Influência dos módulos de resiliência inicias no procedimento de retroanálise de pavimentos flexíveis

Abstract

Currently, a series of computational methods (software) are available that provide the backcalculation of pavement structures. Most of these software uses the deflection measurements as an analysis parameter and compares the measured and calculated deflections values to obtain the resilience module (RM) of the pavement layers. In order to carry out the analyzes, the layer thickness, the Poisson's ratio (ν) and the initial resilient moduli are required as input data. Even with all these tools, the problem does not ensure a closed solution (unique), since several combinations may produce the same deflection basin. The thickness value and the moduli seed moduli interfere directly in the calculations. Therefore, this paper aims to analyze the variability of the resilient moduli obtained from backcalculation programs, having as input data different seed moduli. To this end, data obtained from non-destructive structural evaluation (Falling Weight Deflectometer - FWD) and destructive evaluation were used in three different regions (UFJF highway ring, BR-116RJ CRT and BR-040/GO/MG Via040 highway). With the samples collected in the field, dynamic triaxial tests were performed to obtain the RM in laboratory. Thereafter, the deflection basin values and the seed moduli were inputted into the two backcalculation software (ELMOD and BackMeDiNa). By varying the RM seed of one of the layers by 100%, the percentage differences in the final resilience moduli were calculated. The interface bonding between pavement layers, relations of between moduli obtained from laboratory and field, relations between two different backcalculation programs and correlations between deflection basin parameter and moduli were carried out as well. Besides, with the data provide from backcalculation software and crack monitoring, these were inputted into the flexible pavement design software (MeDiNa), to also analyze the influence of variability of seed moduli in the final result in the pavement reinforcement design, through the cracked area percentage parameter. Thus, it was found that the seed moduli have a high influence on the final moduli in the backcalculation processes, with percentage differences of up to 137%, mainly for the base and sub-base layers of pavement. Even with the difference obtained in the RM values from the variation of the initial RM, it was found that there was no significant impact on the reinforcement design, in which the percentage difference between the cracking predicted for the surface course was less than 7,5%.