Recommendations of RILEM TC 287-CCS: thermo-chemo-mechanical modelling of massive concrete structures towards cracking risk assessment

Abstract

These recommendations have been prepared by the corresponding working group within RILEM TC 287-CCS ''Early-age and long-term crack width analysis in RC structures'', following work by the previously ceased RILEM TC 254-CMS ''Thermal cracking of massive concrete structures''. This recommendations document is developed in complementarity to the state-of-the-art report of RILEM TC 254-CMS and aims to provide expert advice and suggestions to engineers and scientists interested in modelling the thermo-chemo-mechanical behaviour of massive concrete structures since concrete casting. Recommendations regarding geometrical characteristics and complexities, concrete properties and appropriate material models, boundary conditions and loads, and numerical model peculiarities with relevance to the simulation of the thermo-chemo-mechanical behaviour of massive concrete structures are given herein. The recommendations have been reviewed and approved by all members of the TC 287-CCS.These recommendations have been prepared within a framework of RILEM TC 287-CCS. The recommendations have been reviewed and approved by all members of the TC 287-CCS.

Autogenous deformation induced- stress evolution in high-volume GGBFS concrete: Macro-scale behavior and micro-scale origin

“…Stress relaxation is a significant factor that must be considered in the quantification of early-age stress evolution in restrained concrete since the creep/ relaxation of early-age concrete is very high [47][48][49]. Due to the difficulties of continuous measurement of aging creep/ relaxation, the inverse modeling by Bayesian Optimization can be applied in TSTM tests, referring to the author's previous study [50].…”

Predicting early‐age stress evolution in restrained concrete by thermo‐chemo‐mechanical model and active ensemble learning

“…The EAS is a direct index for evaluating the EAC risk by analyzing the stress levels or cracking indexes (i.e., the ratio between the stress level and the tensile strength). In this study, the mechanical field focuses on the EAS evolution in the pre‐cracking stage; therefore, local cracks and damages in stress singular points are disregarded as recommended by the study (Azenha et al., 2021). Besides, the majority of the creep models assume that no damage occurs, and general formulas allowing for parameterization over a wide range of concrete properties and damage status are scarce.…”

“…EAS evolution is a result of multiple physical and chemical processes occurring during the early age of concrete structures, including the hydration reaction of cement, heat transfer, autogenous shrinkage, drying shrinkage, and creep/relaxation (Azenha et al., 2021; Šmilauer et al., 2019). Hence, to account for the interplay of different mechanisms, multifield‐coupled modeling techniques are required.…”

“…Rather than using only a convective boundary, they considered the effect of radiation in the heat transfer model and adopted mix‐ and age‐dependent heat transfer parameters, which allowed them to obtain good prediction performance in several case studies. However, they also acknowledged that the lack of consideration of creep, which should be considered in all EAS/EAC analyses (Azenha et al., 2021), compromises the applicability of their model. In comparison, Di Luzio and Cusatis (2013) proposed the solidification–microprestress–microplane model to better account for the influence of creep, shrinkage, and thermal deformation on the EAS evolution and EAC risk.…”

Operational implementation of concrete thermal modeling for construction projects

“…For basic knowledge on phenomenology and simulation, the reader should refer to up‐to‐date literature, such as the Recommendations of RILEM TC 287‐CCS: thermo‐chemo‐mechanical modeling of massive concrete structures toward cracking risk assessment 8 and the State‐of‐the‐art Report of RILEM TC 254‐CMS on Thermal Cracking of Massive Concrete Structures 7 . They aimed at recommending practices to those that are knowledgeable about the basic principles of thermo‐mechanical simulation at early ages therefore it is not fully detailed in this article.…”