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This study shows statistical information regarding COVID-19 in Colombia up to this date (March 1-2022). Specifically, the daily, monthly and cumulative evolution of infections and deaths, correlated with the distribution of the population according to age and gender. Objective. Show statistical information about COVID-19 that allows help to plan and design, in future Pandemics, public health policy strategies in Colombia. Methods. Daily information since the official declaration of Pandemic in Colombia (March 16 – 2020) was obtained by the National Health Institute (INS) and was organized in a database in order to conduct respective analysis. This information was compared to similar studies obtained based on the bibliographical review. Results and Conclusions. Results and conclusions are similar to those found in the reference literature: most part of those dead by COVID-19 are of senior age and male gender. Regarding Case Fatality Rate (CFR), it notoriously increases with age. The most vulnerable population displays an average age of ≥ 52.8 years. The less vulnerable population are young persons under 30 years of age, but specifically, those within the age range of 10 and 20 years. Gompertz and Logistic models can mathematically simulate the evolution of deaths and the evolution of CFR according to age.

El presente artículo analizó en laboratorio el uso de Agregados Reciclados de Concreto (RCA) cuando son incorporados como agregados gruesos en una mezcla asfáltica densa en caliente mdc-19. El principal problema de la utilización del RCA en mdcs es su elevada absorción originada por el mortero que recubre las partículas, lo cual origina un incremento del contenido óptimo de asfalto y, consecuentemente, altos costos de producción. Para solucionar tal problema, se realizaron tratamientos químicos sobre la superficie del agregado RCA utilizando 1, 3 y 5 ciclos de inmersión en una solución de sulfato de magnesio, conforme al ensayo de durabilidad de agregados especificado por AASHTO T 104-99. Sobre las mezclas que incorporaron RCA (con y sin el tratamiento químico), fueron ejecutados ensayos de resistencia bajo carga monotónica (Marshall y resistencia a la tracción indirecta) y resistencia al desgaste a la abrasión Cántabro. Los resultados evidencian que la utilización del RCA tratado químicamente en la fabricación de mezclas asfálticas aumenta la resistencia bajo carga monotónica (ensayo Marshall y resistencia a la tracción indirecta en condiciones secas), proporcionando mayor cohesión y un leve aumento en la adherencia con referencia a la mezcla de control. Adicionalmente, se evidenció que el agregado RCA sometido a 5 ciclos proporciona similar resistencia en la mezcla asfáltica a la tracción indirecta bajo condición húmeda y desgaste Cántabro que la muestra de control.

El asfalto es un material complejo cuyo desempeño depende en gran medida de su composición química. En el mundo, se han realizado múltiples estudios para intentar correlacionar las propiedades físico-químicas de estos materiales, con el fin de intentar comprender su desempeño ante solicitudes de carga y condiciones medioambientales, similares a las que experimentan cuando forman parte de una mezcla asfáltica en un pavimento. A pesar del amplio número de investigaciones realizadas en estas áreas, el complejo comportamiento viscoelástico que caracteriza a estos materiales amorfos aún no ha sido totalmente entendido. Una técnica que podría ayudar a mejorar el entendimiento de asfaltos es la espectroscopía de impedancia eléctrica compleja. Mediante esta, se pueden medir y evaluar las propiedades dieléctricas de estos materiales, las cuales podrían ser correlacionadas con aquellas de carácter físico-químico. En el presente artículo, se presenta una revisión bibliográfica sobre los estudios realizados a la fecha para medir y analizar propiedades dieléctricas en asfaltos. Se describen los estudios y se reportan las limitaciones de los mismos.

The behavior of the asphalt mixture is mainly attributed to the performance of the asphalt mastic. Several studies have been performed to evaluate the behavior of mastics made with different fillers. Most researchers have added the filler by mass within the bitumen; however, this comparison may be more appropriate by volume. An experimental program was designed to evaluate the behavior of mastics produced with five different fillers (natural limestone, LS; hydrated lime, HL; Portland cement, PC; Linz-Donawitz steel slag, LDSS; and blast furnace slag, BFS), and were dosed by mass and volume. Penetration, softening point, viscosity, multiple stress creep and recovery test, and linear amplitude sweep test were performed. Results showed that analyzed asphalt mastic properties depend on dosage type performed and test type. Furthermore, HL, PC, BFS and LDSS mastics showed better performance compared to control LS mastic.

In Brazil, large quantities of iron ore tailings (IOT) are produced as a result of iron mining, which may affect the environment negatively. This work evaluated the use of IOT in hot mix as...

Natural asphalts (NAs) can be an economical and environmental alternative in pavement construction. Most studies have investigated them as binder and asphalt mixture modifiers due to their high compatibility with conventional asphalts. In this article, some of the studies carried out on the use of NA in pavements are summarized and described in a chronological order. The main aspects described in the reviewed studies were the type of asphalt binder or modified mixture, the type and content of the modifier, the manufacturing processes of the asphalt or modified mixture, tests performed, and main results or conclusions. In general terms, NAs show better performance as binder and asphalt mixture modifiers in high-temperature climates. Additionally, they tend to improve water and ageing resistance. As main limitations, it is reported that NAs tend to negatively affect the workability and performance of asphalt mixtures in low-temperature climates. Finally, recommendations for future study topics are provided at the end of this paper.

espanolLos residuos de concreto son considerados un pasivo ambiental e impactan negativamente el medio ambiente. Estos residuos tienen un alto potencial para ser empleados como materiales alternativos de construccion. El presente estudio evaluo la aplicabilidad de uso de un agregado reciclado de concreto (RCA, por sus siglas en ingles) como sustituto de la totalidad del agregado petreo convencional (AC) de origen natural en una mezcla asfaltica drenante (MD). Inicialmente, se realizaron ensayos de caracterizacion fisica del RCA y se comparo con el AC. Luego se realizaron los disenos de dos mezclas MD utilizando un asfalto modificado con grano de caucho reciclado de llanta (GCR): una MD empleando como agregado AC (muestra de control) y otra donde se sustituyo la totalidad del AC por RCA. Sobre estas mezclas fueron realizados ensayos de laboratorio bajo carga monotonica (resistencia a la traccion indirecta - RTI) y pruebas de adherencia (susceptibilidad de la RTI en condiciones humedas y secas y desgaste a la abrasion Cantabro). Los resultados indican la necesidad de emplear un mayor contenido de asfalto en la MD con RCA con respecto a la mezcla de control. Empleando este mayor contenido de asfalto, se observa similitud en la resistencia a la traccion y aumento de adherencia en la MD con RCA con respecto a la muestra de control. Por tanto, se puede concluir que la aplicacion del RCA en MD de la forma propuesta es viable desde el punto de vista tecnico y ambiental. EnglishConcrete waste is considered an environmental liability with a negative impact. However, this type of waste presents a high potential to be used as an alternative building material. Therefore, the present study aims to evaluate the applicability of substituting the conventional natural stone aggregate (CA) of a draining asphalt mixture (MD) by a recycled concrete aggregate (RCA). Firstly, RCA was physically characterized to be compared with the AC. Then, two MD mixtures were design with rubberized asphalt concrete (GCR by its spanish acronym): one using the conventional aggregate (control sample) and one with the RCA substituting entirely the CA. Experimental tests under monotonic load (indirect tensile strength - RTI) were conducted over the mixtures, as well as adhesion tests (susceptibility of RTI in wet and dry conditions and abrasion wear Cantabro). The results indicate that for MD mixtures with RCA, a higher content of asphalt is required than with CA. Additionally, it wasfound that the presence of higher asphalt content in MD-RCA mixtures increases its adhesion when compared with the control sample. Therefore, it can be concluded that the use the RCA for MD mixtures, in the proposed way, is technically and environmentally viable.

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.

Currently, many studies seek to find materials that are friendlier towards the environment. Warm mix asphalt (WMA) technology helps to decrease manufacturing temperature in traditional hot mix asphalts (HMA), which reduces emissions that are detrimental to the environment. For the case of asphalt pavements, WMA technology, which uses recycled materials such as blast furnace slag (BFS), this could be an interesting alternative technique. Reutilizing these types of industrial waste materials for roadway project constructions could help to minimize negative impacts on the environment. In this study, the coarse fraction of natural aggregate in a control HMA was replaced with BFS. Additionally, a chemical additive was used to lower mixing temperature by 30 °C, and thus manufacture WMA. Marshall, indirect tensile strength, resilient modulus and permanent deformation tests were carried out. This additive helps to reduce air void content, reduces mixing and compacting temperatures and increases asphalt stiffness. Studied WMA that has a 12.5% substitution of coarse natural aggregate fraction with BFS, results in a significant increase in stiffness (under monotonic and cyclic loads), as well as an increase in resistance to moisture damage and to permanent deformations, when compared to control HMA.

Iron production’s waste materials include significant quantities of blast furnace slag (BFS) which could potentially be used as a substitute for natural aggregates in hot mix asphalt (HMA) used in highway projects. Although many of properties of slag are interesting, its porosity and absorption rate would lead to greater consumption of asphalt. For this study, a Portland cement (PC) paste was used to reduce the porosity of a BFS. This PC treated BFS (called BFS-C) was then used in an HMA to replace the coarse fraction of a natural aggregate. Marshall, Indirect Tensile Strength (ITS), resilient modulus and Cantabro tests were then carried out on different HMA mixtures that included BFS-C. Using BFS-C, HMA’s resistance under monotonic loading, stiffness under cyclic loading, and resistance to moisture damage increased remarkably. In addition, the Cantabro abrasion resistance of BFS-C improved was better than that of the HMA mixture produced with untreated BFS.

An experimental program was devised to evaluate the effect on the resistance of a hot mix asphalt, due to the total replacement of a natural aggregate (limestone — LS) by a recycled concrete aggregate (RCA). Two asphalt binders were used: conventional AC 50-70 (penetration grade) and AC 50-70 modified with crumb rubber (CRM). The mechanical properties investigated were the stability and flow ratio (Marshall test), indirect tensile strength, resistance to abrasion (Cantabro test), resilient modulus, resistance to permanent deformation, to fatigue and to moisture damage (modified Lottman test). When the LS is completely replaced by RCA, the resistance under monotonic loading, moisture damage and permanent deformation improved, the mass loss in the Cantabro test and the resilient modulus shows appropriate values, however, the fatigue resistance decreases. Besides, mixtures with RCA using CRM binder showed lower fatigue life under stress controlled tests, but much better rutting resistance.

Leachate has been reported as the most significant source of landfill pollution. Predicting the characteristics of untreated and treated leachate may be useful during optimal scheduling of leachate treatment systems. The objective of this paper is to show an analysis of the operation of a landfill leachate treatment system in a Latin American megacity (Bogota, Colombia) by means of auto-regressive integrated moving average (ARIMA) models. A comparative analysis of the leachate treated with respect to reference legislation is carried out. The influence of climate variables during the operation of the treatment system is also considered. The results suggest that the concentrations of heavy metals (HMs), BOD5, and COD in untreated leachate do not follow the same annual cycles observed for the quantity of solid waste disposed within the landfill. This difference is possibly associated with the hydraulic retention time (HRT) of the leachate inside the conduction and pre-treatment system (storage/homogenization ponds). The ARIMA analysis suggests an HRT of up to one month (AR = 1) for the HMs identified as indicators of untreated leachate (Cu, Pb, and Zn). It is noted that the removal efficiency of HM indicators of the operation of the leachate treatment plant (Fe and Ni) is probably conditioned by operations carried out over a period of one month (AR = 1). The high input concentration of these HM indicators may prevent changing their ARIMA temporal structure during leachate treatment. This is reflected in the low removal efficiencies for all HMs under study (average = 26.1%).

The aspirations of public administrations to meet quality parameters and standards in urban spaces have fostered new strategies and tools that allow users to give safety and well-being. The participation and interaction of different actors during decision-making in the context of allocation of public resources implies a significant degree of complexity when prioritizing actions in public works. The objective of the study focuses on obtaining an urban street condition index (USCI) that allows an efficient diagnosis of urban infrastructure. The study provides an innovation component for decision-making through the construction of guidelines to prioritize spending on investment in urban infrastructure. The case study has been developed in three countries, Brazil, Paraguay and Argentina (Triple Border) with the aim of drawing management guidelines during the process in public entities. The results for Brazil and Argentina present streets with satisfactory USCI. Paraguay reflects a significant lack of urban infrastructure and compliance of accessibility regulations. Regarding the city of Foz de Iguazú, it has been observed that 50% of the roads require prevailing actions to improve the mobility of the roads, 40% of these reflect reduced mobility and deterioration of urban components, configured as an urgent action, and only 10% of the roads studied reflect adequate mobility conditions.

La generación y gestión de residuos sólidos industriales se considera una problemática ambiental a nivel mundial. Razón por la cual, diversos estudios se han enfocado en la implementación de Residuos de obras de Construcción y Demolición (RCD) para capas de pavimentos, centrándose en el uso de Agregados Reciclados de Concreto (RCA por sus siglas en inglés). El objetivo de este artículo fue establecer el impacto de la implementación del RCA en una mezcla asfáltica sobre algunas de sus propiedades físico-mecánicas, bajo tres escenarios: i) sustitución de la fracción gruesa, ii) fina y iii) 100% de la granulometría del agregado convencional (AC). Se evaluó la resistencia bajo carga monotónica de las mezclas (ensayos Marshall y Tracción Indirecta – RTI) y la resistencia al desgaste Cántabro. La sustitución de la fracción fina del AC por RCA, disminuye notablemente la resistencia bajo carga monotónica de la mezcla de referencia. Al sustituir la fracción gruesa, se cumplen los criterios de diseño de la mezcla asfáltica de referencia y se aumenta el RTI, pero se hace necesario incrementar ligeramente el contenido de asfalto. Al sustituir la totalidad de los agregados por RCA, se obtuvo un comportamiento satisfactorio ante la acción de cargas monotónicas, pero también se hace necesario incrementar ostensiblemente el contenido de asfalto. Un aumento del RCA en la mezcla incrementa la pérdida por desgaste Cántabro.

Restrictions apply to the availability of these data. Data was obtained from Red de Monitoreo de Calidad del Aire de Bogotá (RMCAB) and Botanical Garden of Bogotá (JBB), and are available at http://201.245.192.252:81/Report/stationreport (accessed on 6 February 2020) and http://sigau.jbb.gov.co/SigauJBB/VisorPublico/VisorPublico (accessed on 6 February 2020) with the permission of RMCAB and JBB, respectively. [Abstract] Urban areas with trees provide several ecosystem services to citizens. There is a growing interest in ecosystem services for the removal of air pollutants such as particulate matter. The objective of this paper is to show a study on the variation of intercepted particulate matter concentration (IPMC) by tree leaves in the megacity of Bogotá (Colombia). The relationship between IPMC and PM2.5 concentrations observed in air quality stations in two urban zones with different air pollutions was studied. Influences of climate and leaf morphology variables on IPMC were also analyzed. The species under study were Ligustrum-lucidum, Eucalyptus-ficifolia, Tecoma-stans, Callistemon-citrinus, Lafoensia-acuminata, and Quercus-humboldtii. The results showed that leaf IPMC decreased as the PM2.5 concentration increased. Species that best described this trend were Ligustrum-lucidum and Lafoensia-acuminata. These two species also showed the largest IPMC in their leaves. Indeed, species that showed the largest leaf area were those with the highest IPMC. On average, it was observed that for each 5.0 µg/m3 increase in PM2.5 concentration the IPMCs of the species Ligustrum-lucidum and Lafoensia-acuminata decreased by 33.6% and 23.1%, respectively. When wind speed increased, there was also an increase in PM2.5 concentrations and a reduction in the leaf IPMCs. http://201.245.192.252:81/Report/stationreport http://sigau.jbb.gov.co/SigauJBB/VisorPublico/VisorPublico

espanolEste articulo estudia la relacion entre condicion atmosferica (CA) y tasa de mortalidad humana asociada con el material particulado grueso (PM10) en una mega-ciudad de elevada altitud (Bogota-Colombia). Se recolecto informacion de tres estaciones automaticas de monitoreo equipadas con instrumentos de medicion para PM10, temperatura, radiacion solar y velocidad del viento. El periodo de muestreo duro seis anos. Los resultados mostraron el mejor escenario posible para las maximas concentraciones horarias de PM10 (52.3-135 μg/m3). Estos eventos ocurrieron durante periodos diur-nos donde la CA predominante estuvo entre inestable-muy inestable. El riesgo por exposicion a PM10 mostro que febrero>marzo>enero fueron los de mayor riesgo. Estos meses mostraron concentraciones de PM10 un 35.9% mas elevadas que aquellas observadas durante los meses de menor riesgo (agosto>junio>julio). Se sugirio una mayor tasa de mortalidad (+2,0%) en sectores urbanos con menor inestabilidad atmosferica (IA) y predominancia de cobertura impermeable, en comparacion con sectores de mayor IA y predominancia de cobertura vegetada EnglishThis article studies the relationship between atmospheric condition (AC) and human mortality rate associated with coarse particulate matter (PM10) in a high-altitude mega-city (Bogota-Colombia). Information was collected from three automatic monitoring stations equipped with measuring instruments for PM10, temperature, solar radiation and wind speed. The sampling period lasted six years. The results showed the best possible scenario for the maximum hourly concentrations of PM10 (52.3-135 μg/m3) . These events occurred during daytime periods where the predominant AC was between unstable and very unstable. The risk from exposure to PM10 showed that February>March>January were the highest risks. These months showed PM10 concentrations 35.9% higher than those observed during the months of lower risk (August>June>July). A higher mortality rate (+2.0%) was suggested in urban sectors with less atmospheric instability (AI) and predominance of impervious cover compared to sectors with higher AI and predominance of vegetated cover. portuguesEste artigo estuda a relacao entre condicao atmosferica (CA) e taxa de mortalidade humana asso-ciada com o material particulado grosso (PM10) em una megacidade de elevada altitude (Bogota- Colombia). Coletou-se informacao de tres estacoes automaticas de monitoramento equipadas com instrumentos de medicao para PM10, temperatura, radiacao solar e velocidade do vento. O periodo de amostragem teve uma duracao de seis anos. Os resultados revelaram o melhor cenario possivel para as maximas concentracoes horarias de PM10 (52.3-135 μg/m3). Estes eventos ocorreram duran-te periodos diur¬nos onde a CA predominante esteve entre instavel e muito instavel. O risco por exposicao a PM10 mostrou que fevereiro>marco>janeiro foram os de maior risco. Estes meses mos-traram concentra¬coes de PM10 um 35.9% mais elevadas que aquelas observadas durante os meses de menor risco (agosto>junho>julho). Sugeriu-se uma maior taxa de mortalidade (+2,0%) em setores urbanos com menor instabilidade atmosferica (IA) e predominância de cobertura impermeavel, em comparacao com setores de maior IA e predominância de cobertura vegetada.

Durante el lavado de agregados petreos para la ejecucion de ensayos en el laboratorio se consumen grandes cantidades de agua. En el presente estudio se estimo, el volumen de agua que se utiliza cuando se realiza el diseno de una mezcla asfaltica. Adicionalmente se evaluo, el efecto de lavar el agregado en diversas cantidades masicas y con dos niveles de velocidad de salida de agua del grifo. Se realizo un analisis de varianza (ANOVA) para verificar si los resultados obtenidos son significativos o estaticamente iguales. Como conclusion general se reporta, que el consumo de agua disminuye significativamente cuando se lavan mayores cantidades de material al mismo tiempo y se emplea para rociar o humedecer las particulas, menores caudales. Palabras clave: agua, consumo de agua en el laboratorio, lavado de agregados petreos, medio ambiente. Abstract Large quantities of water are consumed during the washing of granular aggregates in laboratory tests. In this study, the volume of water used when is designed a hot mix asphalt - HMA was estimated. Besides, the effect of washing the aggregate in different quantities of mass and with two levels of water speed flow was evaluated. An analysis of variance (ANOVA) was performed to verify if the results obtained are significant or statically equal. As a general conclusion, it is reported that water consumption decreases significantly when larger amounts of material are washed at the same time and used to wash the particles, lower flow rates. Keywords: water, water consumption in the laboratory, washing of unbound granular aggregates, environment. Resumo Durante a lavagem de agregados para a execucao de testes no laboratorio, grandes quantidades de agua sao consumidas. No presente estudo, o volume de agua utilizado no projeto de uma mistura asfaltica quente foi estimado. Adicionalmente, o efeito da lavagem do agregado em varias quantidades de massa e com dois niveis de velocidade de saida da agua da torneira foi avaliado. Uma analise de variância (ANOVA) foi realizada para verificar se os resultados obtidos sao significativos ou estaticamente iguais. Como conclusao geral, e relatado que o consumo de agua diminui significativamente quando quantidades maiores de material sao lavadas ao mesmo tempo e sao usadas para umedecer as particulas, taxas de fluxo menores. Palavras-chave : agua, consumo de agua no laboratorio, lavagem de agregados, meio ambiente

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.

The objective of this paper is to present the development and application of a method to estimate the heavy metal (HM) contribution derived from the wash-off by runoff on road-deposited sediments (RDS) in a high-altitude megacity (Bogota, Colombia). The method is based on the development of a HM wash-off equation which considers two processes: HM transportation and HM leaching. HM contribution by runoff ranges between 24.7% and 50.3%, relative to the total mass per unit area of HMs associated with dry-weather RDS (Mn, Cd, As, Zn, Cu, Ba, Pb, and Fe). The HMs that show a greater contribution are Cd, Zn, and Mn. RDS size fraction below 250 µm contributes on average 81.6% of the total HM load washed-off by runoff. The findings suggest that the RDS size fraction below 250 µm must be the reference fraction for the control systems design of HM pollution in Bogota city. Resumen El objetivo de este artículo es presentar el desarrollo y aplicación de un método para determinar la contribución de metales pesados (MP) derivados del lavado ejercido por la escorrentía sobre sedimentos viales (SV) en una megaciudad de elevada altitud (Bogotá, Colombia). El método está basado en una ecuación que considera dos procesos: transporte y lixiviación de MP. La contribución de MP por escorrentía varía entre un 24.7-50.3%, con respecto a la masa total por unidad de área de MP asociados con SV de tiempo seco (Mn, Cd, As, Zn, Cu, Ba, Pb y Fe). Los MP que presentan una mayor contribución son Cd, Zn y Mn. La fracción inferior a 250 µm de los SV contribuye en promedio con un 81.6% de la carga total de MP. Los hallazgos sugieren que la fracción inferior a 250 µm es referente para el diseño de sistemas de control de contaminación en Bogotá.

Resumen En la fabricación de mezclas asfálticas se consumen grandes cantidades de agregados pétreos de origen natural lo que impacta negativamente el ambiente. Estos agregados pueden ser sustituidos parcial o totalmente por otros que son desechados en escombreras y producidos por las compañías siderúrgicas, como las escorias de alto horno (BFS) y acero (SS). Estos dos últimos materiales poseen propiedades químicas y físicas que los hacen aptos para ser utilizados en múltiples aplicaciones como la construcción, mantenimiento y rehabilitación de carreteras. En el artículo se presenta una revisión del estado del conocimiento del empleo de BFS y SS en la producción de mezclas asfálticas, se describen y definen ambos materiales, se presenta la problemática ambiental, su riesgo toxicológico de uso, sus propiedades químicas y físicas, las ventajas y limitaciones de uso y la forma como han sido estudiados para ser empleados como agregados pé treos de mezclas asfálticas. Con base en la revisión bibliográfica realizada, los autores al final del artículo exponen algunas recomendaciones para continuar los estudios tendientes a sustituir agregados pétreos naturales por BFS y SS en la fabricación de mezclas asfálticas. Abstract In the manufacture of asphalt mixtures, large quantities of natural stone aggregates are consumed, which has a negative impact on the environ ment. These aggregates can be partially or totally replaced by others that are disposed of in dumps and produced by steel companies, such as blast furnace slag (BFS) and steel (SS). These last two materials have chemical and physical properties that make them suitable for use in multiple applications such as road construction, maintenance and rehabilitation. The article presents a review of the state of knowledge of the use of BFS and SS in the production of asphalt mixtures, describes and defines both materials, presents the environmental problems, their toxicological risk of use, their chemical and physical properties, the advantages and limitations of use and the way they have been studied to be used as stone aggregates of asphalt mixtures. Based on the bibliographic review, the authors at the end of the article present some recommendations to continue the studies tending to substitute natural stone aggregates with BFS and SS in the manufacture of asphalt mixtures. Resumo grandes quantidades de agregados pétreos de origem natural são consu midos na fabricação de misturas asfálticas, o que impacta negativamente o ambiente. Esses agregados podem ser substituídos parcial ou totalmente por outros que são descartados em aterros e produzidos pelas companhias siderúrgicas, como as escórias de alto-forno (BFS) e aço (SS). Esses dois últimos materiais apresentam propriedades químicas e físicas que os tornam aptos para serem utilizados em múltiplas aplicações, como a construção, a manutenção e a reabilitação de estradas. No artigo, apresenta-se uma revisão do estado do conhecimento do emprego de BFS e SS na produção de misturas asfálticas, ambos os materiais são descritos e definidos, apresenta-se a problemática ambiental, seu risco toxicológico de uso, suas propriedades químicas e físicas, as vantagens e limitações de uso e a forma como foram estudados para serem empregados como agre gados pétreos de misturas asfálticas. Com base na revisão bibliográfica realizada, os autores ao final do artigo expõem algumas recomendações para continuar os estudos com tendência a substituir agregados pétreos naturais por BFS e SS na fabricação de misturas asfálticas.

Introducción. La rápida urbanización y la intensa actividad humana han hecho de las ciudades un foco de emisiones contaminantes; esta situación genera una variedad de problemas ambientales y de salud pública que involucran metales pesados.Objetivos. Identificar y analizar los factores físicos (FF) que intervienen en la acumulación de metales pesados en sedimentos viales con el fin de facilitar la toma de decisiones en el control de la contaminación metálica desde la salud pública urbana.Materiales y métodos. Se realizó una revisión sistemática internacional de la literatura científica asociada entre el 1 de enero de 1970 y el 31 de diciembre de 2015. Las bases de datos utilizadas fueron Springer, ScienceDirect y Google Scholar. Se desarrolló un índice de frecuencia de citación (Q) para establecer un orden de importancia de FF detectados y se utilizaron las pruebas estadísticas de análisis clúster, t-Student, coeficiente de correlación de Pearson y regresión lineal para estudiar la relación entre las variables identificadas.Resultados. Los estudios citaron la precipitación (Q1), el uso del suelo (Q2) y el tráfico (Q2) como FF dominantes, por lo que una visión integral para la gestión de la salud pública debe considerar dos escenarios con sus correspondientes FF dominantes: el meteorológico (FF: precipitación) y el antropogénico (FF: uso del suelo y tráfico).Conclusión. Se sugiere un orden de intervención diferenciado para las instituciones encargadas del control de la contaminación metálica y la gestión de la salud pública en áreas urbanas. Introduction: Rapid urbanization and intense human activity have turned cities into a focus of pollutants emissions, thus generating all sorts of environmental and public health problems involving heavy metals.Objectives: To identify and analyze the physical factors (PF) involved in the accumulation of heavy metals in road sediments to enable decision-making processes directed to control heavy metal pollution from a urban public health perspective.Materials and methods: An international systematic review was conducted in related scientific literature published between January 1, 1970 and December 31, 2015. Springer, ScienceDirect and Google Scholar were the consulted databases. A citation frequency index (Q) was developed to establish an order of relevance of the detected PF, while cluster analysis, Student’s t-test, Pearson’s correlation coefficient and linear regression tests were used to study the correlation between the variables identified. Finally, 79 documents were selected for the construction of the manuscript.Results: The studies cited precipitation (Q1), land use (Q2) and traffic (Q2) as dominant PF. Therefore, a comprehensive view for public health management should consider two scenarios and their corresponding dominant PFs: meteorological (PF: precipitation) and anthropogenic (PF: land use and traffic).Conclusion: A different intervention order is suggested for the institutions in charge of controlling heavy metal pollution and public health management in urban areas.

SUMMARY In this study an industrial kaolin was subjected to high temperatures for one and two hours in order to eliminate plasticity and swelling properties. This heat-treated kaolin (HTK) was then evaluated for use as a substitute for natural mineral filler (passing No. 200 sieve; 6% by total mass of aggregate) in a Hot Mix Asphalt (HMA). The Marshall stability and flow test and Indirect Tensile Strength (ITS) test were performed to evaluate responses of HMA mixtures. X-ray diffractometry (XRD) and X-ray fluorescence (XRF) tests were carried out on kaolin (with and without thermal treatment). Effects of temperature and time of exposure on the penetration index (PI) and free swell index (FSI) of the HTK are also presented. Increased resistance under monotonic load and moisture damage was found when the natural mineral filler was completely replaced by the HTK. In contrast, when kaolin (K) that has not been heat-treated is used resistance and damage noticeably decrease especially in the presence of water. RESUMEN En el presente estudio, un caolín de origen industrial fue sometido a altas temperaturas durante una y dos horas con el propósito de eliminar sus propiedades de plasticidad y expansión. Este caolín tratado térmicamente (KT) fue utilizado para evaluar su posible uso como sustituto de un llenante mineral (porcentaje pasa 200 en un ensayo de granulometría; 6% de la masa total del agregado) de origen natural en una mezcla de concreto asfáltico (HMA). Para evaluar la respuesta de las mezclas HMA fueron ejecutados ensayos de resistencia Marshall y tracción indirecta (ITS). Se realizaron pruebas de difractometría de rayos X (DRX) y fluorescencia de rayos X (XRF) sobre el caolín (con y sin tratamiento térmico). También se presenta el efecto de la temperatura y el tiempo de exposición sobre los índices de penetración (PI) y expansión libre (FSI) de la KT. Como conclusión general se reporta un incremento en la resistencia bajo carga monotónica y al daño por humedad cuando espejo sustituye totalmente el llenante mineral natural por la KT. Contrario a lo anterior, si el caolín se utiliza sin tratar térmicamente (K), dichas resistencias disminuyen ostensiblemente, principalmente en presencia del agua. SUMÁRIO No presente estudo, um caulim de origem industrial foi submetido a altas temperaturas por 1 e 2 horas, a fim de eliminar suas propriedades de plasticidade e expansão. Este caulim tratado termicamente (KT) foi utilizado para avaliar sua possível utilização como substituto de um fíler de origem natural em uma mistura asfáltica quente. Testes de resistência Marshall e tração indireta foram realizados para avaliar a resposta das misturas. Testes de difratometria de raios X (DRX) e fluorescência de raios X (XRF) foram realizados no caulim (com e sem tratamento térmico). O efeito da temperatura e tempo de exposição nos índices de penetração (PI) e expansão livre (FSI) do KT também é apresentado. Como conclusão geral, um aumento na resistência Marshall e dano por umidade é obtido quando o fíler natural é completamente substituído pelo KT. Em contraste com o acima exposto, se o caulim é utilizado sem tratamento térmico (K), as referidas resistências diminuem ostensivamente, principalmente na presença de água.

One of the main objectives when compiling information from drones, is the generation of digital terrain models - DTM, which are what ultimately allow the creation of cartographic products reliably, efficiently, accurately, economically and quickly. In the present work, information obtained in Colombia is used in 3 types of terrain, with different varying conditions and characteristics. The data is taken with 2 different sensors, located in 2 fixed-wing drones (X8 skywalker with Sony Alpha camera a6000 24MP and UAVER Avian P with Sony RX1R II 42 MP). Information processing was performed and point clouds were obtained about the same area for executing a comparative iterative analysis, and obtaining the optimal parameters of: iteration angle, slope and distance of terrain iteration. A semiautomatic classification of point clouds was used, with 4 different treatments proposed by the authors, called classification MACROS and different DTM was generated. To analyze the behavior of the point clouds and check the accuracy, a control of dimensions in the field was made, the land was divided into 12 plots and the difference in elevation was calculated with a cloud of checkpoints, obtained manually. Finally, a completely randomized block experiment model is designed, created and tested.

Resumen Este artículo presenta los resultados de una fase experimental diseñada para evaluar y comparar la resistencia mecánica que experimenta una mezcla asfáltica tibia con una en caliente cuando ambas son fabricadas a escala real en una planta de asfalto de bacheo. Para tal fin fueron reali zados ensayos de resistencia bajo carga monotónica (Marshall y tracción indirecta) y cíclica (módulo resiliente, deformación permanente y resis tencia a fatiga). Para la fabricación de la mezcla tibia se empleó un aditivo químico que espuma el asfalto a aproximadamente 80 °C. Como ligante, para la fabricación de las mezclas se utilizó cemento asfáltico CA 60-70. La granulometría de control utilizada fue la de una mezcla densa en caliente MDC-19 (1). Esta mezcla de control se fabricó y compactó a temperaturas de 150 y 140 °C, respectivamente. Para el caso de la mezcla tibia, estas temperaturas fueron de 120 y 110 °C, respectivamente. Como conclusión general se reporta que la resistencia mecánica de la mezcla asfáltica tibia fabricada en planta de asfalto es superior a la de control en caliente, a pesar de que la primera fue fabricada y compactada a 30 °C menos. Abstract A relatively recent development in asphalt pavement technology, warm mix asphalt (WMA) offers a number of benefits. We present a comparison of some mechanical properties of warm mix asphalt (WMA) made in an asphalt plant batch with a traditional Hot Mix Asphalt (HMA). WMA mixture was made with asphalt cement CA 60-70 and a chemical additi ve that foams the asphalt at 80 °C. WAM was mixed and compacted at 120 °C and 110 °C, respectively. The control mixture (HMA) was a Dense Graded Mixture MDC-19 proposed by (1), was made with the same mate rials and mixed and compacted at 150 and 140 °C. Mechanical properties were evaluated under two loading modes: monotonic load (Marshall and indirect tensile test) and dynamic loads (resilient modulus, permanent deformation and fatigue). Results showed that mechanical properties of Warm Mixed Asphalts are better than control mixture.

espanolUno de los principales mecanismos de dano de mezclas asfalticas en servicio es el dano por humedad. Este fenomeno ocurre principalmente cuando se separa el ligante asfaltico del agregado petreo debido a la presencia de agua (stripping). Diversos estudios han sido ejecutados con el fin de intentar entender el fenomeno. A pesar del alto numero de investigaciones realizadas, las causas que lo generan no han sido totalmente entendidas e identificadas. El articulo presenta los resultados de un estudio experimental, ejecutado con el fin de evaluar la influencia que tiene el ligante asfaltico sobre el fenomeno, debido solo al efecto del agua. Sobre dos cementos asfalticos - CA (CA 80-100 y CA 60-70), se midio el cambio que experimentaron algunas de sus propiedades fisicas (punto de ablandamiento - ASTM D36, viscosidad absoluta - ASTM D-2171, viscosidad a 135 °C - AASHTO T-316 y penetracion - ASTM D-5), quimicas (ensayo SARA - ASTM D-4124) y reologicas (AASHTO T 315-05) cuando fueron sumergidos en agua durante 12 a 17 meses. Ensayos de resistencia bajo carga monotonica (Marshall, AASHTO T 245-97, 04) y de desgaste por abrasion (Cantabro, NLT 352/86) fueron ejecutados sobre una mezcla asfaltica porosa sumergida en agua durante 17 meses, y sobre la misma mezcla, pero fabricada con los asfaltos sumergidos en agua. Como conclusion general se reporta que los asfaltos en presencia de agua experimentan dentro de la mezcla contraccion del ligante asfaltico, lo que podria ser una de las causas que generen el fenomeno de dano por humedad. EnglishOne of the main forms of distress in asphalt mixtures is the moisture damage. This phenomenon occurs mainly when the asphalt binder is separated from the stone aggregate due to water presence. Many studies have been performed to describe and measure the moisture damage resistance in asphalt mixtures. Despite the high number of research projects performed, this phenomenon has not been fully understood yet. A laboratory study was initiated to investigate the influence of the asphalt binder on moisture damage, due to the effect of water only. Physical (softening point - ASTM D36, viscosity - ASTM D-2171, AASHTO T-316 and penetration - ASTM D-5), chemical (SARA - ASTM D-4124) and rheological (AASHTO T 315-05) properties of two asphalt binders (AC 60-70 and AC 80-100) immersed in water during 12 to 17 months were evaluated. Mechanical characteristics of a porous asphalt mixture immersed in water, and manufactured with asphalt binders also immersed in water were evaluated using Marshall (AASHTO T 245-97, 04) and Cantabro (NLT 352/86) tests. As concluding remark is reported that the interface asphalt binder-aggregate stone is affected for the change in the consistency that undergo the asphalt cements in presence of the water. Additionally, binders in presence of water undergo, inside the mixture, contraction, which may be one of the causes generating the stripping phenomenon.

The waste generated by the construction industry generally has an undesired negative impact on both human and animal life as well as the environment. Among these wastes, recycled concrete aggregate (RCA), due to its good residual physical, mechanical, mineralogical, and chemical properties, has attracted promising potential for re-use and incorporation in the construction of new infrastructural elements. These infrastructure applications include construction of sidewalks, curb and gutters, subbase/base layers, and/or as a partial replacement of natural aggregates (NA) in the production of hot mix asphalt (HMA) mixtures. In this laboratory study, experimental research work was conducted to evaluate the influence of RCA on the mechanical properties and performance of RCA modified HMA mixtures against a control HMA mixture without any RCA. RCAs were obtained from two different concrete sources, namely: (a) one from the demolition of a building (RCAB), and (b) another one from the rehabilitation of a Portland cement concrete pavement (RCAP). Both NA and RCA were characterized taking into account physical and mechanical properties. HMA mixtures were produced using the Marshall mix-design method by replacing 0.0% (control), 15%, 30%, and 45%, respectively, of the coarse NA fraction with RCA. Thereafter, laboratory testing (i.e., Scanning Electron Microscopy [SEM], resilient modulus, indirect tensile strength, etc.) including material property characterization and performance evaluation were conducted on HMA samples. Overall, the laboratory test results showed that the RCA modified mixtures exhibited a similar behavior to conventional HMA mixtures, but with greater environmental benefits and potential cost savings through the recycling and reuse of waste concrete aggregates. However, it was observed that the laboratory performance of RCA modified mixtures is strongly dependent on the RCA source and dosage, with RCAP exhibiting superior performance over RCAB. HMA mixtures produced with RCA provided higher optimum asphalt-binder content (OAC) than that of mixes with NA.

Significant amounts of blast furnace slag (BFS) are generated daily as by-product from iron and steel industries. This waste material usually has interesting physical properties and mineral...