Effect of compressive loading on the risk of spalling

Abstract

Mechanical loading is an important parameter of spalling phenomenon likely to occur in concrete during heating. Several tests in laboratory have shown an increase of the risk of spalling in the compressed areas. In this study, a specific metallic frame has been developed to apply uniaxial and biaxial stresses on slabs during fire tests. Tests carried out on an ordinary concrete (fc28 = 37 MPa) exposed to ISO 834-1 temperature curve with several levels of uniaxial loading are presented. No spalling was observed when samples were loaded at 0, 5 and 10 MPa. In the opposite, spalling was observed when the compressive stress was increased to 15 MPa.