Evaluación de la resistencia mecánica de una mezcla densa en caliente MDC-19 fabricada con un cemento asfáltico (CA) modificado con biocarbón (BC)

Abstract

Population growth in the world has increased the generation of waste or biomass from agroindustrial activities. To reduce negative impacts on the environment, these biomasses can be treated and thermally decomposed through pyrolysis to convert them into Biochar (BC), which is a material that shows interesting properties and is compatible with asphalt binders. In the present study, an Asphalt Cement CA (Asphalt Cement - AC) reference 60-70 (due to its degree of penetration) was initially modified with a BC obtained from oil palm shell – PKS (BC-PKS). This modified asphalt binder was named CA-BC. For the modification, 10% of BC-PKS was used with respect to the total mass of the binder. Conventional physical characterization tests were carried out on CA 60-70 and CA-BC (penetration, viscosity, softening point, ductility, among others). Scanning electron microscope (SEM) visualizations were performed on the BC-PKS and the CA-BC. In a second phase of the study, a Hot Dense Mixture MDC-19 (HMA-19) was manufactured using the CA-BC (called HMA-BC mixture) and its performance was evaluated by carrying out tests under monotonic loading (Marshall and tensile strength indirect – ITS in dry condition – ITSD and wet – ITSW) and cyclical (Resilient Modulus – RM, permanent deformation and fatigue under controlled stress). The Cantabro test was also performed and the Tensile Strength Ratio (TSR) was calculated. The results were compared with those obtained on a Control mixture (HMA made with unmodified CA 60-70). ANOVA analyzes of variance were performed to evaluate whether BC-PSK generated significant changes in the properties of HMA-BC. As a general conclusion, it is reported that BC-PKS is a promising modifier of asphalt binders that tends to increase their rigidity. Likewise, the CA-BC generated a HMA-BC with greater stiffness under cyclic loading (RM) and greater resistance to permanent deformation, moisture damage, abrasive wear and fatigue compared to the Control mixture. This better performance was achieved without the need to: i) increase the optimal asphalt binder content (OAC), ii) change the volumetric composition of the HMA, iii) increase the mixing and compaction temperatures.