Speaker
Description
The biodeterioration of cementitious materials in the wastewater treatment cycle is caused by the biological acid produced by microorganisms. In the case of sewage systems in presence of H2S, sulfuric acid was produced by sulfo-oxidizing bacteria, and in the case of nitrogen pollution treatment in water treatment plants, is nitric acid produced by bacteria. The literature shows that cementitious materials based on calcium aluminate cement (CAC) have better durability than ordinary Portland cement (OPC). However, few studies attempt to explain this improved durability. Thus, mortar samples (CEM I, CEM V, and CAC) were exposed in both networks and wastewater treatment plants. Mineralogical analyses (µ-Raman, XRD, SEM) and physical parameters of the materials (water porosity, BET, mercury porosimetry) were carried out on the samples, before and after different exposure times. Results shows that CAC-type materials initially have finer and more tortuous porosity and microporosity than OPC cements. Furthermore, during biogenic attack on the materials, the calcium in the OPC phases is more easily leached than in the CAC phases, particularly due to the reprecipitation of AH3.These different parameters with the bacteriostatic effect of aluminum may explain the better durability of CAC.
Affiliations
Université Gustave Eiffel, 14-20 Boulevard Newton, MAST-CPDM, F77454 Marne-la-Vallée, France
Contact Email for Corresponding Author: tony.pons@univ-eiffel.fr
| Title | The durability of CAC compared to Portland cements in cases of biodegradation |
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| Keywords | Biodeterioration, sewer treatment, sewer network, calcium aluminate cement, calcium silicate cement |