Development of Initial Strength Promotion Formulation that Ensures Concrete Strength and Quality in Tunnel Lining
By K. Haze, A. Sawamura, M. Murate and E. Takeshita
Concrete Journal, Vol.58, No.12, Dec. 2020
- Synopsis
- In construction projects where the time between concrete placing and formwork removal is relatively short, such as lining concrete in mountain tunnels and secondary lining concrete in shield tunnels, development of the required strength for formwork removal often has a significant impact on the construction cycle of the project. However, depending on the environmental and proportioning conditions, it may be difficult to rapidly the required strength sufficiently rapidly. Currently, this is dealt with by promoting strength development by means such as adjusting the proportioning conditions and the curing practice. Against this background, construction was carried out using various formulations of concrete combined with curing accelerator and high-early-strength type expansive admixture in order to improve the initial strength of concrete. This paper reports the results of laboratory tests conducted during the development process of this method and examples of on-site application.
- Keywords:
- Lining concrete, Initial strength, Strength at early age, Low temperature environment, Long-term durability, Curing accelerator, High-early-strength type expansive admixture
