O emprego do equivalente de areia na avaliação dos finos de agregados basálticos utilizados em misturas asfálticas

Abstract

Flexible pavements are widely used in the majority of Brazilian roads and highways. The early appearance of pathologies has been a variable of interest for research in the road sector and the study of interactions between aggregates and binders is necessary. The sand equivalent (SE) test is a required evaluation in brazilian regulations to assess the quality of fine aggregates. This test aims to evaluate the presence of deleterious materials that may interfere with the pavement performance and durability. The present study aime to quantify the sensitivity of the test in failing materials that are used in paving and do not fit the 55% limit. For this, the collected samples were evaluated regarding the limits of liquidity and plasticity, sand equivalent and adsorption by methylene blue. Factors that interfere in the production of fines were also analyzed, through granulometry tests and crushing monitoring. Based on the results obtained, it is possible to verify there is a good relationship between the behavior of fines <0.075mm and the SE result of the collected sample space. However, based on the cation exchange capacity and specific surface obtained by the methylene blue assay, there is no evidence of the presence of expansive clays, even in samples with low SE. Finally, considering the granulometric correction of the mixture can affect the test’s sensitivity, it is concluded that the SE alone cannot indicate the presence of harmful contamination in the aggregate.