  Projet aPROpaille: Vers une reconnaissance de l’usage de la paille comme matériau isolant dans la constructionLouis, Arnaud  Conference given outside the academic context (2013) Detailed reference viewed: 14 (3 ULg)Moisture equilibrium in straw bale walls; Louis, Arnaud ; et alConference (2012, November) Straw bales technology for buildings is developing in Belgium as in many other countries. The market is growing but significant uncertainties are left concerning how to model its dynamical hygrothermal ... [more ▼] Straw bales technology for buildings is developing in Belgium as in many other countries. The market is growing but significant uncertainties are left concerning how to model its dynamical hygrothermal performances and its long term behaviour. The present paper presents the preliminary analysis conducted on material parameters and component’s response to dynamic heat and moisture solicitations. The simulations use WUFI Pro software based on material parameters form literature and both reference climate files for Belgium and theoretical climates to analyse the interactions between straw bale walls and finishing materials and their influence on component performances and durability. A specific prefabricated wall element sold on Belgian market is detailed and introduced in simulations. The influence on comfort feelings and indoor air quality are discussed with a focus on component´s thermal inertia and moisture regulation capacity. The paper concludes with recommendations on wall composition to help straw bale technologies to develop in building market of Belgium and other countries. [less ▲] Detailed reference viewed: 27 (5 ULg) GPR detection of saturated areas into concrete in the presence of a water gradientLouis, Arnaud ; Van der Wielen, Audrey ; Courard, Luc et alin 2012 14th International Conference on Ground Penetrating Radar (GPR) (2012, June) In the concrete, saturated areas are most of the time limited by a transition zone, presenting a water gradient. This transition zone can affect the GPR wave’s reflection and decrease the reflection ... [more ▼] In the concrete, saturated areas are most of the time limited by a transition zone, presenting a water gradient. This transition zone can affect the GPR wave’s reflection and decrease the reflection coefficient by comparison to the coefficient that would be obtained on a sharp interface. To quantify the impact of the water gradient on the reflection coefficient, we performed finite differences simulations. They showed that the reflection coefficient was reduced by 70% if the thickness of the transition zone was larger than 2/5 of the wavelength. Laboratory experiments, using hygrometric sensors for the water content control, confirmed this trend. [less ▲] Detailed reference viewed: 16 (7 ULg)Mineralization of bio-based materials: effect on cement-based mix propertiesCourard, Luc ; Darimont, Anne ; Louis, Arnaud et alin Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section (2011), LIV(LVIII), The lightweight concrete with bio-based products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Before identifying and ... [more ▼] The lightweight concrete with bio-based products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Before identifying and quantifying the basic physical characteristics of concrete made from wood, miscanthus, hemp or bamboo (acoustic and thermal properties in particular), it is necessary to optimize the composition of the product. It is clear that the final product is not unique and a compromise has to be found between insulation and mechanical properties. The long term stability as well as the reinforcement may be obtained by means of a mineralization process of the natural product: a preparation with a lime and/or cement-based material is necessary to reinforce the cohesion of the bio-based product. Optical and SEM analysis helped to clearly understand the interactions between the bio-based fibrous material and the cementitious materials, the quality of the bond and their effects on the properties of the cement-based concrete products. [less ▲] Detailed reference viewed: 52 (17 ULg)Détection de zones humides dans le béton par GPR en présence d’un gradient d’humidité.Louis, Arnaud Master's dissertation (2011) The objective of this master thesis is to highlight the impact of the presence of a humidity gradient on the detection of a wet area in concrete by combining a numerical approach and experimental results ... [more ▼] The objective of this master thesis is to highlight the impact of the presence of a humidity gradient on the detection of a wet area in concrete by combining a numerical approach and experimental results. In order to achieve this objective, several models have been conducted using a numerical simulation program of electromagnetic waves propagation. Influence of the size of the gradient, but also their position and shape, have been studied. Meanwhile, two experimental programs have been established in order to artificially generate a gradient of moisture into the concrete. This gradient was established by capillary rise in one case and by drying in the other case. Humidity sensors placed in the slabs allowed us to control the evolution of the transition zone located above the wet area. We tried then to correlate the evolution of the gradient with results from a Ground Penetrating Radar with 2.3 GHz antenna. We studied the influence of the gradient on the evolution with time of the electromagnetic field. This experimental program required many preliminary tests to define the dielectric properties of the slabs and the specific response of the sensors. Based on modeling, we concluded that the detection of the wet area remains possible as long as it is far enough from the direct wave and as its thickness is less than 2/5 of the signal wavelength. Regarding the experimental results, we were able to highlight the signal evolution with regard to the evolution of the moisture gradient. In the case of capillary rise, we were also able to confirm the trends predicted by modeling. [less ▲] Detailed reference viewed: 59 (13 ULg)Détection de zones humides dans le béton par GPR en présence d’un gradient d’humiditéLouis, Arnaud ; Courard, Luc ; Nguyen, Frédéric et alPoster (2011) Detailed reference viewed: 62 (17 ULg) |
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