LOAD TRANSFER IN UNDOWELED TRANSVERSE JOINTS OF PCC PAVEMENTS

The results of load transfer evaluations in 21 test sections of the Chilean in-service highway network are presented. Characteristics of transverse joints are described, and procedures to measure the absolute deflections of four points in a slab, plus another one across the transverse joint, are explained. The procedures allow load transfer to be evaluated with good accuracy and repeatability. Measurements conducted over continuous 24-hr cycles in winter and summer show that the load transfer depends upon the thermal conditions of the pavement. Its daily variations are satisfactorily explained by the changes in transverse joint openings. Load transfer on the leave slab is much different from that on the approach slab, unless the joint stiffness is so high that the pavement behaves as a continuous strip. To evaluate internal stresses of pavement slabs, a mechanistic approach is described in which three kinds of joint stiffnesses are proposed to take into account the effects of shear forces and moments developed at joints, as well as compressions built up by the slabs' moisture and temperature.