ANALYSIS OF STRUCTURAL RESPONSE OF CONCRETE PAVEMENTS UNDER CRITICAL THERMAL-LOADING CONDITIONS

Abstract

This paper presents the results of a parametric analysis of structural response of concrete pavements under simultaneous action of traffic loads and temperature variations in the slab. The parameters studied include (1) temperature differential in the slab, (2) slab length, (3) modulus of subgrade reaction, (4) concrete elastic modulus, (5) slab thickness, (6) edge stiffness, and (7) joint stiffness. The effects of using a bonded interface in a composite pavement slab were also analyzed under the thermal-load condition. The finite element computer program FEACONS, developed at the University of Florida, was used to compute the maximum thennal-load-induced stresses in the concrete slabs. Temperature was assumed to vary linearly along the slab depth. The results were also compared with those obtained by the Westergaard equations and the influence charts developed by Pickett and Ray. The results of the analysis show that the temperature differential in the slab has significant effects on the structural response of concrete pavements. Also, the effects of these pavement parameters under critical thermal­ loading conditions are different from those under full subgrade support condition. It was observed that, with the presence of temperature differential in the slab, the effects of modulus of subgrade reaction can not be determined without considering other pavement parameters. For example, with a shorter slab length, the computed maximum thermal-load induced stress increases as the modulus of subgrade increases. The reverse is true for a pavement with longer slab lengths. The use of a bonded interface in a composite pavement slab is most effective in reducing the maximum stresses in the slab when a thinner layer is placed on top of a thicker layer. These observations point to the importance of considering thermal curling effects in concrete pavement analysis and design.