Modeling the degradation of Portland cement pastes by biogenic organic acids

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2010.03.005· OSTI ID:21483642

Devillers, Philippe ^[1]

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1. Centre des Materiaux de Grande Diffusion, Ecole des Mines d'Ales, 6 Av. de Clavieres, 30319 Ales (France)

Reactive transport models can be used to assess the long-term performance of cement-based materials subjected to biodegradation. A bioleaching test (with Aspergillus niger fungi) applied to ordinary Portland cement pastes during 15 months is modeled with HYTEC. Modeling indicates that the biogenic organic acids (acetic, butyric, lactic and oxalic) strongly accelerate hydrate dissolution by acidic hydrolysis whilst their complexation of aluminum has an effect on the secondary gel stability only. The deepest degradation front corresponds to portlandite dissolution and decalcification of calcium silicate hydrates. A complex pattern of sulfate phases dissolution and precipitation takes place in an intermediate zone. The outermost degraded zone consists of alumina and silica gels. The modeling accurateness of calcium leaching, pH evolution and degradation thickness is consistently enhanced whilst considering increase of diffusivity in the degraded zones. Precipitation of calcium oxalate is predicted by modeling but was hindered in the bioleaching reactor.

• OSTI ID: 21483642
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 8 Vol. 40; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADSORBENTS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPLEXES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASPERGILLUS
BIODEGRADATION
BUILDING MATERIALS
CALCIUM COMPOUNDS
CALCIUM SILICATES
CARBOXYLIC ACID SALTS
CEMENTS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
DECOMPOSITION
DISSOLUTION
EUMYCOTA
FUNGI
HYDRATES
HYDROLYSIS
LEACHING
LYSIS
MATERIALS
MICROBIAL LEACHING
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXALATES
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
PLANTS
PORTLAND CEMENT
PRECIPITATION
SEPARATION PROCESSES
SILICA GEL
SILICATES
SILICON COMPOUNDS
SIMULATION
SOLVOLYSIS
SULFATES
SULFUR COMPOUNDS
TRANSPORT THEORY