Feasible use of recycled concrete aggregates and crushed clay brick as unbound road sub-base

Chi Sun Poon, Dixon Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

351 Citations (Scopus)

Abstract

A study was recently conducted at the Hong Kong Polytechnic University to investigate the possibility of using recycled concrete aggregates and crushed clay brick as aggregates in unbound subbase materials. The results showed that the use of 100% recycled concrete aggregates increased the optimum moisture content and decreased the maximum dry density of the subbase materials compared to those of natural subbase materials. Moreover, the replacement of recycled concrete aggregates by crushed clay brick further increased the optimum moisture content and decreased the maximum dry density. This was mainly attributed to the lower particle density and higher water absorption of crushed clay brick compared to those of recycled concrete aggregates. The CBR values (unsoaked and soaked) of the subbase materials prepared with 100% recycled concrete aggregates were lower than those of natural subbase materials. The CBR values further decreased as the replacement level of recycled concrete aggregates by crushed clay brick increased. Nevertheless, the soaked CBR values for all recycled subbases were greater than 30%, which is a minimum strength requirement in Hong Kong. Furthermore, the recorded percentage swells for all subbases were less than 0.13% which can be considered negligible.
Original languageEnglish
Pages (from-to)578-585
Number of pages8
JournalConstruction and Building Materials
Volume20
Issue number8
DOIs
Publication statusPublished - 1 Oct 2006

Keywords

  • Construction and demolition waste
  • Crushed clay brick
  • Recycled concrete aggregates
  • Subbase

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Materials Science(all)

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