Contribuição ao estudo dos métodos de ensaio na avaliação das reações álcali-agregado em concretos. / Contribution to the study of test methods in assessing alkali-aggregate reactions in concrete.
AUTOR(ES)
Leandro Francisco Moretti Sanchez
DATA DE PUBLICAÇÃO
2008
RESUMO
Many concrete structures have been suffering from alkali-aggregate reactions (AAR) since the last decades in Brazil and around the world. The reactions generate expansions that could compromise the strength of a concrete structure as well as its performance in service and its durability. Nowadays, it is completely possible to detect AAR in the field, but repair and reinforce a damaged structure is difficult, very expensive and in most cases inefficient or partial. There is no consensus in the market on how to repair and reinforce damaged structures. However, there is a consensus that the best way to face the problem is the prevention. This work studies the main test methods used to analyze aggregates and the combinations cement/aggregates in the laboratory and finally comparing them. In this work six Brazilian aggregates with four different lithologies (two granites, two basalts, one granite-gneiss and one quartzite) were used. Among the test methods studied were AMBT (accelerated mortar bar test), CPT (concrete prism test), ACPT (accelerated concrete prism test), ACPST (accelerated concrete prism soaked test) and petrographic analysis. Beyond the comparison among used tests, this work presents the attempt to develop a new accelerated test method. The test was called ABCPT (accelerated Brazilian concrete prism test), and it was developed with the aim of being as reliable as CPT and as fast as the ACPST. The results show that all concrete test methods (CPT, ACPT, ACPST and ABCPT) have good correlation among them, and anyone can be used to classify and analyze aggregates in the laboratory. On the other hand, the AMBT test method has showed different classifications for the same aggregates when compared to the concrete test methods and petrographic analysis. Therefore, its parameters need to be rethought and improved.
ASSUNTO(S)
ambt (método acelerado de barras de argamassa) cpt (método dos prismas de concreto) ambt (accelerated mortar bar test) métodos de ensaio alkali-aggregate reaction reação álcali-agregado test methods cpt (concrete prism test)
Documentos Relacionados
- Estudo de tratamentos com lítio no combate da reação álcali-agregado
- Estudo de tratamentos com lítio no combate da reação álcali-agregado
- Reação álcali-agregado nas usinas hidrelétricas do Complexo Paulo Afonso/CHESF: influência da reação nas propriedades do concreto.
- Influência do grau de cristalinidade e deformação do quartzo no desencadeamento da reação álcali-agregado
- Contribuição ao estudo do efeito da incorporação de cinza de casca de arroz em concretos submetidos à reação álcali-agregado