ANALYSIS OF STRESS RELAXATION IN JOINTED PLAIN CONCRETE PAVEMENTS

The cracks in concrete pavements are formed at early-age as consequence of internal stresses in the concrete. Therefore, the stress relaxation has an essential influence on the cracking process. To model this process allows to identify, for instance, the time for saw-cutting the joints or the cracks width that affects load transfer. Previously, the authors proposed a new equation of the relaxation factor, based on a theoretical and practical analysis of the transversal cracking in jointed plain concrete pavements. The objective of the present paper is to analyze the utility of this new equation of relaxation in the design and construction of jointed plain concrete pavements. For that, other cracking processes in plain concrete pavements (jointed and non-jointed) were modelled with the proposed equation. Wherever is possible the modelling results were compared with observations of the real behaviour of pavements. From the design point of view, with the modelling results of transverse crack width (>1.0 mm) is possible to considerate in the design, optimal slabs length with thinner cracks for better aggregate interlock. And for the longitudinal cracking in jointed plain concrete pavements, the modelling and the field observations, yield cracks width that provide load transfer (<0.1 mm). From the construction point of view, the cracking process in non-jointed plain concrete pavements, shows is possible to construct pavements of 7 m width in one gang without cracks risk, and adjustments can be made to a better prediction of the time of occurrence of the 1(st) transverse cracks.