Introdução de um novo coeficiente para análise de desempenho dos tratamentos superficiais a partir dos estudos desenvolvidos nos estados do Ceará/Brasil e Carolina do Norte/USA

Abstract

The Asphalt Surface Treatment, more specifically the chip seal is considered a type of economic coating, much used in Brazil as the first road coating of Low Volume traffic highways. In the United States, European countries, Australia and New Zealand it is used as one of the main measures of preventive maintenance of roads. Even though chi seal is the most frequent surface coating on Brazilian highways, and state highways in Ceará, there are few studies in the area aimed at improvements in the design method, construction and evaluation of such surface course. Currently, specific publications and national standards are outdated and do not follow the most current findings of the international scientific community on the subject. Therefore, the present study aimed to investigate the materials and methods used in the North Carolina State University (NCSU), which has extensive experience and tradition with this type of coating in order to propose improvements to procedures and research carried out in Brazil. It was conducted a thorough literature review on all aspects relevant to the study of chip seals, such as construction methods, types of materials used, field equipment, rolling process, design methods, performance evaluation methods and identification of specific defects. As a result, it was decided to introduce nationally the concept of PUC (Performance-Based Uniformity Coefficient), a parameter introduced by Kim & Lee (2008b) associated with the particle size distribution of the aggregate, which tries to predict the aggregate percentage prone to generate exudation or to loosen the coating. From the PUC calculation of various aggregates studied in the state of Ceará and a comparison with the wear obtained in Wet Track Abrasion Test assays (WTAT) adapted, did not identify a direct relationship between the parameters and it was concluded that it is not can compare the PUC of different backgrounds aggregates. Nevertheless, it was concluded that the PUC is a coefficient that can assist in preliminary choice of materials, since the grain size has a strong influence on the aggregate loss of chip seals. Moreover, compared with the PUC granulometric ranges recommended by DNIT and it was observed that even aggregates belonging to them can generate high PUCs and therefore become unsuitable for employment in chip seals. Ao final foi anexado um checklist de inspeção de TSPs utilizado pelo departamento de transporte da Carolina do Norte. By the end was attached an inspection checklist for chip seals used by the North Carolina Department of Transportation.