硅灰改性喷射混凝土回弹率控制技术

Control Method for Rebound Rate of Silica Fume Modified Shotcrete

摘要: 为降低喷射混凝土回弹率，从而达到节省成本、绿色建造的目的，本文依托德昌至会理高速公路东山隧道段，通过试验对比干喷法及湿喷法两种施工工艺下基础配合比、添加普通硅灰、添加复合硅灰三种配合比方案的回弹率差异，结果表明湿喷法使回弹率降低5.6%~22.1%；复合硅灰可以通过增加混凝土粘附力，将回弹率降低至3.2%；而普通硅粉由于其SiO2与水泥水化颗粒产生反应，过量添加可能导致回弹率增加。

Abstract: The main purpose of this research is to cut costs and protect the environment by reducing the rebound rate of shotcrete. The research is based on the project of Dongshan Tunnel in DeChang-HuiLi Expressway. By comparing the rebound rates of concrete samples in 3 different mix ratio (Basic mix ratio, Adding ordinary silica fume, Adding composite silica fume) under 2 construction techniques (Dry spray method, Wet spray method) respectively, the results show that the wet spray method reduces the rebound rate by 5.6%~22.1%; Composite silica fume can reduce the rebound rate to 3.2% by increasing the adhesion of concrete; In addition, due to the reaction between SiO2 and cement hydration particles, excessive addition of ordinary silica fume may lead to an increase in rebound rate.