Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

Keun-Hyeok Yang,Myung-Sug Cho,Jae-Sung Mun

doi:10.1155/2015/965471

Abstract

This study examined the relative strength-maturity relationship of high-strength concrete (HSC) specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1) isothermal curing conditions of 5°C, 20°C, and 40°C and (2) terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

Highlights

There has been an increasing interest in the practical application of high-strength concrete (HSC) in the fast-track construction of nuclear facility structures with a prestress system
The present discussion focuses on the effect of water-to-binder ratio (W/B) on the apparent activation energies at setting and hardening phases and the compressive strength development of the concrete at various temperature histories to investigate the tendency of the maturity function in HSC
The difference between the setting times according to W/B decreased with increasing curing temperature

Summary

Introduction

There has been an increasing interest in the practical application of high-strength concrete (HSC) in the fast-track construction of nuclear facility structures with a prestress system. As demonstrated by several studies [1, 2] accelerated construction schedules of structures can be achieved by using HSC because of its naturally high early-age strength gain compared to normal-strength concrete (NSC). The accurate evaluation of the early-age in-place properties of HSC is important for determining the following construction phases [2]: (1) the minimum stripping time of the concrete form and shoring; (2) the minimum concrete age for applying prestressing force to a structural element; and (3) the temperature and the length of time for accelerated in situ curing processes, in cold weather. Much less maturity data are available for HSC [2, 12] than for NSC

Objectives

Results

Conclusion