# Thermomechanical Behavior of Textile Reinforced Cementitious Composites Subjected to Fire
## 4 Conclusions  
This paper investigated the thermomechanical behavior of textile reinforced cementitious composites subjected to elevated temperatures. The specimens were made of a cementitious matrix with quartz sand and technical textiles coated with styrene-butadiene coating. The heating of the specimens was achieved by one-sided exposure, utilizing a standard fire curve (temperature versus time), which was followed for 15 and 30 min, after which the specimens were cooled down naturally. Flexural tests were performed to heated and not heated specimens, to determine their structural degradation due to the high temperatures. Additionally, compressive tests were performed to heated and unheated TRC specimens, for the same purpose. Moreover, coating burn-off tests were performed to the textiles, to determine the mass loss of coating as a function of temperature. The basic conclusions are the following:  
* The most critical parameter that defines the residual strength of the TRC specimens after heating is the coating of the textiles. After the 15-min long fire test, where the temperature at the effective depth did not exceed 400 \({}^{\circ}\)C, the degradation was less severe, since the coating was not completely lost (less than 30%). The specimens in this case contained hybrid reinforcement of glass and carbon textiles and they suffered reductions of 74% and 48% in the initial and the post-cracking stiffness, respectively. The maximum force also dropped by 25%, while the corresponding maximum displacement increased by 68%. * The textiles that were coated with a thermoplastic material retained a practically negligible residual strength after being subjected to a 30-min fire test, where the temperature at the level of the effective depth (most stressed fibers during the bending test) exceeded 500 \({}^{\circ}\)C. This corresponds to a mass loss of 90% or higher and is explained by the fact that the loss of the coating, which is an intermediate layer between the fibers and the matrix, leads to failure of the bond between the fibers and the matrix. The same result was observed regardless of the fiber material (glass or carbon), the thickness of the concrete cover (8 mm or 12 mm) and the moisture saturation of the specimens (0% or 50%). * The degradation of the mortar due to the high temperature was also significant and could be another dominant parameter. Regarding the compressive strength and the elastic modulus, it was observed that the latter dropped faster with respect to the temperature of exposure. However,in both cases the degradation was not severe until 200 \({}^{\circ}\)C (5% and 23%, respectively), while it became critical at 500 \({}^{\circ}\)C (63% and 82% loss, respectively). * The temperature profile within the cross section of the one-sided exposed specimens of TRC was not uniform. Specifically, the temperature reduction through the top part of the specimens appeared to be higher due to the lower thermal conductivity of the top, hotter, layers. Thus, the concrete cover is also a potential critical parameter that could determine the residual strength of the heated specimens. The effect of the concrete cover, though, was not quantified in this study. * Finally, it was concluded that a highly asymmetrical design scheme can be disastrous for the case of one-sided exposure to fire, since the double asymmetry (in heating and in axial stiffness) can lead to premature failure of the specimens solely due to thermal stresses. Conceptualization, P.K., T.T. ([PERSON]) and T.T. ([PERSON]); Investigation, P.K. and M.E.K. ; Methodology, J.W., T.T. ([PERSON]) and T.T. ([PERSON]); Supervision, T.T. ([PERSON]) and T.T. ([PERSON]); Writing--original draft, P.K. ; Writing--review & editing, M.E.K., J.V., M.D.M., J.W., [PERSON] ([PERSON]) and [PERSON] ([PERSON]). This research was funded by the Agentschap voor Innovatie en Ondernemen (VLAIO), grant number IWT140070, and partially by the Structural Materials Laboratory at the University of Patras.