Leaching of both calcium hydroxide and C-S-H from cement paste: Modeling the mechanical behavior

Carde, Christophe; François, Raoul; Torrenti, Jean‐Michel

doi:10.1016/0008-8846(96)00095-6

Cited by 218 publications

(121 citation statements)

References 4 publications

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“…The effect of degradation on the properties of cementitious materials has been reported in several studies in the literature (Adenot and Buil 1992;Carde et al 1996;Faucon et al 1996Faucon et al , 1998Haga et al 2005;Maltais et al 2004). In these studies leaching of calcium from cementitious materials have been accomplished both through immersion of the solid cementitious specimens in water (Faucon et al 1996;Haga et al 2005;Mainguy et al 2000) and through immersion of the specimens in chemical agents in order to accelerate the leaching process (Adenot and Buil 1992;Faucon et al 1996Faucon et al , 1998Haga et al 2005;Heukamp et al 2001;Mainguy et al 2000;Maltais et al 2004;Revertegat et al 1992;Ryu et al 2002;Saito et al 1992;Wittmann 1997).…”

Section: Introductionmentioning

confidence: 99%

Physical and Mechanical Properties of Cementitious Specimens Exposed to an Electrochemically Derived Accelerated Leaching of Calcium

Babaahmadi

Tang

Abbas

et al. 2015

International Journal of Concrete Structures and Materials

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Simulating natural leaching process for cementitious materials is essential to perform long-term safety assessments of repositories for nuclear waste. However, the current test methods in literature are time consuming, limited to crushed material and often produce small size samples which are not suitable for further testing. This paper presents the results from the study of the physical (gas permeability as well as chloride diffusion coefficient) and mechanical properties (tensile and compressive strength and elastic modulus) of solid cementitious specimens which have been depleted in calcium by the use of a newly developed method for accelerated calcium leaching of solid specimens of flexible size. The results show that up to 4 times increase in capillary water absorption, 10 times higher gas permeability and at least 3 times higher chloride diffusion rate, is expected due to complete leaching of the Portlandite. This coincides with a 70 % decrease in mechanical strength and more than 40 % decrease in elastic modulus.

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Section: Introductionmentioning

confidence: 99%

Physical and Mechanical Properties of Cementitious Specimens Exposed to an Electrochemically Derived Accelerated Leaching of Calcium

Babaahmadi

Tang

Abbas

et al. 2015

International Journal of Concrete Structures and Materials

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“…Degradation in mildly acidic solutions characteristic of municipal wastewater is attributed to leaching of calcium ions over a long period. The slow dissolution and loss of calcium hydroxide by diffusion can eventually lead to a reduction in structural integrity and mechanical properties (Carde, François, & Torrenti, 1996); however, the timeline for this type of degradation is only a concern for structures with design lives in the order of thousands of years (Hidalgo, Andrade, & Alonso, 2001) and is negligible in wastewater collection networks when compared with the short-term threat presented by MIC. Under highly acidic conditions, the dissolution of calcium hydroxide is accompanied by the decalcification of less soluble hydration products such as CSH, sulfoaluminates, and ferroaluminates.…”

Section: Mechanisms Of Acid Degradationmentioning

confidence: 99%

Review of Microbially Induced Corrosion and Comments on Needs Related to Testing Procedures

House¹,

Weiss²

2014

Proceedings of the 4th International Conference on the Durability of Concrete Structures

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Concrete is the most widely used material for the construction of the wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated Portland cement may make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multistage degradation process known as microbially induced corrosion (MIC). MIC begins with the production of aqueous hydrogen sulfide (H 2 S (aq) ) by anaerobic sulfate-reducing bacteria present below the waterline. H 2 S (aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur-oxidizing bacteria Thiobacillus that resides on concrete surfaces above the waterline. Sulfuric acid then attacks the cement paste portion of the concrete matrix through decalcification of calcium hydroxide and calcium silica hydrate coupled with the formation of expansive corrosion products and loss of coarse aggregate. The attack proceeds inward, resulting in reduced service life and potential failure of the concrete structure. There are several challenges associated with assessing a concrete's susceptibility to MIC. First, no standard laboratory tests exist to assess concrete resistance to MIC. Straightforward reproduction of MIC in the laboratory is complicated by the use of microorganisms and hydrogen sulfide gas. Physicochemical tests simulating MIC by immersing concrete specimens in sulfuric acid offer a convenient alternative but do not accurately capture the damage mechanisms associated with biological corrosion. Comparison of results between research studies is difficult due to discrepancies that can arise in mixture design, specimen preparation, and experimental methods even if current ASTM standards are followed.

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“…The accelerated lixiviation test with ammonium nitrate (CEA, ENS Cachan) has been introduced in order to characterize the degradation phenomena within an appropriate time duration [2,3] profile. The physical mechanisms introduced by the accelerated test are very close to those obtained with weak mineral water, but the test duration is shortened.…”

Section: Concrete/environment Interactionsmentioning

confidence: 99%

Probabilistic and predictive performance-based approach for assessing reinforced concrete structures lifetime: The applet project

Crémona

Adélaïde

Berthaud

et al. 2011

EPJ Web of Conferences

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Abstract. Concrete deterioration results in different damage extents, from cracking to concrete spalling, from losses of reinforcement cross-sections to bond losses. A relevant prediction of this performance is the basis for a successful management of the concrete structures. Conversely, the large amount of uncertainties related to parameters and models require a specific analysis in order to provide relevant results. The APPLET project intends to develop a probabilistic and predictive performance-based approach by quantifying the various sources of variability (material and structure), studying the interaction between environmental aggressive agents and the concrete material, ensuring a transfer of the physical-chemical models at the material scale towards models at the structure level, including and understanding in a better manner the corrosion process, integrating interface models between reinforcement and concrete, proposing relevant numerical models, integrating know-how from monitoring or inspection. To provide answers, a

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Leaching of both calcium hydroxide and C-S-H from cement paste: Modeling the mechanical behavior

Cited by 218 publications

References 4 publications

Physical and Mechanical Properties of Cementitious Specimens Exposed to an Electrochemically Derived Accelerated Leaching of Calcium

Physical and Mechanical Properties of Cementitious Specimens Exposed to an Electrochemically Derived Accelerated Leaching of Calcium

Review of Microbially Induced Corrosion and Comments on Needs Related to Testing Procedures

Probabilistic and predictive performance-based approach for assessing reinforced concrete structures lifetime: The applet project

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