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Bethune, France

Goudjil N.,1230 Rue Of Luniversite | Djelal C.,1230 Rue Of Luniversite | Vanhove Y.,1230 Rue Of Luniversite | Kada H.,1230 Rue Of Luniversite | Heloun N.,Outinord
Construction and Building Materials | Year: 2014

A recent study proposed a new process for demoulding concrete elements based on the principle of electro-osmosis, consisting of applying an electric potential between the reinforcement and formwork which causes the water displacement towards the concrete/formwork interface where a film of water is formed avoiding the adhesion of the concrete on the formwork. The quality of facing and demoulding has been shown to be dependent on the polarization parameters (voltage value, time and duration of its application) and therefore optimal parameters were assessed. However these parameters were found in a very limited condition of temperature, only at 20 ± 2 C. In this new study we consider the parameters optimization scheme in other room temperature conditions. In this respect an experimental device was developed in order to quantify the amount of displaced water at (20 ± 2 C) and (8 ± 2 C) according to the voltage value and duration of its application. We showed that, under the same polarization conditions, the quantity of water transported decreases with decreasing room temperature. This decreasing of water quantity caused the alteration of demoulding and facing quality. To overcome this issue, the optimal polarization conditions have been revisited in order to take into account the temperature. When transposed in situ, our method performed successfully at 20 ± 2 C and at 8 ± 2 C as well and it could be a better choice than the previous demoulding methods like those using vegetable oils, developed recently to replace mineral oils, they cannot be used at low temperatures.© 2013 Elsevier Ltd. All rights reserved. Source


Kesteloot S.,1230 Rue Of Luniversite | Djelal C.,Structure and Rehabilitation | Benslimane I.,Structure and Rehabilitation | Khoufache N.,1230 Rue Of Luniversite
Construction and Building Materials | Year: 2015

A reduction in rehabilitation costs by about 20% is the main objective of this project while reducing response times in situ and maintaining an equivalent efficiency of the reinforcement. The first part recounts the history of the various stages of the Parisian sewer system construction. It subsequently takes stock of the pathologies, the repair techniques and the investigation methods of these structures. The second part deals with the design of test pieces through numerical calculation while taking into consideration the various parameters applied to each material. The selected model is a vault representing the upper part of an ovoid. The third part is an experimental approach to characterizing materials and in particular the coating/glue/composite interface. © 2015 Published by Elsevier Ltd. Source


Miao Y.,University of Lille Nord de France | Miao Y.,Ecole Nationale Superieure de Chimie de Lille | Miao Y.,French National Center for Scientific Research | Miao Y.,1230 Rue Of Luniversite | And 10 more authors.
Polymer | Year: 2011

The 4-dimethylaminopyridine (DMAP) catalyzed ring-opening polymerization of lactide using various carbohydrate initiators has been assessed for the functionalization of polylactide. Selectively protected glucose derivatives bearing a free primary alcohol (Glc-1r) and a free secondary alcohol (Glc-2r), glucose and cyclodextrin diol derivatives (Glc-diol and CD-diol), methyl-α-d-glucopyranoside (Glc-Me) and native β-cyclodextrin (CD) were used as initiators. According to the solubility of the carbohydrate derivative, the polymerizations were conducted in chlorinated solvents and in the bulk. Relatively narrow distributions are obtained in high yields in the absence of side reactions, affording a 100% functionalization efficiency. The catalytic synthesis of new carbohydrate link-functionalized polylactides and carbohydrate core star polylactides is reported. © 2011 Elsevier Ltd. All rights reserved. Source

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