Value-added recycling of waste concrete fines into alternative aggregates for river sand conservation

Renjie Zhou, Yunjie Luo, Mingfang Ba, Zihua Zhang, Jianghua Fang, Chi Sun Poon, Xiaoliang Fang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Due to the depletion of river sand, the construction industry is eager to develop upcycling techniques for transforming secondary by-products derived from construction and demolition (C&D) waste into quality fine aggregates. This paper presents a study of replacing river sand with enhanced recycled fine aggregate through a wet carbonation process developed by the authors previously. The fine recycled concrete aggregate (FRCA) ranging from 0.15 to 5 mm was prepared by demolishing a concrete with a known mixture design. After wet carbonation, the particle size, water absorption, and density of the FRCA were tested and compared with the original samples. The chemical characteristics of the original and carbonated FRCA (C-FRCA) were analyzed by a series of experiments. The results showed that (1) an increase of carbonation products and a significant reduction of hydration products; (2) microscopic observation of the C-FRCA showed a surface layer densified by calcite after wet carbonation; and (3) no significant strength loss were observed when replacing up to 50% river sand by C-FRCA in mortar specimens. The potential environmental and economic impacts were also analyzed.

Original languageEnglish
Article number102802
JournalJournal of CO2 Utilization
Volume83
DOIs
Publication statusPublished - May 2024

Keywords

  • Chemical treatment
  • Fine recycled concrete aggregate
  • Low-carbon construction materials
  • Waste upcycling
  • Wet carbonation

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Waste Management and Disposal
  • Process Chemistry and Technology

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