Thermal, spalling, and mechanical behaviour of various types of cementitious composites exposed to fire: Experimental and numerical analysis

Abstract

Nowadays, new types of cementitious composites are increasingly being used for the construction of structural members. This poses a problem regarding the structural fire safety design as the thermal behaviour and mechanical properties at high temperatures of these materials are usually not known. The main aim of this paper is to investigate and present the thermal behaviour, propensity to spalling, and residual strength of various types of cementitious composites exposed to fire. Namely, the following materials are investigated: ordinary normal-weight concrete with or without fibres, light-weight aggregate (LWA) concrete with or without fibres, recycled aggregate concrete with or without fibres, LWA concrete with open structure, and two novel cementitious composites – LWA concrete containing crushed textile and foam plastic, and concrete containing mineral wool insulation shreds. Additional aim of this investigation is to resolve whether widely-used simple transport and material models are suitable for numerical simulations of thermal behaviour of unusual cementitious composites. For the purposes of the investigation, experimental program was proposed and executed, and numerical simulations were performed. The experimental program consisted of fire test of wall-panel specimens and cube specimens in a vertical furnace and of measurement of physical and mechanical properties of the investigated materials. The numerical simulations consisted of finite element analysis of temperature evolutions in the wall-panel specimens. The paper summarizes the results and conclusions of the experimental and numerical investigations. Within the paper, compressive strengths and residual compressive strengths of the investigated materials are presented and discussed. Moreover, experimentally measured thermal behaviour is analysed and compared with the thermal behaviour predicted by numerical simulations. In addition to this, spalling behaviour and surface damage of the specimens made of the investigated materials are presented and discussed. The main conclusion of this paper is that widely-used simple heat transport and material models are suitable for numerical simulations of thermal behaviour of various cementitious composites. Additional important conclusion is that concrete containing mineral wool shreds performs very well when subjected to fire.