Multi-level chemical characterization of dutch fine recycled concrete aggregates: a comparative study

Marija Nedeljković, Jeanette Visser, Timo G. Nijland, Siska Valcke, E. Schlangen

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

In the Netherlands, beside cement replacement with more green cement types, there is also an urgent need for alternative materials for natural sand in new concrete in order to make it circular. Furthermore, the recyclers have raised questions regarding upscaling and the potential of fine recycled concrete aggregates (fRCA) in structural concrete elements since the availability of recycled construction rubble is increasing. The variations in their chemical and physical properties and lack of standards for their quality evaluation is the main reason for not yet using fRCA in new concrete. In this paper, an in-depth characterization of different fRCA is performed in order to define their chemical properties. The properties can be eventually related to concrete mix design and performance (next step), so that fRCA can be classified as a material that can be used in more advanced applications. This is achieved with a multi-level chemical characterization of individual and total fractions (0-0.25 mm, 0.25-4 mm and 0-4 mm) for finding type and content of the original sand and cement phases and potential contamination of selected fractions. The tests include quantification of element composition with X-ray fluorescence (XRF), qualitative and quantitative phase analysis with X-ray diffraction (XRD) and Rietveld method. In addition, cement paste content, chlorides and sulfates of each type of fRCA was measured in order to evaluate contamination of studied material. It was shown that fRCA from different origins have similar chemical and mineralogical composition and contain comparative chloride content. The chemical composition testing can provide a first line control regarding composition and potential contamination of fRCA. After that, it can be decided which additional tests are necessary to be done in order to evaluate the suitability of fRCA for replacement of primary natural fine aggregates in new concrete.
Original languageEnglish
Title of host publication4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites
Subtitle of host publicationMicrodurability 2020
EditorsGuang Ye, Hua Dong, Jiaping Liu, Erik Schlangen, Changwen Miao
PublisherDelft University of Technology
Pages104-112
Number of pages9
ISBN (Electronic)978-94-6366-422-6
Publication statusPublished - 2021
Event4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites - Online, Delft, Netherlands
Duration: 29 Apr 202127 May 2021
Conference number: 4
https://www.microdurability2020.com/99721

Conference

Conference4th International Rilem Conference on Microstructure Related Durability of Cementitious Composites
Abbreviated titleMicrodurability
CountryNetherlands
CityDelft
Period29/04/2127/05/21
Internet address

Keywords

  • Fine recycled concrete aggregates
  • phases
  • contamination
  • XRF

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