Reciclagem de materiais fresados de diferentes fontes em misturas estabilizadas para uso em camadas granulares de pavimentos

Abstract

The recycling of Reclaimed Asphalt Pavement (RAP) materials generated in road restoration services is a technique that allows the preservation of financial and environmental resources. This research evalu-ated the use of two types of RAP (RAP-RS400 and RAP-BR290) in unbonding granular mixtures used in pavement base and/or sub-base layers. In addition to the RAPs, virgin aggregates from the Della Pasqua quarry, located in Itaara-RS, were used. In all, nine mixtures were produced with different grain sizes and RAP contents: four using RAP-RS400, four with RAP-BR290, and one mixture composed only of virgin aggregates, without RAP (M0-100%AV). All mixtures were submitted to tests to deter-mine their maximum measured density, maximum dry bulk density, and optimum moisture content, to enable a satisfactory molding process. The impact compaction process was used, adopting the modified energy for all molded samples. All mixtures were then submitted to Repeat Load Triaxial (RLT) tests to estimate theirs resiliences modulus (RM). The results showed that the addition of RAP generated a sig-nificant growth trend in the RM values. From the non-linear regression analysis, it was possible to de-termine parameters to estimate the MR of the mixtures for different stress levels, according to five analyzed forecast models. Then, three mixtures (M0-100%AV, M3-30%RAP-RS, and M1-100%RAP-RS) were submitted to RLT tests for evaluation of permanent deformation (PD). The results showed different performances for each stress level. The M1-100%RAP-RS mixture showed lower strains than the others for intermediate stress levels, but for higher stress levels it presented the highest strain values. From the results, it was possible to determine regression parameters to estimate PD, according to the Guimarães model, obtaining a good correlation with the experimental data. Through the results and mechanistic analysis using the MeDiNa and different levels of traffic, it is concluded that the use of RAP materials analyzed in this research in granular layers of asphalt pavements was able to improve the performance of structures, promoting durability and saving resources. However, it emphasizes the need to analyze the performance of the RAP materials for each case, as these present a high variability. Thus, researches that analyze different applications and types of materials become relevant for promoting the recycling of RAP and all the benefits that this technique can generate for society.