<p>Construction and demolition (C&D) waste poses significant environmental challenges due to its large volume. Improper disposal of C&D waste can lead to adverse environmental impacts such as leachate generation and soil, and groundwater contamination. To address these issues, researchers have continually explored various methods to recycle C&D waste and reduce landfill burden. One such approach involves separating concrete from C&D waste, crushing it finely, and converting it into fine aggregate or powder, commonly referred to as recycled concrete powder (RCP). Although these recycled aggregates are weaker than natural aggregates, they can be effectively used in applications where lower strength is acceptable. In this study, foamed concrete (FC) was developed by replacing the filler material with RCP at 10%, 20%, and 30% replacement levels using the mixed foam method. The effect of RCP incorporation on air content, fresh density, consistency, and stability was systematically evaluated, along with hardened-state properties including compressive strength, flexural strength, water absorption, and thermal conductivity. Results show that 10% RCP replacement achieves the lowest demoulded density of 664 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\mathrm{kg/m}^{3}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mi mathvariant="normal">kg</mi> <mo stretchy="false">/</mo> <mi mathvariant="normal">m</mi> </mrow> <mn>3</mn> </msup> </math></EquationSource> </InlineEquation> and thermal conductivity of 0.2532 Wm<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>K<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>. Notably, the stability of the FC mixture is enhanced at 10% replacement due to improved particle packing among the constituents.</p> Graphical abstract <p></p>

Effect of recycled concrete powder on air content in foam concrete produced using mixed foam method

期刊论文
发表日期：

2026年7月31日

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Amit Kumar Sahu,
Rahul Kumar Sonker,
Vishal Kumar Mishra,
Indu Siva Ranjani Gandhi,
Prakash Nanthagopalan

摘要

Construction and demolition (C&D) waste poses significant environmental challenges due to its large volume. Improper disposal of C&D waste can lead to adverse environmental impacts such as leachate generation and soil, and groundwater contamination. To address these issues, researchers have continually explored various methods to recycle C&D waste and reduce landfill burden. One such approach involves separating concrete from C&D waste, crushing it finely, and converting it into fine aggregate or powder, commonly referred to as recycled concrete powder (RCP). Although these recycled aggregates are weaker than natural aggregates, they can be effectively used in applications where lower strength is acceptable. In this study, foamed concrete (FC) was developed by replacing the filler material with RCP at 10%, 20%, and 30% replacement levels using the mixed foam method. The effect of RCP incorporation on air content, fresh density, consistency, and stability was systematically evaluated, along with hardened-state properties including compressive strength, flexural strength, water absorption, and thermal conductivity. Results show that 10% RCP replacement achieves the lowest demoulded density of 664 $\mathrm{kg/m}^{3}$ ${kg / m}^{3}$ and thermal conductivity of 0.2532 Wm $^{-1}$ $^{- 1}$ K $^{-1}$ $^{- 1}$ . Notably, the stability of the FC mixture is enhanced at 10% replacement due to improved particle packing among the constituents.

Graphical abstract