Positief toekomstbeeld dankzij nieuwe recylingmethoden beton

Kansen in de circulaire economie zijn er voor beton volop.Hoewel de winst het grootste is door hergebruik van gebouwen of constructies is het bekendste voorbeeld nog altijd het hergebruik van betonpuin als granulaat in nieuw beton.Maar dat laatste levert lang niet altijd een reductie op van deCO₂-uitstoot. Door nieuwe recyclingmethoden kunnen de kwaliteit en vervangingspercentage van het granulaat echter flink worden verhoogd en ontstaan meer kansen met betrekking tot CO₂-reductie.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen

Groene gevels

Structural EngineeringCivil Engineering and Geoscience

Comparative experimental approach to investigate the thermal behaviour of vertical greened façades of buildings

Greening the building envelope is not a new concept, however it has not been fully approved as an energy saving method for the built environment. Vertical green can provide a cooling potential on the building surface, as plants are functioning as a solar filter and prevent the adsorption of heat radiation of building materials extensively. In this study a comparative thermal analysis of vertical green attached to a façade element is presented. An experimental set up (stationary conditions) has been developed to measure the temperature gradient through a reference cavity wall, in order to quantify the contribution of vegetation to the thermal behaviour of the building envelope. The results show temperature differences between the bare wall and between the different vertical greening systems analysed, up to 1.7 °C for the direct greening system and 8.4 °C for the living wall system based on planter boxes after 8 h of heating for summer conditions, due to the different “material” layers involved. However, the insulation material of the bare wall moderates the prevailing temperature difference between the outside and inside climate chamber, resulting in no temperature difference for the interior climate chamber for summer conditions.Materials and Environmen

Onderzoek aan 'groen' beton

Structural EngineeringCivil Engineering and Geoscience

A method for determining the remaining time to chloride induced corrosion initiation of existing concrete structures

Owners of concrete structures would benefit from knowing when to expect corrosion initiation in a particular structure. Presently, no accepted procedures for testing existing structures for the remaining time to corrosion initiation are available. This paper proposes such a procedure, based on our experience and additional considerations. From about 20 years age, existing structures contain the concrete’s response to actual environmental loads, e.g. chloride ingress profiles. By measuring the actual cover depth, taking chloride profiles, assuming a few parameters and a simple model, the expected time to corrosion initiation for a particular test area can be predicted. Numbers of cores and samples per core are given. Uncertainties can be taken into account by applying a calculatory reduction of the cover depth. Results of at least six cores per test area are classified and suggested interpretations are given. Because of large variability, the results are classified in three ranges of time to corrosion initiation: five years or less, five to fifteen years, or more than 15 years. The procedure has been approved by the relevant national Standards committees and is issued early 2018. It was applied to a field case and the obtained results are discussed.Materials and Environmen

Evaluatiemodule voor Urbane Ecosysteemdiensten

Bijna alle stedelijke klimatologische problemen zijn te herleiden naar het ontbreken van ecosysteemdiensten. Dat blijkt uit onderzoek van de TU Delft Faculteit Civiele Techniek, afdeling Materialen en Duurzaamheid. ‘Ook vonden we dit gebrek medeverantwoordelijk voor veel stedelijke sociale problemen,’ aldus de auteurs. Op basis van het onderzoek ontwikkelden zij een module die inzicht verschaft in de verbeteringen die ecosysteemdiensten ons bieden.Materials and Environmen

Nabehandeling essentieel voor kwaliteit beton: Opnieuw aandacht aan nabehandeling in Stutech-studierapport

De essentie van het goed nabehandelen van beton is al vaak besproken. Nabehandeling is noodzakelijk voor beton met een lange levensduur en een mooi uiterlijk. Een CROW-onderzoek naar betonaantasting in combinatie met mosgroei was aanleiding het thema nogmaals te bestuderen. Resultaat is een nieuw studierapport van Stutech-studiegroep 68 ‘Nabehandeling’.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen

The Role of Geometry on a Self-Sustaining Bio-Receptive Concrete Panel for Facade Application

Bio-receptivity refers to the aptitude of a material to allow for the natural growth of small plant species on stony surfaces with minimum external influence. Despite the numerous associated environmental benefits, the growth of mosses and lichens on facades has always been viewed as a negative phenomenon due to the random and shabby growth conditions. This research dealt with the design of a self-sustaining bio-receptive concrete facade system with an aim to create a more sustainable and green concrete for the construction industry. The research used surface geometry as a design variable to facilitate moss growth on concrete panels in an ordered and systematic manner. The exercise was an attempt to not only address the functional aspect of bio-receptivity but also its aesthetical quality, which has a primary influence on people’s perception of bio-receptivity and can promote mass use of this type of concrete material. The research was conducted in a top-down approach, where first, through design by research, six distinctly designed concrete panels were fabricated using adapted material composition (blast furnace cement with 75% slag, 0.6 water/cement, sand 0–4 mm and gravel 5–8 mm) as the boundary condition. The concrete mixture together with no curing policy resulted in highly porous concrete panels, suitable for bio-receptive properties. Next in the design validation phase, the influence of surface geometry/roughness on the water retention ability of the panels and the subsequent moss growth on the panels were evaluated through in vitro experiments. The water retention experiment of the panels was based on quantitative measurements for weight, relative humidity and temperature at several time intervals. The moss-growing experiment was carried out within an ideal greenhouse condition where the panels were initially inoculated with moss spores; the results were based on qualitative observation for a period of 4 months. According to the comparative analysis of these results, with the same material composition, Panel 2 showed the highest bio-colonization owing to its prominent surface geometry, whereas Panel 5 showed the least bio-colonization owing to its plain surface despite high absorption capacity. Thus, the role of geometry has been extensively proven in this research and as an outcome a set of general design guidelines have been formulated for a self-sustaining bio-receptive concrete facade panel, using geometry as a design variable for bio-receptivity.Design of ConstrutionMaterials and Environmen

Implementation of a microclimate design model in the early design of new building projects: Case study Ecohof Noorderveer in the Netherlands

Given the ongoing global urbanization and the rise of heat, flooding, and drought in cities, the integration of climate adaptive measures based on “ecosystem functions and services” becomes imperative in design. This study details the implementation process of a microclimate design model in the design and retrofitting of the housing project Ecohof Noorderveer in Wormerveer, the Netherlands. The model, which quantifies local urban heat and mitigating measures through ecosystem functionalities, was incorporated into the program of requirements. The design process followed a research-by-design trajectory, involving iterative creative collaboration among all stakeholders, including future residents, the municipality, the water board, and the architect. The research employed the CFIR method to compare anticipated implementation outcomes with actual results. The findings suggest that introducing the microclimate design model into the program of requirements proved beneficial for the implementation process in the early design stage. The research-by-design approach was also deemed helpful, contingent on careful involvement of all participants in the knowledge-sharing process. This implementation method demonstrates significant potential for scaling up to standard urban development projects.Materials and EnvironmentPractice Chair Urban Area DevelopmentMaterials- Mechanics- Management & Desig

Exploring the Possibility of Using Bioreceptive Concrete in Building Façades

A bioreceptive material allows for biological content (biofilms) to grow on it, without necessarily affecting the material itself. If a bioreceptive concrete could therefore be integrated into a building façade, it could lead to green façades that do not need additional technical systems. As part of previous research by the authors, a promising bioreceptive concrete mixture was formulated. The aim of this research is to develop this concept by using the previously developed mixture to create a bioreceptive concrete façade panel prototype, made using commonly available materials, that can direct where the biological growth takes place. The latter is done by combining the bioreceptive concrete with a non-bioreceptive (UHPC-based) concrete in the same panel, through a two-stage pouring process. A biofilm was developed on this prototype panel and results show that full coverage of the bioreceptive parts of the panel can be achieved within two weeks under optimal growing conditions and biological growth can be directed. However, exterior survivability is an issue for now. The concept of bioreceptive façades therefore shows promise, yet further investigation into improving exterior survivability is necessary, while further research into the underlying ecology, material, economics, and climate effects is also necessary.Support AE+TDesign of ConstrutionMaterials and Environmen