THERMALLY-INDUCED INTERFACE STRESSES IN POLYMER CONCRETE - PORTLAND CEMENT CONCRETE COMPOSITE BEAMS

摘要

A narrow transverse strip of a polymer concrete overlay was modeled as a two-layered composite beam to quantify the thermally-induced internal stresses when the polymer concrete overlay is subjected to environmental temperature changes. Interface shear and normal stresses in the composite beam model subjected to a uniform temperature change were analytically determined using an existing analytical procedure in plane stress. Parametric studies were then performed to investigate the influence of the thickness and the modular ratios of the top layer (thin polymer concrete) to the bottom layer (portland cement concrete substrate) on stress development. All analysis results were presented for the uniform temperature drop of 100 °C. The material properties included very low elastic modulus of polymer concrete and very thin overlay to investigate the thermally-induced stresses in a realistic polymer concrete overlay. The results of analysis revealed that the development of interface shear and normal stresses is confined to a narrow region near the end of the beam over a distance approximately equal to the total thickness of the composite beam. The parametric study results revealed that the interface shear and normal stresses decrease with decreasing thickness and elastic modulus of the top layer when the thickness of the top layer is significantly smaller than that of the bottom layer. Interface shear stress played a more dominant role than the interface normal stress in thin polymer concrete overlays subjected to the uniform temperature changes. The current study results can be used to estimate the thermally-induced interface stresses in a two-layered structure such as polymer concrete overlays.