PSI - Issue 67

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2024) 000 – 000 Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ

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Procedia Structural Integrity 67 (2025) 107–114

International Symposium on Nanotechnology in Construction Materials NICOM8 Enhancing alkali-silica reaction resistance with nanomaterials: A comparative study of nano metakaolin and carbon nanotubes Hwan Lee a , Savitha Srinivasan a *, and Raissa Douglas Ferron a

a Department of Civil, Environmental, and Architectural Engineering The University of Texas at Austin, Austin, Texas, USA

Abstract Alkali-silica reaction (ASR) is a major durability concern affecting concrete infrastructure. Research on the mitigation of ASR has seen a resurgence due to the reduced availability of common mitigation materials like supplementary cementitious materials (SCMs) and lithium-based compounds. This study explored the efficacy of using nano metakaolin (NMK) and carbon nanotubes (CNTs) for ASR mitigation. In addition to examining ASR resistance, compressive strength, and bulk resistivity of the mixtures with and without nanomaterials were examined. The results show that when NMK and CNT are incorporated at appropriate dosages significant improvement in ASR resistance, compressive strength, and resistivity can occur. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of NICOM8 Chairpersons Keywords: Nano metakaolin; Carbon nanotube; Alkali-silica reaction; Resistivity; Compressive strength Introduction Alkali-silica reaction (ASR) has been a major concern for concrete durability since its discovery by Thomas Stanton in California in the 1930s (Stanton 1942). Certain types of aggregates are prone to dissolution in the alkaline conditions present in concrete pore solutions, forming a hygroscopic gel. This swelling ASR gel imposes stress on the concrete structure, which can lead to cracking and, ultimately, structural failure (Luo et al. 2022; Rajabipour et al. 2015). Additionally, ASR-induced cracks often accompany other deleterious issues such as delayed ettringite formation (Martin et al. 2013), freeze-thaw damage (Gong et al. 2020), and corrosion of reinforced bars (Ueda et al. 2014). Given the destructive consequences of ASR, mitigating its effects is crucial for extending the lifespan of concrete structures and reducing maintenance costs (Luo et al. 2022). Several strategies have been proposed to mitigate ASR, such as (a) limiting the total alkali loading in concrete (Folliard et al. 2006); (b) use of non-reactive or low-reactive aggregates (ASTM C1260 2014; ASTM C1293 2015); © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of NICOM8 Chairpersons

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of NICOM8 Chairpersons

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of NICOM8 Chairpersons 10.1016/j.prostr.2025.06.013