Glicério Trichês

A crescente preocupação com os impactos ambientais da infraestrutura viária tem incentivado o uso de materiais reciclados na pavimentação, com o Reclaimed Asphalt Pavement (RAP) se destacando como uma alternativa sustentável. Este artigo apresenta uma revisão sistemática da literatura sobre a aplicação de RAP em misturas asfálticas, com foco na Avaliação do Ciclo de Vida (ACV) como ferramenta para analisar sua viabilidade ambiental. A pesquisa foi conduzida em quatro fases, com análise de 14 estudos selecionados a partir das bases de dados Scopus e Web of Science. Os resultados indicam que o uso de RAP pode reduzir significativamente a extração de agregados virgens e o consumo de ligantes asfálticos, além de mitigar impactos ambientais, especialmente quando se aumenta o teor de RAP nas misturas. A ACV se mostrou uma ferramenta essencial para avaliar soluções sustentáveis, pois possibilita a quantificação dos impactos ambientais ao longo do ciclo de vida do pavimento. No entanto, os estudos apresentam variações metodológicas em aspectos como limites do sistema, unidades funcionais e bancos de dados, evidenciando a falta de padronização. Além disso, ainda há uma necessidade de maiores investimentos no Brasil para a aplicação eficaz dessa solução, visando uma implementação mais ampla de práticas sustentáveis no setor viário.

Brazil’s dependence on road transportation, combined with the high extent of the network and the lack of investment management in maintenance and restoration, makes traffic conditions poor, resulting in unwanted costs and environmental impacts. Life cycle assessments are a promising tool that assists in decision making. This study aimed to evaluate the environmental performance of three roads, applying different restoration and maintenance techniques throughout the analysis cycle. To develop this study, the ecoinvent database and the OpenLCA software were used to model, based on studies developed in the HDM-4 (Highway Development and Management) software, and the interventions were applied for the initial year and for 30 years. Using the life cycle assessment methodology, the environmental impacts generated for the categories of acidification, climate change, eutrophication, ecotoxicity, human toxicity and photochemical oxidation were identified. The results show that, when analyzing the restorations in their implementation, deep recycling generates more environmental impacts; however, when planning the restorations throughout the cycle, deep recycling becomes, on average, 47% less impactful than the structural reinforcement technique, which is the same behavior that has been identified with the Whitetopping technique. It becomes evident that the use of rigid structures, such as Whitetopping or semi-rigid structures and deep recycling with Portland cement additions, generate fewer environmental impacts when compared to flexible structures that consume a large amount of asphalt binder, and that require interventions at shorter intervals.

Asphalt rubber mixtures have been used as pavement surface layers due to their ability to prevent early degradation, and are considered a sustainable option. This study performed analysis comparing the fatigue resistance of asphalt rubber mixtures of different combinations of asphalt bases, crumb rubber, and gradation, in order to estimate the performance of asphalt rubber mixtures as pavement surface layers. The methodology was developed in a laboratory and involved asphalt rubber production by continuous and terminal blend systems with different crumb rubbers and asphalt base types. Asphalt rubber mixtures with varying gradations and an unmodified asphalt mixture as a reference were produced. The mechanical behavior as a dynamic modulus and with respect to fatigue resistance was evaluated using a four-point bending test. In order to verify each of the asphalt rubber mixtures’ contribution as a surface layer, pavement structures were designed and their lifespans were compared. The findings showed that all asphalt rubber mixtures presented higher fatigue resistance than the reference. For pavement design, in comparison with the reference mixture, the thickness of the surface layer could be reduced by at least 50% while achieving the same life, proving its successful performance. This study demonstrated the effective contribution of crumb rubber from scrap tires as an asphalt modifier for producing sustainable mixtures with adequate fatigue performance.

Adequately predicting overlay behaviour is essential for flexible pavement rehabilitation to reach the predicted lifespan. Reflective cracking is one of the main failure mechanisms affecting overlay performance. This failure may occur due to cracks in the lower layers that propagate to the overlay due to traffic loads, temperature variations, shrinkage cracking of cement-treated layers, and subgrade movements. This work aims to assess the reflective cracking phenomenon of asphalt rubber mixtures as an overlay through laboratory tests and numerical simulation. Four-point bending equipment and the reflective crack device were used to perform the laboratory tests. A numerical simulation through the finite element method was accomplished to estimate the von Mises strain and develop reflective cracking fatigue laws. The results showed that the asphalt rubber mixtures are suitable for extending overlay lifespan considering reflective cracking. The evaluated asphalt rubber mixtures presented reflective cracking resistance almost eight times greater than the conventional ones.

Fatigue cracking and rutting are among the main distresses identified in flexible pavements. To reduce these problems and other distresses, modified asphalt mixtures have been designed and studied. In this regard, this paper presents the results of a study on rheological behavior and resistance to permanent deformation and to fatigue of four different asphalt mixtures: (1) with conventional asphalt binder (CAP 50/70); (2) with binder modified by nanoclay (3% NC); (3) with binder modified by styrene–butadiene–styrene polymer (SBS 60/85); and (4) with binder modified by nanoclay and SBS (3% NC + 2% SBS). For this analysis, the mixtures were evaluated based on complex modulus, permanent deformation tests, and fatigue tests (4PB, in the four-point bending apparatus), with the subsequent application of numerical simulations. The results obtained show a better rheological behavior related to greater resistance to permanent deformation for the mixture 3% NC + 2% SBS, which could represent an alternative for roads where a high resistance to rutting is required. Otherwise, on fatigue tests, higher resistance was observed for the SBS 60/85 mixture, followed by the 3% NC + 2% SBS mixture. Nevertheless, based on the results of the numerical simulations and considering the possibility of cost reduction for the use of the 3% NC + 2% SBS mixture, it is concluded that this modified material has potential to provide improvements to the road sector around the world, especially in Brazil.