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INFLUENCE OF TOTAL AND EFFECTIVE WATER-CEMENT RATIO ON COMPRESSIVE STRENGTH OF CONCRETES MADE WITH FINE RECYCLED CONCRETE AGGREGATES



Author(s): María E. Sosa, Yury A. Villagrán Zaccardi, Claudio J. Zega, Ángel A. Di Maio
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: 390-397
Total Pages:
Language : English


Abstract: Cement paste contained in fine recycled concrete aggregates (FRCA) makes a major
difference in comparison with fine natural aggregates (FNA). Because of this, FRCA
generally shows lower density and higher absorption than FNA. These differences have been
considered as detrimental for concrete properties such as slump loss, compressive strength,
drying shrinkage and elastic modulus of elasticity. However, different researchers report
opposite results regarding the influence of FRCA on c oncrete performance. Some of them
conclude that replacements of FNA by FRCA cause a minor impact on concrete properties;
while others suggest that the use of FRCA is technically inconvenient. These contradictory
results could be not only as a consequence of different FRCA origins but also as a result of
the way in which FRCA water absorption is considered. It is a common practice to add an
amount corresponding with the FRCA absorption capacity to the mixing water. However, if
this additional water is not fully uptaken by the aggregate, it could exert a detrimental
influence on hardened properties of concrete.
This work presents an assessment of the relationship between the total and effective
water/cement ratios with the compressive strength of concrete made with FRCA. Less
correlation is generally obtained when mixing water is corrected for the assumed water uptake
by the aggregate. The results suggest that the estimations of effective w/c based on current
test methods for the determination of the water absorption are not reliable enough.


Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00


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