DURABILITY OF RECYCLED AGGREGATE CONCRETE COATED IN THE FRACTION OF 5-9 MM

Author(s): Sandra Lichtblau, José Fernando Martirena Hernández, Stefan Linsel
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: 357-365
Total Pages: 09
Language : English

Abstract: This paper presents the first results of a long-time study on the durability behaviour of
concrete specimens produced with 100% of recycled concrete aggregate. The problem of the
higher porosity of the recycled aggregate is minimized by coating the intermediate fraction
from 5-9 mm with a thin cement layer, which reduces the water absorption of the material.
The comparison is made with natural aggregate concrete (NAC) with the same w/c ratio. The
compressive strength of the RAC reached 30 MPa and is only 6% less than that for natural
concrete. Samples of each concrete are exposed to three sites of different aggressiveness
depending on the distance to the sea, which involves for one site wet-dry cycles by tides or
changes in the relative humidity and the chloride content of the ambience. After 5 months of
exposure following tests were realized; air permeability, electrical resistivity, carbonation
depth, water absorption by capillarity and rapid chloride permeability test. The progress of
carbonation is lower in RAC. However, remaining tests show better results for NAC with 4
times higher chloride and 3 times higher electrical resistance. Also, the porosity is nearly 50%
and air permeability between 22% to 68% lower than for RAC.

Online publication : 2018
Publication type : full_text
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