【摘 要】
：
In biogas production plants, concrete structures suffer chemical and biological attacks during the anaerobic digestion process.The attack on concrete may be linked to the effects of (i) organic acids,
【机 构】
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Université de Toulouse, UPS, INSA, LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135
【出 处】
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The 14th International Congress on the Chemistry of Cement (
论文部分内容阅读
In biogas production plants, concrete structures suffer chemical and biological attacks during the anaerobic digestion process.The attack on concrete may be linked to the effects of (i) organic acids, (ii) ammonium and CO2 co-produced by the microorganisms metabolisms, and (iii) the bacterias ability to form biofilms on the concrete surface.In a context of biogas industry expansion, the mechanisms of concrete deterioration need to be better understood in order to propose innovative, efficient solutions.This study aims, firstly, to characterise the evolution of the biochemical composition of the biodegradable wastes during digestion so as to identify the compounds that are aggressive for concrete.Secondly, it aims to evaluate the mechanisms of concrete deterioration in anaerobic digesters.CEM I paste specimens were immersed in synthetic inoculated biowaste in anaerobic digestion conditions.The liquid fractions were analysed chemically.The alteration mechanisms of the cementitious matrices were investigated using XRD and SEM analyses.The maximal total concentration of organic acids was 65 mmol/L in the liquid fraction during the digestion process.The pH evolution showed two phases: acidification in the first few days and then a slow increase to pH 7-8.In only 6 weeks, an abundant biofilm developed on the cement paste surface.Biodeterioration leads to calcium leaching and carbonation of the cement paste.
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