Study and Characterization of Special Gypsum-Based Pastes for Their Use as a Replacement Material in Architectural Restoration and Construction.

Within the construction sector, the use of gypsum-based pastes features in the majority of monuments, giving this material significant relevance in conservation and restoration projects affecting the world's cultural heritage. In this research, we evaluated special gypsum-based colored pastes mixed with air lime, hydraulic lime and sodium silicate, and eight different pigments for their use as replacement materials in architectural restoration and construction. We analyzed the suitability of their physical and chemical properties and their hydric characteristics, mechanics and colorimetric implications in two different studies after 28 days and 120 days. The characterization of the products has mainly confirmed the suitability of the pastes containing pigments for use in the most common applications for these kinds of mixes, highlighting that their specific capacities are worth leveraging. The crystallization of gypsum minerals, observed in all of the mixes, helps to consolidate the shrinkage cracks which appear inside the pastes, improving their mechanical strength values. Another observation of the pastes is related to the amorphous silica precipitates in the mixes which contained sodium silicate: the latter provided to them good mechanical behavior. The improvement observed in the pastes containing the green earth pigment is substantial, due to the inclusion of aluminum silicates and Mg, which is partly responsible for the increased compressive strength of the pastes. Finally, the colorimetric analysis is of vital importance in determining the loss of intensity of the colors of the pastes used, since subjective observation leads to serious errors of interpretation.

Analysis and Comparison of the Corrosive Behavior of Nickel-Based and Cobalt-Based Dental Alloys.

Nickel-based and cobalt-based metal alloys are frequently used in dentistry. The introduction of various elements in the alloy changes its characteristics, and a thorough study of each alloy should be completed to determine its appropriate corrosion resistance and biocompatibility in contact with physiological fluids. There are scarce investigations on these widely used dental alloys in Ringer solution, and findings in this research bring new experimental data and information. The present study evaluated and compared the corrosion behavior of six NiCr- and two CoCr-based dental materials in Ringer solution, using the following techniques: potentiostatic polarization curves (chronoamperometry), microstructural analysis, and EIS (electrochemical impedance spectroscopy). The results obtained in this investigation showed that in the NiCr-based specimens Ni4, Ni5, and Ni6 the stability of the passive layer was destroyed after polarization and a development and growth of stable pits was found in the microstructural analysis after electrochemical treatment. In terms of susceptibility to corrosion, two different groups of specimens were derived from this investigation. A first group which included the two CoCr (Co1 and Co2) and three of the six NiCr alloys studied (Ni1, Ni2, and Ni3). A second group with the other NiCr alloys investigated Ni4, Ni5, and Ni6.

Green space networks as natural infrastructures in PERI-URBAN areas.

Focusing on the analysis of green spaces of urban and peri-urban borders, this paper puts into practice a methodology designed for the analysis of green areas and peri-urban spaces as green infrastructures, but from a multifunctional and integrating perspective, as it is stated in the European Strategy for Green Infrastructures and the 2030 Agenda for Sustainable Development goals. The deadline for implementing European legislation in this area means that strategic plans are being developed at local and regional level. In Spain there are municipal and regional strategies already developed and implemented but the national strategy has not yet been approved. To this end, the development of monitoring and evaluation tools such as the one presented in this article, can help not only in local decision-making, but also in the establishment of common criteria to help assess its future evolution. This research analyses the large peri-urban parks located in the southwest of the Community of Madrid (Spain). The evaluation is carried out from a local to a regional scale applying multifunctionality criteria to the planning, design, execution, maintenance and resilience phases. From the point of view of landscape structures, the findings of this study reflect a high environmental and social services delivery value, which makes it possible to understand the need to create networks to integrate the peri-urban spaces into the city and to attend to and understand the needs of all actors involved: citizens, political leaders, municipal technicians and private companies, providing them a common vision that improves the future of these spaces. This makes them core areas from which to design strategic plans for natural infrastructure and improvement of biodiversity in the urban area, being, likewise, an example that can be extrapolated and applied to large cities whose urban areas are adjoined and where peri-urban parks can be the starting point for designing supramunicipal strategies for open spaces. Based on these results we can conclude that south-west Madrid provides the ideal conditions for implementing a supra-municipal strategy for green infrastructures which, starting with its large forest parks, showcases the periurban areas which connect them with the urban green network. The Móstoles Green Network and Bosquesur are two strategic projects which, together with the forest parks, constitute a working framework based on which the Supra-municipal Strategy for Open Spaces in South-west Madrid can be devised.

Environmental analysis of the use of plant fiber blocks in building construction.

Construction is a sector which produces high greenhouse gas emissions, which cause global warming. As such, it is becoming increasingly important to use sustainable materials which reduce the environmental impacts. The properties of the plant fiber block make it one of the most adequate building materials for the construction of the building envelope. However, there is no in-depth research that encompasses the extraction of the raw material, the transport to the factory and the manufacturing process. The present research analyzes the environmental impact associated with the production of plant fiber blocks as a building material, using the Life Cycle Assessment methodology. In addition to looking at the sustainability of this material, it also compares it with other conventional building materials. The results show that the impact category which made the biggest contribution in the manufacturing of a plant fiber block for its use in construction was that of the total primary energy consumption (9.74 MJ/kg straw). With reference to the emission of the greenhouse gases produced during manufacturing, the main contributors are the nitrogen and urea-based fertilizers used in cereal cultivation (0.73 kg of the total 0.96 kg of CO2 per kg of straw). However, the impacts caused by manufacturing a PFB are much lower than those produced from other insulating materials such as expanded polystyrene, extruded polystyrene or polyurethane foam (4.67E+03 kg CO2 eq. for the PFB compared to 1.23E+04 kg CO2 eq. for the fiberglass and 1.33E+04 kg CO2 eq. for the polyurethane).

Analysis of the impact of health and safety coordinator on construction site accidents: The case of Spain.

The figure of the Health and Safety Coordinator (HSC), as a necessary and competent engineer in the construction sector, emerged in Spain on December 25, 1997 as a result of the implementation of European Directive 92/57/EEC. The coming of age of this figure is a sufficient period of time for determining its implementation and impact within the construction sector. The research carried out in this article arose from the analysis of statistical data obtained through Public Authorities and Professional Bodies. The quantitative study of the data extracted is complemented by the creation of specific benchmark indicators which connect four fundamental variables in the construction industry: the number of accidents, volume of workers employed, building units, and health and safety coordination posts. Furthermore, the legislation governing the HSC engineer in each of the 28 Member States of the European Union is studied. The results show a high implementation rate for the figure of the HSC, as well as a positive impact in relation to the reduced accident rate in the construction sector. Likewise, an update to the procedures of the various authorities is considered to be necessary in order to make the data concerning the actual work of the health and safety coordinators public. Finally, a review of the Spanish legislation concerning the HSC Coordinator is considered to be inevitable, in order to bring it up to the levels of professional skill and competence defined by the majority of European Union Member States.

Acoustic and economic analysis of the use of palm tree pruning waste in noise barriers to mitigate the environmental impact of motorways.

This research has a twofold environmental benefit. On the one hand, there is the recycling of a waste by-product and, on the other hand, the reduction of traffic noise pollution levels. The objective of this study is to determine and evaluate the use of a mixture of shredded palm tree pruning waste with dampened topsoil in the construction of noise barriers. With a view to efficiently recycling pruning waste and using an environmentally-friendly material which does not pose any environmental risks at the end of its useful life, the composition offering the best sound absorption has been analyzed. Based on the results obtained, a completely eco-friendly roadside noise barrier (RNB) 1:1 scale model was built, and noise levels measured at various points close to it. Significant sound absorption benefits were detected, not only in the shaded area behind the barrier, but also in the unprotected area immediately above the barrier. Furthermore, the economic feasibility of both the construction and recycling processes has been calculated.