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Author
Carino, N. J. | Knab, L. I. | Clifton, J. R.
Title
Applicability of the Maturity Method to High-Performance Concrete.
Coporate
National Institute of Standards and Technology, Gaithersburg, MD
Sponsor
National Institute of Standards and Technology, Gaithersburg, MD Department of Transportation, Washington, DC Army Corps of Engineers, Washington, DC
Report
NISTIR 4819, May 1992, 64 p.
Distribution
Available from National Technical Information Service
Keywords
concretes | curing | silica | fumes | temperature | maturity method | mortar | regression analysis
Abstract
This study examines whether the maturity method is applicable to represent the strength development of high-performance concrete mixtures cured at different temperatures. Two mortar mixtures were investigated having water to cementitious solids ratios of 0.29 and 0.36. The mixtures were made with Type I cement, silica fume (10% by mass of cement), and a high-range water reducing admixture. Ten batches of mortar were prepared to make cube specimens, which were cured under water of three temperatures: 7, 23, and 40 deg C. Compression strengths were measured at ages ranging from 4 hours to 139 days. The strength-age data were analyzed using three models to determine the rate constant for strength development at each curing temperature. The models included two hyperbolic equations (linear and parabolic) and an exponential equation. The rate constant versus curing temperature relationship for each model was represented by a simple exponential equation, which was used to convert test ages to equivalent ages of curing at 23 deg C. The strength development of the various mortar batches could be described by a single equation relating relative strength to equivalent age. Thus it was concluded that the maturity method is applicable to describe strength development of the low water-cement ratio mixtures. It was also observed that the estimted long-term strength of the batches did not appear to be affected by the curing temperature. This is in direct contrast with the known behavior of conventional concrete mixtures.