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Influence of shrinkage-reducing admixtures on the reduction of plastic shrinkage cracking in concrete / José Mora-Ruacho in Cement and concrete research, Vol. 39 N° 3 (Mars 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 3 (Mars 2009) . - pp. 141–146 Titre : Influence of shrinkage-reducing admixtures on the reduction of plastic shrinkage cracking in concrete Type de document : texte imprimé Auteurs : José Mora-Ruacho, Auteur ; Gettu, Ravindra, Auteur ; Antonio Aguado, Auteur Année de publication : 2009 Article en page(s) : pp. 141–146 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Drying;  Fresh  concrete;  Durability;  Shrinkage;  Admixtures Résumé : Fresh concrete exposed to high evaporation rates is prone to plastic shrinkage cracking, especially in structures with large surface area/volume ratios. The present work shows that the reduction of the surface tension of the mixing water is an effective way for decreasing such cracking. In this study, conventional and high strength concretes with superplasticizers and shrinkage reducing admixtures (SRAs) were exposed to drying in the plastic state. Continuous monitoring of the surface displacement facilitated the identification of the different stages of plastic shrinkage cracking. Measurements of capillary pressure, settlement, internal temperature and evaporation rate were also made. The results show the effectiveness of SRAs in reducing plastic shrinkage cracking, even in high strength concrete. This is attributed to the reduction in the evaporation rate, delay of the peak capillary pressure due to the development of menisci in the pores and lower settlement. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000052 [article] Influence of shrinkage-reducing admixtures on the reduction of plastic shrinkage cracking in concrete [texte imprimé] / José Mora-Ruacho, Auteur ; Gettu, Ravindra, Auteur ; Antonio Aguado, Auteur . - 2009 . - pp. 141–146. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 3 (Mars 2009) . - pp. 141–146 Mots-clés : Drying;  Fresh  concrete;  Durability;  Shrinkage;  Admixtures Résumé : Fresh concrete exposed to high evaporation rates is prone to plastic shrinkage cracking, especially in structures with large surface area/volume ratios. The present work shows that the reduction of the surface tension of the mixing water is an effective way for decreasing such cracking. In this study, conventional and high strength concretes with superplasticizers and shrinkage reducing admixtures (SRAs) were exposed to drying in the plastic state. Continuous monitoring of the surface displacement facilitated the identification of the different stages of plastic shrinkage cracking. Measurements of capillary pressure, settlement, internal temperature and evaporation rate were also made. The results show the effectiveness of SRAs in reducing plastic shrinkage cracking, even in high strength concrete. This is attributed to the reduction in the evaporation rate, delay of the peak capillary pressure due to the development of menisci in the pores and lower settlement. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609000052