Accelerated test design for biodeterioration of cementitious materials and products in sewer environments / M. Peyre Lavigne in MATERIAUX & TECHNIQUES, Vol. 103, N° 2 (2015)  

[article]  inMATERIAUX & TECHNIQUES > Vol. 103, N° 2 (2015) . - 9 p. Titre : Accelerated test design for biodeterioration of cementitious materials and products in sewer environments Type de document : texte imprimé Auteurs : M. Peyre Lavigne, Auteur ; A. Bertron, Auteur ; C. Patapy, Auteur ; X. Lefebvre, Auteur ; E. Paul, Auteur Année de publication : 2015 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Français (fre) Catégories : Egouts Essais accélérés (technologie) Matériaux cimentaires -- Biodégradation Mortier Index. décimale : 620.13 Matériaux de construction : pierre, ciment, béton, liants de Résumé : A new test method for evaluating the resistance of cementitious products and materials to biogenic acid attack has been developed. It consists of inoculating pipes with a highly diverse microbial consortium (from an urban wastewater treatment plant), and trickling a feeding solution containing a safe and soluble reduced sulfur source over the inoculated surface in order to select a sulfur-oxidizing activity. A sulfur substrate, thiosulfate, was used in the feeding solution, which facilitated the monitoring of the bacterial activity, and of the leaching of cementitious ions. The functioning of the test in terms of selection of sulfur oxidizing microorganisms, acid and sulfate production, and degradation mechanisms occurring in the cementitious materials has been validated previously. This paper aims (i) to evaluate the reproducibility and repeatability of the test when the source of the sludge used for the inoculation is changed and (ii) to optimize the test design. The following changes were carried out with a view to intensifying the biological and chemical reactions: change of sulfur substrate (tetrathionate instead of thiosulfate), increased sulfur flow rate at the surface of the biofilm, and increased temperature. The results highlight good reproducibility of the test: the change in the inoculum and in the sulfur substrate led to the same phenomena in terms of (i) transformation of reduced sulfur species into sulfate and production of acid and (ii) degradation mechanisms of the cement linings. Moreover, the change of the sulfur substrate combined with the reduction of the exposed surface locally intensified the alteration kinetics. In contrast, in the experimental conditions, the increase in temperature did not seem to have any positive influence on the microbial activity. Note de contenu : - EXPERIMENTAL ASPECTS : Pipe products - Test set-up - Chemical analysises of the leaching solution - Microstructural characterization of the cementitious linings - RESULTS : pH and composition of leaching solution - Intensification of biological process responsible for mortar lining degradation - Microstructural analysis on BFSC mortar - Microstructural analysis on CAC mortar - DISCUSSION : Analyses of the test design - Optimization of test design Référence de l'article : 204 DOI : http://dx.doi.org/10.1051/mattech/2015018 En ligne : http://www.mattech-journal.org/articles/mattech/pdf/2015/02/mt150024.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24192 [article]

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