Durability Design for Concrete Structures

基于材料、设计细节和结构的综合评价，提出了混凝土结构耐久性设计体系。它是对每个构件抗环境攻击的耐久性性能的检查系统，类似于安全设计系统。通过对现有混凝土结构的实际应用，普遍证实该系统能很好地实现预期的功能。通过对该系统的实验和分析研究，获得了一些有价值的信息。(1)材料评价阐明了骨料性能和膏体微观结构对混凝土渗透性和吸水性的影响。对流动混凝土的偏析性能作为一种材料性能进行了定性评价，开发了具有高变形性和高抗偏析性能的新型混凝土。(2)设计细节的评价，确定了新混凝土填充构件覆盖部分的细节设计的重要性。(3)定量阐明了低温混凝土和含高炉渣混凝土养护对耐久性的施工影响评价。从耐久性角度评价了布置缝和降水施工方法的有效性。期望该设计体系能对提高混凝土结构的可靠性和阐明耐久性研究的意义有所帮助。

Based on the comprehensive evaluation of materials, design details and constructions, the system of durability design for concrete structures was proposed. It is the check system for durability performance of each members against the environmental attack, similar to the safety design system. It was generally confirmed that this system fulfills the intended function well by applying to the actual existing concrete structures.From experimental and analytical studies for improving this system, some valuable informations were obtained. (1) Evaluation for materials The influences of aggregate properties and micro-structures of paste on the permeability and property of absorption of concrete were clarified. Property of segregation of flowing concrete was evaluated qualitatively as a material property and the new concrete with the properties of high deformability and high segregation resistance was developed. (2) Evaluation for design details It was confirmed that it is important how to design the details for filling fresh concrete into the cover portions of members. (3) Evaluation for construction Influences of curing for cold weather concrete and for concrete containing blastfurnasd slag on the durability were clarified quantitatively. Placing joints and the effectiveness of dewatering construction method were evaluated from a view point of durability.In future we expect this design system to be useful for improving the reliability of concrete structures and for clarifying the significance of researches concerning durability.