Field and laboratory performance evaluation of a field-blended rubber asphalt.

• Ano de defesa: 2016
• Autor(a) principal: Camargo, Felipe Filizzola
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Aslafto-borracha field blend; Deformação permanente; Ensaios acelerados de pavimentos; Fadiga; Fatigue; Fiel-blended rubber asphalt; Full scale accelerated pavement tests; HDM; Pavimentação de asfalto-borracha; Permanent deformation
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/3/3138/tde-01072016-111905/

Rubber asphalt has been used in Brazil as early as 2001. Among the fabrication processes of rubber asphalt, the most widely used in Brazil is the terminal blend. However, the use of field-blended rubber asphalt has been around in the United States for decades, especially in the state of Arizona. This process results in a highly viscous material with enhanced engineering properties, but requires specific equipment that is typically installed at the job site, or close to the supplying asphalt plant. Thus, keeping in mind the possible technological advantages of using a field blended rubber asphalt mixture and the lack of information regarding this technique in Brazil, there is a necessity to develop studies to assess the performance of this type of material in our environmental conditions and axle loading configurations. Therefore, a laboratory study was conducted to determine the rheological properties of a field-blended rubber asphalt and compare them to those of typical binders used in Brazil (an AC 30/45 penetration grade and a binder modified with SBS, an elastomeric polymer). Binder permanent deformation was determined using the Multiple Stress Creep and Recovery (MSCR) test, whereas binder fatigue behavior was determined using the Time Sweep and Linear Amplitude Sweep (LAS) tests. Subsequently, the permanent deformation and fatigue behavior of a gap-graded mixture using the field-blended rubber asphalt were assessed in the laboratory and in the field. The permanent deformation of the mixture was determined in the laboratory using the LCPC wheel track test, whereas the fatigue behavior was determined using the four point bending flexural test. A test section was built after the rehabilitation job of highway RJ-122, where a field-blended rubber asphalt mixture was first used in the country. The mixture performance was studied in situ through accelerated pavement tests using a full scale, large mobile traffic simulator. The results were used to model the performance of the structure with the rubber asphalt mixture by means of the Highway Development and Management Model (HDM-4) cracking and permanent deformation models, calibrated to local conditions. Accelerated pavement tests were validated through periodic pavement monitoring campaigns conducted for four years in a test section in Highway RJ-122. The field-blended rubber asphalt showed a good performance in terms of permanent deformation and fatigue determined in the laboratory at the binder and mixture levels, which confirms what was verified in the field.