Work

Mitigating the efflorescence of alkali-activated slag mortars by aluminosilicate-based lightweight fine aggregate

Year: 2025

Type: article

Abstract: Efflorescence is a significant aesthetic and structural issue for alkali-activated materials (AAMs). This study addressed this issue at the aggregate level for the first time. The results indicated that substituting sand with aluminosilicate-based lightweight fine aggregate (LWFA) by 20 % or 50 % in volume reduced the efflorescence of alkali-activated slag (AAS) mortars by 14.6 % or 43 %, respectively. The mitigation mechanisms of LWFA were proposed in terms of gels, pore solution and microstructure. Specifically, the pozzolanic reaction of LWFA provided gels with additional Si and Al, which contributed to binding Na + in the pore solution, thereby reducing the available Na for efflorescence formation. Combined with its internal curing effect, LWFA densified the surrounding pastes, which hindered the transport of ions and water, thus limiting the formation of efflorescence products. Furthermore, the incorporation of LWFA enhanced the flexural strength of mortars without significantly compromising compressive strength.

Source: Cement and Concrete Research

DOI: 10.1016/j.cemconres.2025.107917

Authors: Chen Liu, Zhenming Li, Guang Ye

Institutions: Delft University of Technology, Harbin Institute of Technology

Language: English

Topic: Concrete and Cement Materials Research

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: hybrid

Estimated APC paid: $5,180