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Boehme L.,Catholic University College of Bruges-Ostend | Boehme L.,Catholic University of Leuven | Vrijders J.,Belgian Building Research Institute BBRI | Van Gysel A.,Catholic University of Leuven | Van Gysel A.,Lessius University College Antwerp
fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings

This paper presents some relevant aspects in using recycled concrete aggregates (RCA) in structural concrete: variability of the properties of RCA, mix design and durability of concrete with RCA. The aim of this research is to investigate the potential use of RCA in structural concrete C20/25 & C25/30 in the exposure classes X0, XC1, XC2, XC3, XF1, by replacing 100 % of the coarse aggregates by RCA. The properties of RCA provided by the recycling industry are investigated, as well as the properties of fresh and hardened recycled concrete. Finally, durability tests regarding to the exposure classes, are performed. Source

Holeyman A.,Catholic University of Louvain | Bertin R.,Catholic University of Louvain | Whenham V.,Belgian Building Research Institute BBRI
Soil Dynamics and Earthquake Engineering

This paper describes analytical solutions for assessing the axial dynamic response of the shaft of a pile subjected to vibratory loads, with particular reference to pile vibratory driving. Radial inhomogeneity arising from shear modulus degradation is accounted for by assuming continuous variations of the medium properties. This approach alleviates wave reflections from the interface between inner (nonlinear) and outer (linear) zones. Novel analytical solutions are presented for two cases describing the radial decrease of the soil modulus according to (a) a linear law and (b) a parabolic law. The results are evaluated over a wide range of parameters and compared with those obtained by a semi-analytical model derived from Michaelides et al. [14,15] and by a radial discrete model simulating the pile and soil movements from integration of the laws of motion (Hipervib-II model) (Holeyman [8]). © 2012 Elsevier Ltd. Source

Whenham V.,Belgian Building Research Institute BBRI | Holeyman A.,Catholic University of Louvain
Geotechnical and Geological Engineering

The vibratory driving technique consists in applying a vibratory load onto a profile to reduce the ground resistance and allow penetration of the profile under its own weight. The vibratory action is produced by counter-rotating eccentric masses actuated within the exciter block. A proper definition of this mechanical action is fundamental for vibratory driving analyses. The vibratory force transferred from the vibrator onto the pile during vibratory driving is however generally neither well defined nor understood, in particular when using simplified closed form solutions for the analysis of pile driving. Few authors have pointed out the very low ratio observed between the force measured in the pile and the nominal inertial force developed by the eccentrics, but without offering a theoretical framework to explain and predict this low ratio. The objective of this paper is to develop a better understanding of the so-called 'efficiency factor' of the vibratory driving process. Analytical solutions are presented, along with more advanced numerical simulations. Theoretical solutions are illustrated with reference to field measurements collected at different test sites. © 2012 Springer Science+Business Media B.V. Source

Mlecnik E.,Passiefhuis Platform vzw PHP | Mlecnik E.,Technical University of Delft | Kondratenko I.,Passiefhuis Platform vzw PHP | Cre J.,Passiefhuis Platform vzw PHP | And 10 more authors.
Energy Procedia

In theory, there is huge potential for reducing the energy consumed by existing single-family houses by thoroughly renovating them. For the successful market development of highly energy-efficient integrated renovations, supply chain collaboration is very important, while at the same time customer demand for integrated renovations has to be stimulated. A research and networking methodology was developed within the framework of the One Stop Shop project to identify and develop collaboration opportunities for advanced housing renovation in Belgium, Denmark, Finland and Norway. The research identified key supply-side needs through interviews and questionnaires, and analysed important elements for the development of a web-based portal that can connect supply and demand. The project further developed ideas and methods for collaboration and business model generation between different players on the renovation market. These different research results contributed to defining new business opportunities related to process innovation to unburden the homeowner and to achieve less fragmented renovation processes. © 2012 The Authors. Source

Pierard J.,Belgian Building Research Institute BBRI | Pollet V.,Belgian Building Research Institute BBRI | Cailleux E.,Belgian Building Research Institute BBRI | Pierre C.,Belgian Research Center for the Cement Industry
fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings

The lower hydration rate of cements containing high Ground Granulated Blast-Furnace Slag (GGBFS) contents generally makes the concrete more sensitive to drying, with the result that a weak surface layer may be formed. A previous study indicated that some chemical admixtures and mineral additions are effective to accelerate the setting and hardening of mortars made with cements containing 70% to 85% of GGBFS. In this paper, the influence of these products on the early-age strength and some durability properties of high slag cement based concrete is investigated. The results show in particular that the use of a calcium nitrate based accelerator increases the 2-day compressive strength by up to 75% and helps to enhance the concrete carbonation resistance. Source

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