Title: Elevated Temperature Effects on HSC Residual Strength

Author(s): George C. Hoff; Alain Bilodeau; and V. Mohan Malhotra

Publication: Concrete International

Volume: 22

Issue: 4

Appears on pages(s): 41-48

Keywords: polypropylene fibers; fire tests; high-strength concrete; lightweight concrete; modified normal density concrete; residual strength; mixture proportions; ultrasonic pulse velocity measurements; aggregates; spalling; weight loss.

DOI:

Date: 4/1/2000

Abstract:
Three types of high-strength concrete (HSC) were evaluated for residual strength after being exposed to temperatures up to 1100°C (2012°F). These temperatures are usually associated with hydrocarbon fires. The three concrete types included normal density concrete, using granite or limestone aggregate, with 28-day compressive strength between 75 and 83 MPa (11,000 and 12,000 psi), modified normal density concrete (55% normal weight coarse aggregate plus 45% lightweight expanded slate coarse aggregate) with 28-day compressive strengths between 62 and 69 MPa (9000 and 10,000 psi), and lightweight aggregate concrete using expanded slate or expanded slag with 28-day compressive strengths between 48 and 64 MPa (7000 and 9000 psi). Polypropylene fibers were included in some mixtures. For all three types of concrete, there appeared to be a slight improvement in residual strength at 200°C (392°F) exposure when compared to 100°C (212°F). At exposures of 300°C (572°F) or higher, there is a significant loss of strength. At these higher temperatures, the residual strength of HSC is not significantly different than for normal strength concrete. At exposure temperatures of 900°C (1652°F), all the concretes had no structural integrity