Evaluation of the evolutionary behavior of concrete shrinkage at 28 days - focus on slabs on grade in Brazil

Abstract

This article aims to present the feasibility of predicting the evolutionary behavior of hydraulic concrete shrinkage at ages below 56 days, with the goal of reducing the analysis timelines for testing. Thus, it is expected that this study will be useful in minimizing planning failures, generating positive economic impacts, and addressing a technical gap in this field. The research is situated within the context of studies on the durability of concrete structures, focusing on shrinkage as one of the main mechanisms that exacerbate pathologies in slabs on grade. The available literature highlights the importance of assessing shrinkage at different ages of concrete but lacks robust information on optimizing timelines for obtaining reliable results. A robust database was utilized, containing over 200 shrinkage tests conducted between 2020 and 2023, covering different regions of Brazil. The data were analyzed by comparing the results obtained at different ages (14, 28, and 56 days), while also considering variables such as the water/cement ratio, the type of cement, and the use of shrinkage-compensating admixtures. It was concluded that the feasibility of optimizing the evaluation period for the results by 50% allows for the adoption of 28 days as a design parameter. In summary, the study highlights the importance of methodological innovations aimed at constructive and sustainable efficiency. The study is pioneering in proposing a methodology to predict concrete shrinkage at ages below 56 days, allowing for the introduction of a new parameter for evaluation. The value of the research lies in its contribution to optimizing construction processes and improving the quality of slabs on grade.