Application of nano rebound reducing admixture in shotcrete in high speed tunnel engineering
To solve the high rebound rate problem of shotcrete during wet spraying operations,this article takes a tunnel along the Yangtze River in Sichuan Province as a project support,and adds nano rebound reducing admixtures to the concrete to carry out the engineering application of spraying rebound reducing.The use of nano rebound reducing admixtures has improved the workability of concrete,resulting in a sufficient amount of concrete slurry and good wrapping properties,enhancing the adhesion of sprayed concrete and effectively improving the spraying effect.Compared with ordinary shotcrete,the rebound rate of shotcrete with added admixtures decreased 12.41 percentage points,combined with SBT-N(Ⅱ)liquid alkali free accelerator effectively reduces the rebound rate of 13.65 percentage points,with good economic benefits.