WATER ABSORPTION OF CRUSHED CONCRETE AGGREGATES BY THE MODIFIED PYCNOMETER METHOD

Author(s): Madumita Sadagopan, Katarina Malaga, Agnes Nagy
Paper Category: proceedings
Book Title: Proceedings of the International Conference on Sustainable Materials,
Systems and Structures (SMSS2019)
Editor(s): Ivana Carević Stjepan Lakušić Dirk Schlicke
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication Year: 2019
Pages: 40 - 41
Total Pages: 2
Language: English

Abstract: Crushed Concrete Aggregates (CCA) as fine and coarse aggregates in new concrete demands
the knowledge of the water absorbed by the CCA to ensure fulfilment of the workability
requirements and mechanical performance of the concrete. Sedimentation and air entrapment
are the practical challenges encountered while performing the water absorption of fine CCA
using the EN 1097-6 standard method. Additionally, Saturated Surface Dry (SSD) state
assessment seems operator specific and non-reproducible. Contrary to the standard 24 hour
water absorption values, findings from this paper show results at 15 minutes are influential for
concrete workability. The modified pycnometer method measures the water absorbed by the
combined CCA fraction consisting of coarse and fine CCA as proportioned in the concrete
recipe. Sedimentation and air entrapment is prevented by the use of a dispersant solution
produced using superplasticizer. Ultimately, the combined CCA is drained to SSD condition by
vacuum filtration, which is easy to handle by professional operators. Therefore the appropriate
water amount to saturate the CCA is determined from the water absorption development of the
combined fraction CCA from starting point to 24 hours.

Online Publication: 2019
Publication Type: full text
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