Improving interfacial bonding between ordinary Portland cement and geopolymer concrete using acid/alkaline-catalyzed nano-SiO₂ sols: Insights into performance and mechanisms

Document Type

Article

Publication Date

9-5-2025

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

Concrete infrastructure deterioration necessitates eco-friendly and durable repair materials. As an innovative material, geopolymer concrete (GPC) offers a strong alternative to conventional ordinary Portland cement (OPC) due to its low carbon footprint, yet its interfacial bonding with OPC remains a substantial obstacle. This work assesses the implications of acid- and alkaline-catalyzed nano-silica (NS) sols, synthesized via sol-gel methods, on the performance of GPC and its interfacial bonding with OPC. Results indicate that alkaline-catalyzed NS (AlC-NS) shows superior dispersion and significantly enhances compressive strength and interfacial bonding strength while reducing drying shrinkage. The optimal dosage of 5 wt% AlC-NS increases the interfacial bonding strength by 45.91 % (6.07 MPa). Microstructural analysis reveals that the improved interfacial transition zone (ITZ) is attributed to the formation of dense C-(A)-S-H/N-A-S-H gels and enhanced mechanical interlocking. These findings offer a promising pathway for developing green and durable repair materials in concrete infrastructure.

Publication Title

Construction and Building Materials

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