Estabilização de alto teor de material fresado com ligante álcali-ativado à base de metacaulim e cinza de casca de arroz

Abstract

Main modal of Brazilian transport, the road modal presents itself in deficient quantity and quality, causing negative impacts to the provision of services, durability, costs for construction and maintenance, as well as to the environment. The present work seeks an alternative to replace Portland Cement in the stabilization of high contents of Recycled Asphalt Pavement (RAP) for application in base and subbase of pavements, using alkali- activated rice husk ash to generate an alternative binder paste. It was decided to use 60% of RAP in the composition of the mixture, with aggregates and additions of 0 %, 20 %, 30 % and 40 % of alternative binder, composed of rice husk ash, metakaolin, sodium hydroxide and water. The mixtures were subjected to a study of physical-mechanical behavior, through compaction tests, to determine the maximum dry specific weight and the optimal moisture and Uniaxial Compressive Strength (UCS) and were also subjected to a mineralogical and microstructural study, through X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). After that, it was possible to identify that higher percentages of alternative binder and longer curing times results, in a linear increase in the Uniaxial Compressive Strength (UCS). It was found that the UCS of the mixtures was significantly influenced by the binder content, in addition to the binder-curing time interaction, and the curing time. XRD and SEM analyzes with EDS confirm the emergence of alkali-activation reactions and the presence of gels.