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This work analyzes the influence of added plastic polycarbonate waste from recycled compact discs (CDs) and digital optical disc (DVDs) on the mechanical and environmental properties of composites with a gypsum matrix. Fifteen mixtures were produced including different percentages by weight of plastic aggregate with two different granulometries. In each case, the strength properties (flexural and compressive) and density of the new composites were tested. In addition, scanning electron microscopy (SEM) and X-ray computed tomography (XCT) were performed in order to know the internal structure and porosity of the new composites. Finally, a simplified environmental study was conducted using the Life Cycle Assessment (LCA) method. The results show that lighter and more eco-efficient materials can be obtained that have, in some cases, better mechanical properties than the reference material (gypsum). A density reduction of a 9.89% was achieved for mixtures with 60% of plastic waste, having also an environmental improvement of 35% compared to the reference sample. In all the cases, the minimum values for mechanical properties required by the standard were obtained. These properties make the composites suitable for use in new products and in construction works.

The continuous and rapid evolution in the field of computing, and in particular in the field of storage devices, has led to the obsolescence of optical discs in favour of mass storage devices. In that sense, a large number of CDs and DVDs become obsolete each day in the world. In trying to create a recovery solution for those pieces, research in which polycarbonate (PC) waste from recycled discs have been used to develop new gypsum coating materials and products has been conducted. In a previous study, the physical and mechanical properties of new gypsum plasters, with PC waste as aggregate, were studied. Following that study, this article aims at creating new gypsum plaster false ceiling plates, using CD and DVD residues in different scenarios: as crushed aggregate in the gypsum matrix, as full reinforcement pieces of the plates and as a combination of both. The mechanical behaviour and the thermal conductivity of the new pieces have been analysed in this paper. The results showed an important improvement in the mechanical and thermal properties of the plates when the PC waste was used in many scenarios.

This study analyses a procedure to manufacture mortars with different percentages of ceramic waste as partial replacement for aggregates. The study also examines the physical, chemical and mechanical properties of the new mortars, analysing substitution ratios that range from 10% to 50%. Prior to this, all the materials used in the production of the mortar were characterised using X-ray diffraction (XRD) and fluorescence (XRF). The objective was to determine the similarity between different types of ceramic waste, as well as the differences in the minerology and chemical composition with the aggregate. The results of the study show that it is possible to obtain mortars with lower densities compared to the same product with no recycled content. The product’s characteristics make it ideal for the manufacture of prefabricated components for structural floors for rehabilitation works. Finally, the pieces are used in a real rehabilitation case study, highlightining the structural advantages. Caracterización de morteros con cerámica reciclada y su uso en piezas prefabicadas para entrevigado de forjados. Este trabajo analiza morteros con diferentes porcentajes de cerámica reciclada como sustituto parcial de la arena. Además el estudio examina las propiedades físicas, químicas y mecánicas de los nuevos morteros, empleando diferentes porcentajes de sustitución (10% - 50%). Con anterioridad, se caracterizaron todos los materiales empleados en este trabajo mediante difracción y fluorescencia de rayos-X. El objetivo fue determinar las diferencias y similitudes en la composición química y mineralógica de los distintos tipos de residuos cerámicos y del resto de áridos utilizados. Los resultados muestran que es posible obtener morteros con menor densidad frente a las muestras sin contenido reciclado. Sus características los hacen idóneos para la creación de piezas prefabricadas de entrevigado para rehabilitación de forjados. Finalmente. Las piezas se usaron en un caso de estudio real, destacando las ventajas estructurales que conlleva su uso.

The research carried out studies how the addition of plastic polypropylene fibers from recycled non-degradable wet wipes can influence on the physical and mechanical behavior of composites with a gypsum binder matrix. Four different plaster blends were studied, corresponding to percentages of 2, 2.5, 3 and 3.5% by weight of recycled plastic fibers. To characterize the different test specimens, properties such as density and strength (flexural and compressive) were determined. Also, in order to find out about the internal structure of the different composites developed at a microscopic level, a Scanning Electron Microscopy (SEM) test was performed. The results show that more efficient materials can be obtained with a little decrease in their density compared to the reference material (gypsum). However, the improvement in the novel composites’ mechanical properties represents one of the most notable achievement of the study. A flexural strength rise of a 19% was achieved for mixtures with 2,5% of recycled PP fibers compared to the reference specimen. These results confirm the feasibility of using the gypsum composites produced for the design of new construction products and its application in building systems as wall and ceiling lining.

Large amounts of different types of waste are generated each day in the world. Most of them do not receive proper management at the end of its useful life. In that sense, and trying to apply eco-efficiency criteria, the construction sector has recently been working on the design of new building materials that incorporate some types of residues. Those new construction materials improve some of the properties given by traditional options, such as thermal conductivity or lightness. However, many types of research in which new building products are generated do not exist. Subsequently, this paper aims at generating new gypsum plaster false ceiling plates by incorporating two different types of residues: wood waste from the demolition of traditional wooden slabs and polycarbonate (plastic) waste from crushed rejected CDs and DVDs. The flexural strength of the developed plates is tested using the procedure described by UNE-EN 14246. Furthermore, the thermal conductivity of the new pieces is obtained following the method defined by ASTM D5930-09. The results show that for all the scenarios under study when wood and plastic waste is added to the plates, the lightness and the thermal conductivity of the pieces improved. In addition, in some scenarios, the incorporation of polycarbonate waste is linked to an improvement in the mechanical behaviour of the pieces compared to the reference plate. On the other hand, when wood waste is added to the mixtures, the flexural behaviour of the plates decreases, but always achieving the minimum requirements made by the standards. Finally, it must be said that adding waste to the plasters, the amount of gypsum powder used to generate the plates decreases considerably, which represents a significant improvement in the eco-efficiency of new products.

The construction sector consumes 95% of the total production of gypsum due to its multiple applications. Gypsum plaster is one of the most common indoor coating material (pastes and mortars), but it can also be used in prefabricated products like plasterboards, blocks and decorative elements. Gypsum waste recycling provides a solution to an important environmental problem from the use of gypsum plaster, which is the generation of large amounts of wastes at different phases (production, construction, rehabilitation and demolition). This paper studies two different replacement alternatives of natural gypsum: Flue Gas Desulphurization (FGD) gypsum and gypsum waste obtained from industrial plasterboard production. The influence of the previous types, amounts of waste (25, 50, 75 and 100 wt%) and different heating temperatures (100 °C, 150 °C and 180 °C) and processes on the workability of gypsum plasters is evaluated and discussed, based on a microstructure analysis using XRD and SEM techniques. This research highlights the feasibility, in terms of workability, of using Gypsum Plasterboard Waste (GPW), without any heating process, as a replacement gypsum in plasters. Despite the fact that a higher amount of water was necessary in the production of the mixes, a good workability was achieved. On the other hand, the unfeasibility of using unheated FGD as a constituent of plasters was demonstrated. However, a good performance, in terms of workability, of the FGD was obtained when the powder was subjected to a heating process at 180 °C during 6 h.

In this study, wood waste from demolition was used by replacing natural aggregate for developing lightweight mortars. Many domestic buildings in the historical city centers of Spain have wo...

Large amounts of wood waste are generated each year in the world. In an attempt to identify a good recovery option for those residues, wood waste from construction and demolition works were used as raw materials in gypsum plasters. However, wood is a biodegradable material which implies that the products or materials that contain it are susceptible to suffering an important deterioration, due to exposure in certain environments. For that reason, the aim of this work was to simulate the effects that, in the long term, the atmospheric exposure of wood waste&ndash, gypsum composites would have. To do that, the plasters were subjected to 5, 10, and 15 wetting&ndash, drying cycles in a climatic chamber. In this study, the density, flexural and compressive strength, and ultrasonic velocity of these composites were determined by the influence of the aging process on their mechanical properties. Furthermore, in order to detect changes on their internal structure, scanning electron microscopy tests (SEM) were used. The results showed that they were suitable to be used as indoor coverings of buildings. However, a treatment to reduce the moisture absorption of the wood waste must be studied if mixtures with high percentages of wood shavings (WS20) are used in wet rooms.

The aim of this study is to determine the limits of the infrared thermography technique applied to the inspection and characterization of elements and wooden building systems which may exist in rehabilitation work. This work is the response to a previous study carried out in a laboratory where environmental and work parameters are monitored (such as Ta, relative humidity, and distance to target). Several situations are analysed. The influence of wood density is studied with various wood samples. Moreover, a range of internal defects according to different sizes and depths are considered. Furthermore, defects with different moisture content, normally associated with wood decay, are studied to determine the result in the thermal image.

A nondestructive technique for inspection and evaluation in place timber structures and components based on ultrasonic pulse velocity, and moisture content is presented herein. By applying this methodology we could obtain the bending strength and elasticity modulus of timber beams, as well as the damage in them. The quantitative determination of the existing strength of timber beams will provide information necessary to take the most suitable decisions in rehabilitation works involving timber structural elements., Este artículo presenta el desarrollo de un método de ensayo, no destructivo, para la inspección y evaluación in situ de elementos estructurales de madera, basado en las medidas de la velocidad de ondas ultrasónicas y determinación de humedad. Mediante la aplicación de este método se podrá obtener una estimación de la resistencia a flexión y del módulo de deformación de la madera estudiada, así como la detección de estados de deterioro de la misma. Esto aportará información suficiente a la hora de tomar decisiones en una obra de rehabilitación con elementos estructurales de este material.