O efeito da modificação de ligante asfáltico com o liquido da castanha de caju (LCC) na resistência ao dano por umidade em misturas asfálticas

Abstract

Moisture damage is a frequent distress on pavements and is considered a major contributor to premature deterioration. Physicochemical properties of the Cashew Nut Shell Liquid (CNSL) showed to be potentially useful to improve the adhesion between asphalt binder and aggregates. The main objective of this study is to evaluate the potential of the CNSL modified asphalt binder to increase the hot mixture asphalt (HMA) resistance to moisture damage, and as a promoter of adhesiveness between binder and aggregates. Pure and modified asphalt binders with different CNSL contents were characterized chemically and rheologically. The aggregates were characterized by X-ray fluorescence and using Aggregate Imaging Measurement System (AIMS). HMAs with binders modified with CNSL were designed using the Superpave methodology. HMA mechanical characterization consisted of modified Lottman test, Resilient Modulus and Cantabro. Results were compared with those obtained using two different HMAs: (i) one with conventional asphalt binder and natural aggregates, and (ii) another one using 2% of lime as a filer. The stripping resistance of asphalt binders were characterized through digital image processing (DIP). The findings showed the CNSL decreased the asphalt binder viscosity. Both, the pure and the modified asphalt binder, were classified as PG 70-28. The granitic aggregates were classified as sub rounded, with low sphericity and smooth texture. The findings showed that the HMA contain binder modified with CNSL had better stripping resistance and behavior mechanical performance than other evaluated HMAs. It’s expected that the effectiveness of the CNSL can be used as an additive to prevent striping in asphalt mixtures and to provide a greater resistance to breakdown caused by water.