Replacing natural aggregates (NA) for blast furnace slag (BFS) is seen as a technique that is beneficial for the environment. Additionally, in high temperature climates, rigidizing the asphalt by employing gilsonites (G) could be an alternative in order to increase rutting resistance. This study substituted in volume, part of the coarse fraction of NA for BFS in a hot mix asphalt (HMA) that employed asphalt modified with G in wet process. Physical properties of BFS are presented, as well as its chemical and mineral compositions. Additionally, physical properties of asphalt modifi ed are shown. In regards to HMAs, their resistance under monotonic load (Marshall test and indirect tensile strength test), cyclic (resilient modulus, permanent deformation and fatigue) and moisture damage (tensile strength ratio – TSR) was evaluated. All HMAs were manufactured employing the same asphalt content from the control mix. An ANOVA variance analysis was conducted. Based on ANOVA, when the NA volume is substituted with BFS, Marshall stability/ /flow relation significantly drops. However, when such substitution is carried out using G-modified asphalt, resistance under monotonic load, stiffness under cyclic load, resistance to permanent deformation and moisture damage notably increase. Fatigue resistance also increases but such increase is not statistically significant.

Correlation between vehicular traffic and heavy metal concentrations in road sediments of Bogotá, ColombiaRelación entre tráfico vehicular y concentraciones de metales pesados en sedimentos viales de Bogotá, Colombia

The growth of the world population has increased the production of wastes. These are generally incinerated or deposited in outdoor landfills, which impacts the environment and affects human health. A technique that allows to reuse of wastes and diminishes adverse effects on the environment is pyrolysis. Through this technique, a material known as Biochar (BC) is produced, which has proven to have interesting physical-chemical properties for it to be used as an asphalt modifier, and simultaneously, helps to mitigate negative impacts on the environment. The foregoing article presents a bibliographical review on the use of BC as a modifier for asphalt binders and asphalt mixes. This has the purpose of becoming a starting point for future research efforts. In the reviewed literature, there was no review found on this topic. In general terms, BC increases the performance of asphalt binders in high-temperature climates, and tends to reduce its performance in low-temperature ones. Few studies have evaluated the performance of BC on asphalt mixes and the long-term properties associated with durability. Based on the reviewed literature, at the end of the article, recommendations are provided for future study topics.

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RESUMENObjetivo Realizar una evaluación climática (diaria) de la concentración de metales pesados (Pb y Cu) asociada con el sedimento depositado sobre las superficies viales de las localidades de Kennedy y Puente Aranda (Bogotá D.C., Colombia). Adicionalmente, se evaluaran las concentraciones detectadas con respecto a la legislación seleccionada como de referencia para la protección de la salud humana en suelo urbano. Métodos La concentración se determinó mediante espectrometría de absorción atómica con llama; previamente las muestras fueron digeridas en una mezcla de ácido clorhídrico y nítrico (3:1; agua regia). Resultados Se evidencia con respecto a la fracción de tamaño del sedimento vial más cercana a la potencialmente inhalable desde el punto de vista de la salud pública (≤10 µm), que las concentraciones metálicas en promedio tienden a aumentar en tiempo seco (29 %). Al respecto, las concentraciones durante estos períodos de tiempo son en promedio 1,69 veces superiores al valor límite más bajo fijado por la normatividad de referencia. No obstante, se sugiere que las concentraciones metálicas están dominadas por el uso del suelo antes que por las condiciones climáticas. Conclusiones Los hallazgos se constituyen en un punto de referencia a nivel colombiano para la discusión y publicación de normatividad ambiental asociada con la protección de la salud humana por metales pesados, y para visualizar futuras líneas de investigación acerca del efecto del cambio climático sobre las concentraciones metálicas en ambientes urbanos.Palabras Clave: Contaminación ambiental, escorrentía pluvial, metales pesados, salud pública, sedimento (fuente: DeCS, BIREME).