Influence of normal stress and reinforcement ratio on the behavior of LWAC interfaces

Autor: Hugo Costa, R.N.F. Carmo, Eduardo Júlio
Rok vydání: 2018
Předmět:
Zdroj: Construction and Building Materials. 192:317-329
ISSN: 0950-0618
DOI: 10.1016/j.conbuildmat.2018.10.116
Popis: This experimental study aims to characterize the behavior of LWAC-to-NWC interfaces, using a substrate of normal weight concrete (NWC) with different surface roughness and three lightweight aggregate concrete (LWAC) mixtures for the overlay, with a density ranging between 1500 and 1900 kg/m3 and a compressive strength varying between 45 and 75 MPa. The NWC-to-NWC interfaces were also tested to be used as reference, only one NWC with a compressive strength of 50 MPa was used. Two more parameters were considered in this study, the normal stress applied at the interface and the reinforcement ratio crossing the interface. Results were analyzed and compared with predictions according to Eurocode 2, fib Model Code 2010 and ACI 318-14, showing significant differences, mainly when LWAC is added, proving that the binding matrix strength is an important parameter in this analysis and that the cohesion component is underestimated by codes. It was also concluded that the incorporation of the lightweight aggregates decreases the interface strength and the rebars did not have a clear increase in the maximum shear strength, contrary to predictions of some codes. Expressions based on the roughness parameter are presented to predict the coefficients of cohesion and friction.
Databáze: OpenAIRE
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