Escuela de Politécnica Superior

Researchers are investigating eco-friendly binders like coconut shell ash (CSA), metakaolin (MK), and calcined clay (CC) as supplementary cementitious materials (SCM) in high-strength concrete (HSC). Abundantly available as industrial or agricultural waste, these materials, when combined with Portland cement (PC), offer synergistic benefits. This not only improves concrete performance but also addresses waste disposal issues, presenting a sustainable and environmentally friendly solution for long-term use in HSC production. However, this study performed on fresh and mechanical characteristics of HSC blended with CSA, MK, and CCA alone and together as SCM after 28 days of curing. A total of 504 samples of standard concrete were cast and the cubical samples were tested to achieve the targeted compressive strength about 80 MPa after 28 days. The experimental results indicated that the rise in tensile, flexural and compressive strengths of 9.62%, 8.27%, and 10.71% at 9% of CSA, MK, and CC as SCM after 28 days of curing. As SCM content increases, the density, porosity and water absorption of concrete decrease. Moreover, the workability of fresh concrete is getting reduced when the concentration of SCMs increases in HSC. In addition, the concrete’s sustainability assessment revealed that employing 18% MK, CC, and CSA as SCM reduced carbon emissions by approximately 11.78%. It is suggested that using 9% CC, MK and CSA together in HSC yields the best results for practical applications in civil engineering.

Recently, studies on sustainability and ecology have become widespread in almost all sectors. One of the most important reasons for this spread is the rapid increase in industrialization and, thus, the increase in waste caused by industries. In this context, significant efforts are being made to evaluate some of these wastes. One of these efforts is the production of geopolymers. In this research, metakaolin and slag-based geopolymer mortar samples were manufactured, and polyvinyl Alcohol, basalt, and macro synthetic polypropylene fibers were used to enhance the physical, mechanical, and high-temperature resistance of the sample. Physical and mechanical tests of the produced samples were performed after 28 days. Then, elevated-temperature experiments were conducted to evaluate the behavior of the fibers under the influence of high temperature. Following the high-temperature test, physical, mechanical and microstructure tests of the samples were performed. As a result, basalt fiber enhanced the compressive strength of 800 ◦C-exposed samples by 7.72% compared to the fiber-free sample. Also, polyvinyl Alcohol fiber increased the energy absorption capacity of the samples by increasing Charpy impact values to 72.22% compared to fiber-free sample. Moreover, macro synthetic polypropylene fiber reduced capillary water absorption value up to 12.44% compared to fiber-free sample.

As a primary goal, Inadequate energy consumption and outdated construction systems are causing financial losses for homeowners. Spain’s failure to meet European guidelines on CO2 emissions highlights the urgent need to address the energy inefficiency of buildings, responsible for 40% of such emissions. This article presents a comprehensive refurbishment project undertaken in the Lagos Park residential building in Madrid. The paper offers a detailed analysis of common building issues related to excessive humidity in the surrounding areas and deficiencies in the energy performance of the building envelope, including facades and roofs. Precise measures for achieving compliance with the Spanish Technical Building Code (CTE), as well as enhancing energy efficiency and functionality, are explained through the renovation of the building envelopes. The study also encompasses improvements made to the domestic hot water supply systems and the air-conditioning system, which contribute to the building’s attainment of an optimal energy rating (energy Class A). The extensive renovation undertaken in the complex has transformed Lagos Park homes into “zero energy consumption” residences. The strategies employed, ranging from electrical appliances to the house’s structural design, are all geared towards maximizing energy usage efficiency, resulting in significantly reduced monthly electricity bills by 65%–75%.

As the disposal of materials and commodities in the management of construction projects has evolved into a critical issue, certain building materials are likely to be thrown away as rubbish at the end of a structure’s useful life. However, tearing down houses and dumping huge amounts of garbage in landfills are not the best feasible solutions to the problem. The depletion and loss of building materials on the project site are exacerbated by the significant amount of waste generated during construction. The tearing down and rebuilding of previously existing buildings are two other methods contributing to rubbish production. Trash management that is as effective as possible has become a need in light of the depletion of natural resources and raw materials, as well as the rise in the pollution brought on by waste from construction projects. One technique that might be taken to address these challenges is the implementation of concepts related to reverse logistics (RL). By considering energy management in construction utilizing sustainability and environmental criteria, this study aims to identify the inverse logistics issues of construction management and smart building. An integrated method of multi-criteria decision-making called MARCOS and ordinal priority approach (OPA) for ranking solutions and weighing criteria is presented in this study. The findings indicate that out of the 23 challenges that must be overcome to implement reverse logistics effectively and achieve sustainability in the construction industry, the one with the most weight and impact on sustainability is “Workforce errors and mistakes during execution. Out of the ten potential solutions, “determining reverse logistics as a part of a sustainability program” and “strategic collaboration with reverse logistics partners” offer the most viable options for resolving the issue and overcoming the obstacles.