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Niki C.,Belgian Building Research Institute | Pierard J.,Belgian Building Research Institute | Bams V.,Belgian Building Research Institute
Concrete - Innovation and Design: fib Symposium Proceedings | Year: 2015

The homogeneity of colour tone is one of the basic characteristics and most important criteria for surfaces in exposed concrete. Both on site and in precast industry, colour tone homogeneity causes discussions about the acceptability of certain variations. On the one hand, it concerns a technical discussion about the cause of these variations, the technical requirements to reduce such variations and the overall feasibility of mastering them (the challenge for each contractor). On the other hand, it concerns a discussion about the acceptability of colour differences in concrete (an important issue for architects and building owners), the possibilities to quantify these differences and to link them to standards or recommendations. Some standards and recommendations refer to the use of reference gray levels, only few to the use of colorimetry, while this is common practice for a number of other (building) products. This paper introduces the use of colorimetry for the evaluation of fair-faced concrete and its sensitivity when applied on coloured concrete. The application of some existing criteria is discussed, usually based on colour differences, and the use of a new evaluation method is evaluated, one which tries to take into account the actual human perception of colour differences. The Jatter is in fact the application of CIE2000-colour difference formula for concrete.


De Geetere L.,Belgian Building Research Institute | Ingelaere B.,Belgian Building Research Institute
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

In this paper, a new building concept for multi-family lightweight timber frame housing is proposed. This concept combines party walls, floors and fa?ade elements ensuring comfort levels equal or better than currently encountered in typical Belgian heavy constructions. Low frequency behaviour and prefabrication potential were the key points in the design process of the new wall and floor types. Nevertheless, structural aspects, fire safety issues and thermal capacity have been taken into account as well. Solutions were found by maximally exploiting the mass-spring-mass mechanism. Finally, a holistic approach was followed to develop a building concept in which the walls, floors and fa?ade elements are connected in an optimized way.


Goethals K.,Ghent University | Delghust M.,Ghent University | Delghust M.,Flemish Institute for Technological Research | Flamant G.,Belgian Building Research Institute | And 2 more authors.
Energy and Buildings | Year: 2012

Multizone building energy simulation (BES) programs become popular among building designers. They include a wide variety of techniques and advanced heat transfer models, yet require only limited computational time. Unfortunately, the use of correlations to predict the convective heat transfer undermines their reliability. The available correlations actually apply only to specific cases. For example, they are only valid for one diffuser type at a particular location. Yet, convective heat transfer modelling is particularly important in mixed convection regimes with high ventilation rates, such as night cooling. So it is self-evident that researchers would investigate to what extent including more room/system design parameters is necessary to model mixed convection heat transfer. The authors of this study imitated sequences of typical mixed convection cooling regimes (a day regime possibly preceded by night cooling) in a modified PASLINK cell and varied the air supply/exhaust configuration and added to some cases a thermally massive floor. The analysis is based on airflow data and the convective heat flux. The results indicate that the supply/exhaust configuration is particularly important when high ventilative flow rates are combined with (heterogeneously distributed) thermal mass. Unfortunately, existing convection correlations cannot predict the convective heat flux accurately for the studied cases. © 2012 Elsevier B.V. All rights reserved.


De Geetere L.,Belgian Building Research Institute
Proceedings of Forum Acusticum | Year: 2011

The rain noise behaviour of multilayered lightweight roof constructions is studied, in particular for membrane incorporating roof systems. This is done by a theoretical study, experiments and by simulations. Several effects are studied: adding a rigid elastic layer (polycarbonate sheet) in the cavity, adding porous layers in the cavity and adding rain retaining meshes on the top layer. Rain noise tests are performed on 10 roof systems according to ISO 140-18:2006 and are compared to simulations based on a rain noise extension of the Transfer Matrix Method for multilayered systems. The overall correspondence was quite satisfying and resulted in a correct ranking of the measured roof systems. This demonstrates that the model can be used in parameter sensitivity analysis and to further optimise multilayered lightweight roof systems.


Courard L.,University of Liège | Michel F.,University of Liège | Pierard J.,Belgian Building Research Institute
Construction and Building Materials | Year: 2011

High workability together with a good resistance to segregation is needed for cement based composites, specifically fresh self-compacting mortars (SCM); in this prospect, the amount of coarse materials has to be reduced and replaced by fine material. Several limestone fillers are here compared and analysed. These by-products are issued from different industrial sectors, such as the aggregate and lime production industry (quarrying operations) and the ornamental stones industry (sawing operations). Particular attention has been paid to clay content, as consistency of fresh mortars was varying, while other physical characteristics like granulometry remained the same. Relationship between the physico-chemical properties of the fillers and the properties of fresh and hardened mortars are brought forward. Even if it may affect fresh properties of mortars, results clearly show that clay type and content has minor influence than limestone filler itself. © 2010 Elsevier Ltd. All rights reserved.


Laverge J.,Ghent University | Van Den Bossche N.,Ghent University | Heijmans N.,Belgian Building Research Institute | Janssens A.,Ghent University
Building and Environment | Year: 2011

Ventilation is ambiguously related to the energy saving rationale originating from the mitigation of global warming, the reaching of peak oil or health concerns related to fossil fuel burning. Since it makes up for about half of the energy consumption in well-insulated buildings, it is an attractive target for energy saving measures. However, simply reducing ventilation rates has unwanted repercussions on the indoor air quality. Two main strategies have been developed to reconcile these seemingly opposing interests: heat recovery and demand control ventilation. This paper focuses on the energy saving potential of demand controlled mechanical exhaust ventilation in residences and on the influence such systems may have on the indoor air quality to which the occupants of the dwellings are exposed. The conclusions are based on simulations done with a multi-zone airflow model of a detached house that is statistically representative for the average Belgian dwelling. Four approaches to demand based control are tested and reported. Within the paper exposure to carbon dioxide and to a tracer gas are used as indicators for indoor air quality. Both energy demand and exposures are reported and compared to the results for a standard, building code compliant, exhaust system, operating at continuous flow rates. The sensitivity of the control strategies to environmental and user variations is tested using Monte-Carlo techniques. Under the conditions that were applied, reductions on the ventilation heat loss of 25-60% are found, depending on the chosen control strategy (with the exclusion of adventitious ventilation and infiltration). © 2011 Elsevier Ltd.


Barns V.,Belgian Building Research Institute
34th International Conference on Cement Microscopy 2012 | Year: 2012

In Flanders (north of Belgium), a shortness of gravel is at hand. Therefore, the "Research committee" was established to financially support projects in order to find alternatives for gravel in all its applications. With this subsidy, VITO (Flemish Institute for Technological Research) and BBRI (Belgian Building Research Institute) worked together on the research of the mechanisms of pop-outs in concrete and of the nature of the damaging secondary granulates, i.e. residues coming from different industries such as bottom ashes, slag, ⋯. This kind of research is required in order to be able to estimate the risks when using stony residues in concrete. Once the causes identified, directives can be stated to minimize the risks of popouts. Pop-outs are esthetical and structural unwanted holes that appear on the concrete by flied off surface material. The ejection of concrete pieces is caused by the pressure that is built up around an aggregate as a result of physical or chemical reactions. After mineralogical, chemical and micro structural analysis, the selected aggregates were used to make concrete samples. Three tests were developed to which the samples were exposed in order to evoke pop-outs in the concrete. Of the four different tested aggregates, only one lead to pop-outs and this with only one of the developed tests. Examining the core of the created pop-outs with the electron microscope, the hydration of calcium oxides proved to be the cause. Other than pop-outs, the damaged samples showed also an intense Assuring from which the origin could be revealed by SEM-analysis. Several attempts to make thin sections of the concrete samples failed because of the hard slag components and up till now the cause of the Assuring remains a question mark.


Crispin C.,Belgian Building Research Institute | Ingelaere B.,Belgian Building Research Institute
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013

The standard EN 12354-1 proposes a calculation method to predict the flanking sound transmission between rooms. These calculation formulas are however not relevant for lightweight constructions. Recently, several adaptations on how to include formulas when dealing with lightweight constructions have been proposed. These new adaptations require new input quantities to be measured in laboratory. This article presents a set of laboratory measurement results for these new parameters, measured on different kinds of junctions composed of lightweight walls. Differences between cross laminated timber walls, gypsum boards on metal frame and OSB boards on wooden frame are discussed.


Crispin C.,Belgian Building Research Institute | Mertens C.,Belgian Building Research Institute
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013

The creep of materials used under floating floor corresponds to a time-dependent deformation process which leads to a modification of the mechanical characteristics of the product, mainly in terms of a progressive stiffening. Information about the evolution of the material's stiffness under long term exposure to structural loads is an important parameter when assessing the acoustical performances of the material in time. This article presents a setup which allows to measure the dynamic stiffness under a long term stress and discusses the measurement results for typical materials used under floating floor.


Wastiels L.,Belgian Building Research Institute | Schifferstein H.N.J.,Technical University of Delft | Wouters I.,Vrije Universiteit Brussel | Heylighen A.,Catholic University of Leuven
International Journal of Design | Year: 2013

Designers' visual way of knowing and working tends to be highly valued in design research. In architecture such an approach is increasingly criticized. Since people experience buildings with all their senses, architects' visual focus is said to the run the risk of disregarding non-visual aspects. This study focuses on the visual and tactile assessment of building materials. Analyses show that architecture students assess several experiential qualities differently by touch than by vision. Vision dominates the overall assessment, yet does not always anticipate touch correctly. Moreover architecture students seem to be unaware of how common building materials feel, and are unable to identify them by touch only. This identifies the need for a more elaborate consideration of non-visual aspects during design in general and design education in particular. © 2013 Wastiels, Schifferstein, Wouters, and Heylighen.

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