RECYCLED FINE AGGREGATE IN NEW CONCRETE

Author(s): A. Katz, D. Kulisch
Book Title: III Progress of Recycling in the Built Environment
Editor: I. Martins, C. Ulsen and S. C. Angulo
e-ISBN: 978-2-35158-158-2
Publisher: RILEM Publications SARL
Publication year: 2015
Pages: 124-131
Total Pages: 8
Language: English

Abstract: The quantities of construction and demolition waste (C&DW) are getting larger and larger nowadays as the construction market increases in the modern world. Many studies have proved the possibility of incorporating the coarse fraction of the waste obtained after sorting, crushing and treating. Replacing 10-20% of the virgin coarse aggregate by coarse recycled aggregate is acceptable in many standards without damaging the properties of the new concrete, or with minor effect that can easily be corrected with slight increase of the cement content. As for the fine fraction of C&DW, there is a wide consensus that its effect on the properties of new concrete is more significant and the risk of damaging the properties of the new concrete is high. The study presented here examines the effect of replacing recycled fine aggregate (RFA) on the properties of new concrete. Aggregate was obtained from two regional recycling facilities thus they represent mixed and non-uniform waste. The results showed that the recycled fine aggregates are more porous and weaker compared to natural aggregate obtained by crushing natural stone. It also may contain some impurities that affect the hydration of the new concrete. When all the fine aggregate was replaced, the compressive strength has reduced by 34%-53% in concrete having low water to cement ratio (w/c=0.40) and by 19%-53% for higher w/c of 0.60. When only 30% of the aggregates were replaced by RFA the reduction was 3%-29% for w/c=0.40 and 9%-29% for w/c=0.6. Other properties also showed inferior results compared with the reference concrete prepared with virgin aggregates.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00