Mechanical properties and microstructure of high performance concrete containing stabilized nano-silica

Materia

França, Fabrício Carlos¹  Quinõnes, Alberto Delgado²  Abreu, Gustavo Braz de³  Gumieri, Adriana Guerra³  Costa, Suéllen Mota Marques³  Calixto, José Márcio Fonseca³  Silva, Cláudio⁴ 

[1] Holcim, Pedro Leopoldo, Brasil;Tecnosil/Silicon, Itupeva, Brasil;Universidade Federal de Minas Gerais, Belo Horizonte, Brasil;Wanmix, Lagoa Santa, Brasil

关键词: Nano-silica;    high performance concrete;    compressive strength;    secant modulus of elasticity;    microstructure.;   

DOI  :  10.1590/s1517-707620170002.0156

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 】

Nanotechnology can significantly improve the mechanical strength and durability of concrete. At the nanoscale, good dispersion of constituent materials is an essential factor for the improvement of concrete properties. In this scenario, the objective of this research was to evaluate the mechanical properties of high performance concrete containing stabilized nano-silica. The incorporation of nano-silica to the polycarboxylate chemical admixture allowed its application in concrete, since the nano-silica was evenly dispersed in the concrete mass. For this study, three different concretes were employed: a reference concrete, one containing stabilized nano-silica and another containing a mixture of silica fume and stabilized nano-silica. The evaluated concrete mechanical properties were the axial compressive strength and secant modulus of elasticity measured in three different ages. The results indicated a substantial increase in concrete compressive strength and modulus of elasticity with the addition of stabilized nano-silica combined with a reduction in cement content. The results also showed that use of stabilized nano-silica proved to be very advantageous, especially when mixed with silica fume. When they were combined, a synergy effect occurred in the concrete that was of chemical nature in addition to the physical effect of better concrete particle packaging. Analysis by scanning electron microscopy showed the improvement in microstructure of concretes with stabilized nano-silica, which contributed to gains in mechanical properties.

【 授权许可】

CC BY