Distribution du livre et librairie

Interventions de François Gèze, Frédéric Mériot, Jean-Guy Boin, Erik Fitoussi, et Christian Thorel dans le cadre des journées d’hommage à Jean Gattégno

Hydratation en solutions diluées de brownmillerite extraite de ciments SR et de brownmillerite synthétique

International audienceThe aim of this study is to investigate the reactivity of ferrites extracted from Sulfate Resisting (SR) Portland cement clinkers, until now often neglected. Industrial materials and synthetic materials have been studied and compared in the whole range of the Al/Fe ratio. Highly diluted aqueous suspensions were used, ranging betweenpure water and more complex solutions simulating the pore solution in cement. Conductimetry was combined with ICP.The reactivity of ferrite depends on the environment and the aluminum content of ferrite. The reactivity of ferrites extracted from industrial SR0 and SR3 clinkers (C3A = 0 wt% and C3A ≤ 3 wt% respectively) can be distinguished from one another. Additionally, industrial ferrite was found to be more reactive than synthetic ferrite. The iron content of katoite and ettringite was investigated using XRD. It depends on the Al/Fe ratio offerrite and the presence of calcium hydroxide in the solution

From selective dissolution to crystal chemistry of brownmillerite in sulfate resisting cement

International audienceThe aim of this study is to extract brownmillerite from sulfate resisting Portland cement (SRPC) in order to determine its crystal chemistry and the effects of dissolution protocols. Brownmillerites (C4AF) from four SRPC were extracted and systematically studied by X-ray diffraction (XRD), electron probe microanalysis (EPMA) and X-ray fluorescence spectroscopy. Two extraction steps were used. The first is the SAM protocol that leaves a residue rich in ferrite, C3A and sulfates. Precipitated hydrated sulfate minerals are also observed for clinker with high molar SO3/Na2Oeq ratio. The second, developed in this paper, uses acetic acid (AcA) to dissolve C3A and sulfates. The Rietveld refinements showed that all brownmillerites of this study crystallize in Ibm2 space group. Two families of brownmillerite were identified by their aluminum content and cell parameters, related to the presence of C3A in the clinker. EPMA indicated that ferrites from SR0 and SR3 cements have Al/Fe ratios about 0.7 and 0.8-1.0 respectively. XRD allows to predict the (Al+Mg+Si)/Fe ratio in brownmillerite in good agreement with EPMA. The SAM protocol is the best way to study crystal chemistry of brownmillerite and the AcA protocol is recommended to dissolve sulfates and C3A for further reactivity studies

Journées d’hommage à Jean Gattégno. Une voix qui manque toujours

Jean Gattégno nous a quittés il y a 20 ans, le 31 mai 1994. Spécialiste de la littérature anglaise du XIXe siècle et figure importante du syndicalisme universitaire, il fut nommé en 1981, à un moment clé du développement des politiques culturelles, à la tête de la direction du livre et de la lecture. Jusqu’à son départ en 1989 (il rejoint alors l’EPBF), il y conduit avec ténacité et pertinence une politique qui restera comme une sorte d’exemple pour chacun de ces deux domaines d’intervention. Ce colloque a pour ambition non seulement d’interroger les politiques du livre aujourd’hui, 33 ans après les premières mesures dont certaines demeurent emblématiques, mais aussi de rendre hommage à cette figure d’universitaire si brillant devenu haut fonctionnaire