The Effect of Specimen Size on the Results of Concrete Adiabatic Temperature Rise Test with Commercially Available Equipment.

Byung Lee,Jin Bang,Kyung Shin,Yun Kim

doi:10.3390/ma7127861

Abstract

In this study, adiabatic temperature rise tests depending on binder type and adiabatic specimen volume were performed, and the maximum adiabatic temperature rises and the reaction factors for each mix proportion were analyzed and suggested. The results indicated that the early strength low heat blended cement mixture had the lowest maximum adiabatic temperature rise (Q∞) and the ternary blended cement mixture had the lowest reaction factor (r). Also, Q and r varied depending on the adiabatic specimen volume even when the tests were conducted with a calorimeter, which satisfies the recommendations for adiabatic conditions. Test results show a correlation: the measurements from the 50 L specimens were consistently higher than those from the 6 L specimens. However, the Q∞ and r values of the 30 L specimen were similar to those of the 50 L specimen. Based on the above correlation, the adiabatic temperature rise of the 50 L specimen could be predicted using the results of the 6 L and 30 L specimens. Therefore, it is thought that this correlation can be used for on-site concrete quality control and basic research.

Highlights

Mass concrete structures experience restrained stress due to heat of hydration, which is generated during concrete placement
The reaction factor of the early strength low heat blended cement (EBC) mixture was from 20.7% to 51.8% higher than that of the ternary blended cement (TBC)
For the mass concrete applications, the fact that the EBC had a higher reaction factor than the TBC needs to be sufficiently taken into account

Summary

Introduction

Mass concrete structures experience restrained stress due to heat of hydration, which is generated during concrete placement. This restrained stress can induce thermal cracks that are harmful to structures [1,2,3,4,5,6]. By performing an finite elements analysis of hydration heat and thermal stress, the possibility of thermal cracks during construction processes can be evaluated in the designing and placement planning stages. The factors that affect these cracks include the adiabatic temperature rise of concrete, thermal conductivity, specific heat, convection coefficient, placement temperature, and ambient temperature [7]. The adiabatic temperature rise of concrete is the most significant factor in regard to the result of the analysis of thermal cracks [1,2,3,4]

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