Degradação térmica e mecânica de geossintéticos utilizados em restauração de pavimentos flexíveis com concreto asfáltico

Abstract

The road transport is responsible for a large part of the transport of cargo and people in Brazil, therefore, keeping pavements in good condition implies benefits for the economy and for users, however, it is common for flexible pavement to crack throughout its lifetime. Usually, a new bituminous layer is adopted to repair cracked pavements, but in a short time the cracks are reflected or propagated from the old layer to the new one. A solution adopted to reduce and delay the reflection cracking is the use of geosynthetics, however, these materials can be thermally and mechanically damaged during the installation process. In this way, it is important to verify if these damages are considerable and if they hinder the materials from fulfilling the function for which they were designed. Thus, this research aims to analyze the thermal and mechanical degradation suffered by geosynthetics used as anti-reflective cracking systems and, additionally, to verify if there is an improvement in this analysis with the use of aluminum foil. For this, four types of geocomposites were used and their samples were classified into: virgin samples, which were not subjected to damage; thermal damage samples, on which the asphalt concrete with high working temperature was deposited and uniformed; thermal and mechanical damage samples, which, in addition to being subjected to the effect of high temperature, were also exposed to mechanical action due to asphalt concrete compaction. All the damaged samples were divided symmetrically and in one part aluminum foil was placed before exposure to the damage and in the other part the asphalt mixture was placed directly, therefore, the damaged samples were categorized as with and without aluminum foil. Afterwards, the samples were cut and subjected to uniaxial tensile tests. The results of the tensile tests provided parameters such as tensile strength, grip displacement and slope of the lines. Such parameters were analyzed and used as degradation indicators. Regarding tensile strength, the biggest reduction was for glass fiber geocomposite that was subjected to thermal and mechanical damage, while, the smallest, 2,45%, was for the polyester geocomposite exposed only to the high temperature of the asphalt concrete. From the results, it was possible to conclude that the materials suffer degradation in the installation process and that its severity depends on the geosynthetic raw material, as well as the damage to which it was subjected.