Mechanism of graphene oxide concrete macro-micro properties evolution under large temperature difference freeze-thaw action

In high altitude and large temperature difference areas, concrete construction faces the problem and challenge of insufficient frost durability. This paper investigates the macro-micro properties evolution of graphene oxide concrete (GOC) under large temperature difference freeze-thaw action and confirms the good frost resistance of concrete endowed with graphene oxide. The macro test results showed that graphene oxide effectively increased concrete's strength and relative dynamic modulus of elasticity at the initial and final stages of freezing and thawing, reduced the mass loss of concrete, and delayed the apparent damage process of concrete. Microscopic tests revealed that graphene oxide refined the pore size distribution of concrete, increased the number and percentage of gel pores in it, induced the growth of hydration products into petal-like and polyhedral crystalline clusters, better filled the pores inside the concrete, and inhibited crack expansion. The promotion effect of graphene oxide on the macro-micro properties of concrete was proportional to its content, but it was limited when the content reached 0.05%. A freeze-thaw damage model and a residual strength prediction model of concrete were developed using freeze-thaw test data and the Weibull distribution function to simulate and predict the deterioration process of concrete macroscopic properties. The findings of the study can be used to guide the design, construction, and operation of similar concrete structures in alpine regions.