Optimal Freeze-Thaw Resistance Air-Entrained Concrete with Designed Nanoparticle Stabilised Bubble System

Freeze -Thaw (F -T) damage in cementitious materials is a significant concern in the construction and civil engineering industry, which refers to the deterioration of concrete and other cement -based materials when subjected to cycles of freezing and thawing. Incorporating air -entraining agents (AEAs) in concrete is widespread for introducing tiny air bubbles to improve F -T resistance while ensuring the stability and uniform distribution of the air void system, which poses a considerable challenge. To stabilise durable pore networks established by airentraining agents (AEAs), nanoparticles (NPs) with antithetical ionic functional groups are co -used in the concrete for bearing F -T sufferings. Mechanical properties, F -T resistance, and micro -properties of end products are tested via universal machine, XRD, SEM, and nano -CT. Results verify a positive synergistic effect between AEAs and NPs, embodied by high efficacy and compatibility in generating a stable air system, a 33.3 % higher compressive strength, and a 28.3 % higher flexural strength relative to the control. Moreover, the F -T test results indicate a remarkable enhancement in resistance, with specimens resiliently enduring beyond 300 F -T cycles despite experiencing a modest 2.05 % mass loss and an impressive 4.6 % compressive strength loss.