The application of alkali-activated industrial by-products for the stabilization of reclaimed asphalt pavement (RAP), can become a sustainable solution to reduce the carbon footprint of road construction and maintenance activities. Furthermore, this approach can also reduce the increasing depletion of natural resources. Thus, the durability and long-term mechanical performance of RAP stabilized with alkali-activated fly ash were assessed in this study. The alkaline activator was a solution composed of sodium hydroxide and sodium silicate. To this extent, unconfined compressive strength (UCS) and durability tests were conducted in this research. The proposed alkali-activated binder significantly increased the UCS of RAP mixtures, with long-term (365 days) results reaching values up to 32 MPa; fulfilling the strength requirements for cement-stabilized soil mixtures and even stable inorganic binder materials for road base and sub-base layers of pavements. These results indicate that when stabilized with an alkali-activated fly ash binder, RAP presents several applications for road engineering; even when subjected to seasonal variations in humidity and temperature, as shown by the durability tests.
ResumoO presente relato técnico objetivou estudar formas lícitas de auxiliar empresas do ramo da construção civil a manterem-se atuantes e capitalizadas através da redução do ônus fiscal. O estudo das formas de diminuição de pagamento de tributos chama-se elisão fiscal. Para tanto, foi realizado um estudo e levantamento de dados dos fatos geradores de impostos e a relação de tais tributos com o compromisso fiscal. Buscou-se investigar a melhor opção tributária
The objective of this paper is to evaluate a method based on image analysis to obtain shape parameters in crushed sand grains. There is no consensus about standards and rules for testing aggregates, the lack of methodology to prepare and conduct tests may produce incorrect results, which do not satisfactorily represent the aggregate characteristics. One way to perform these analyzes is the use of images obtained with magnifying glasses or similar equipment. To contribute to this, three experiments were prepared with samples of crushed sand from the city of Passo Fundo. The fixed and evaluated parameters were: samples preparation, zoom used for image acquisition and number of grains representative of the shape parameters. The results were statistically analyzed and significant differences were obtained to the shape factor regarding the fixed parameters, except for the number of grains needed to characterize it, which differs from the currently literature used by academic studies. According to this work it is possible to realize that it is necessary to standardize the tests for shape analysis to eliminate errors generated by the interpretation of incorrect results, which may have been generated by changes in the methodology for conducting the tests.
O cimento atualmente é um dos produtos mais consumidos mundialmente da mesma forma, é um dos maiores responsáveis pela emissão de dióxido de carbono (CO2) na atmosfera resultado da forma em que é produzido. Com isto, surge a necessidade urgente da substituição deste ou ao menos da redução de seu consumo. A tendência global é que a sociedade parta para um consumo e reaproveitamento de seus próprios resíduos gerados tanto pela necessidade em virtude de escassez de matéria-prima natural quanto pela inevitabilidade de tratamento destes que necessitam de um correto descarte. Desta forma, inúmeros materiais alternativos vêm surgindo suscetíveis a substituição dos até então convencionas, que é o caso da Cinza de Casca de Arroz – CCA proveniente da queima em leito fluidizado do material orgânico remanescente da descasca do arroz. No atual trabalho, é verificada a substituição parcial e total do cimento por cinza de casca de arroz avaliando seu potencial de utilização na pavimentação. As substituições se deram nos teores de 20%, 50% e 100% em relação a massa seca do cimento. Um peso específico aparente seco de 20 kN/m³ foi adotado bem como um teor de umidade de 7% para confecção de corpos de prova seguindo a metodologia Marshall. Estes posteriormente foram avaliados quanto a resistência à tração por meio de compressão diametral. A substituição de 20% se mostrou favorável atendendo as exigências mínimas de utilização estabelecidas pela norma DNIT 167/2013-ES, portanto, podendo representar uma drástica redução no consumo de cimento nestes casos, contribuindo de forma técnica, econômica e ambientalmente.
This work presents a comparison between the main environmental certifications: AQUA, LEED and Selo Casa Azul by comparing the demands of analogs requirements. For the appreciation of the certifications, the type of the buildings was considered as residential. The implementation of the environmental certification is an improvement that the construction industry can adopt. The discrimination of analogs requirements allowed comparing the similarities and differences between the requirements, making possible to determine which certification is more detailed and more appropriate to the desired situation. This proceeding can help the industry construction professionals involved in the conception of residential projects. Thereby, the promotion of sustainability will be guaranteed, reducing environmental impact and generating economy and quality of life for the user. The differences between the assessed requirements for each certification are in the requirements´ demand level that evaluate the same situation and in the items contemplated in only some certifications, such as the concern with acoustic evaluated by LEED and AQUA. Only one of the certifications, LEED, have requirements that are scored according to the region where the project is located. The Selo Casa Azul is a good option for the company that wants to ideate the first project with environmental certification, having fewer requirements and simpler demands to be adopted. After the evolution of the process within the company's projects coordination, the path to the search for a more detailed certification as LEED or AQUA can be the next step, thus improving the final product by adding value and quality to the user.
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