Title: Fiber Reinforced High Strength Concrete: Residual Strength and Pore Structure Subjected to High Temperatures

Author(s): X. Luo, W. Sun, Y. M. Zhang, and S. Y. N. Chan

Publication: Symposium Paper

Volume: 216

Issue:

Appears on pages(s): 49-62

Keywords: fiber; high strength concrete; high temperature; pore structure; residual strength

DOI: 10.14359/12891

Date: 10/1/2003

Abstract:
The mechanical properties and pore structure of fiber reinforced high strength concrete subjected to different high temperatures and cooling regimes were investigated. The results showed that the residual strength of high strength concrete with or without fibers worsened after exposure to high temperatures. Evident drop in compressive and splitting tensile strengths took place between 400°C and 600°C. However, the decline in flexural strength mainly took place before 400°C. Among the specimens, the concrete with 10% of silica fume, 25% of fly ash and 1% of steel fiber provided the highest residual strength and relative residual strength. Steel fibers played a significant role in preventing the worsening of the mechanical properties, particularly at the temperature from 400°C to 600°C. Thermal stress was not the key factor that caused the spalling or explosive spalling in high strength concrete under high temperatures. The re-curing brought recovery of the residual strength in the concretes damaged at high temperatures due to the remarkable improvement of the pore structure.