Functional and Structural Assessment of an Experimental Section Gap Graded Modified with Sugarcane Bagasse Ash

Abstract

Gap-graded aggregate combined with asphalt rubber is a high-performance alternative for roads with high traffic volumes which offers advantages over other conventional mixtures in terms of permanent deformation (rutting), fatigue life and texture. In this study, which made use of the already known mixture, conventional filler was replaced by sugarcane bagasse bottom ash (SCBA) at the proportion of 5% of the total mineral aggregates. The aim was improving the mechanical performance of asphalt coating and, at the same time, making sure that this type of waste will have an adequate destination. The residue, which was lighter, finer and rougher than conventional filler, changed the volumetric properties of the Marshall design, which means that the volume of voids in mineral aggregates and the voids filled with asphalt were increased considering the same volume of air voids (5.3%). Thus, there was an increase in the Marshall Stability (40%) and Indirect Tensile Test (22%) mechanical parameters. After laboratory analysis, the mixtures were applied as asphalt coating to a field of a high-traffic highway (BR-158). Field specimens showed that the modified mixture had an increase of 18% in the Resilience Modulus (4,088 MPa; 3,478 MPa). In addition, its Flow Number was 73% higher (16,707; 9,681) and its permanent deformation rate was 28% lower within 10,000 cycles in the dynamic creep test, which was corroborated by an 11% smaller permanent deformation rate in the Hamburg Wheel Tracking Device (HWTD), within 20,000 cycles (3.2 mm; 3.6 mm). Finally, it can be stated that partial replacement of conventional filler by sugarcane bagasse ash, within the established granulometric range, has proven technical feasibility both in laboratory and in the field.