In the structural design of continuously reinforced concrete pavement (CRCP), thermal stresses should be properly taken into account. Thermal strains and temperatures in concrete slabs were measured on test sections of CRCP. Measured strains were divided into axial, curling, and nonlinear components, and each component was examined. It was found that the curling component is predominant in terms of transverse stress, which is important in the structural design. However, the maximum thermal stress is reduced by 25 percent because of the nonlinear component. On the basis of the results, a procedure for estimating the thermal stress in CRCP was proposed.

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In the structural design of composite pavement with a concrete pavement slab overlaid with an asphalt surface course, it is very important to estimate the temperature gradient in the concrete slab. An asphalt surface course reduces the temperature gradient in an underlaid concrete slab, resulting in the reduction of thermal stress of the concrete slab. This effect was investigated by temperature measurement in model pavements and by thermal conductivity analysis. Thermal properties were estimated by a backanalysis by using measured temperatures over 1 year. From the numerical simulations varying the thickness of asphalt surface and concrete slab, the relationship between the reduction effect and the asphalt thickness was derived as a function of the thickness of asphalt surface course, which can be used in the structural design of the composite pavement.

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This paper describes a structral design method developed for composite pavement which consists of a continuously reinforced concrete slab (CRCS) and a asphalt surface layer. The design method is based on the fatigue analysis of CRCS. In the analysis, loading and thermal stresses in CRCS are calculated by plate FEM model. Two effects of asphalt layer are considered in the design. One is a mechanical effect which reduces the load stress in CRCS. The other is a thermal effect which reduce the temperature differential in CRCS. The former is taken into account by using the concept of equivalent thickness besed on the composite plate theory. The latter is incorporeted by intorducing a reduction factor for temperature differential in CRCS. Values of paramters required in the method were obtained from field measurements. Based on the model, the effects of design parameters on the fatigue damage were also investigated.