Guillaume Habert

ETH Zurich | ETH Zürich · Department of Civil, Environmental and Geomatic Engineering

The aim of this paper is to study the influence of the deflocculation/flocculation process on the cohesion of clay-based materials by investigating the changes in their internal structure. Indeed, as the cohesion of earth materials finds its origin in the capillary forces between clay particles, strongly linked to the porosity of the material, the...

The renovation and construction of buildings presents an opportunity for climate change mitigation in urban environments. Bio-based construction is particularly promising since the plant’s sequestered carbon offsets the building’s carbon emissions. However, the required land to cultivate suitable biomass and the feasibility of environmentally susta...

Buildings are responsible for a large share of CO2 emissions in the world. Building renovation is crucial to decrease the environmental impact and meet the United Nations climate action goals. However, due to buildings’ long service lives, there are many uncertainties that might cause a deviation in the results of a predicted retrofit outcome. In t...

The climate crisis is urging us to act fast. Buildings are a key leverage point in reducing greenhouse gas (GHG) emissions, but the embodied emissions related to their construction often remain the hidden challenge of any ambitious policy. Therefore, in this paper, we explored material GHG neutralization where herbaceous biobased insulation materia...

Combining the low environmental impact of vernacular earthen construction and the cost efficiency of the modern concrete pouring technique, poured earth is becoming more attractive for the construction sector nowadays. However, the development of poured earth is still in its infancy and few design options have been reported. In this study, we prese...

Global objectives to mitigate climate change in the construction industry have led to increasing geopolymer development as an alternative to carbon-intensive cement. Geopolymers can have similar mechanical properties and a lower carbon footprint. However, geopolymer production is not as homogeneous as cement because it is produced by synthesizing a...

This study compares the environmental impacts of blast furnace slag-, fly ash-, and metakaolin-based alkali-activated concretes with Portland cement (PC) concretes using life cycle assessment methodology. The variability in production processes of mix constituents across Europe and uncertainty associated with transportation distances are evaluated...

The low environmental impact of earth – or soil – materials makes them interesting alternatives to lower CO2 emissions from the construction sector. Nevertheless, since they are often stabilized with Portland cement, the improvements in technical performance come at an environmental cost. In this paper, we revisit a vernacular stabilization techniq...

Explicitly accounting for uncertainties is paramount to the safety of engineering structures. Optimization which is often carried out at the early stage of the structural design offers an ideal framework for this task. When the uncertainties are mainly affecting the objective function, robust design optimization is traditionally considered. This wo...

Limiting global warming to 1.5°C requires immediate and drastic reductions in greenhouse gas (GHG) emissions. A significant contributor to anthropogenic global GHG emissions is the production of building materials. Biobased materials offer the potential to reduce such emissions and could be deployed in the short term. Timber construction has receiv...

Challenging climate goals demand immediate greenhouse gas emissions reductions for long-term temperature stabilization. Given the nearly linear relationship between warming and cumulative net emissions, the carbon budget approach is a useful tool to quantify remaining carbon allowances for countries, sectors, and even buildings. The built environme...

Buildings’ construction and operation are major contributors to global greenhouse gas (GHG) emissions, and the substantial reduction of GHG emissions across their full life cycle is required to enable meeting international climate targets. For effective climate change mitigation - as recent studies have shown - a special focus has to be put on lowe...

Stringent limits and reduction strategies paths on greenhouse gas (GHG) emissions are being defined at different levels for long-term temperature stabilization. Given the nearly linear relationship between warming and cumulative net emissions, a carbon budget approach is required to limit global warming, as stated by the IPCC. In this setting, the...

The construction industry is responsible for one-quarter of the solid waste generated globally, much of which is excavated soil. Repurposing this soil for the use of earthen architecture (EA) will reduce a considerable amount of this waste. However, little research has been conducted on how to assess the use of EA within the architectural, engineer...

Reducing the embodied emissions of materials for new construction and renovation of buildings is a key challenge for climate change mitigation around the world. However, as simply reducing emissions is not sufficient to meet the climate targets, using bio-based materials seems the only feasible choice as it permits carbon storage in buildings. Vari...

In order to deliver on the Paris agreement, the decarbonisation of the building sector is critical. An accurate assessment of its life cycle GHG emissions is essential to identify emissions hotspots and decarbonisation potentials in order to prepare future policies such as sectoral carbon budgets. However, today a lack of common GHG emissions accou...

The humanitarian sector is committing towards a green transition of their operations, in order to contribute to the global fight to climate change. To implement such change a scale within construction operations, a sustainable construction and design-assistance tool has been developed to support humanitarian staff and local actors in adopting appro...

Binder jet 3D printing of geopolymers is a newly developed manufacturing technique that combines a material with a low carbon footprint with a material-saving processing. In this work, the embodied energy of the printed building parts is further decreased by replacing the virgin silica sand with waste materials from local stone quarries. The use of...

The project aims to develop BIM-based method for design integrated life cycle assessment during the planning phase, starting in the crucial early design phases. The research provides a critical review and understanding of the current BIM, LCA and code of practice for architects and engineers. In doing so it presents possible workflows (some develop...

The construction industry's high contribution to global greenhouse gas emissions is well documented. This has driven many countries to develop strategies aiming to achieve net-zero emissions in their built environments. Currently, the development of near-zero construction materials is still a niche, especially for insulation materials. In this pape...

The provision of sustainable housing solutions is one of the main challenges in emerging economy countries. Furthermore, it is clear that a sustainable solution should be based on renewable bio-based materials. Scientific and practical evidence clearly suggests that the use of bamboo in the provision of housing solutions provides communities with b...

Boosting building renovation is urgently needed to achieve carbon neutrality by 2050. Building retrofit can be achieved by energy-efficient measures such as thermal insulation or replacement of a fossil heating system. Currently, conventional materials that are mostly used for envelope insulation raising the risk of a lock-in situation where measur...

Explicitly accounting for uncertainties is paramount to the safety of engineering structures. Optimization which is often carried out at the early stage of the structural design offers an ideal framework for this task. When the uncertainties are mainly affecting the objective function, robust design optimization is traditionally considered. This wo...

The objective of this paper is to propose a simple and robust additive solution to improve the water-resistance of clay materials by revisiting a traditional recipe of vernacular construction. The influence of the combination of oak tannin with iron chloride on the properties of clay materials in terms of rheological behavior, compressive strength,...

National policies are increasingly being introduced worldwide to establish a sustainable economy that includes principles of a circular economy (CE). The construction industry is particularly in focus with such policies, as it is responsible for almost 50% of the worldwide annual resource consumption and waste production. The Implementation of CE p...

The accelerated development of cities involves important inflows and outflows of resources. The construction sector is one of the main consumers of raw materials and producers of waste. Due to its quantity and potential for recovery, waste from the construction sector constitutes significant deposits and requires major action by bringing together d...

This research explores the carbon removal of a novel bio-insulation composite, here called MycoBamboo, based on the combination of bamboo particles and mycelium as binder. First, an attributional life cycle assessment (LCA) was performed to define the carbon footprint of a European bamboo plantation and a bio-insulation composite, as well as its ab...

Renovation of the building stock in Europe is urgent to decrease the environmental impact from the building sector and meet the United Nations climate action goals. However, it is often hard to define a robust scenario for a renovation due to numerous uncertainties, which occur during the production, operation and end-of-life stage. One can cite th...

The global challenge of large-scale climate change mitigation requires action also in the building and construction sector. From a life cycle perspective, and considering the mitigation timeframe, the issue of reducing embodied GHG emissions is gaining attention. Effective ways to reduce embodied GHG emissions have been proposed by the use of fast-...

The global challenge of large-scale climate change mitigation requires action also in the building and construction sector. From a life cycle perspective, and considering the mitigation timeframe, the issue of reducing embodied GHG emissions is gaining attention. Effective ways to reduce embodied GHG emissions have been proposed by the use of fast-...

The book explores 33 projects in a span of 100 years that were exemplary prototypes of modular construction. The case studies in this book represent illustrations in terms of time for assembly and dismantling, modularity, prefabrication, and reuse. They all use design and engineering strategies able to boost the building’s overall environmental per...

Building demolition is one of the main sources of waste generation in urban areas and is a growing problem for cities due to the generated environmental impacts. To promote high levels of circular economy, it is necessary to better understand the waste-flow composition; nevertheless, material flow studies typically focus on low levels of detail. Th...

Medium and highly sulfidic tailings are high-volume wastes that can lead to severe environmental damage if not properly managed. Due to the high content of sulfide minerals, these tailings can undergo weathering if put in contact with oxygen and water, generating acid mine drainage (AMD). The moderate-to-high sulfide content is also an important te...

In order to limit global warming, remaining carbon budgets have been defined by the IPCC in 2018. In this context translating global goals to local realities implicates a set of different challenges. Standardized methodologies of allocation can support a target-cascading process. On the other hand, local strategies and norms are not currently desig...

There is an increasing effort of the cement and concrete industry to increase material efficiency and reduce CO2 emissions. Several strategies have been identified to achieve this goal, but the implementation of a circular economy (CE) strategy is being pursued most actively by governments and public organizations to increase material efficiency an...

The construction industry is responsible for large quantities of construction and demolition waste and almost 50% of the worldwide annual resource consumption, putting the environment, its natural resources, and ecosystems under high pressure. Therefore, governments are implementing regional policies that support a circular economy (CE). But how do...

Cement is used globally in construction materials for nearly all civil infrastructure systems supporting improved quality of life, and there is currently no substitute that can meet its functional capacity. The magnitude of cement production leads to more than 7% of annual anthropogenic greenhouse gas (GHG) emissions, resulting from both energy use...

The provision of sustainable housing solutions is one of the main challenges in emerging economy countries. Furthermore, it is clear that a sustainable solution should be based on renewable bio-based materials. The scientific and practical evidence clearly suggests that the use of bamboo in the provision of housing solutions not only brings environ...

The construction industry faces many pressures including: to deliver both rapid urbanization and a steep decarbonization of the materials that it uses. Radical reductions in GHG emissions are needed by 2030, so the construction industry must drastically reduce its operational and embodied emissions within a short time frame. It is imperative to sta...

In the next decades, a large share of residential buildings in EU-28 is expected to be renovated and a large amount of insulation materials will be produced. Bio-based materials are a valuable alternative to insulate the buildings and the biogenic carbon can be stored in the built environment for a relative long time. This article investigates the...

Substituting the industrial additives in building materials with natural ones can reduce the embodied carbon in the construction sector. In this paper, the dispersing effect of oak tannin as natural dispersant on clay materials is studied in combination with sodium hydroxide. Through rheological measurements, adsorption tests, and zeta potential me...

Abstract presented at the 75th RILEM annual week 2021

The informal settlements in the Global South, mostly comprising of inadequate building solutions, are growing rapidly, therefore calling for more sustainable construction interventions and upgrading strategies. Within this context, this study considers that appropriate construction strategies are capable of engaging with the local economy, affected...

Buildings play a vital role in reaching the targets stated by the Intergovernmental Panel on Climate Change to limit global warming to 1.5 degrees. Increasing the use of wood in construction is a proposed upcoming strategy to reduce the embodied greenhouse gas emissions of buildings. This study examines existing life cycle assessments of wooden bui...

With the increasing globalization of waste-derived raw materials, region-oriented circular economy measures that stimulate resource recovery can cause far-reaching ripple effects in geographically dispersed markets, with unintended environmental effects. Identifying, quantifying, and characterizing these implications in a multiregional economic sys...

Reducing the embodied carbon of reinforced concrete structures is crucial to mitigate climate change. Several stakeholders in the construction value chain can contribute to this effort. Therefore, this work quantifies the influence of various decisions made by different stakeholders on the global warming potential (GWP) of a reinforced concrete str...

The fast precipitation of ettringite in conventional Calcium Sulfo Aluminate (CSA) cement causes rapid stiffening of the cement paste and is directly associated with short setting times and self-desiccation. To extend the time during which those types of cement remain workable, retarding admixtures can be used. However, retarders may affect the amo...

Earthen construction is regaining popularity as an ecological and economical alternative to contemporary building materials. While building with earth offers several benefits, its performance due to water ingress is a concern for its widespread application. This limitation is often solved by adding chemical stabilisers such as Portland cement and h...

The climate crisis is urging us to act fast. Buildings are a key leverage point to reduce greenhouse gas (GHG) emissions, but the embodied emissions related with their construction remain often the hidden challenge of any ambitious policy. Considering that a complete material substitution is not possible, we explore in this paper a material GHG com...

The use of biomass for construction is a promising strategy to store carbon and decrease the construction sector's carbon footprint. This paper aims to determine how much biomass-namely timber for new structures and biogenic fibers for thermal insulation-and the relative land occupation would be needed to satisfy the material demand of the EU resid...

Locally available and with infinite recycling possibilities, the use of earth as building material leads to one of the lowest environmental impacts in the construction sector. Recent advances in the earth materials field have been made based on concrete and ceramics technologies to facilitate its uses in dense areas. It is possible to modify clay p...

Weak water resistance is a big obstacle for clay materials to overcome in modern construction industry. Compared to the hydraulic stabilized additives, bio-additives have a lower carbon footprint and have been used in many vernacular construction techniques to immobilize clay. In this work, the traditional recipes of tannin and iron have been revis...

To decarbonize the portland cement sector worldwide, the Cement Sustainability Initiative recommends systematically reducing the clinker-to-cement ratio down to 60% by 2050. However, the sources of usable clinker substitutes-the supplementary cementitious materials (SCMs)-are unevenly distributed geographically and will become increasingly scarce i...

The objective of this paper is to define a mix design strategy allowing the implementation of geopolymer in powder bed 3D printing. In a selective binder approach, an aluminosilicate powder bed is activated through the deposit of an alkaline silicate solution. We first show that, in comparison to casting, this technology requires mastering the spre...

Today's cities are ever-growing, especially in the Global South, inducing massive construction activity. To satisfy these needs we need feasible and environmentally sustainable construction materials, the use of local solutions and, if possible, to enable synergies between sectors for maximum environmental benefit. In South Africa and beyond, invas...

This article presents the descriptive statistics of service life data of building elements, gathered through an international, European and Swiss literature review of LCA, LCC and other sources called “Real-Estate Management sources” that include building owners, banks, insurances, associations of tenants and owners, etc. Furthermore, the propertie...

Life Cycle Assessment (LCA) is increasingly used for decision-making in the design process of buildings and neighbourhoods. Therefore, visualisation of LCA results to support interpretation and decision-making becomes more important. The number of building LCA tools and the published literature has increased substantially in recent years. Most of t...

Building thermal retrofit plays a key role to limit global warming. However, the spatial and temporal dynamics of urban-scale renovation are not well understood. We propose a new methodology that is based on a bottom-up building stock model and links dynamic Material Flow Analysis with dynamic Life Cycle Assessment to include the temporal dynamics...

Action is needed to mitigate climate change. As the building sector is one of the main contributors to energy consumption, renovation of existing buildings is a key strategy. However, for a drastic greenhouse gas emissions (GHG) reduction, sensible material solutions are required. Bio-based products seem to be a promising alternative thanks to carb...