Abstract:
The awareness of environmental problems, caused by CO2 emissions, have led the scientific community
to seek more sustainable solutions, from both environmental and economical perspectives. Regarding
concrete, this goal can be reached through the use of low binder concrete (LBC), consisting of partially
replacing Portland cement by additions and increasing the packing density.
This paper presents a research conducted to analyse the viability of using LBC in reinforced concrete
(RC) structures, namely by studying the bond behaviour between LBC and reinforcing bars (rebars).
With this aim, an experimental program including monotonic pull-out tests to assess the influence of
concrete’s packing density {0,82; 0,84; 0,86} and the influence of aggregates’ optimization distribution
(Alfred and Faury curves) was planned. In addition, concrete’s compressive and tensile strength tests
and rebars’ rib measurement and rebars’ tensile strength tests were carried out to characterize the
materials’ properties.
The following main conclusions were drawn: (1) LBC’s packing density has a positive effect on the
bond behaviour at both service and ultimate limit states, (2) the aggregates should be smaller than the
rebars’ ribs spacing, (3) the design expression of fib Model Code 2010 for bond stress between rebars
and concrete does not give accurate values when LBC is adopted, and (4) the compressive strength of
LBC is mainly due to the high packing density of the mixture, corroborating previous studies.