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Revista IBRACON de Estruturas e Materiais

On-line version ISSN 1983-4195

Rev. IBRACON Estrut. Mater. vol.3 no.3 São Paulo Sept. 2010

http://dx.doi.org/10.1590/S1983-41952010000300004 

Effects of LiNO3 on Alkali-Silica reaction and comparison with the effects of fly ash on reaction

 

 

D. J. F. SilvaI; V. FazzanII; C. F. FioritiIII; J. L. AkasakiIV; H. M. BernardesV

ICivil Engineer, Universidade Estadual Paulista, Department of Civil Engineering, Ilha Solteira Campus, eng_djfsilva@hotmail.com, Rua Oliveira Marques n° 3924, CEP: 79830-040, Dourados-MS, Brasil
IICivil Engineer, Universidade Estadual Paulista, Department of Civil Engineering, Ilha Solteira Campus, jvfazzan@hotmail.com, Alameda Bahia n° 550, CEP: 15385-000, Ilha Solteira-SP, Brasil
IIIProfessor, Universidade Estadual Paulista, Department of Environmental Planning and Urbanism, Presidente Prudente Campus, cffioriti@hotmail.com, Rua Roberto Simonsen, n° 305, CEP: 19060-900, Presidente Prudente-SP, Brasil
IVAssistant Professor, Universidade Estadual Paulista, Department of Civil Engineering, Ilha Solteira Campus, akasaki@dec.feis.unesp.br, Alameda Bahia n° 550, CEP: 15385-000, Ilha Solteira-SP, Brasil
VAssistant Professor, Universidade Estadual Paulista, Department of Civil Engineering, Ilha Solteira Campus, haroldom@dec.feis.unesp.br, Alameda Bahia n° 550, CEP: 15385-000, Ilha Solteira-SP, Brasil

 

 


ABSTRACT

Lithium-based additives have shown satisfactory results in the expansion reduction due to alkali-silica reaction (ASR), but many doubts remain about the mechanisms of ASR. The study herein assessed the effects of a lithium nitrate based (LiNO ) chemical addition, using several dosages, in order to understand its expansion mechanisms due to ASR. The study of the effects of LiNO3 on ASR was conducted by the accelerated mortar bar method (ASTM C-1260), using two kinds of reactivate aggregates, consequently, the test lasted up to 30 days. Mortar bars were also molded with a fly ash (FA) based mineral addition to compare the effects of a mineral addition with a chemical one on the expansion due to ASR. The results from the ASTM C-1260 test indicated that the LiNO3 addition was effective in the expansion reduction, but presented different addition values for the acceptable threshold of 0.10% at 14 days for each kind of aggregate. It was also observed that mixtures containing LiNO3 reduced the expansion up to 30 days, while for the mixtures containing fly ash the expansion continued to increase throughout the test. The test indicated that the dosages of lithium addition (Li2O/Na2Oeq), efficient in the expansion reduction for the acceptable threshold of 0.10% at 14 days, were very high when compared to those found in the literature. Folliard et al. (2003), states that the use of cement with a high alkali content (Na2Oeq= 0.9±1.0%) and the modification of the ASTM C-1260, would be the best solution to obtain lithium addition values compatible with field applications.

Keywords: alkali-aggregate reaction, expansion, lithium composed, mortar.


 

 

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5.   References

[01]   McCOY, W. J.; CALDWELL, A. G. New approach to inhibiting alkali-aggregate expansion. Journal of the American Concrete Institute, Detroit, v. 22, n. 9, 1951, p.693-706.         [ Links ]

[02]   Monteiro, P. J. M.; Kurtis, K. E. Chemical additives to control expansion of alkali-silica reaction gel: proposed mechanisms of control. Journal of Materials Science, v. 38, n. 10, 2003, p. 2027-2036.         [ Links ]

[03]   Ramyar, K. et al. Comparison of alkali-silica reaction products of fly-ash or lithium-salt-bearing mortar under long-term accelerated curing. Cement and Concrete Research, v. 34, n. 5, 2004, p. 1179-1183.         [ Links ]

[04]  Feng, X. et al. New observations on the mechanism of lithium nitrate against alkali-silica reaction (ASR). Cement and Concrete Research, in prees, corrected proof, available online 15 august 2009.         [ Links ]

[05]   Schneider, J. F. et al. Effect of lithium nitrate on the alkali-silica reaction gel. Journal of the American Ceramic Society, v. 9, n. 10, 2008, p. 3370-3374.         [ Links ]

[06]   Mo, X. Laboratory study of LiOH in inhibiting alkali-silica reaction at 20°C: a contribution. Cement and Concrete Research, v. 35, n. 6, 2005, p. 499-504.         [ Links ]

[07]   AMERICAN SOCIETY FOR TESTING AND MATERIALS. ASTM C-1260: Standard test method for potential alkali reactivity of aggregates (mortar-bar method). West Conshohocken, 2005.         [ Links ]

[08]   Folliard, K. J. et al. Report No. FHWA-RD-03-047: Research, development, and technology: guidelines for the use of lithium to mitigate or prevent alkali-silica reaction (ASR), - Turner-Fairbank Highway Research Center, FHWA - Federal Highway Administration, 2003, 86p.         [ Links ]

[09]   Collins, C. L. et al. Examination of the effects of LiOH, LiCl and LiNO on alkali-silica reaction. Cement and Concrete Research, v. 34, n. 13, 2004, p. 1403-1415.         [ Links ]

 

 

Received: 28 Jan 2009
Accepted: 20 Jan 2010
Available Online: 10 Sep 2010

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