Cracking occurrence due to shrinkage related effects is a widely recognised issue which is frequently evaluated with the shrinkage restraining ring test. This paper provides a state-of-the-art review of the ring test method, which has been used for the last four decades. The last review on such matter was conducted only in early 2000s; however, a significant amount of studies has been conducted since then and considerable advancements or modifications in this testing method have taken place over the last decade. Studies on the traditional ring test, i.e. a circular concrete ring cast around a steel ring, are identified and the history, tendencies, practices and quantitative methods are analysed thoroughly. Furthermore, any modifications/advancements in the testing method with respect to their purpose, applications and capabilities based on current knowledge, are addressed. Finally, an insight on the challenges that the developers of testing methods for restrained shrinkage are faced with is given together with perspectives for their future potential improvement.
Kanavaris, F., Azenha, M., Soutsos, M., & Kovler, K. (2019). Assessment of behaviour and cracking susceptibility of cementitious systems under restrained conditions through ring tests: A critical review. Cement and Concrete Composites, 95, 137-153. https://doi.org/10.1016/j.cemconcomp.2018.10.016