A quantitative approach to the concept of concrete repair compatibility
B. Bissonnette , F. Modjabi-Sangnier , L. Courard , Andrzej Garbacz , A.M. Vaysburd
AbstractThe work reported in this paper is part of a wider research program intended to provide the repair industry with improved fundamental knowledge to implement rational design methods and rules for repairs. In that regard, there is a strong need to study the fundamental relationships and parameters that underlie the repair compatibility concepts, in particular those relating to dimensional compatibility. In the first part of the paper, classical formulas derived for thick cylindrical specimens were used to analyze the tensile stress buildup in annular restrained shrinkage test specimens, taking into account the restraining conditions of the investigated ring test method and the individual concrete properties/phenomena determined experimentally (elastic modulus, creep coefficient, drying shrinkage deformation). By comparing the ring test results with the calculated tensile stresses, the validity and accuracy of the theoretical approach could be appraised. A quantitative approach for the evaluation of the performance of concrete repair in terms of dimensional compatibility was then developed. Derived from the basic strain balance approach (ratio between the total deformability in tension and the drying shrinkage deformation), a parameter referred to as dimensional Compatibility Index (CI) was introduced in order to analyze the evolution of dimensional compatibility as a function of time for a given concrete mixture, taking into account the actual degree of restraint in the element. Compatibility Index evolution curves were calculated for various repair concrete mixtures in order to highlight material behavior relating to composition parameters and temperature. As it requires the evaluation of a limited number of individual properties that are for most readily available (i.e. strength, elastic modulus, shrinkage), the Compatibility Index expressed in terms of deformation carries a lot of potential as a relatively simple and convenient analytical tool for assessing the cracking sensitivity of concrete repair materials. Overall, it can be stated that a good correlation was found between the ring test results and the tensile stress values calculated based on individual concrete properties / phenomena and that the proposed calculation method lays ground for evaluating quantitatively the dimensional compatibility of repair materials and defining suitable performance criteria.
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|Book||Dehn F. et al (eds.): Concrete Repair, Rehabilitation and Retrofitting IV: Proceedings of the ICCRRR-4, 5-7 October 2015, Leipzig, Germany, 2016, Taylor & Francis Group, ISBN 978-1-138-02843-2, [978-1-315-67754-4], 246 p.|
|Score|| = 15.0, 17-03-2020, BookChapterMatConfByConferenceseries|
= 15.0, 17-03-2020, BookChapterMatConfByConferenceseries
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