Structural response of concrete pavement slabs under hygrothermal actions

Abstract

This paper presents a comprehensive evaluation of the structural response of concrete pavement slabs subjected to ambient environmental actions. Experimental data come from six bonded concrete overlay of asphalt pavements built with rapid strength concrete mixtures. The mixtures contained either portland cement or calcium sulfoaluminate cement, and included an internally cured concrete with pre-wetted lightweight aggregates. The pavement slabs were instrumented with temperature, relative humidity, and strain sensors. The measured temperatures and strains were analyzed by using a model that includes two components, one for moisture-related shrinkage and another for thermal deformations. The analysis of data collected over fifteen months shows that the ambient environment actions considerably impact the coefficient of thermal expansion (CTE) of pavement slabs concrete. Because of drying, the thermal deformations of the slabs were up to 65% larger than predicted based on the CTE determined in the laboratory under saturated conditions following AASHTO T 336. The analysis of the experimental data supplements the understanding of how drying and autogenous shrinkage accumulates in concrete pavement slabs in the field, depending on mixture type and weather conditions. Experimental results from this study question the validity of a number of assumptions adopted in current mechanistic-empirical design procedures for concrete pavements, including the constant CTE of the concrete and the depth of drying penetration in pavement slabs.