Issue 78

C. S. Karadumpa et alii, Fracture and Structural Integrity, 78 (2026) 146-167; DOI: 10.3221/IGF-ESIS.78.09

Development and performance evaluation of hybrid nano-modified SCM-based concretes

Chandra Sekhar Karadumpa Department of Civil Engineering, BMS College of Engineering, Bangalore, India chandrasekhark.civ@bmsce.ac.in, https://orcid.org/0000-0002-5210-0201 Mallikarjun Perumalla Department of Civil Engineering, National Institute of Technology Puducherry, India pvm.rao@nitpy.ac.in, http://orcid.org/0000-0001-5755-3800

Citation: Karadumpa, C. S., Perumalla, M., Development and performance evaluation of hybrid nano modified SCM-based concretes, Fracture and Structural Integrity, 78 (2026) 146-167.

A BSTRACT . Concrete production contributes approximately 8-10% of global CO ₂ emissions necessitating sustainable alternatives. This study investigates hybrid nano-modified composite cement concrete with Ordinary Portland Cement (OPC) partially replaced by Ground Granulated Blast-furnace Slag (GGBS, 30-35%) and Fly Ash (10-15%) by weight of cement, nano-reinforced using Graphene Oxide (GO, 0.01-0.05%) and Carbon Nanotubes (CNT, 0.1 0.3%) by weight of cement. Eight mixes were designed and evaluated for fresh properties, mechanical performance (compressive, split tensile, and flexural strength at 7, 28, and 56 days), and microstructure (SEM, XRD, and EDAX). Nanomaterials were dispersed using magnetic stirring to ensure uniform distribution. Optimal formulations achieved significant enhancements, specifically, GO 0.03% reached 34.5 MPa compressive (+23.2%) and 15.6 MPa flexural (+108%); CNT 0.1% achieved 33.53 MPa compressive (+19.8%) and 3.23 MPa tensile (+31.8%); the hybrid (GO 0.03% + CNTs 0.1%) demonstrated 33.9 MPa compressive (+21.1%) and 14.92 MPa flexural (+98.9%). Early-age strength improved by 69-77%, compensating for slower pozzolanic reactions associated with GGBS and Fly Ash. Microstructural characterization revealed densified C-S-H gel, refined ITZ (from 20-50 μ m to 10-15 μ m), reduced porosity (from 12.3% to 7.8%), enhanced crystallinity, and optimal Ca/Si ratios (1.36-2.14). Environmental assessment showed 39.2% CO ₂ reduction and a 50.7% improvement in carbon intensity. The hybrid approach provides a viable route to sustainable, high-performance concrete for infrastructure applications.

Received: 04.04.2026 Accepted: 22.07.2026 Published: 13.08.2026 Issue: 10.2026

Copyright: © 2026 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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