ABSTRACT

The number of historically-significant concrete structures which require conservation and repair is ever-increasing. The use of unsuitable proprietary materials has led to poor quality repairs of historically-significant structures in the United Kingdom, some of which have resulted in damage to the historic character of the structure and accelerated deterioration of the substrate. As a result, the approach to the repair of historic concrete structures has shifted from the use of mass-produced proprietary repair materials to purpose-made ‘like-for-like’ replacements which, theoretically, have similar mechanical and aesthetic properties. In order to create like-for-like repair materials, the original mix proportions and water/cement (w/c) ratio of the substrate have to be established. However, there are concerns regarding the accuracy of existing techniques and standards used for the analyses of hardened concrete. Furthermore, due to a lack of available material, analyses are often carried out on samples that are much smaller than the minimum requirement for a representative sample, or from areas which are not representative. This paper discusses these issues and hopes to provide information to conservators and analysts on the limitations of techniques, the variability of the material and the importance of representative samples.

摘要

需要保护和维修的具有历史意义的混凝土结构的数量正在不断增加。在英国，使用不合适的专有材料导致对具有历史意义的结构进行质量低劣的维修，其中一些导致结构的历史特征受损和基材加速劣化。因此，修复历史混凝土结构的方法已从使用大规模生产的专有修复材料转变为专门制造的“同类”替代品，理论上，这些替代品具有相似的机械和美学特性。为了制造同类修复材料，必须确定基材的原始混合比例和水/水泥 (w/c) 比例。然而，人们担心用于分析硬化混凝土的现有技术和标准的准确性。此外，由于缺乏可用材料，通常对比代表性样品的最低要求小得多的样品或来自不具有代表性的区域进行分析。本文讨论了这些问题，并希望为保护者和分析人员提供有关技术局限性、材料可变性和代表性样本重要性的信息。