Recycled glass mixtures as cast glass components for structural applications, towards sustainability

The problem of sustainability represents one of the most important issues that the world has to face nowadays, not only in terms of energy consumption and of the consequent CO2 emissions, but also in terms of material waste streams that end in landfill. 38 million tons of glass waste are produced every year in the European Union and new targets have been set for 2020 towards a more sustainable management of such wastes. Nowadays, only the container glass industry has reached a considerable recycling rate, while for all the other sectors we are still witnessing downgrading processes. Looking at the world of construction, glass has been more and more employed as a structural material thanks to its high transparency and compression strength. Although the use of glass can be attractive under multiple aspects and its production is continuously increasing, once employed as a construction element, it is rarely reused or recycled due to the high-quality requirement demanded to the industry of production. Nevertheless, besides its main applications as a 2-dimensional element, the new technology of cast glass has been recognised as a potential mean of glass recycling. Here, glass is designed and used under the form of repetitive 3-dimensional units assembled in a whole geometrical shape. In fact, thanks to its higher load-bearing capacity under monolithic shapes, this glass can admit less restrictions and potentially incorporate different types of waste. For this reason, the aim of this experimental work is to find a possible combination between glass families, specifically soda-lime, borosilicate and lead-crystal glass, to be recycled as cast glass components. Each type of glass was powdered or grinded under the form of cullet and different mixtures were prepared to be melted at temperatures of 970°C, 1120°C and 1200°C through the kiln-cast tecnique. Finally, an experimental splitting test was performed to define a force trend and a fracture behaviour for each sample. Some preliminary results have been achieved drawing the guidelines for a further investigation. Soda-lime-silica glass and lead-crystal glass mixture revealed to be the most compliant glass recipe with the required physical and mechanical properties, when reheated at 1120°C. The decrease in the melting temperature of the compound and the higher transparency given by the addition of lead glass revealed the potential benefit, in terms of sustainability, for future projects

Climate Change and Extreme Wind Events: Overview and Perspectives for a Resilient Built Environment

The frequency and intensity of extreme weather events have increased in the last few years. Buildings resiliency against natural hazards (hurricanes, flooding, wildfires, etc.) is fundamental for the adaptation to climate change, however it is hardly included in their design. Buildings exposed to extreme climate conditions may become drivers of vulnerability, rather than providing shelter for users, leading to human and economic losses. The building stock assessment appears to be quite detailed about seismic vulnerability and energy demand related to climate change, but not towards other hazardous events, such as extreme winds. Furthermore, climate data provided by current standards and used for building design need to be seriously reconsidered, since they no longer represent the real weather variables. During windstorms, the main threats are mainly due to the detaching and flying of materials and elements from buildings and urban furniture. The chapter deals with the effects and consequences of strong wind events on the built heritage and calls for an urban transition to create resilient and safe environments for the people. An overview of the current standards related to building design against wind is presented, and mitigation and adaptation strategies are proposed to respond to current and future climate threats

Photocatalytic self-cleaning coatings for building façade maintenance. Performance analysis through a case-study application.

Façade maintenance has become a key aspect in building management, due the specific actions involved and operation related costs. In this frame, the application of titanium dioxide photocatalytic sol-gel products on façade elements offers a wide range of opportunities to ensure proper functionalities maintenance overtime. This paper illustrates the self-cleaning performance of titanium dioxide and silicon dioxide based coatings applied to different kind of cladding materials. All tested samples were opaque. Preliminary laboratory tests were performed to verify hydrophobic and hydrophilic behaviour, prior to outdoor application, through water contact angle measurements. Afterwards, outdoor tests were performed to monitor color variation during 36 months to verify product effectiveness and its durability. Results proved that the application of functionalized nanotechnological coating to façade can significantly ease cleaning operations and reduce their necessary frequency over time. In addition, output provide some preliminary information about exposure condition influence on self-cleaning performance, which could be further investigated in the future

Study of a BIPV Adaptive System

The paper presents the first results of research that was partly conducted within the framework of European COST Action TU1403 – Adaptive Façades Network, on the development of an adaptive BIPV (Building Integrated Photovoltaic) solution able to change its curvature in relation to the external environmental conditions, orientating itself in order to optimise the energy production without the aid of any mechanical and electrical systems. After analysing the characteristics of the main adaptive materials that are currently used for such applications, the contribution outlines the main features of the proposed system, which consists of thin film solar cells coupled with a thin layer of hygromorphic material, manufactured from two wooden slats joined together and produced from different types of wood and trunk cuts. The hygromorphic layer thus obtained can change its shape as a function of temperature and relative humidity of outdoor conditions, thanks to the different expansion coefficients of the two wooden slats. To evaluate the performance of the component, three shape configurations for the adaptive strips have been assumed. For each hypothesis, the lamellae have been modelled using the Rhinoceros 5 Software, according to the curvatures taken during the different months of the year. The Rhino models have been imported into Autodesk Ecotect Analysis to calculate the incident solar radiation and to study the self-shadowing effect in the various configurations (in relation to the climatic conditions of the city of Milan). The paper outlines the system and PV energy production optimisation process, as well as possible applications in the field of façade design

What is an adaptive façade? Analysis of Recent Terms and definitions from an international perspective

Adaptive façades can improve the building’s energy efficiency and economics, through their capability to change their behaviour in real time according to indoor-outdoor parameters, by means of materials, components, and systems. Therefore, adaptive façades can make a significant and viable contribution to meeting the EU´s 2020 targets. Several different types of adaptive façade concepts have already been developed, and an increase in emerging, innovative solutions is expected in the near future. According to recent research, the word ‘adaptive’ in the context of building façades is often associated in the literature with a long list of similar words. Moreover, there is no consistent definition of façade adaptability, although studies exist in relation to characterisation issues, design parameter, and classification. Even within the discipline of architecture and engineering, words such as ‘smart’, ‘intelligent’, ‘interactive’, ‘adaptive’, or ‘responsive’ have been used loosely and interchangeably, creating confusion as to their specific meaning and their conceptual relationship to building performance and design. In response to this, the goal of this paper is to build a provisional lexicon, or descriptive, behavioural, and methodological words, to assist researchers and designers in navigating the field of high-performance façades that incorporate materially innovative and feedback-based systems. It offers a brief overview of current advances in this nascent and rapidly evolving field and articulates a broader conceptual territory for the word ‘adaptive’, used in many cases to describe the technological systems that interact with the environment and the user by reacting to external influences and adapting their behaviour and functionality. The objective of this paper is to contribute to these developments by presenting the findings. Furthermore, common definitions will be proposed, based on the characterisation design parameters, classification approaches, and real case studies

Photocatalytic self-cleaning coatings for building facade maintenance. Performance analysis through a case-study application

Facade maintenance has become a key aspect in building management, due the specific actions involved and operation related costs. Within this framework, the application of titanium dioxide photocatalytic sol-gel products on facade elements offers a wide range of opportunities to ensure proper functionality maintenance over time. This paper illustrates the self-cleaning performance of titanium dioxide and silicon dioxide based coatings applied to different kinds of cladding materials. All tested samples were opaque. Preliminary laboratory tests were performed by means of water contact angle measurements to verify hydrophobic and hydrophilic behaviour prior to outdoor application. Afterwards, outdoor tests were performed to monitor colour variation over a 36-month period to verify product effectiveness and durability. Results proved that the application of functionalized nanotechnological coating to a facade can significantly facilitate cleaning operations and reduce the necessary frequency over time. In addition, the output provides some preliminary information about the exposure condition influence on self-cleaning performance, which could be further investigated in the future

Case Studies:

Adaptive building envelopes can provide improvements in building energy efficiency and economics, through their capability to change their behaviour in real time according to indooroutdoor parameters. This may be by means of materials, components or systems. As such, adaptive façades can make a significant and viable contribution to meeting the EU´s 2020 targets. Several different adaptive façade concepts have already been developed, and an increase in emerging, innovative solutions is expected in the near future. In this context the EU initiative COST Action TU 1403 aims to harmonize, share and disseminate technological knowledge on adaptive facades at a European level. According to the definition given by this COST Action, an adaptive façade is a building envelope consisting of multifunctional and highly adaptive systems that is able to change its functions, features, or behaviour over time in response to transient performance requirements and boundary conditions, with the aim of improving the overall building performance. In order to explore the available and emerging technologies focusing on adaptive façades, Working Group 1 of the COST Action undertook research to form a database of adaptive façade case studies and projects structured in accordance with a simple classification – materials, components and systems. In addition to this, details of the purpose of the systems/components/materials with adaptive features and the working principle of each technology were also collected together with data regarding design practice, technology readiness, and economical aspects, among others. The information was collected with the help of a specific online survey (structured in the following main sections: detailed description - metrics- characterization- economic aspects – references). The database includes 165 cases of adaptive façade systems, components, and materials that allowed a variety of analyses to be carried out. According to the classification adopted within WG1 (materials, components, systems), each of the classification terms are introduced together with examples from the case study database in the following sections. This volume ends with a section dedicated to future developments, where different issues are addressed such as embedded functionality and efficiency amd biomimetic inspirations. The importance of adaptive façades through their flexibility, and intelligent design within the context of smart cities is also discussed. The work within Working Group 1 - Adaptive technologies and products was developed within four distinct sub-groups (SG) in order to provide outputs according to the objectives of this WG and the COST Action: SG1 – Database, SG2 – Educational Pack, SG3 – Publications and Reports and SG4 – Short Term Scientific Missions (STSM). This work was possible due to the strong commitment and work of all WG1 members: Laura Aelenei, Aleksandra Krstić-Furundžić, Daniel Aelenei, Marcin Brzezicki, Tillmann Klein, Jose Miguel Rico-Martínez, Theoni Karlessi, Christophe Menezo, Susanne Gosztonyi, Nikolaus Nestle, Jerry Eriksson, Mark Alston, Rosa Romano, Maria da Glória Gomes, Enrico Sergio Mazzucchelli, Sandra Persiani, Claudio Aresta, Nitisha Vedula, Miren Juaristi