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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Measuring the water absorption of recycled aggregates, what is the best practice for concrete production?

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Author(s):
Quattrone, M. ; Cazacliu, B. ; Angulo, S. C. ; Hamard, E. ; Cothenet, A.
Total Authors: 5
Document type: Journal article
Source: CONSTRUCTION AND BUILDING MATERIALS; v. 123, p. 690-703, OCT 1 2016.
Web of Science Citations: 14
Abstract

In this paper, we compare different methods for determining the water absorption of recycled aggregates (RAs) and, highlighting advantages and critical points, attempt to suggest alternatives for a better way to measure it. Water absorption (WA) capacity has two purposes: (a) measuring the interconnected porosity, which is useful for mechanical concrete analysis and durability issues, and (b) allowing adjustment of the amount of water used in concrete production. Our analysis shows that vacuum during soaking is recommended for the RAs' interconnected porosity determination. This approach enables shorter testing time (from >= 24 h to <= 1 h) and increases the accuracy of the measurement. The saturated surface dry (SSD) state determination can also be fastened using centrifuge, air flow drum, laser scattering, and microwave drying evaporometry, without significant differences. The use of these techniques is still restricted due to such factors as commercial availability, geometric limitations of the sample containers, and difficulty in controlling the temperature and the relative humidity. For concrete production, WA kinetics during the first 30 min is fundamental. Accuracy of the results is arguable regarding the practical issues, for example, vibration or trapped air bubble. Mathematical artefacts can overcome those problems but need to he calibrated with experimental data determined by standard tests over time. Because the WA kinetics probably changes when RAs are in contact with cement paste, a method to understand and quantify this phenomenon is still a research demand. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 12/15195-9 - Improving of recycled mixed CDW aggregates performance by means of thermal and coating treatments
Grantee:Marco Quattrone
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 12/25496-6 - Strategies for eco-efficient dry-concrete formulation with recycled aggregates
Grantee:Sérgio Cirelli Angulo
Support type: Regular Research Grants