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Microorganisms, such as bacteria, cyanobacteria, fungi, algae,
and lichens, are liable to grow on building materials. Biological activity
contributes to deterioration of building material. Fungi are among the most
harmful organisms associated to biodeterioration of organic and inorganic
materials. Cement-based materials are porous and contain organ...
Context in source publication
Context 1
... Aspergillus niger is often identified from samples of monuments or buildings degraded, its growth on the cementitious materials was not observed. Similar results were obtained by Wiktor [18] . However, a significant growth of Aspergillus niger on the paper sheet was observed, confirming the good conditions of development. Fig. 5 represents the specimens inoculated with Coniosporium uncinatum after 52 days of incubation. With the exception of the High Content of Aluminate Mortars (HCA-M), C. uncinatum colonies developed on all specimens (black dots). However, for Portland cement-based mortars (WP-m and PL-M) these colonies of C. uncinatum were the most ...
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Citations
... Enfin, il est observé dans la littérature que les matériaux à base de CAC présentent une plus faible colonisation par les microorganismes (Dalod et al., 2014;Govin et al., 2014;Herisson et al., 2014;Lors et al., 2018;Peyre Lavigne et al., 2015;Voegel, Giroudon, et al., 2019), ce qui est favorable pour leur durabilité. ...
... En revanche, les auteurs (Voegel et al., 2015;Voegel, Giroudon, et al., 2019) ont montré les meilleures performances des pâtes de CAC face à cette attaque biochimique, et ces résultats ont été confirmés par les essais in situ (Voegel, 2017). Ce meilleur comportement peut être lié à une plus faible colonisation microbienne de la pâte en comparaison avec les autres liants étudiés, déjà mise en avant par d'autres auteurs (Dalod et al., 2014;Govin et al., 2014;Lors et al., 2018). D'après ces auteurs, la résistance à la biodétérioration des matériaux à base de CAC serait liée aux caractéristiques physicochimiques du CAC. ...
... De plus, sa surface est toujours composée des phases cristallisées initialement présentes dans le matériau sain. La meilleure résistance du CAC comparée aux liants à base de ciment clinker (CEM I et CEM III notamment) pourrait être liée à sa faible porosité (24,0 % porosité H2O, Tableau IV -1) ou à la plus faible colonisation des pâtes de CAC par les microorganismes (Dalod et al., 2014;Govin et al., 2014). Herisson et al. (2014) expliquent cela par l'effet bactériostatique de l'aluminium, présent en grande quantité dans les ciments d'aluminate de calcium. ...
Anaerobic digestion allows the transformation of organic matter into biogas. In the current context of ecological transition towards renewable energies and the reduction of greenhouse gas emissions, the development of the sector is encouraged in Europe and the sector is growing fast. On an industrial scale, this bioprocess is implemented in concrete structures that are in direct contact with the biowastes being digested and undergo biodeterioration phenomena. Indeed, the liquid medium contains a wide variety of metabolites produced during digestion (volatile fatty acids, NH4+, dissolved CO2) whose concentrations can reach several grams per litre, as well as the microorganisms themselves, colonizing the surface of the concrete in the form of biofilm.This thesis, carried out within the framework of the ANR project BIBENdOM, aimed at (i) analysing the mechanisms of biogeochemical interactions between cementitious materials made from different types of binders, biowaste in digestion, and biofilm in the anaerobic digestion environment and (ii) providing a thorough experimental and numerical understanding of the mechanisms of alteration of cementitious materials in order to tend towards the prediction of the durability of concrete in these complex and variable environments.On one hand, the experimental work was carried out on complete environments in laboratory and highlighted local scale interaction mechanisms between a panel of materials (CEM I, CEM III/B, CAC, alkali-activated metakaolin and alkali-activated slag) and two substrates being digested (cattle manure and maize breakage) allowing to vary the composition and the aggressiveness of the environment toward the materials (during 5 digestion cycles, or about 6 months per experience). The anaerobic digestion process was monitored and analysed in terms of composition of the liquid medium and biogas production, microbial populations and microstructural, chemical and mineralogical modifications of the materials. On the other hand, the individual actions and combined effects of the chemical compounds metabolised during the digestion were finely studied in order to characterise the kinetics and thermodynamic equilibria governing degradation, with a view to proposing a model tending towards the prediction of deterioration in media of varied compositions. For this purpose, aggressive solutions were analysed (cation and anion concentrations) over time and the degradation of cementitious materials was characterised (mass loss, structural, mineralogical and chemical modifications).The work has shown that the presence of materials in the liquid phase only impacts the digestion process in the short term and on a local scale only. The use of substrates of agricultural origin generated environments rich in dissolved CO2 (1000 - 2000 mg.L-1) and favoured the carbonation of the materials, which seems to play a major role in the deterioration mechanisms of Portland based cements, ahead of those of other metabolites (organic acids, ammonium, phosphate salts...). Among the materials used, alkali-activated metakaolin stands out for its very good behaviour and low degradation. It is also the material that has had the greatest impact on digestion, in terms of the composition of the medium (NH4+), digestion kinetics and pH as well as the microbial populations developed. Finally, the experiments carried out on chemical metabolites alone have enabled the development of a thermodynamic model applied to the interactions between cement pastes and aggressive agents, allowing to predict the chemical evolution of the solid phase during degradation and as a function of the metabolite studied.
... Aggressiveness class according to NF EN 206 [30] In the biowaste studied could also be noted that the peripheral zone maintained a relatively high density. The fact that the CAC paste performs best could be linked to lower colonization of the CAC pastes compared to other binders [63,64]. Herisson et al. [65] explained this by the bacteriostatic effect of aluminium, present in large amounts in the CAC cements. ...
In anaerobic digestion plants, biological activities transform biowaste into a renewable energy: the biogas. This process produces aggressive and complex media in direct contact with the structure. Few studies have focused on the deterioration of concrete in such environments. In order to support the sustainable development of biogas production growing sector, this study intends to provide thorough information on the biowaste chemical composition and on materials biodeterioration mechanisms occurring in biogas plants. Cementitious materials with various surface compositions (pastes of CEM I, CAC and CEM I treated with oxalic acid) were immersed in the liquid phase of laboratory bioreactors reproducing anaerobic digestion conditions. Altered depths measurements in time highlighted the better resistance of the CAC material. The microbial biofilm coverage on the material's surface was delayed by the surface pretreatment with oxalic acid and was less dense for the CAC paste. Chemical and mineralogical analyses mainly showed leaching and carbonation phenomena.
In dry mix formulations calcium aluminate cement (CAC) is often used as a set accelerator for ordinary Portland cement (OPC). However, a critical amount of CAC is able to delay the main reaction of OPC significantly. This delay can be counteracted by adding an appropriate amount of calcium sulfate (C$) to the binary blend of OPC and CAC. The underlying hydration mechanisms of these blends vary significantly from the mechanisms known from neat OPC or neat CAC hydration and are up to now not fully understood. Direct phase quantification of pastes by XRD using the G-factor method combined with heat flow calorimetry and analysis of pore solution are used to investigate this issue and to shed light on the underlying hydration mechanisms. Investigations of binary (OPC/CAC) and ternary (OPC/CAC/C$) OPC-rich mixtures provide valuable insights into the influence of calcium sulfate on the hydration of CAC and OPC. The experimental set-up is used to study the phase development in dependency of the pore solution chemistry. The initial period of hydration is dominated by flash ettringite precipitation mainly from CA from CAC and C$ from OPC or additionally added C$. Analyses of the pore solution reveal that an unfavorable composition of the pore solution is not only able to delay the silicate reaction of OPC but also to retard the renewed C3A dissolution of OPC. The start of both reactions can be detected after a significant change of the pore solution chemistry. The results show that this change is induced by the precipitation of aluminum containing hydrate phases probably creating the necessary conditions. In a second step the complex mortar system is reduced to the main phase of OPC (C3S) and CAC (CA). C3S and CA were obtained by solid state reaction from pure CaCO3, SiO2 and CaCO3, Al2O3, respectively. The influence of CA on hydration of C3S was investigated to shed light on the underlying hydration mechanisms capable of delaying the silicate reaction for several hours. This reaction is mainly responsible for the strength development in OPC. Due to further development of analytical methods, like direct phase quantification of pastes by XRD using the G-factor method, we can accurately analyze the dissolution of C3S, CA and the precipitation of the different crystalline hydrate phases. The findings of the performed study particularly provide new knowledge regarding the kinetic factors underlying the C3S hydration reaction, which, although having been studied for several decades, are still in discussion. The observed different C3S reaction rates are in the focus of this study. Furthermore, a new data set regarding the dissolution of C3S with respect to the Ca/Al ratio in the pore solution will be presented.
