METHOD AND SPRAY AGGREGATE FOR POURING AIR-PLACED CONCRETE

摘要

A process for applying a layer of air-placed concrete to a surface in which a pumpable and sprayable air-placed concrete mix is prepared from cement, aggregates, optionally additives and water. A predetermined volume stream of the air-placed concrete mix is delivered by a concrete delivery pump through a concrete delivery pipe to an air-placing unit comprising means for introducing propelling air under a delivery pressure of several bar. The propelling air is charged with synthetic silica having a BET surface of at least 25 m3/g. The synthetic silica is introduced with the propelling air into the volume stream of the air-placed concrete mix in such a quantity that, immediately after application, the air-placed concrete applied undergoes a spontaneous increase in temperature of a few degrees Kelvin. An air-placing unit for carrying out the process is also described.