Abstract:
Aiming at reducing the environmental impact of structural concrete, the authors conducted a study to
analyse the viability of using low binder concrete (LBC) in reinforced concrete (RC) structures. The
study focused on the bond behaviour between LBC and the reinforcing bars (rebars) and is presented in
a companion paper. Afterwards, with the goal of further improving the eco-efficiency of LBC, the
authors studied the possibility of partially replacing natural aggregates by recycled aggregates from
construction and demolition waste (CDW), giving rise to what they called a low cement recycled
aggregate concrete (LCRAC).
This paper presents a research study conducted to analyse the viability of using LCRAC in RC
structures, namely by studying the bond behaviour between LCRAC and reinforcing bars. Similarly to
the first study, an experimental program including monotonic pull-out tests was set, this time with the
aim of assessing the influence of replacing natural aggregates by recycled aggregates from CDW on the
bond behaviour between LCRAC and rebars. Additionally, concrete’s compressive and tensile strength
tests and rebars’ rib measurement and rebars’ tensile strength tests were also carried out to characterize
the materials’ properties.
The following main conclusions were drawn: (1) recycled aggregates appear to have a negligible
effect on bond behaviour, (2) nevertheless, contrary to natural aggregates, the size of recycled aggregates
should be larger than the rebars’ ribs spacing, and (3) this study corroborated the conclusion that packing
density improves concrete-to-rebar bond behaviour.