Early Age Thermal Crack Control In Concrete

This guide provides a method for estimating the magnitude of crack inducing strain and the risk of cracking; and where cracking will occur guidance is provided on the design of reinforcement to control crack widths.

This text brings together knowledge on early-age thermal cracking, which occurs when the restrained thermal contraction strain exceeds the tensile strain capacity of the concrete. It aims to help both the designer and contractor to understand the significance of cracking, the mechanisms and factors influencing early-age thermal cracking, and its methods of control. Thermal expansion, temperature fall from a peak during hydration of the cement and restraint factors are all discussed. The book shows how early-age thermal strains can be reduced by taking appropriate measures during the design and construction of concrete elements, and develops equations for the control of crack width.

An important new report from the RILEM Technical Committee 119. This book presents models and methods to determine thermal stresses and cracking risks in concrete. The possible influences on and causes of thermal cracking of concrete are discussed and cases of practical measures for avoiding cracking are detailed.

Restraint and intrinsic stresses in concrete at early ages are vitally important for concrete structures which must remain free of water-permeable cracks, such as water-retaining structures, tunnel linings, locks and dams. The development of hydration heat, stiffness and strength, also the degree of restraint and, especially for high-strength concrete, non-thermal effects, are decisive for sensitivity to cracking. Determining thses stresses in the laboratory and in construction components has led to a clearer understanding of how they develop and how to optimize mix design, temperature and curing conditions. New testing equipment has enabled the effects of all the important parameters to be qualified and more reliable models for predictiong restraint stresses to be developed. Thermal Cracking in Conrete at Early Ages contains 56 contributions by leading international specialists presented at the RILEM Symposium held in October 1994 at the Technical University of Munich. It will be valuable for construction and site engineers, concrete technologists and scientists.

This book provides a State of the Art Report (STAR) produced by RILEM Technical Committee 254-CMS ‘Thermal Cracking of Mas-sive Concrete Structures’. Several recent developments related to the old problem of understanding/predicting stresses originated from the evolution of the hydration of concrete are at the origin of the creation this technical committee. Having identified a lack in the organization of up-to-date scientific and technological knowledge about cracking induced by hydration heat effects, this STAR aims to provide both practitioners and scientists with a deep integrated overview of consolidated knowledge, together with recent developments on this subject.

This book presents new guidelines for the control of cracking in massive reinforced and prestressed concrete structures. Understanding this behavior during construction allows engineers to ensure properties such as durability, reliability, and water- and air-tightness throughout a structure’s lifetime. Based on the findings of the French national CEOS.fr project, the authors extend existing engineering standards and codes to advance the measurement and prediction of cracking patterns. Various behaviors of concrete under load are explored within the chapters of the book. These include cracking of ties, beams and in walls, and the simulation and evaluation of cracking, shrinkage and creep. The authors propose new engineering rules for crack width and space assessment of cracking patterns, and provide recommendations for measurement devices and protocols. Intended as a reference for design and civil engineers working on construction projects, as well as to aid further work in the research community, applied examples are provided at the end of each chapter in the form of expanded measurement methods, calculations and commentary on models.

Restraint and intrinsic stresses in concrete at early ages are vitally important for concrete structures which must remain free of water-permeable cracks, such as water-retaining structures, tunnel linings, locks and dams. The development of hydration heat, stiffness and strength, also the degree of restraint and, especially for high-strength concr