Improved durability testing for field placed concrete and emerging cement systems

越来越多的混凝土结构是根据性能规范建造的。这导致了行业的创新，因为生产商能够以新的方式利用传统材料或非常规材料，因为他们不再受到规定要求的限制。拟议的项目将包括对新兴水泥系统的耐久性调查；例如石灰石水泥、新开发的混合水泥和碱活化体系。性能规格通常包括在现场生产的样品上进行的标准化测试。不符合性能措施可以追溯到不当的混合料交付，但也可能是由于不良的施工实践。由于后者尚未得到很好的研究，因此计划检查当前耐久性试验对检测（识别）不良固化或固结混凝土的敏感性。由于大型项目的建设进展迅速，需要及时确定合规性。随着混凝土性能的发展，对实际现场混凝土进行测试非常重要，因此开发现场无损检测是必要的。该计划将检查诸如吸收、表面电阻率和嵌入式电子传感器等方法，以便在此类情况下使用。由于不断变化的现场条件，如温度和相对湿度可能会影响测试结果，因此也将对这些影响进行研究。该项目旨在通过研究材料选择和场地问题对耐久性的影响，结合实验室和现场测试，采用一种新颖的方法来研究混凝土系统。预计将在不良安置做法对耐久性的影响方面作出原创性贡献，向生产商和承包商提供有关场地问题的有用信息以及适当的早期现场测试。本研究的结果有可能对现场测量混凝土性能的方法产生重大影响，并提高工程师和行业的知识。

Increasingly, concrete structures are built according to performance-based specifications. This leads to innovation in the industry as producers are able to utilize traditional materials in new ways or unconventional materials since they are no longer constrained by prescriptive requirements. The proposed program will include durability investigations of emerging cement systems; such as limestone cements, newly developed blended cements, and alkali-activated systems. Performance specifications typically consist of standardized tests performed on site-produced specimens. Non-conformance to performance measures can be traced to improper mixture delivery, but could also result from poor construction practice. As the latter is not well studied, it is planned to examine the sensitivity of current durability tests for the detection (identification) of poorly cured or consolidated concrete. As construction proceeds rapidly on large scale projects, timely determination of compliance is desired. As it is important to test actual field-placed concrete as its properties develop, developments for in situ non-destructive testing are necessary. This program will examine such methods as absorption, surface resistivity, and embedded electrical sensors for their use in such instances. As changing site conditions, such as temperature and relative humidity may affect test results, these influences will be investigated as well. The program aims to take a novel approach to concrete systems through study of the impact of material selection and site issues on durability that will combine laboratory and field testing. Original contributions are anticipated regarding the influence of poor placement practices on durability providing useful information to producers and contractors regarding site issues as well as appropriate early situ testing. The results of this research have the potential to significantly influence the method in which concrete performance is measured on site and enhance the knowledge of engineers and industry.