Use of Prediction Relations
Chetan G. Date and Russell H. Schnormeier
Appears on pages(s):
accelerated tests; acceptability; compression tests; compressive strength; concretes; cylinders; estimates; least squares method; models; predictions; quality control; specifications; statistical analysis.
The current trend of fast construction has necessitated knowledge of the 28-day strength of concrete at an early stage. This article presents 28-day strength prediction models based on 7- and I4-day strength of a concrete cylinder. A large amount of data collected over a period of one year from the Laboratory of the City of Phoenix was statistically analyzed using the orthogonal polynomial method of the least square curve fit to obtain the prediction relations, which then were compared to the ones presented by previous researchers. A general method is presented to obtain these relations. These simple prediction relations enable the engineer to accept the concrete and/or predict its 28-day strength at an early stage of the curing.