加抗裂减缩材料等优化措施制备的C40混凝土和工程常用道床C40混凝土在力学性能、体积稳定性和开裂敏感性方面的差异。试验结果表明:降低混凝土胶凝材料总量和用水量的措施对混凝土工作性能有一定不利影响,但通过适当提高含气量则可有效补偿工作性能的降低;采用优化措施后的道床混凝土早期强度有所降低,但56 d抗压强度均满足C40混凝土要求;在体积稳定性方面,降低胶凝材料总量和用水量后混凝土24 h塑性收缩变形比基准工程混凝土显著降低;抗裂减缩材料的掺入对降低混凝土干燥收缩变形贡献最大;掺抗裂减缩材料混凝土的抗裂能力最好;试验设定的两种坍落度对混凝土力学性能和体积稳定性没有明显影响。In view of the cracking problem of roadbed concrete used in CRTSⅢslab ballastless track structure,the performance difference between the optimized C40 concrete which prepared by reducing the total amount of binding materials and water consumption,reducing slump,increasing air content and adding anti-cracking materials and the C40 concrete used normally in-site were studied,including mechanical property,volume stability and cracking sensitivity.The results show that the measures to reduce the total amount of binding materials and water consumption have some adverse effects on concrete workability,but can be effectively compensated by appropriately increasing the air content.The early strength of roadbed concrete decreases obviously after adopting the optimized measures,but the 56 d compressive strength all meet the requirements of C40 concrete.In terms of volume stability,24 h plastic shrinkage deformation of concrete after reducing the total amount of binding materials and water consumption is significantly lower than that of the reference engineering concrete.The addition of anti-cracking materials contributed the most to reducing the drying shrinkage deformation of concrete.The crack resistance of concrete mixed with anti-crack shrinkage reducing material is the best.The two kinds of slumps set in the test have no obvious influence on the mechanical properties and volume stability of concrete.

关 键 词：板式无砟轨道结构 底座混凝土 试验研究 开裂 体积稳定性 开裂敏感性 

分 类 号：TU528[建筑科学—建筑技术科学]