Author: Miriam Orozco López

Análisis del comportamiento de diferentes asfaltos mexicanos con la incorporación de aditivos químicos empleados para la elaboración de mezclas asfálticas tibias

Miriam Orozco López (2013)

Asphalt Mixtures Using tibiae, in the construction of flexible pavements has spread worldwide due to the great benefits they provide, which is mainly reflected in a large reduction of pollution as well as better performance and longer life. The Asphalt Mixtures in Mexico Tibias not yet used on a large scale, however already has an obligation to use them for paving work, resurfacing and patching in the Federal District. This research aims to make a comparison of the behavior of three asphalt AC-20 different Mexican refineries in its natural state and using two types of chemical additives for the manufacture of Asphalt Mixtures Tibias dense grain. The assessment of their property shall be by rheological parameters and UCL® method.

El uso de Mezclas Asfálticas Tibias, en la construcción de pavimentos flexibles se ha extendido a nivel mundial debido a los grandes beneficios que proporcionan, los cuales se traducen principalmente en una amplia disminución de la contaminación así como un mejor desempeño y mayor vida útil. Las Mezclas Asfálticas Tibias en México aun no se utilizan a gran escala, sin embargo ya se tiene la obligación de utilizarlas en todos los trabajos de pavimentación, repavimentación y bacheo en el Distrito Federal. Esta investigación tiene como objetivo realizar una comparación del comportamiento de tres asfaltos AC-20 de diferentes refinerías mexicanas en su estado natural y empleando dos tipos de aditivos químicos para la elaboración de Mezclas Asfálticas Tibias de granulometría densa. La valoración de sus propiedades se hará mediante parámetros reológicos y el Método UCL®.

Master thesis

INGENIERÍA Y TECNOLOGÍA FIC-M-2013-0140 Facultad de Ingeniería Civil. Maestría en Infraestructura del Transporte en la Rama de las Vías Terrestres Mezcla asfáltica tibia Pavimento flexible Construcción

Recycled Al Reinforced with Oxide Nanoparticles Produced by Stir-Casting Method


Aluminum alloys reinforced with hard nanoparticles named Metal Matrix Nanocomposites (MMNCs) are very attractive in many applications in the industry, this kind of materials exhibit improved mechanical properties with relatively low contents of reinforcement. Automotive and aerospace industries are demanding these composites for critical applications taking into account their low density and high temperature resistance characteristics. MMNC’s are materials reinforced with hard particles (e.g. oxides and nitrides) with size ranging from 10 nm to 100 nm. In the present work, nanocomposites based aluminum with hard nanoparticles of TiO2 and CeO2 were fabricated by combining two techniques such as mechanical milling and the stir-casting method. Compared to other routes, melt stirring process has some important advantages, e.g., the wide selection of materials, better matrix–particle bonding, easier control of matrix structure, simple and inexpensive processing, flexibility and applicability to large quantity production and excellent productivity for near-net shaped components [1,2]. Nanoparticles and metallic powders, in the weight ratio of Recycled Al/nanoparticles = 3, were separately milled using a Spex ball mill in uncontrolled atmosphere during 2h. The device and milling media used were made from hardened steel. The milling ball to powder weight ratio was set to 5:1. Consolidated samples were added into molten recycled Al using a resistance furnace equipped with a graphite stirring system. Each cylinder was hot extruded in a direct extrusion system at 550 °C. The specimens in both as-milled and as-sintered conditions were studied by scan electron microscopy (SEM) and atomic force microscopy (AFM). The SEM bright-field image (see Fig. 1a) shows the microstructure of the Al-TiO2 nanocomposite, the inset shows a close up image of the TiO2 nanoparticles dispersed into the recycled Al matrix; these particles are in the size range of about 80 to 100 nm. Fig. 1b shows the AFM topography image of the Al-TiO2 composite after the hot extrusion process, the image reveal a homogeneous crystallite size distribution of about 50 to 100 nm. The inset shows the profile of the crystallite.

Conference proceedings