Concrete fire protection with lightweight aggregate concrete

RUANO SANDOVAL, GONZALO; ARAOZ, GABRIEL; LUCCIONI, BIBIANA MARÍA

Buenos Aires

Congreso; PANACM 2015; 2015

AMCA

Construction of structures is progressively requiring the use of higher compression strength cement basedmaterials to withstand extreme loads. As a counterpart, these materials are more brittle and exhibit higherspalling tendency when subjected to high temperatures. Steel fibers are usually added to counteract theseeffects and improve tensile behavior. Lightweight aggregate concrete covering can also contribute to fireprotection to concrete core [1].The effect of temperature exposure on concrete and fiber reinforced concrete (FRC) protected withdifferent types of lightweight aggregate concrete is numerically simulated in this paper. Concrete ismodelled with a thermo-mechanical plastic model including thermal damage [2]. An elastoplastic modelthat takes into account the effect of temperature is used to simulate fibers and fiber debonding [3][4]. Thethermo-mechanical behavior of FRC is obtained through a simple homogenization procedure based on amodification of mixture theory [3].The proposed model is first validated with numerical examples and comparison with experimental results.For this purpose, thermal problems [5] in concrete proves with lightweight aggregate concrete cover andresidual flexure behavior of FRC beams previously exposed to elevated temperatures [6] are numericallyreproduced. Then, the mechanical behavior of protected concrete and FRC elements exposed to elevatedtemperatures is simulated to show the benefits of using this type of fire protection. Numerical results showthat thermal deterioration of concrete core can be attenuated with these thermal barriers. The numerical tooldeveloped is useful for the design and assessment of this kind of thermal protective covers.