Improving recycled aggregate quality by mechanical pre-processing
2020 (English)In: Materials, E-ISSN 1996-1944, Vol. 13, no 19, article id 4342Article in journal (Refereed) Published
Abstract [en]
Concrete with crushed concrete aggregates (CCA) shows lesser compressive strength than reference concrete with natural aggregates. The goal of this study is to improve the strength of structural concrete with 53% and 100% CCA replacements without increasing the cement content. Thus, improvements in CCA quality are induced by combining mechanical and pre-soaking pre-processing techniques. Mechanical pre-processing by rotating drum is separately pursued on fine and coarse CCA for 10 and 15 min respectively. Results show, adhered mortar content and CCA water absorption reduces as pre-processing duration increases. Pre-processing influences CCA particle grading, flakiness index, shape index, void-content, unit-weight and density, jointly seen as packing density, which increases with pre-processing duration. Water amount to pre-soak CCA before concrete mixing is stable despite grading modifications, due to reduced water absorption resulting from mechanical pre-processing. Compressive strength and workability for pre-processed CCA50 and CCA100 concrete are comparable to reference concrete and show similar trends of improvement with packing density. Packing density markedly shows the quality improvements induced by pre-processing on CCA, maybe considered as one of the quality assessment indexes for CCA. Packing density should be investigated for other recipes to see the stability of the trend with workability and compressive strength. © 2020 by the authors.
Place, publisher, year, edition, pages
MDPI AG , 2020. Vol. 13, no 19, article id 4342
Keywords [en]
Aggregate quality, Aggregate shape, Compressive strength, Concrete recycling, Mechanical pre-processing, Packing density, Recycled aggregates, Sustainability, Workability, Aggregates, Concrete mixing, Concrete mixtures, Grading, Water absorption, Compressive strength and workability, Flakiness index, Natural aggregate, Particle grading, Quality assessment, Quality improvement, Structural concretes, Concrete aggregates
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-50360DOI: 10.3390/ma13194342Scopus ID: 2-s2.0-85093938328OAI: oai:DiVA.org:ri-50360DiVA, id: diva2:1498739
Note
Funding text 1: Funding: This study is a part of a Swedish research project RE: Concrete financed by Gunnar Ivarson’s foundation, project Doktorand Byggavfall.
2020-11-052020-11-052024-07-04Bibliographically approved