Thermal stability of composite slab-structures in harsh environment

摘要

This paper presents a complete analysis of the effect of harsh environment found in the Arabian Gulf region, especially in UAE, on thermal stability of composite slab-structures with temperature-sensitive internal heat generation. These structures can include building slabs, highway bridge slabs and tunnels, cooling towers, silos, and rotundas. Depending on the application, composite slab-structures may be subjected to sudden and violent thermal effects on their surface due to different applications and various severe environmental conditions. The combination of theses conditions with the possible internal heat generation can provoke some defects that may lead to the degradation of the material properties and the structure function. Therefore, thermal instability of structures will result if the structure fails to dissipate all heat conducted into and generated from/within the structure. It is very important for a designer to select the appropriate material for an application and predict the structure behavior under different operating conditions. In this regard, it is interesting to note that the Great Coulee dam in France was poured with pre-chilled concrete just to compensate for the heat release for the exothermic reaction within the concrete long after the pouring process. An analytical model was developed for the generalized problem that includes the effect of the non-linearity and non-homogeneity of the internal heat generation. Three case studies with combinations of encountered severe boundary conditions are presented and analyzed. The results of these analyses indicate that the critical parameters for thermal stability are critically dependent on the environmental curing process, structure size, the material properties, the heat transfer coefficients, and other constants accrued from the structure environment. The critical values for thermal stability of the composite slab structures may be significant to the service-worthiness of industrial products, to the life span of the structures, as well as to public construction safety.