A Comparative Study on the Rheological, Mechanical, and Techno-Economic Performance of Cementitious Grouts Incorporating Natural Zeolite, Microsilica, and Metakaolin

Akhavan Tavakkoli, Maedeh; Fallahnezhad, Reyhane; Ardakani, Alireza

doi:10.22075/jrce.2025.2468

A Comparative Study on the Rheological, Mechanical, and Techno-Economic Performance of Cementitious Grouts Incorporating Natural Zeolite, Microsilica, and Metakaolin

Document Type : Regular Paper

Authors

Maedeh Akhavan Tavakkoli ¹

Reyhane Fallahnezhad ²

Alireza Ardakani ²

¹ Department of Civil Engineering, Imam Khmoeini International University, Qazvin, Iran

² Department of Civil Engineering, Imam Khomeini International University (IKIU), Qazvin, Iran

10.22075/jrce.2025.2468

Abstract

The increasing demand for sustainable materials in geotechnical engineering necessitates replacing Ordinary Portland Cement (OPC) in grouts. This study presents a comprehensive comparison of natural zeolite (NZ), microsilica (MS), and metakaolin (MK) as 10% and 20% by-weight OPC replacements, evaluating rheological, mechanical, microstructural, and techno-economic performance. Metakaolin (MK) delivered superior mechanical performance, with the MK10 mix increasing 28-day compressive strength by 150% (to 38.1 MPa) and modulus of elasticity by 116.5%. Microsilica (MS) offered a balanced profile, enhancing strength by 110% (to 32.0 MPa) while significantly improving toughness. Natural zeolite (NZ) was the most economical option, reducing material costs by 6.4% with a moderate 48% strength gain. Rheologically, all grouts were shear-thinning fluids (Herschel-Bulkley model). MK and MS dramatically increased viscosity—up to 52-fold—and yield stress, which eliminated bleeding entirely in the MS20 mix and confirmed superior stability for injection applications. Microstructural analysis revealed distinct enhancement mechanisms for each SCM. Critically, the techno-economic analysis quantified the value proposition: while NZ20 was the lowest-cost mix, MK10 provided the highest strength-to-cost ratio, reducing the cost per MPa by over 59% compared to the control. This study delivers a novel multi-criteria framework for selecting optimal SCMs based on project-specific tra de-offs between performance, rheology, and budget.

Keywords

Grouting

Cost-Benefit Analysis

Microstructure

Sustainability

Supplementary Cementitious Materials (SCMs)

Subjects