Improved durability testing for field placed concrete and emerging cement systems

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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.