The amount of springback is the mixture that bounces off the sprayed surface due to the collision of rock surface, steel bar or aggregate during the spraying process.
According to the air pressure at the injection position, the water cement ratio and the maximum particle size and gradation of aggregate, the rebound of coarse aggregate is larger at the initial stage of injection, but the rebound of coarse aggregate will decrease when the plastic layer is formed.
Therefore, the spray thickness should be adjusted to control the springback amount, and because the cement content in the springback material is small and mainly coarse aggregate, it is not suitable for reuse to affect the final spray quality.
