HIGH QUALITY RECYCLED CONCRETE AGGREGATES IN UHPC: A PRELIMINARY STUDY

Author(s): Zeger Sierens, Miquel Joseph, Brecht Vandevyvere, Jiabin Li
Paper category: Proceedings
Book title: IV International Conference Progress of Recycling in the Built Environment
Editor(s): Isabel M. Martins, Carina Ulsen, Yury Villagran
ISBN:
e-ISBN: Isabel M. Martins, Carina Ulsen, Yury Villagran
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 366-373
Total Pages: 08
Language : English

Abstract: Mainly, due to the poor mechanical properties of recycled aggregates, they are used in low
valued applications. However, innovative techniques can improve the quality of recycled
aggregates so they can be used in high valued applications. In this paper, high quality recycled
concrete aggregates are mixed with steel fibres in UHPC concrete. The compressive strength,
flexural tensile strength and elastic modulus are examined on two mix designs: a natural
aggregate mixture and a mixture where the natural aggregates are replaced with recycled
concrete aggregates of the same fraction (4-8mm). Due to the angular shape of recycled
concrete aggregates, the water absorption is compensated in order to obtain the same
workability as with natural coarse aggregates (50%, 75% and 100%). Results show that the
consistency of UHPC with 50% of water absorption compensation, has the same consistency
of UHPC with natural coarse aggregates. Moreover, the compressive strength decreases more
when the water absorption is compensated more. Results indicate that the compressive
strength does not decrease more when more than 75% of the water absorption is compensated.
The results of the flexural tests and elastic modulus tests show the same tendency.

Online publication : 2018
Publication type : full_text
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