Invited Lecturer
Prof Jan CARMELIET, ETH Zurich, Switzerland
Changing urban microclimate and role of urban vegetation
The urban microclimate has an important impact on the comfort and health of its inhabitants and on the hygrothermal and energy performance of buildings. Climate change and the increase in frequency and intensity of heatwaves starts to highly determine the cooling demand, which is much higher in cities due to the urban heat island effect. Among different mitigation measures, vegetation in the form of urban forests, street trees, green roofs and green facades may play an important role.
To understand the changing urban microclimate, we use 30 years meteorological data records and hybrid mesoscale meteorological modelling for different cities to map the heat intensity and find local hot spots in cities. The influence of building and urban morphology, like building density and impervious soil fraction, sky view factor, and the presence or absence of vegetation and urban ventilation explains the observed high variation of heat intensity over the city. UrbanmicroclimateFoam, a software developed over the past ten years at the Chair of Building Physics is used to model the local urban climate at the hot spots during heat waves. Three case studies are discussed. First, we study the local urban microclimate at a square in Zurich during a heatwave, and compare two mitigation measures: shadowing + transpirative cooling by trees and evaporative cooling by water spraying on porous pavements. The second study involves the densification of an avenue in Zurich and the possible mitigation by trees and nighttime cooling by cool winds from the surrounding hills. Finally, we study the local climate on the Saint Helens island located in the Saint Lawrence River in Montreal, which is a urban location for recreation and visitors attractions. Improvement of the local climate during heatwaves is studied by transforming paved parking lots in green zones with trees. All cases studies demonstrate that vegetation in combination with ventilation by wind may importantly improve the local climate when properly selecting the size and type of trees as well as the location where vegetation as mitigation measure is implemented.
Biography
Jan Carmeliet is an architectural engineer holding a PhD in Civil Engineering / Building Physics from KU Leuven in Belgium. He was assistant, associate and full Professor Building Physics at KU Leuven from 1998 until 2008 and part-time Professor at TU Eindhoven from 2001 until 2008. Since June 2008, Jan Carmeliet is full professor at the Chair of Building Physics at the department of Mechanical Engineering at ETH Zürich in Switzerland. He was head of Laboratory of Multiscale Studies in Building Physics at the Swiss Federal Laboratories for Materials Science and Technology, Switzerland from 2008 to 2017.
His research interests concern urban climate and urban heat island mitigation, multiscale behaviour of porous materials and their fluid interactions, and building energy demand at building and urban scale. His research resulted in more than 350 scientific journal papers. His h-index is 81 on Google Scholar. He has graduated more than 40 PhD students. He was research councillor of the National Science Foundation Switzerland from 2017 to 2020 and expert of the Swiss Innovation Agency (InnoSuisse) from 2013 to 2020. He was director of the graduate program ‘master integrated building systems’ at ETHZ from 2014 to 2018. He was member of the research commission of ETH Zürich from 2012 to 2016, the scientific commission of the CCEM (Centre of Competence Energy and Mobility) from 2012 to 2016 and the Board of Energy Science Centre ETH Zürich from 2010 to 2017.
Prof. Evelyne TOUSSAINT, Université Clermont Auvergne, France
What are the main contributions of full field measurements in the mechanical characterization of vegetal concretes at macro and micro scales ?
Bio based materials are increasingly used in construction because they are real sources of thermal, water and acoustic comfort. They also significantly contribute to the capture of C02 during their life cycle. However, these materials suffer from poor mechanical performance for structural applications. Understanding the deformation mechanisms of these materials is an issue that requires macroscopic characterization tests at the scale of the structure, of the structural element, but also by observations at the scale of the binder/aggregate interfaces. Full field measurements, widely used in the field of mechanics of materials, are now widely used in civil engineering. We thus propose in this presentation to implement the digital image correlation technique to highlight the strong heterogeneities which cohabits within the vegetable concrete, to underline the importance of the manufacturing process and to identify the evolution of the mechanical properties during the loading.
Biography:
Pr. Évelyne Toussaint is full professor at Clermont Auvergne University since 2012. Trained as a mechanic, she has developed skills in the development and the use of non-contact field measurements to characterize the mechanics of materials and structures. Over the past ten years, she has been developing her skills for understanding various mechanisms such as cracking, damage, highlighting local heterogeneities in materials and civil engineering structures, among them bio-resourced materials. She is the author of 67 scientific journal papers, and she has graduated 15 PhD students. She is involved in several national research projects on biosourced materials for construction (ANR BIOUP and ANR PACS+) and is involved in TC 275 Rilem dedicated to Hygrothermal behaviour and Durability of Bio-aggregate based building materials. She was director of the graduate program Civil engineering at Clermont Auvergne university from 2017 to 2019 and she was deputy head of the mechanical and civil engineering research team at Pascal Institute from 2017 to 2020.
Prof Guillaume HABERT, ETH Zurich, Switzerland
Natural and industrial material difference to guide future development related with emerging trends of circularity and digitalization
In natural materials, the environmental impact lies in the refinement process. The matter itself has no or very few environmental impacts. A rock has been produced by nature and it is its transformation from rock to stone which creates impact. This is the same for the transformation from a tree to timber products. In the opposite, it is the production of the matter itself which is associated with environmental impact of an industrial material. From steel to cement, the environmental impact is linked with the production of the matter.
Such fundamental difference induces an opposite strategy when dealing with sustainable use of such materials. Indeed, for cement and steel the strategy is to reduce their use. The less material is used in the structure, the better it is for the environment. For stone or timber, the logic is opposite. Actually, the more cut is done to a rock, the more environmental impact it has. Therefore, in order to reach a lower environmental impact (and a lower economic costs), it is better to use the material as raw as possible. The more raw rock or tree we use the lower the environmental impact we have in the building.
How such differences helps us now to design sustainable strategies in our current debate of circularity and digitalization? Digital fabrication is usually presented as a way to save material, which therefore would make sense if the material used is industrial. Circularity is associated with urban mining idea which would therefore make sense if the matter extracted is used as raw as possible. Are such trends consistently followed or do we have digital fabrication of natural materials and processing of extracted urban matter? And what are the consequences for sustainable construction?
This is what I would like to explore in the lecture.
Biography:
Guillaume Habert holds a PhD in structural geology and has worked successively in geology, material sciences, civil engineering and sustainability sciences. Since 2012, he is associate professor for sustainable construction at ETH Zurich. He leads a group of scientists, engineers and architects that aim to ground sustainability in the disciplines of the built environment. The objective is to identify the relevant parameters that influence the environmental impacts of buildings at various scale in order to implement sustainable practices throughout the development of innovative strategies adapted to each actor. This involves interdisciplinary works and draws on Life Cycle Assessment, urban metabolism and material science. Beyond the more than 100 peer reviewed scientific journals he has co-authored, the outreach of his work includes regular collaboration with architects for implementation of innovative materials or innovative sustainability concept in their practice, advisory role for policy makers at national, city or real estate portfolio level for implementation of decarbonization strategies, knowledge transfer and capacity building for professionals in global North and global South as well as in humanitarian sector for appropriate implementation of sustainable construction. These outreach activities materialize through exhibition, digital tools and start ups.
Dr. Sandrine MARCEAU, Université Gustave Eiffel, France
Life time assessment of biobased insulation materials.
The knowledge of the lifetime of materials used in the building industry is an essential parameter to guarantee their performance to the end users and to provide reliable data for conducting their life cycle assessments. In the case of plant-based concretes, various studies have already been carried out, using accelerated ageing protocols in laboratory or collecting real data during the natural ageing of instrumented buildings.
The comparison of results obtained at several scales and during accelerated and natural ageing allows the identification of different ageing factors of materials and their degradation mechanisms.
This research allows the development of material formulations and provides recommendations on their implementation and use in order to extend their life time, reduce the environmental impact of biobased insulation materials and generalise their use.
Biography:
Sandrine Marceau is researcher at the Gustave Eiffel University in the "Physicochemical Behaviour and Durability of Materials" laboratory since 2008. She has developed skills on the relationship between the physicochemical and microstructural properties of construction materials and their functional properties. Since 2012, she has been leading projects on the durability of biobased insulation materials and has participated in the activities of the RILEM TCs BBM (Biobased Building Materials) and HDB (Hygrothermal behaviour and Durability of Bioaggregate based building materials). Since 2022, she is the scientific coordinator of the BIO-UP project, funded by the French National Research Agency, which concerns the tayloring of the performances of plant-based concretes according to their formulation.
Dr. Edwin Zea ESCAMILLA, ETH Zurich, Switzerland
Dude, where is my CO2? Material, Energy and CO2 flow analysis of Engineered Bamboo production
The current crisis we are facing on the built environment has put the discussion of CO2 emission and reduction on the main stage of the public, politic and scientific discourses. It is clear that we are in dire need of solutions to overcome this challenge and that the building sector has a major role to play. Bio based materials, like bamboo and timber had been widely promoted as the solution to all this problem. Nevertheless, the discussion and the whole decision making process has reached a level of statement and the implementation of such strategies have not been put forward at large scale. One factor contributing to this situation is the lack of consensus on how to account for the CO2 and especially how to account for the storage of biogenic CO2 in the built environment. Life Cycle Assessment is the most used and widely recognized methodologies to assess environmental impacts of products and services. Moreover, LCA provided information for decision making processes related to improvement of production process and/or comparing options. Unfortunately, when faced with questions related to dynamic processes like the regrowth of biomass, LCA is limited and cannot fully portray beneficial effects like carbon capture nor storage. To overcome this limitation many competing approaches had been put forward in the last decade. They range from the very simplistic to overly complicated and data demanding. LCA has been described as a very simple representation of a very complex reality and thus we would like to take a methodological step back and analyze the question of biogenic CO2 of engineered bamboo using material and energy flow analysis. Moreover, following these principles we aim to map the flows of CO2 through the life cycle of the engineered bamboo products from bamboo forest to the built environment, their future release into the atmosphere and consequent recapture of the bamboo forest. This approach showed that a large part of biogenic CO2 stays captured in the bamboo forest, thus serving as a natural carbon sink. Furthermore, the stock on the built environment will steadily grow with the application of engineered bamboo on long lasting applications like buildings. Moreover, the relation between the mass flow and energy flows of these products highlights how the current practice of using waste flow form bamboo production on co-generation of heat and electricity can significantly reduce the energy demand of such products and consequently their carbon footprint. Finally, engineered bamboo products can serve not only structural purposes but also as biogenic CO2 storage in the built environment.
Dr. Edwin Zea is Senior Assistant at the Chair for Sustainable Construction ETH Zürich in Switzerland. In 2016, Edwin was appointed as Head of Sustainable Building and Real Estate at the Centre for Corporate Responsibility and Sustainability (CCRS) at the University of Zürich. Edwin has been a member of the Construction Task Force on Bamboo of the International Organization for Bamboo and Rattan since 2016, and will start chairing the task force in 2023.
His PhD dissertation focused on the development of simplified methodologies for the life cycle assessment of construction materials with special emphasis on bamboo based construction materials. Edwin also withholds a Diploma in Architecture from the Catholic university in Colombia and a MSc. in Urban Environmental Management from Wageningen University in the Netherlands. His work focuses on the use of bamboo as strategy for regenerative development combining expertise from material science to engineering and construction. He led the development of LCA datasets of bamboo-based construction materials, and currently works on strategies for carbon accounting of fast-growing bio-based materials like bamboo. He had collaborated with NGOs and research institutions in China, Colombia and the Philippines in the development of sustainability assessment approaches for social housing and post-disaster reconstruction projects.
Dr. Emmanuel KEITA, Université Gustave Eiffel, France
Challenges and Solutions for Earthen Construction Massification
The utilization of earthen materials in construction can be traced back thousands of years and is a testament to their versatility as building resources.
In recent years, there has been a growing interest in earthen construction as a sustainable and environmentally friendly alternative to conventional building materials. However, the massification of this technique has been hindered by several challenges; this presentation focuses on the main one: water resistance and standardization.
Water resistance is a critical issue in earthen construction because it can affect the durability and stability of the building. Several methods, such as mineral and bio-based additives, have been developed to improve water resistance in earthen construction.
Standardization is another challenge in earthen construction, as the properties of the soil can vary greatly depending on the location and composition of the earth. This can lead to variations in the quality and performance of earthen buildings. To address this challenge, on-site tests are being developed.
Addressing these challenges is crucial for the widespread adoption of this sustainable building technique, which has the potential to reduce the environmental impact of the construction industry and promote local economic development.
Emmanuel Keita, researcher at Navier Laboratory, has organized the first International RILEM Conference on Earthen Construction in March 2022 and chairs the RILEM Technical Committee on processing of earth-based materials. He is a regular expert of CSTB for unstandardized construction sites with earthen materials. He is the scientific coordinator of a French program on Monitoring and Rehabilitation of earthen buildings (funded by ANR). He is working on water transport in porous media and its consequences on drying kinetics, imbibition, recycled aggregates, 3D Printing and Earth- based building materials. He has expertise in soft matter and non-
destructive imaging techniques (MRI, X-ray microtomography). Since 2018, he has been leading the project Alluvium on using excavated soils for buildings in urban areas.
Prof. Mohammed SONEBI, Queens University of Belfast, Northern Irland, UK
The overlooked sustainable response to the urban affordable housing crisis: Case study of experimental house using local sustainable material “Plaster”
Cement makers around the world have pledged to cut their greenhouse gas emissions by up to a quarter this decade and reach net zero by 2050, in a move they said would make a major difference to the prospects for the Cop26 climate summit. However, it is important to promote other sustainable materials having low carbon footprint to be used in some countries for social housing where a huge reserve of local materials such as gypsum. Gypsum is one the most mined materials in the world after mainly aggregates, iron ore and lime, and the world production of gypsum in 2011 was 148 million tons. In Morocco, it is estimated the production of gypsum in Morocco 600 thousand metric tons.
The experimental house was built with local plaster to promote affordable housing of in Rabat in 1988 with plaster mortar (Béton banché in French). Using sustainable material such as plaster instead cement saved significantly the cost and reduce the time of construction and carbon emissions. This presentation gives a summary of architectural design, construction method, materials, mix composition with mechanical performances, and cost saving with carbon footprint.
Biography:
Mohammed Sonebi is a Professor of Sustainable and Structural Materials at School of Natural and Built Environment at Queen’s University Belfast, UK. He is a RILEM Regional Convenor Middle East and North Africa, a Fellow of RILEM Development Advisory Committee (DAC) and RILEM Editorial Advisory Committee. He is the Chair of RILEM Committee on TC-266 “Measuring Rheological Properties of Cement-Based Materials”. He served as a member of 15 committees with RILEM.
He is a Fellow of American Concrete Institute. He was a Vice-Chair of American Concrete Institute ACI 552 –Cementitious Grouting and actually he is still a voting member of six ACI Committees (236, 237, 2.38, 241, 552, 564). He is also a member of ASTM International (C09-47-Self-Consolidating Concrete), fib TG8.8, ISHMII and MIIFC. He is a Fellow of Institute on Concrete Technology (UK).
He is authored/co-authored more than 290 peer-review journal, conference papers and 34 books/chapters with high citations (6268, h-index: 43) and Top 2% researcher globally in “Building and Construction” (Elsevier - Stanford University Classification - October 2020, 2021, & 2022).