Abstract: Utilizing construction and demolition waste as subgrade filler is an effective measure for the rational use of discarded resources. Construction and demolition waste is characterized by low strength and easy breakability. To further investigate the crushing characteristics of construction and demolition waste under impact loading, this paper conducted impact load tests with different input energies on recycled brick aggregate and recycled concrete aggregate, which are the main components of recycled construction waste, under four single particle sizes. Considering the particle size effect based on the Lade crushing model, a relative crushing rate prediction model based on input energy was proposed. Results show that the fractal behavior of both recycled brick aggregate and recycled concrete aggregate is influenced by the initial particle size; the vertical strain of recycled brick aggregate and recycled concrete aggregate can be categorized into three stages with the change of input energy, and the vertical strain of recycled brick aggregate is significantly more affected by particle size than that of recycled concrete aggregate; the larger the particle size, the higher the initial crushing sensitivity and ultimate crushing state, and the initial crushing sensitivity and ultimate crushing state of recycled brick aggregate are less affected by particle size than those of recycled concrete aggregate; the crushing rate prediction model considering the particle size effect demonstrate a good prediction effect.