Avaliação da aderência entre camadas asfálticas por meio de ensaio de arrancamento em campo

Abstract

Interlayer adhesion in asphalt pavements is a fundamental requirement for the overlay to perform monolithically, reducing the occurrence of premature distresses associated with interfacial debonding, such as slippage and accelerated degradation. Tack coat, usually performed with asphalt emulsion, is the primary bonding mechanism between layers; however, its quality and effectiveness in the field can be affected by construction and environmental variables, such as surface macrotexture, temperature, and the presence of fines. In this context, in situ tests capable of quantifying adhesion have been studied as an alternative for technological control, with emphasis on direct tension methods such as the pull-off test. This study experimentally evaluated the adhesion between asphalt layers in two field experimental sections, using different RR-1C emulsion application rates, and measuring strength through pull-off tests with metal plates bonded by epoxy adhesive (Sikadur). Sixty tests were conducted, distributed across strips per experimental section, allowing for a comparative analysis and discussion of how results vary due to real-world conditions. The results indicated an absence of a direct proportional trend between the emulsion rate and the obtained strength, suggesting that adhesion depends on external variables, especially ambient and pavement temperatures, as well as surface conditions. It is concluded that field pull-off testing is a promising tool for adhesion diagnosis and control, but it requires a joint interpretation of the strength value and the failure mode, as well as attention to the control of environmental and construction factors.