Innovative and sustainable shrinkage-compensating concretes

该项目是克拉布拉瓦尔(拉瓦尔大学)持续努力的一部分，旨在帮助将混凝土维修确立为一门合法的工程学科。归根结底，基本目标是为维修行业提供实施合理的维修设计方法和规范所需的知识。在这一探索中，实现尺寸兼容性仍然是最重要的考虑因素之一，以便始终如一地实现不会出现有害裂缝的持久修复工程。硅酸盐水泥混凝土的干燥收缩通常是不可避免的，尽管可以通过优化或修改组成参数来减小其大小，但它仍然明显大于其极限拉应变。相反，通过使用矿物膨胀剂，补偿收缩混凝土(ShCC)的使用可以实现干燥收缩的零维平衡。拉瓦尔大学近年来开展的评估补偿收缩混凝土(ShCC)用作修补材料的潜力的实验工作实际上产生了相当有希望的结果。然而，需要更多的研究才能将ShCC系统变成一种真正可靠和多功能的维修方案。在仍未解决的问题中，修复收缩补偿过程背后的工程尚未开发。需要深入研究膨胀过程的类型及其对各种水泥/粘结剂系统的有效性的总体影响。预期的研究工作将为优化规格、细节和施工方法(修补厚度、粘结或锚固、材料选择、养护技术和持续时间等)提供基础。ShCC修理部。需要解决的另一个方面是缺乏适当的测试方法来表征ShCC，指导规范和执行质量控制。将致力于调整或开发测试程序，以更好地捕捉ShCC的特定体积变化行为。虽然研究计划将主要致力于开发更耐用和可持续的收缩补偿修复混凝土，但研究的一个目标是评估收缩补偿是否可以成功地应用于其他一些特种混凝土。最终，这些发现有望使整个混凝土建筑行业朝着可持续发展的方向发展。

This project is part of a continuing effort at CRIB Laval (Laval University) intended to help establishing concrete repair as a legitimate engineering discipline. Ultimately, the fundamental objective is to provide the repair industry with the knowledge required to implement rational design methods and specifications for repairs. In that quest, the achievement of dimensional compatibility remains one of the most important considerations in order to consistently achieve lasting repair works that do not undergo harmful cracking. Drying shrinkage of Portland cement concrete is generally inevitable and, although its magnitude can be reduced by optimizing or modifying the composition parameters, it remains significantly larger than its ultimate tensile strain. Conversely, the use of shrinkage-compensating concrete (ShCC) may allow to achieve a zero-dimensional balance with respect to drying shrinkage, through the use of a mineral expansive agent. The experimental work carried out in recent years at Laval University to evaluate the potential of shrinkage-compensating concretes (ShCC) for use as repair materials has in fact yielded quite promising results. Nevertheless, more research is required to turn ShCC systems into a truly dependable and versatile repair option. Among the issues still unresolved, the engineering behind the shrinkage compensation process for repairs has yet to be developed. The overall influence of the type of expansive processes and their effectiveness with a variety of cement/binder systems needs to be investigated in depth. The anticipated research work will provide a basis for optimizing specifications, detailing and construction methods (repair thickness, bonding or anchoring, material selection, curing technique and duration, etc.) of ShCC repairs. Another aspect that needs to be addressed is the lack of suitable tests methods to characterize ShCC, to guide the specifications and to perform quality control. Efforts will be devoted to adapt or develop test procedures intended to better capture the particular volume change behavior of ShCC's. While the research program will be primarily dedicated to the development of more durable and sustainable shrinkage-compensating repair concretes, an objective of the research is to evaluate whether shrinkage compensation can be successfully exploited in some other specialty concretes. Ultimately, the findings are expected to benefit the overall concrete construction industry towards sustainability.