Influence of specimen geometry and boundary conditions on concrete cracking in the restrained elliptical ring test

Author(s): Wei Dong, Xiangming Zhou, Wenyan Yuan
Paper category: Proceedings
Book title: Proceedings of the 2nd International RILEM/COST Conference on Early Age Cracking and Serviceability in Cement-based Materials and Structures Volume 2
Editor(s): Stéphanie Staquet and Dimitrios Aggelis
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 761-766
Total Pages: 6
Language : English

Abstract: The restrained shrinkage elliptical ring test has been established as an efficient method for assessing the cracking potential of concrete at early ages, because an elliptical ring can provide a higher degree of restraint compared with a traditional circular ring. In addition to the ring geometry, the boundary conditions, i.e. drying from outer circumference or top and bottom surfaces of an elliptical concrete ring also affect the fracture process. In this study, a series of restrained circular and elliptical concrete rings restrained by steel rings with various thicknesses were tested under the two above-mentioned drying conditions. By comparing concrete cracking ages under different conditions, the effects of ring geometry, steel ring thickness and drying condition on crack initiation and propagation were discussed. Furthermore, numerical analyses were conducted to investigate the fracture mechanism for circular and elliptical rings through applying a fictitious temperature field to simulate the shrinkage effect of concrete. It is found that the increase of steel ring thickness can enhance the degree of restraint, therefore shorten the cracking age for both circular and elliptical rings. However, the improvement is more significant for circular rings. Compared with outer circumferential drying, the cracking age of a concrete ring occurs much earlier under top and bottom drying because of a greater exposed area-to-volume ratio. In general, compared with circular rings, the elliptical rings demonstrate the advantage of providing a higher degree of restraint under the same condition, i.e. steel ring thickness and drying condition. The elliptical ring test method can therefore supplement

Online publication : 2017
Publication type : full_text
Public price (Euros) : 0.00

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