Abstract: In order to study the frost resistance of fiber recycled concrete, improve the service life of recycled concrete structures in cold areas. Five groups of recycled concrete with different basalt fiber content were prepared by using equal volume recycled aggregate instead of gravel. The damage deterioration law of frost resistance of recycled concrete with fiber was discussed from the aspects of mass loss rate, relative dynamic elastic modulus, compressive strength and tensile strength. The research results show that: At the beginning of freezing and thawing, the mass loss rate of recycled concrete exhibits a negative growth phenomenon, and the relative dynamic elastic modulus, compressive strength and tensile strength curves show a downward trend with the increase of the number of freezing and thawing cycles; the addition of basalt fiber can slow down the freezing of recycled concrete. When thawing failure, the frost resistance of recycled concrete is the best when the dosage is 1.2 kg·m^-3; the effect of fiber addition on the tensile strength of recycled concrete under freeze-thaw action is better than compressive strength. A linear and polynomial damage degradation model based on relative dynamic elastic modulus and strength as damage variables is established. The model can accurately predict the degree of freeze-thaw damage and degradation of fiber recycled concrete.

Key words: fiber recycled concrete, quality loss rate, strength, freeze-thaw damage, damage deterioration, composites