Penetração de cloretos em concretos compostos com diferentes teores de cinza de casca de arroz

• Ano de defesa: 2004
• Autor(a) principal: Missau, Fabiano
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; BR; Engenharia Civil; UFSM; Programa de Pós-Graduação em Engenharia Civil
• Palavras-chave em Português: Engenharia civil; Concreto; Cinza de casca de arroz; Materiais de construcao; Cloreto; Estrutura de concreto; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
• Link de acesso: http://repositorio.ufsm.br/handle/1/7674

The service life of concrete structures can be extended by controlling aggressive agents often found in the environment that attack concrete. Such agents may cause structures to deteriorate and result in technical losses (physical damage) and financial losses (repair costs). Chloride ions are among the most aggressive agents that attack concrete structures, causing steel bar corrosion. Several research studies have been performed to develop a concrete composition that would lend optimal chloride ion protection. The present study investigated the chloride resistance behavior of concrete compositions using different contents of rice husk ash (RHA). The concrete samples were tested for axial compressive strength, chloride penetration ASTM C 1202 (RCPT), chloride retention, chloride penetration by silver nitrate spray, mercury porosimetry and pore solution composition. Binder mixtures with 10%, 20% and 30% RHA were investigated and compared with the cement-only reference sample. Test results show that higher RHA concentrations yielded a drop in the charge passed, in the concentration of retained chloride, in the mercury intrusion volume, in the critical diameter and in specific electrical conductivity. At the same time, the chloride penetration depth measured by silver nitrate spray increased. This behavior can be attributed to a reduction in chloride retention and a lower concentration of aluminates resulting from the lower cement content used, a factor that has a more significant influence that the changes in pore structure. A strong correlation was observed between chloride penetration and compressive strength, the concentration of retained chloride, the mercury intrusion volume, the critical diameter and the specific electrical conductivity.