State-of-the-art green roofs: Technical performance and certifications for sustainable construction

Green roof systems, a technology which was used in major ancient buildings, are currently becoming an interesting strategy to reduce the negative impact of traditional urban development caused by ground impermeabilization. Only regarding the environmental impact, the application of these biological coatings on buildings has the potential of acting as a thermal, moisture, noise, and electromagnetic barrier. At the urban scale, they might reduce the heat island effect and sewage system load, improve runoff water and air quality, and reconstruct natural landscapes including wildlife. In spite of these significant benefits, the current design and construction methods are not completely regulated by law because there is a lack of knowledge of their technical performance. Hence, this review of the current state of the art presents a proper green roof classification based on their components and vegetation layer. Similarly, a detailed description from the key factors that control the hydraulic and thermal performance of green roofs is given. Based on these factors, an estimation of the impact of green roof systems on sustainable construction certifications is included (i.e., LEED—Leadership in Energy and Environment Design, BREEAM—Building Research Establishment Environmental Assessment Method, CASBEE—Comprehensive Assessment System for Built Environment Efficiency, BEAM—Building Environmental Assessment Method, ESGB—Evaluation Standard for Green Building). Finally, conclusions and future research challenges for the correct implementation of green roofs are addressed

Advanced coatings for buildings

Based on five Special Issues in Coatings, this e-book contains a series of fifteen articles demonstrating actual perspectives and new trends in advanced coatings in buildings. Innovative materials and multiperformance solutions provide a basis, contributing also to better protection of buildings’ surfaces during the service life, and users’ wellbeing

Mechanical properties of concrete using recycled aggregates obtained from old paving stones

Nowadays, construction, maintenance, reparation, rehabilitation, retrofitting, and demolition from infrastructure and buildings generate large amounts of urban waste, which usually are inadequately disposed due to high costs and technical limitations. On the other hand, the increasing demand for natural aggregates for concrete production seriously affects mountains and rivers as they are the source of these nonrenewable goods. Consequently, the recycling of aggregates for concrete is gaining attention worldwide as an alternative to reduce the environmental impacts caused by the extraction of nonrenewable goods and disposal of construction and demolition waste (C&DW). Therefore, this article describes the effect on the mechanical properties of new concrete using recycled aggregates obtained from old paving stones. Results show that replacing 50% by weight of the fine and coarse aggregate fractions in concrete with recycled aggregate does not meaningfully affect its mechanical behavior, making the use of recycled aggregates in new precast paving stones possible. Therefore, the latter can reduce environmental impacts and costs for developing infrastructure and building projects

Economía circular en el sector de la construcción: un estudio de caso de Santiago de Cali (Colombia)

17 páginasThe circular economy, a new paradigm of technological and economic development, is of great importance in developing countries, particularly in the construction sector, one of the most relevant in Colombia. In the Latin American context, Colombia has one of the most important construction industries, contributing to the social and productive development of the country. However, this sector is also responsible for serious environmental problems and social conflicts. Therefore, it is imperative to work with all actors of the value chain to transform the construction sector from a linear economy to a circular economy model. Therefore, this article describes the circular economy model proposed for Santiago de Cali, which is mainly oriented to the analysis and efficient use of construction materials, mostly taking into account the recovery of ecosystems and the circular flow of rocky materials. This model includes an analysis of the production of construction materials, construction process, use and operation, and completion of the life cycle of buildings and infrastructure. In particular, the model proposes an innovative product portfolio for the use of construction and demolition waste (C&DW) supported in applied research (case studies). The portfolio consists of family products, such as recycled aggregates or eco-aggregates, eco-concretes and mortars, eco-prefabricated products and modules, and smart construction materials. In addition, this model describes the C&DW management system and some characteristics of the Technological and Environmental Park (TEP), the main strategy for C&DW valorization in the city.La economía circular, un nuevo paradigma de desarrollo tecnológico y económico, es de gran importancia en los países en desarrollo, particularmente en el sector de la construcción, uno de los más relevantes de Colombia. En el contexto latinoamericano, Colombia cuenta con una de las industrias de la construcción más importantes, contribuyendo al desarrollo social y productivo del país. Sin embargo, este sector también es responsable de graves problemas ambientales y conflictos sociales. Por lo tanto, es imperativo trabajar con todos los actores de la cadena de valor para transformar el sector de la construcción de un modelo de economía lineal a uno de economía circular. Por lo tanto, este artículo describe el modelo de economía circular propuesto para Santiago de Cali, el cual está orientado principalmente al análisis y uso eficiente de materiales de construcción, teniendo en cuenta mayoritariamente la recuperación de ecosistemas y el flujo circular de materiales rocosos. Este modelo incluye un análisis de la producción de materiales de construcción, proceso constructivo, uso y operación, y finalización del ciclo de vida de edificios e infraestructura. En particular, el modelo propone una cartera de productos innovadores para el aprovechamiento de residuos de construcción y demolición (RCD) apoyados en investigación aplicada (estudios de caso). El portafolio se compone de productos familiares, como áridos reciclados o ecoáridos, ecohormigones y morteros, productos y módulos ecoprefabricados y materiales de construcción inteligentes. Además, este modelo describe el sistema de gestión de RCD y algunas características del Parque Tecnológico y Ambiental (PET), principal estrategia para la valorización de RCD en la ciudad

Life Cycle Assessment on Construction and Demolition Waste: A Systematic Literature Review

Life Cycle Assessment (LCA) is considered an innovative tool to analyze environmental impacts to make decisions aimed at improving the environmental performance of building materials and construction processes throughout different life cycle stages, including design, construction, use, operation, and end-of-life (EOL). Therefore, during the last two decades, interest in applying this tool in the construction field has increased, and the number of articles and studies has risen exponentially. However, there is a lack of consolidated studies that provide insights into the implementation of LCA on construction and demolition waste (C&DW). To fill this research gap, this study presents a literature review analysis to consolidate the most relevant topics and issues in the research field of C&DW materials and how LCA has been implemented during the last two decades. A systematic literature search was performed following the PRISMA method: analysis of selected works is based on bibliometric and content-based approaches. As a result, the study characterized 150 selected works in terms of the evolution of articles per year, geographical distribution, most relevant research centers, and featured sources. In addition, this study highlights research gaps in terms of methodological and design tools to improve LCA analysis, indicators, and connection to new trending concepts, such as circular economy and industry 4.0

Evaluation of semi-intensive green roofs with drainage layers made out of recycled and reused materials

Green roof systems represent an opportunity to mitigate the effect of natural soil loss due to the development of urban infrastructure, which significantly affects natural processes such as the hydrological water cycle. This technology also has the potential to reduce the indoor building temperature and increase the durability of waterproof membranes, reduce run-off water and heat island effects, create meeting places, and allow the development of biological species. However, despite the described benefits, the use of this technology is still limited due to the costs and the environmental impact from using non-renewable building materials. Therefore, this article presents the hydraulic and thermal analysis of different semi-intensive green roofs using recycled (rubber and high density polyethylene (HDPE) trays) and reused materials (polyethylene (PET) bottles) in their drainage layers. Then, three roof systems were evaluated and compared to traditional drainage systems made with natural stone aggregates. Results showed that some systems are more useful when the goal is to reduce temperature, while others are more effective for water retention. Additionally, this study presents evidence of the potential of reducing the dead loads and costs of green roofs by using recycled and reused materials in drainage systems

LCA based recommendations for the selection of eco-concretes using blast furnace slag and fly ash

The development of circular economy models for the construction sector brings important challenges and opportunities to research and particularly to make knowledge transfer, for example through public policies. Santiago de Cali, third major city of Colombia (South America), is developing a circular economy model policy, which is mainly based on waste valorisation. Among others, the model includes a family of eco-concrete products that replaces Portland cement by blast furnace slag and fly ash coming from local industries. Therefore, the aim of this research is to develop scientific based recommendations to stakeholders for the selection of different concrete products (i.e. beams, columns, slabs) using blast furnace slag and fly ash (eco-concretes). Considering that life cycle assessment (LCA) is the most employed tool for consolidating, comparing, and assessing sustainability impacts [1], the LCA of these concrete products for the design of a sustainable residential house was performed. The LCA software Building for Environmental and Economic Sustainability (BEES) developed by the National Institute of Standards and Technology (NIST) was selected for the study. Results include a discussion on the environmental impacts. Furthermore, a methodology for the selection of sustainable building materials is presented

Mechanical Properties of Concrete Using Recycled Aggregates Obtained from Old Paving Stones

Nowadays, construction, maintenance, reparation, rehabilitation, retrofitting, and demolition from infrastructure and buildings generate large amounts of urban waste, which usually are inadequately disposed due to high costs and technical limitations. On the other hand, the increasing demand for natural aggregates for concrete production seriously affects mountains and rivers as they are the source of these nonrenewable goods. Consequently, the recycling of aggregates for concrete is gaining attention worldwide as an alternative to reduce the environmental impacts caused by the extraction of nonrenewable goods and disposal of construction and demolition waste (C&DW). Therefore, this article describes the effect on the mechanical properties of new concrete using recycled aggregates obtained from old paving stones. Results show that replacing 50% by weight of the fine and coarse aggregate fractions in concrete with recycled aggregate does not meaningfully affect its mechanical behavior, making the use of recycled aggregates in new precast paving stones possible. Therefore, the latter can reduce environmental impacts and costs for developing infrastructure and building projects

Circular Economy: Adding Value to the Post-Industrial Waste through the Transformation of Aluminum Dross for Cement Matrix Applications

In light of globalization and escalating environmental concerns, society is increasingly confronted with the challenge of implementing the concept of a circular economy, which promotes the recycle of waste materials and offers a promising solution. Aluminum dross, a byproduct of the aluminum production process, poses environmental issues when not properly managed. Therefore, this study examined the technical and financial feasibility of implementing an industrial process for the recovery and transformation of aluminum dross into raw materials for use in cementitious materials. From a technical perspective, two processes were evaluated: washing and the grindability of the material. An X-ray diffraction analysis allowed to verify an approximately 88% reduction in AlN (a compound that produces ammonia gases when reacting with water) after washing the material. The most efficient grinding process was achieved using an impact mill. The financial feasibility study was carried out through cash flow forecasting, which revealed that a minimum selling price of USD 0.12 per kilogram of processed material could generate a return rate of 9.7% over a five-year period. These results present opportunities for the metal and construction industries to develop products with low CO2 emissions by reintegrating aluminum dross into a productive cycle. Moreover, this work serves as a valuable reference for policymakers and environmental authorities seeking to formulate new legislation or incentives that encourage companies to invest in environmentally focused projects