Abstract
To address the coupled effects of cementitious materials, aggregates, and air content on the salt freeze–thaw resistance of concrete, this study proposes a multiscale decoupling analysis method that integrates macroscopic performance testing with nanoscale mechanical characterization. Concrete specimens were prepared using various binder systems (ordinary Portland cement and slag/fly ash-blended systems), aggregate types (granite and limestone), and target air contents ranging from 3% to 6%. Salt freeze–thaw tests were conducted in a 5% NaCl solution, accompanied by permeability testing, freeze–thaw durability evaluation, and air-void spacing factor measurements. Salt freeze–thaw damage was quantitatively assessed based on mass loss and relative dynamic modulus reduction. In addition, the PeakForce QNM mode of atomic force microscopy (AFM) was employed to characterize the micromorphology and nanoscale mechanical properties of the interfacial transition zone (ITZ), focusing on the spatial distribution of Young’s modulus. The results demonstrate that fly ash-based binder systems significantly increase the Young’s modulus of the ITZ, indicating improved interfacial mechanical performance. In contrast, the use of granite aggregate leads to higher ITZ porosity and weaker interfacial bonding, negatively impacting durability. Concrete with an air content of approximately 4.5% exhibited the best resistance to both conventional and salt freeze–thaw cycling, highlighting the critical role of optimized air entrainment in durability design.
Keywords
freeze-thaw resistance, Young’s modulus, atomic force microscopy (AFM), concrete durability
Date of Version
2025
DOI
10.5703/1288284318213
Recommended Citation
Shao, Yu; Rong, Jie; Liu, Yue; Guo, Yongzhi; Guo, Baolin; and Li, Qinfei, "Multiscale Decoupling Analysis of Concrete Durability and Interfacial Micromechanics Using AFM-QNM" (2025). International Conference on Durability of Concrete Structures. 13.
https://docs.lib.purdue.edu/icdcs/2025/tmc/13
Multiscale Decoupling Analysis of Concrete Durability and Interfacial Micromechanics Using AFM-QNM
To address the coupled effects of cementitious materials, aggregates, and air content on the salt freeze–thaw resistance of concrete, this study proposes a multiscale decoupling analysis method that integrates macroscopic performance testing with nanoscale mechanical characterization. Concrete specimens were prepared using various binder systems (ordinary Portland cement and slag/fly ash-blended systems), aggregate types (granite and limestone), and target air contents ranging from 3% to 6%. Salt freeze–thaw tests were conducted in a 5% NaCl solution, accompanied by permeability testing, freeze–thaw durability evaluation, and air-void spacing factor measurements. Salt freeze–thaw damage was quantitatively assessed based on mass loss and relative dynamic modulus reduction. In addition, the PeakForce QNM mode of atomic force microscopy (AFM) was employed to characterize the micromorphology and nanoscale mechanical properties of the interfacial transition zone (ITZ), focusing on the spatial distribution of Young’s modulus. The results demonstrate that fly ash-based binder systems significantly increase the Young’s modulus of the ITZ, indicating improved interfacial mechanical performance. In contrast, the use of granite aggregate leads to higher ITZ porosity and weaker interfacial bonding, negatively impacting durability. Concrete with an air content of approximately 4.5% exhibited the best resistance to both conventional and salt freeze–thaw cycling, highlighting the critical role of optimized air entrainment in durability design.
