Title:
Sustained High Temperature Effect
on Concretes Made With Normal Portland
Cement, Normal Portland Cement and Slag, or Normal Portland Cement and Fly Ash
Author(s):
G. G. Carette K. E. Painter, and V. M, Malhotra
Publication:
Concrete International
Volume:
4
Issue:
7
Appears on pages(s):
16
Keywords:
DOI:
Date:
7/1/1982
Abstract:
This investigation was undertaken to determine the changes in the mechanical properties of concrete after long-term exposure to sustained temperatures ranging from 75 to 600 C (167 to 1112 F). The water-cement ratio or water-to-cementitious materials ratio of three types of concrete investigated ranged from 0.45 to 0.60. Crushed dolomite limestone and natural sand were used as the coarse and fine ag gregates. The concrete test specimens were exposed for up to eight months to temperatures ranging from 75 to 600 C. Conditioning of test specimens prior to any temperature exposure consisted of moist-curing for 28 days, followed by storage in room conditions for a minimum of 16 weeks. Test results indicate that the use of blast furnace slag or fly ash as partial substitutes for cement in concrete, in general, does not improve the mechanical properties of concretes that have been exposed to sustained high temperatures. Any major changes in the properties of the concretes occur within the first month of exposure. The severe disruption of concrete under sustained exposure at 150 C (302 F) is attributed to the instability of some coarse aggregate particles at this temperature.