Research on Mechanical Properties and Damage of Recycled Concrete After Being Subjected to Freeze-Thaw Cycles

In order to study the effects of recycled concrete with 100% replacement rate of coarse aggregate and common concrete on mechanical properties and frost resistance, an experimental study was conducted by changing the number of freeze-thaw cycles. The freeze-thaw damage model was established by analyzed loss rate of compressive strength, mass and dynamic elastic modulus, and also aimed at the anti-freeze durability lives of recycled concrete was predicted for the Inner Mongolia area. The result of research shows that the compressive strength and splitting tensile strength of recycled concrete was inverse to the number of freeze-thaw cycles. For every 50 additional freeze-thaw cycles, the average compressive strength decreased by 33.1%, and the average splitting tensile strength decreased by 33%. In the early stage of the freezing and thawing, the ordinary concrete and recycled concrete anti-freeze performance were similar, but the performance degradation and the recycled concrete degradation are greater than ordinary concrete with the increase of freeze-thaw cycles. The establishment of freeze-thaw damage model can intuitive clearly reflect the mechanical properties of recycled concrete macroscopic changes because of the higher fitting accuracy of dynamic modulus of elasticity loss of freeze-thaw damage model.