Title: In-Place Strength of High-Performance Concretes

Author(s): F. Michael Bartlett and James G. MacGregor

Publication: Symposium Paper

Volume: 167

Issue:

Appears on pages(s): 211-228

Keywords: Compressive strength; concrete cores; evaluation; fly ash; high-strength concretes; silica fume; slags; temperature.

DOI: 10.14359/6288

Date: 3/1/1997

Abstract:
The ratio between the in-place compressive strength of high performance concretes and the strength of standard 28-day cylinders is investigated. Strength data for 771 cores from 3 1 large elements cast using 22 concrete mixes reported in five investigations by others are analysed. It is observed that the ratio of in-place strength to standard cylinder strength decreases as the maximum temperature sustained during hydration increases. If the concrete mix contains silica fume, Class C fly ash, or slag, the ratio of the in-place strength at 28 days to the standard 28-day cylinder strength of the same concrete is markedly less than that observed for concretes which do not contain supplementary cementitious materials. In all elements investigated, the average in-place strength continued to increase after 28 days. The relative strength gain of silica fume concretes after 28 days was significantly less than that of conventional concretes.