Present status and issues of control technology for cracking of mass concrete in Japan

Abstract

This paper presents the current state of the control technology for cracks caused by heat generation due to the hydration of cement during construction in Japan. For the prediction analysis for thermal cracking of mass concrete, this paper presents the CP method that was developed for the first time in the world, the thermal cracking probability, the simple evaluation method that can predict and estimate the thermal cracking without performing complicated analysis and the evaluation method for expansive materials using the mechanical energy conservation hypothesis. In addition, issues are introduced for the next revision of the guidelines.

Standardized models for cracking due to restraint of imposed strains—The state of the art

“…This approach was advocated by the Japan Concrete Institute until the 2016 version of their report 13 after which it was replaced with a fully three‐dimensional FEM‐based method for determination of stresses caused by volumetric changes. Alongside, a concept of cracking index was introduced which is used for the assessment of cracking risk and crack width calculation 31 . The formula for the maximum crack width calculation according to the cracking index and reinforcement ratio is an empirical formula derived with a statistical analysis of a large database of the results obtained in numerical simulations of wall‐ and non‐wall structures in Japan.…”

“…Alongside, a concept of cracking index was introduced which is used for the assessment of cracking risk and crack width calculation. 31 The formula for the maximum crack width calculation according to the cracking index and reinforcement ratio is an empirical formula derived with a statistical analysis of a large database of the results obtained in numerical simulations of wall-and non-wall structures in Japan. The formula has been calibrated so its physical meaning is implicit.…”