Title:
Strength development and temperature rise in large concrete blocks containing high volumes of low-calcium (ASTM Class F) fly ash
Author(s):
W. S. Langley, G. G. Carette, and V. M. Malhotra
Publication:
Materials Journal
Volume:
89
Issue:
4
Appears on pages(s):
362-368
Keywords:
compression tests; cores; curing; high-strength concrete; fly ash; temperature; Materials Research
DOI:
10.14359/2514
Date:
7/1/1992
Abstract:
Three large concrete blocks, 3.05 x 3.05 x 3.05 m, were cast in Halifax in 1988 to monitor the long-term strength development of concrete. Two blocks were cast from concrete incorporating approximately 55 percent ASTM Class F fly ash and the third block was a control block using concrete incorporating portland cement only. The water-to-cementitious materials ratio of these concretes ranged from 0.27 to 0.49, and their cementitious content ranged from 400 to 225 kg/m3. A large number of 150 x 300-mm cylinders were cast for testing up to 3 years, with half of the cylinders being cured under moist room conditions and the other half under field conditions. A large number of 100 x 300-mm cores were drilled from the blocks up to 24 months to monitor the in situ strength development of concrete. The ratio of the 42-day core compressive strength to the 28-day laboratory-cured compressive strength ranged from 78 percent for the control concrete to 120 percent for the high-volume fly ash concrete from the block having a total cementitious content of 400 kg/m3. At 365 days, the respective ratios were 78 and 92 percent, and at 730 days, the respective ratios were 88 and 98 percent. Blocks incorporating 400 kg/m3 of portland cement, 180 kg/m3 of portland cement and 220 kg/m3 of fly ash, and 100 kg/m3 of portland cement and 125 kg/m3 of fly ash reached peak temperatures of 83 C at 24 hr, 54 C at 96 hr, and 30 C at 168 hr, respectively. 181-592