Estudio de la durabilidad de Hormigones y Morteros reforzados por residuos industriales (Fibras Metálicas) = Study of the durability of Concretes and Mortars reinforced by industrial waste (Metallic Fibers)

Durante mucho tiempo, los residuos han alimentado varias cadenas de valor. Ante esta problemática, se han buscado cadenas de valor en ingeniería civil. Esta operación de recuperación reúne una ventaja económica y una cuestión medioambiental. El proceso de valorización en el ámbito de la construcción permite dar respuesta a múltiples problemas, tales como: la preservación de las reservas naturales de áridos mediante la valoración de los materiales de sustitución de las obras de ingeniería civil, y la reducción del transporte y de las emisiones de CO2. La gestión de los desechos sólidos es una de las principales preocupaciones ambientales del mundo. Con la reducción de los espacios para vertederos y debido a su elevado coste, el uso de residuos se ha convertido en una alternativa atractiva disponible para diversas aplicaciones. Por otro lado, la sostenibilidad es un objetivo de calidad para el ingeniero. La durabilidad del material de hormigón en su entorno se considera una preocupación importante en el sector de la construcción. El mecanismo de degradación química de este material es su descalcificación gradual en el tiempo en contacto con un entorno agresivo. Esta degradación provoca cambios en las propiedades fisicoquímicas y mecánicas del hormigón. Para evaluar experimentalmente la durabilidad del hormigón, hay que estudiar su comportamiento en relación con una serie de mecanismos que podrían degradarlo. El problema se puede tratar como la durabilidad del hormigón en ambientes agresivos. En este estudio se investigó el efecto de la adición de residuos industriales (fibras metálicas) sobre la durabilidad de hormigones y morteros que contienen un 10% de fibras en sustitución del cemento. Los resultados presentados se refieren a los obtenidos con las siguientes pruebas: Prueba de humectación-secado, prueba de lixiviación monolítica, ataque químico y evaluación de resistencia a la compresión mediante prueba de oscultación sónica.AbstractFor a long time, waste has fuelled several value chains. Faced with this problematic, value chains in civil engineering have been sought. This recovery operation brings together an economic advantage and an environmental issue. The process of valorization in the field of building and construction makes it possible to answer to multiple problems, such as: the preservation of the natural reserves of aggregates by the valuation of the materials of substitution for the works of civil engineering, and the reduction of the transport and CO2 emissions. Solid waste management is one of the main environmental concerns in the world. With the shrinking of spaces for landfilling and because of its high cost, the use of waste has become an attractive alternative made available for various applications. On the other hand, sustainability is a quality goal for the engineer. The durability of the concrete material in its environment is considered a major concern in the building sector. The mechanism of chemical degradation of this material is its gradual decalcification over time in contact with an aggressive environment. This degradation causes changes in the physicochemical and mechanical properties of the concrete. To experimentally evaluate the durability of concrete, one must study its behaviour in relation to a number of mechanisms that could degrade it. The issue can be treated as the durability of concrete in aggressive environments. In this study, we investigated the effect of the addition of industrial waste (metallic fibers) on the durability of concretes and mortars containing 10% of fibers in substitution of cement. The results presented concern those obtained with the following tests: Wetting-Drying Test, Monolith Leaching Test, Chemical Attack and Evaluation of Compression Resistance by Sonic Auscultation Test

Use of metallic fibers in concretes

The addition of a waste (fibers) in construction materials, particularly, the concretes is a technique increasingly used, for several reasons, either ecological, or economic, or to improve some properties in a fresh or hardened state. In our work we studied the behavior of the concrete and the mortar containing metallic fibers resulting from the unit BCR which is in Bordj-Menaiel in Algeria (metallic fibers resulting from the rejection at the end of the domestic operation of silvering of the tools and which is stored in plastic bags which are preserved in metal containers). Our work consists to study the behavior of the concretes and the mortars containing these fibers of cement substitution. We noted that the use of these fibers in the concretes in substitution of cement decreases its of compressive strength and flexural strength but to 10% of waste these strength remain acceptable

Study of the mechanical characteristics and chemical degradation of concretes based on machining sludge

The main objective of this work is to study the mechanical characteristics and the chemical degradation of mortars and concretes made obtained by substituting the cement by the machining sludge. Several materials were carried out by substituting the cement with different amount of machining sludge (5, 10, 15 and 20%). The obtained materials are compared to those without substitution (ie: 00wt% of machining sludge). Mechanical and physical properties of the two materials (mortars and concretes) as flexural and compressive strengths were studied. Physical properties as shrinkage, the bloating effect, loss in mass, slump concretes and porosity were evaluated. In addition, chemical degradation is studied for the conservation of these concretes and mortars from machining sludge in different aggressive environment. Moreover, the addition of 5wt% of the machining sludge in the mixture of the mortar and the concretes seems to be interesting

Study of the mechanical characteristics and chemical degradation of concretes based on machining sludge

The main objective of this work is to study the mechanical characteristics and the chemical degradation of mortars and concretes made obtained by substituting the cement by the machining sludge. Several materials were carried out by substituting the cement with different amount of machining sludge (5, 10, 15 and 20%). The obtained materials are compared to those without substitution (ie: 00wt% of machining sludge). Mechanical and physical properties of the two materials (mortars and concretes) as flexural and compressive strengths were studied. Physical properties as shrinkage, the bloating effect, loss in mass, slump concretes and porosity were evaluated. In addition, chemical degradation is studied for the conservation of these concretes and mortars from machining sludge in different aggressive environment. Moreover, the addition of 5wt% of the machining sludge in the mixture of the mortar and the concretes seems to be interesting

Valorización de relaves de mineral de oro de la mina Amesmessa en mortero de cemento: propiedades mecánicas, químicas y de microestructura = Valorization of gold ore tailing from Amesmessa mine in cement mortar: mechanical, chemical and microstructure properties.

La necesidad de responder a los problemas ambientales causados por los rechazos mineros, muchos enfoques llevados a cabo para resolver estos problemas. En este trabajo, se estudió el relave de mineral de oro proporcionado por la mina Amesmessa como sustitución en el mortero de cemento. Las cantidades de sustitución estudiadas fueron 0, 10, 20, 30 y 40 % del cemento en peso. Se relevó la composición mineralógica de las principales fases de la hidratación del cemento. Se realizaron pruebas experimentales como la compresión, la porosidad y la absorción de agua. Las pruebas revelaron que la sustitución del cemento al 10% es la cantidad óptima para sustituir el cemento. Se demostró una resistencia a la compresión de 33 Mpa, una porosidad de 10,31% y una absorción de agua de 4,83%. Estos valores se acercan a los de las muestras de referencia. Esta sustitución permite preservar el medio ambiente desde dos puntos de vista, mediante la valorización de los residuos de mineral de oro y la disminución de la emisión de CO2 con la disminución de la producción de cemento.AbstractThe need to respond the environmental problems causing by mining rejects, many approaches carried out to resolve these problems. In this work, we studied the gold ore tailing provided by Amesmessa mine as replacement in cement mortar. The substitution amounts studied 0, 10, 20, 30, and 40 % of cement in weight. The mineralogical composition was relieved the principal phases of the cement hydration. Experimental tests carried out such as compressive, porosity, water absorption. The tests revealed that the replacement of cement at 10% percent is the optimum amount to replace cement. It showed 33 Mpa of compressive strength, 10.31% porosity, 4.83% water absorption. These values are so close to those of reference samples. This substitution allows preserving the environment from two sides, by valorizing the gold ore tailing and diminishing the CO2 emission with diminishing the cement production