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Comparison of two processes for treating rice husk ash for use in high performance concrete / Andres Salas in Cement and concrete research, Vol. 39 N° 9 (Septembre 2009) 

Public ISBD [article]  in Cement and concrete research > Vol. 39 N° 9 (Septembre 2009) . - pp. 773–778 Titre : Comparison of two processes for treating rice husk ash for use in high performance concrete Type de document : texte imprimé Auteurs : Andres Salas, Auteur ; Silvio Delvasto, Auteur Année de publication : 2009 Article en page(s) : pp. 773–778 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Durability;  Mechanical  properties;  Pozzolan;  Silica  fume;  High  performance  concrete Résumé : Rice husk ashes (RHA) have been used as pozzolanic admixtures for high performance concrete (HPC). This study reports on a chemical treatment before burning that improves the effectiveness of the RHA. The resulting ash (ChRHA) was compared to ash produced by conventional incineration (TRHA). The digestive chemical treatment before burning produced an RHA with properties comparable to silica fume. The ChRHA was highly amorphous, white in color, presented higher specific surface area and exhibited greater pozzolanic activity. The fresh and hardened properties of HPC made with different percentages of these RHAs were compared. The hardened concrete testing included the determination of the modulus of elasticity and the compressive and flexural properties. It was shown that ChRHA and TRHA were effective supplementary cementing materials, although concrete mixes required higher dosages of superplasticizer compared to the control concrete mix. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001094 [article] Comparison of two processes for treating rice husk ash for use in high performance concrete [texte imprimé] / Andres Salas, Auteur ; Silvio Delvasto, Auteur . - 2009 . - pp. 773–778. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 9 (Septembre 2009) . - pp. 773–778 Mots-clés : Durability;  Mechanical  properties;  Pozzolan;  Silica  fume;  High  performance  concrete Résumé : Rice husk ashes (RHA) have been used as pozzolanic admixtures for high performance concrete (HPC). This study reports on a chemical treatment before burning that improves the effectiveness of the RHA. The resulting ash (ChRHA) was compared to ash produced by conventional incineration (TRHA). The digestive chemical treatment before burning produced an RHA with properties comparable to silica fume. The ChRHA was highly amorphous, white in color, presented higher specific surface area and exhibited greater pozzolanic activity. The fresh and hardened properties of HPC made with different percentages of these RHAs were compared. The hardened concrete testing included the determination of the modulus of elasticity and the compressive and flexural properties. It was shown that ChRHA and TRHA were effective supplementary cementing materials, although concrete mixes required higher dosages of superplasticizer compared to the control concrete mix. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884609001094