Utilization of Construction and Demolition Waste in Concrete as Cement and Aggregate Substitute: A Comprehensive Study on Microstructure, Performance, and Sustainability

TY - JOUR

T1 - Utilization of Construction and Demolition Waste in Concrete as Cement and Aggregate Substitute

T2 - A Comprehensive Study on Microstructure, Performance, and Sustainability

AU - Mao, Ning

AU - Zheng, Junfeng

AU - Jiang, Jun

AU - Yang, Fengyuan

AU - Ying, Xiaoming

AU - Ge, Peng

AU - Zheng, Li

AU - Lu, Zhongyuan

N1 - Publisher Copyright: © 2025 by the authors.

PY - 2025/11/13

Y1 - 2025/11/13

N2 - Construction and demolition waste (CDW) was successfully utilized as an aggregate with 100% replacement of natural aggregates and mineral admixtures, with up to 60% replacement of ordinary Portland cement (OPC) in the production of recycled concrete. The effects of ratios of concrete-based CDW (concrete-CDW)/brick-based CDW (brick-CDW) in both aggregates and CDW mineral admixture contents in the binder on recycled concrete were investigated in terms of their workability and compressive strength, microstructure, and sustainability. The results showed that with an increase in the ratios of brick-CDW/concrete-CDW aggregates, the concrete workability continuously deteriorated, while the compressive strength firstly increased and then decreased. Compared to the 100% dosage of concrete-CDW aggregates, the 28-day compressive strength of the recycled concrete was 37.4 MPa; the optimized relative proportions of brick-CDW and concrete-CDW aggregates were 20% and 80%, respectively; and the 28-day compressive strength was the highest, reaching to 46.7 MPa, and increasing by 24.9%. In a binder study, the microstructure of the paste was found to be improved, with the dosage of brick-CDW and concrete-CDW admixtures at up to 20%. In this range, the workability changed slightly when the relative proportion of brick-CDW admixture increased, the 28-day compressive strength of the recycled concrete increased, and the pore structure was refined. Furthermore, the utilization of a large amount of CDW as a mineral admixture and aggregate in concrete significantly reduced costs and CO2 emissions in different regions.

AB - Construction and demolition waste (CDW) was successfully utilized as an aggregate with 100% replacement of natural aggregates and mineral admixtures, with up to 60% replacement of ordinary Portland cement (OPC) in the production of recycled concrete. The effects of ratios of concrete-based CDW (concrete-CDW)/brick-based CDW (brick-CDW) in both aggregates and CDW mineral admixture contents in the binder on recycled concrete were investigated in terms of their workability and compressive strength, microstructure, and sustainability. The results showed that with an increase in the ratios of brick-CDW/concrete-CDW aggregates, the concrete workability continuously deteriorated, while the compressive strength firstly increased and then decreased. Compared to the 100% dosage of concrete-CDW aggregates, the 28-day compressive strength of the recycled concrete was 37.4 MPa; the optimized relative proportions of brick-CDW and concrete-CDW aggregates were 20% and 80%, respectively; and the 28-day compressive strength was the highest, reaching to 46.7 MPa, and increasing by 24.9%. In a binder study, the microstructure of the paste was found to be improved, with the dosage of brick-CDW and concrete-CDW admixtures at up to 20%. In this range, the workability changed slightly when the relative proportion of brick-CDW admixture increased, the 28-day compressive strength of the recycled concrete increased, and the pore structure was refined. Furthermore, the utilization of a large amount of CDW as a mineral admixture and aggregate in concrete significantly reduced costs and CO2 emissions in different regions.

KW - construction and demolition waste

KW - hardened performance

KW - microstructure

KW - recycled concrete

KW - sustainability

UR - https://www.scopus.com/pages/publications/105023054614

U2 - 10.3390/su172210135

DO - 10.3390/su172210135

M3 - Article

AN - SCOPUS:105023054614

SN - 2071-1050

VL - 17

JO - Sustainability (Switzerland)

JF - Sustainability (Switzerland)

IS - 22

M1 - 10135

ER -