超早强ECC材料在模数式伸缩缝中的应用研究

Research on Application of Ultra-early-high-strength ECC in Modular Expansion Joints

为实现高速公路桥梁模数式伸缩缝的快速修复以减少对交通的影响并延长使用寿命,对所研制的超早强ECC材料进行了基本力学及长期耐久性能试验,同时在此基础上提出了基于超早强ECC材料的桥梁模数式伸缩缝构造设计方案并介绍实体应用工程。结果表明:研制的超早强ECC材料3 h抗压强度可达35.7 MPa,满足早期强度要求,各龄期单轴拉伸应变均不低于3%,单轴拉伸强度均不低于4 MPa,在四点弯曲荷载作用下同样具有较强的变形能力;干燥收缩值仅524με,抗氯离子渗透性能较普通ECC差,但其是固化氯离子的理想材料,应用设计时应注意保护层厚度,抗冻等级可达F200;超早强ECC材料适用于高速公路桥梁模数式伸缩缝的快速维修改造,在提升耐久性的同时降低全寿命周期成本。

In order to realize the rapid repair of modular expansion joints in expressway bridges to reduce traffic congestion and prolong service life,researches on mechanical properties and durability of ultra-early-high-strength ECC is carried out.The structural design scheme of bridge modular expansion joints based on the ultra-early-high-strength ECC is proposed and its application project is introduced.The results show that the 3 h compressive strength of the ultra-early-high-strength ECC can reach 35.7 MPa,which meets the requirement of early strength.The uniaxial tensile strain and strength at each age is not less than 3%and 4 MPa respectively,with strong bending capability under four-point bending load.The drying shrinkage of the ultra-early-high-strength ECC is only 524μe.The anti-chloride ion penetration performance of the ultra-early-high-strength ECC is worse than ordinary ECC,but it is an ideal material for curing chloride ions,so attention should be paid to the thickness of protective layer in project practice.The frost resistance grade can reach F200.The ultra-early-high-strength ECC is suitable for the rapid maintenance and reconstruction of modular expansion joints in expressway bridges,which improves durability while reducing the whole life cycle cost.