INFLUENCE OF THE RAP CONTENTON THE GRANULOMETRY AND THE ASPHALT CONTENT IN THE RECYCLED MIX

Abstract

The granulometry of the recycled mixtures is determined by combining that of the natural aggregate and that recovered from the RAP; although in manufacturing, the percentage of asphalt in the RAP that participates in this process is a variable whose exact value is unknown. To obtain the percentage of natural asphalt to be added in the mixtures, formulas validated in studies that consider the percentage of Rap and the asphalt present in it are used. In this sense, the objective of this work is to analyze the variation of the granulometry and the asphalt content in the recycled mixtures by means of the initial considerations of the designs and the results obtained at the end of their manufacture. Comparing these variations with the tolerances established in NC 253: 2005. For these comparisons, mixtures were manufactured by the Marshall method with four asphalt contents (3.5%, 4%, 4.5%, 5%) and three percentages of RAP (0%, 10% and 20%). Then, the solvent extraction test is carried out with the use of the continuous flow centrifuge, to determine the total asphalt content that they present and once the asphalt is separated from the aggregate, the granulometric analysis of the studied mixtures is carried out. Obtaining as results that the variations between the asphalt contents (initial and rectified) comply with the tolerance established for the designs with 0% and 20% RAP, while the granulometries fail to comply with them for all mixtures, yielding the highest results for the 9.52mm sieve.