Seasonal variation of structural response of concrete pavements

Variations in temperature and moisture conditions affect the deflection response of concrete pavements. In Kansas, concrete pavements are tested for deflection response using an NDT device, Falling Weight Deflectometer (FWD). Temperature, subgrade moisture content, and FWD-deflection data were collected monthly on two concrete pavement test sections for a year. The subgrade and concrete pavement slab moduli were backcalculated using the elastic layer theory. Joint load transfer efficiencies were also calculated from the FWD deflections measured at the joints. The results show that the range of moisture content encountered in the in-service concrete pavement subgrades over the seasons was not broad and did not appear to affect the subgrade response appreciably. High temperature induces slab curling pavements, thereby affecting the obtained by the backcalculation process. Higher temperature also affects calculated joint load transfer efficiencies. It is recommended that the FWD tests be done in moderate climate in order to avoid high temperature effects.