Talk:Alkali–silica reaction

Examples of ASR

It seems inappropriate to single out the Los Angeles 6th St Viaduct as an example, unless you intend to comprehensively list the many thousands of US structures affected by ASR. An better alternative would be to provide an anonymous picture of typical ASR attack. . . .LinguisticDemographer 14:13, 11 August 2007 (UTC)

Raleigh,NC ripping up 8 lanes, 2 feet thick, 11 miles; after 11 years of service.~ — Preceding unsigned comment added by Wikipietime (talk • contribs) 02:39, 20 March 2013 (UTC)

Merge proposal

I think that Alkali Silica Reaction and Alkali-aggregate reaction are essentially the same thing and propose that the latter be merged and changed to a redirect to here. –Moondyne 01:57, 9 December 2008 (UTC) Not true.. ACR and ASR are branches of AAR —Preceding unsigned comment added by 142.151.178.65 (talk) 02:39, 14 December 2008 (UTC)

They are not the same thing. Alkali-aggregate reaction is the umbrella term for a few types of reaction. So should not merge. —Preceding unsigned comment added by 82.38.179.224 (talk) 17:28, 17 January 2009 (UTC)

I agree that the two should be merged. However, the final article should be Alkali Aggregate Reaction, with Alkali Silica Reaction being a sub-heading, along with Alkali Carbonate Reaction and Alkali Silicate Reaction, etc. All should redirect to AAR. This is how they are conceived and discussed in the Civil Engineering community. Garbagemania (talk) 02:31, 30 January 2009 (UTC)

I agree with the immediate above. Alkali-Silica, Alkali-Silicate and Alkali-Carbonate Reactions are all sub-headings for Alkali Aggregate Reactions and each should be discussed under a unified AAR heading —Preceding unsigned comment added by 57.66.53.93 (talk) 14:22, 11 March 2009 (UTC)

Definition issues

Editors and experts . . . I feel like the first few lines of an article should give a clear and concise definition of the topic. As such, I'm wanting to edit the first line to be more like this:

Alkali-Silica Reaction (ASR) is a reaction which occurs in portland cement concrete between reactive (amorphous) silica (in concrete aggregates) and an alkali (usually present in the cement), which results in the formation of a gel.

Would these edits be wrong? Am I making it too specific/exclusive?

Please advise. Thanks. Garbagemania (talk) 03:40, 30 January 2009 (UTC)

Well, the reaction could happen from sodium and potassium at the same time. The formation of the gel is only the prelude to degradation: it expands in contact with water. The mechanism of the reaction as described in the article is actually controversial: there are reported cases of reaction throughout the aggregate with gel pockets forming.

ASR can also happen in bitumen (and I suspect in CACs also): it is fundamentally about the aggregates. Cement provides an alkaline environment, but the alkalis could come from an external source.CyrilleDunant (talk) 14:21, 5 February 2009 (UTC)

How to tackle this sea of information on ASR?

Since the first publication on ASR by Stanton (1940), 83–84 years ago, a so huge amount of papers has been published in the literature that it is a superhuman task to read only a fraction of them and to make a good synthesis of the most relevant. Readers are overwhelmed by the avalanche of information available on the subject and are often drown in the sea of publications.

How to adequately sort this huge mass of information to only extract the most relevant and appropriate one? How to search literature in the most effectively way? According to the impact factors of journals or popularity ranking index in a Google scolar search? According to the h-index of authors to attempt to assess their citation impact? Or by mainly referring to state-of-the art books and up-to-date review works as advised by Wikipedia policy? An excellent discernment is definitely required to properly cite the main conclusions and outcomes of the best works and to give proper credit to the true discoverers while in particular avoiding works simply repeated every decade without added value. It would be useful to gather and to centrally maintain up to date a limited list of mandatory references and list of essential books and review works while avoiding useless inflation. The aim being, of course, to guide the reader and to provide him with a clear vision to try to better understand a very complex system. Shinkolobwe (talk) 13:48, 28 April 2020 (UTC)

Another source of invaluable information is also the long series (since 48–49 years) of ICAAR Conferences. Shinkolobwe (talk) 15:51, 28 April 2020 (UTC).

"ICAAR 2020: International Conference on Alkali-Aggregate Reaction in Concrete (ICAAR) history". Retrieved 2020-04-28. The following 15 editions of ICAAR have taken place: Copenhagen (Denmark), 1974; Reykjavik (Iceland), 1975; London (United Kingdom), 1976; Purdue (USA), 1978; Cape Town (South Africa), 1981; Copenhagen (Denmark), 1983; Ottawa (Canada), 1986; Kyoto (Japan), 1989; London (United Kingdom), 1992; Melbourne (Australia), 1996; Montreal (Canada), 2000; Beijing (China), 2004; Trondheim (Norway), 2008; Austin (USA), 2012; São Paulo (Brazil), 2016; and, Lisboa (Portugal), 2020.

And also the State-of-the-Art reports of different RILEM Technical Committees, as, e.g.:

"RILEM Technical Committee 106-AAR : Alkali-aggregate reaction". www.rilem.net. Retrieved 28 April 2020.

"RILEM Technical Committee 258-AAA : Avoiding alkali aggregate reactions in concrete – Performance based concept". www.rilem.net. Retrieved 28 April 2020.

Future works and support required

It would be useful to develop the following aspects:

Chemical mechanisms of ASR

• Mechanism at the level of individual aggregate with didactic figures
• Osmotic effects (S. Chatterji, Danemark)
• Electrical double layer (EDL) (G. Sposito, USA)
• Effect of lithium ions on the ASR mitigation: how does it works?
  • Various hypotheses, mechanisms, processes and theories
• Positive and negative effects of silica fume addition
• Chemical coupling with delayed ettringite formation (DEF), same mitigating effect by lithium ions, blast furnace slag (BFS) or supplementary cementitious materials (SCM), CEM III (OPC-BFS), ...

Effect of deicing salts on ASR

Effect of deicing salts (NaCl) on alkali-silica reaction. It is observed that deicing salts increase the sensitivity of silicate minerals to ASR, but the reason is less well known and several mechanisms could play a role:

• Anion exchange in calcium aluminates leading to the formation of Friedel's or Kuzel's salts (chloroaluminate, AFm phases), simplified as: Cl^– + AFm–OH → AFm–Cl + OH^–
• However, this effect is counteracted by other reactions occurring with AFm, a.o. the following ones:
  • AFt + OH^– → AFm (reaction favoring delayed ettringite formation, DEF)
  • AFt + Cl^– → Friedel's salt + SO₄^2– + OH^–
• Effect of ionic strength (IS) on the solubility of different solid phases in concrete
  • Reference: Heisig, Anne; Urbonas, Liudvikas; Beddoe, Robin E.; Heinz, Detlef (2016-10-01). "Ingress of NaCl in concrete with alkali reactive aggregate: effect on silicon solubility". Materials and Structures. 49 (10): 4291–4303. doi:10.1617/s11527-015-0788-y. ISSN 1871-6873. Retrieved 2020-04-28.
• Physical effect due to an increase of the concrete porosity where deicing salts penetrate
• Chatterji hypothesis of ultrafiltration of ions selectively penetrating into the aggregate: SiO₂ + 2 Na⁺ + 2 Cl⁻ + Ca²⁺ + 2 OH⁻ → Na₂SiO₃ + CaCl₂ + H₂O
  Ca²⁺ and Cl^– remaining out of the aggregates while only Na⁺ and OH^– could only penetrate inside the porous silica network to form the soluble alkali gel (effect of selective membrane played by the gel or the porous structure of amorphous silica).
• Certainly not simply the direct reaction of NaCl or KCl with portlandite (implausible route, closed door): 2 NaCl + Ca(OH)₂ → CaCl₂ + 2 NaOH.
  Indeed, the equilibrium of this reaction is strongly displaced to the left because of the low solubility of portlandite.
• and maybe other totally unsuspected ways, or entrance doors, still exist to explain the effect of deicing salts on ASR.
• ...

Shinkolobwe (talk) 18:20, 29 April 2020 (UTC)

Pessimum effect

• Definition of the notion of pessimum
• Proportion of reactive aggregates in concrete
• Size or dimension of reactive aggregates
• ...

Expansion kinetics

• Lab experiments: sigmoidal curves, S-shape curves,
• Modelling: hyperbolic tangent or logistic curve
• PhD Work of Catherine Larive (1997) at ECPC (now IFSTTAR) and Victor Saouma modelling works (Colorado University)

Mechanical strength

• Lab tests
• Modelling
• ...

Long-term durability

Listed here simply by countries:

• Canadian works: Laval University, Bérubé, Fournier, ...; Toronto University, Hooton, CNSC, ...
• French works: ECPC – IFSTTAR, J.M. Lorrenti; CEA, S. Poyet; INSA, S. Multon, A. Sellier ... .
• Swiss works: ETHz, B. Lothenbach, A. Leemann; EPFL, K. Scrivener,
• USA works: FHWA, US-NRC,
• Works in Denmark (S. Chatterji), UK, Finland, Germany, Japan, Spain, Belgium, ...
• ...

Structural stability

• Large civil engineering structures: bridges, dams, nuclear power plants, ...
• Effects of earthquakes
• Shear walls tests
• ...

In advance, thank you for developing some aspects your are familiar with and adding relevant references and supporting didactic materials (photographs, technical diagrams, figures, tables, ...). Shinkolobwe (talk) 14:37, 28 April 2020 (UTC)

Concrete Cancer?

Most sources outside wikipedia describe "Concrete Cancer" as corrosion of steel reinforcement, not ASR. At best there are different types of "concrete cancer"; perhaps the term is used to describe different phenomena in different parts of the world. At worst, this page is simply wrong.

I believe redirecting "Concrete Cancer" to this page is a mistake. Pjaymes (talk) 14:39, 5 September 2023 (UTC)

@Pjaymes: I understand your remark. Concrete cancer is a colloquial term poorly defined and bearing several possible meanings. It deals with concrete pathologies affecting the reinforced concrete structures durability. Concrete degradation is often driven by internal expansive reactions leading to the formation of cracks in reinforced concrete and spalling at its surface. So the corrosion of steel reinforcement is not the only type of concrete cancer: any internal expansive reaction (with considerable swelling inside the concrete) severely damaging concrete structures may also deserve this name, as it is the case for the alkali–silica reaction, also widely known as concrete cancer in the literature. This is justified by the intrinsic nature of the degradation mechanism itself directly affecting the concrete matrix integrity. So this colloquial term is not restricted to the only rebar corrosion. To resolve the question you have raised about this ambiguous expression, I have converted the page Concrete cancer from a Redirect to a Disambiguation page. Best regards, Shinkolobwe (talk) 14:04, 7 September 2023 (UTC)