Atividade pozolânica da sílica ativa: análise em pastas cimentícias com diferentes teores de substituição

Materia

article

Marcella Amaral¹  Gustavo Macioski¹  Marcelo Henrique Farias de Medeiros¹ 

[1] Universidade Federal do Paraná

关键词: Supplementary Cementitious Materials;    Silica Fume;    Chapelle modified test;    Pozzolanic activity;    Portlandite;   

DOI  :  10.1590/S1517-707620210003.13023

学科分类：工程和技术（综合）

来源: Universidade Federal do Rio de Janeiro * Coordenacao dos Programas de Pos-Graduacao de Engenharia

【 摘 要 】

The use of supplementary cementitious materials with a pozzolanic character, such as silica fume, has been widely studied in order to consolidate its mechanical efficiency and increase in the durability of concretes and mortars. The present paper aims to investigate the chemical effect of silica fume by quantifying the effective reactivity of silica fume incorporated in cementitious pastes with a water/binder ratio of 0.58, considering the partial replacement of cement in 5, 10, 15 e 20%. Over 105 days of hydration, the remaining portlandite content was quantified through a simplified gravimetric loss, which was performed in a muffle furnace. After the analysis period, it was possible to identify that the modified Chapelle test, indicated by NBR 15895 (2010), does not effectively represent the pozzolanic activity of silica fume in cementitious composites, since there were many agglomerations of anhydrous material. Moreover, there is less ion mobility in the hardened porous composite than in an aqueous solution, requiring a study of the composition of the hardened binder to quantify the effective pozzolanic activity if the silica fume used as supplementary cementitious material.

【 授权许可】

CC BY