Abstract:Ramming pastes was synthesized using calcined anthracite coal, baked scrap, coal derived pitch coke as aggregate; modified pitch, coal tar as binder and adding SiO2 powder. The effect of SiO2 addition on the basic properties, expansion/shrinkage process and microstructure of ramming paste were investigated. The results indicated that as the SiO2 addition increases, the ash and electrical resistivity increases, bulk density, compressive strength, volume expansion and carbonized temperature decreases. The SiO2 additive is mainly distributed on the surface of aggregate particles and binding coke. The expansion/shrinkage rate of ramming paste reached an excellent level when the addition of SiO2 was 4%.