Variabilidade da aderência e das propriedades mecânicas do concreto auto-adensável

Abstract

ResumoThis main objective of this research is to evaluate the variability of the mechanical properties (compressive strength, modulus of elasticity and tensile strength) and bond strength of the self-compacting concrete (SCC), with 50 MPa compressive strength at 28 days, varying the maximum aggregate size and the SCC fluidity. The tests were made in 15 x 30 cm concrete cylinders and in beams standardized by Rilem-Ceb-Fib (1973). In agreement with the obtained results, can be concluded that the variability of the self-compacting concrete is small for the modulus of elasticity and for the compressive strength, but the tensile strength presented a significant variability due to the failure mode. About the bond strength, the variability was small showing that the self-compacting concrete is reliable and possesses great potential for use in the civil construction. Keywords: Self-compacting concrete, variability, hardened state, steel-concrete bond, beams, statistical analysis.Esta pesquisa tem como objetivo estudar a variabilidade das propriedades mecânicas (resistência à compressão, módulo de elasticidade longitudinal e resistência à tração) e da resistência de aderência do concreto auto-adensável (CAA), com resistência à compressão do concreto de 50 MPa aos 28 dias, variando o tamanho máximo do agregado graúdo e sua fluidez. Os ensaios foram realizados em corposde-prova de 15 x 30 cm e em vigas padronizadas de acordo com o Rilem-Ceb-Fib (1973). De acordo com os resultados obtidos, pode-se concluir que a variabilidade do concreto auto-adensável é pequena para o módulo de elasticidade e para a resistência à compressão e grande para a resistência à tração por causa do modo de ruptura do modelo. Com relação à resistência de aderência, a variabilidade foi pequena mostrando que o concreto auto-adensável é material confiável com grande potencial de utilização no mercado da construção civil.Palavras-chave: concreto auto-adensável, variabilidade, estado endurecido, aderência aço-concreto, vigas, análise estatística.

Steel Reinforced Self-Compacting Concrete (SCC) Cantilever Beams: Bond Behaviour in Poor Condition Zones

“…They observed minor spalling between reinforcing steel and concrete under service loading (Wu et al, 2018). Almeida et al (Almeida Filho et al, 2008) studied the mechanical properties (compressive strength, modulus of elasticity and tensile strength) and bond strength of SCC by testing concrete cylinders (150 mm dia. × 300 mm deep) of 50 N/mm 2 compressive strength at 28 days.…”

“…× 300 mm deep) of 50 N/mm 2 compressive strength at 28 days. The studied variables were: (i) maximum aggregate size and (ii) SCC fluidity (concrete of very high workability using superplasticizer) (Almeida Filho et al, 2008). They concluded that the variability of the SCC was small for the modulus of elasticity and for the compressive strength, but the tensile strength presented a significant variability due to the failure mode (Almeida Filho et al, 2008).…”

“…The studied variables were: (i) maximum aggregate size and (ii) SCC fluidity (concrete of very high workability using superplasticizer) (Almeida Filho et al, 2008). They concluded that the variability of the SCC was small for the modulus of elasticity and for the compressive strength, but the tensile strength presented a significant variability due to the failure mode (Almeida Filho et al, 2008). In addition, the variability of the bond strength was small which indicated the reliability of SCC in the civil construction (Almeida Filho et al, 2008).…”