Title: Estimating 28-Day Strength of Concrete from Earlier Strengths-Including the Probable Error of the Estimate

Author(s): Jacob J. Creskoff

Publication: Journal Proceedings

Volume: 41

Issue: 4

Appears on pages(s): 493-512

Keywords: none

DOI: 10.14359/8693

Date: 4/1/1945

Abstract:
Presents a method for estimating the 28-day strength of concrete from earlier strengths. Using a simple basic formula, its coefficient is adjusted by apply-ing the method of least squares to a small number of data obtained from the mix under consideration. The method is noteworthy because it demonstrates that: only limited data are required for estimating purposes; earlier strengths in weighted combination can be used to estimate 28-dav strenqth with in- creased accuracy; the formula ‘can be computed accurately with a IO-in. slide rule; and, because it presents a criterion for judging accuracy of estimates.