Finite element simulation of curling on concrete pavements.

摘要

Curling results from the temperature and/or moisture differential across the concrete pavement slab thickness. The slab curls downward and upward when the slab experiences positive (temperature of the pavement top is higher than the bottom surface) and negative temperature differentials, respectively. Curling affects the pavement smoothness adversely.; In this study, three-dimensional Finite Element (FE) simulation of curling of concrete pavement has been presented. A finite element software, ANSYS was used to perform the simulation. A number of FE models were built using geometric and material properties obtained from several newly built concrete pavements in Kansas. The pavement sections were modeled as a three-layer system with Portland cement stabilized base (BDB) and lime-treated subgrade. Materials in different layers were modeled as linear elastic. Contact elements option available in the ANSYS library was used to model the interaction between the concrete slab and the dowel bars embedded in concrete. Temperature data was obtained using thermocouples and digital temperature data loggers. Regression models were developed for curling deflection and International Roughness Index (IRI), a roughness statistics, resulting from the curled profiles, based on different simulation parameters. Hourly curling deflections were also measured for several days on a test section. The results obtained from the field measurements were compared with the simulation results.; The results obtained from the simulation show that the curling deflection and IRI calculated form these deflected profiles are affected by the slab thickness, compressive strengths of the concrete and base layers, and temperature differential across the pavement slab thickness. Both curling deflection and IRI increase with an increase in temperature differential between the pavement top and bottom surfaces and compressive strength of the stabilized base layer. Curling deflections obtained from the field measurement show trends similar to those obtained from the FE simulation and are in very good agreements for lower temperature differentials. Effect of wheel loads, in addition to temperature load on curling, was also examined. For positive temperature gradient, critical stresses occurred when wheel loads were applied at the edge of the pavement. However, for negative temperature gradient, corner load produced the critical stresses.; The significant contributions of this study include digital separation of curling form the profile data, identification of the pavement design, material and climatic factors that affect curling, field measurement of curling, and a proposed modeling technique based on three-dimensional finite element analysis.