Conjugated action of rice husk ash and calcium hydroxide in Portland cement composites: porosity, hydrated compounds, alkaline reserve and compressive strength

Materia

article

Pamela Albino Campos¹  Marcelo Henrique Farias de Medeiros¹  Juarez Hoppe Filho² 

[1] UniversidadeFederal do Paraná;UniversidadeFederal do Oeste da Bahia

关键词: Rice husk ash;    Alkaline reserve;    Pozzolanic activity;   

DOI  :  10.1590/1517-7076-RMAT-2022-0018

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 】

Rice husk ash (RHA) is a pozzolan with high reactive potential that, when added to cementitious systems, promotes the reduction of the alkaline reserve. Within this context, the incorporation of calcium hydroxide (CH) aims to attenuate the impact on the alkaline reserve caused by the pozzolan. The present study aims to analyze the influence of the joint incorporation of SCA and CH (in different contents) in cementitious systems, under the physical-chemical and mechanical aspects. The results indicated that SCA in partial replacement of cement causes a delay in the gain in compressive strength, but is not harmful at older ages. It was also verified that SCA tends to increase the apparent porosity of the system. In general, the presence of SCA resulted in a reduction in the content of hydrates formed. The alkaline reserve was reestablished when the levels of SCA and CH were equal. The increase in alkaline availability increased the CH content fixed by the pozzolanic activity of SCA. The proportion of 10% SCA and 15% CH was the combination that best explored the reactive potential of the pozzolan, in addition to being able to maintain the porosity and alkaline reserve similar to the reference sample.

【 授权许可】

CC BY