Leaching behaviour of sprayed concrete

lime deposits in drainage systems have turned out the most serious problem affecting the operation of drained traffic tunnels in recent years. The maintenance cost for underground water drainage systems may become very high and account for a large share of the current expenditure. it therefore stands to reason to take preventive measures when planning new tunnels. Apart from the geological and hydrological conditions, the leaching of sprayed concrete has proved primarily responsible for such deposits. The application of a shotcrete with low leachability for current and future projects is therefore seen as the most promising way of how to reduce sintering. Based on tests carried out on shotcrete produced under strictly defined conditions, the leaching behaviour will be discussed and recommendations be given for the production of an optimal shotcrete in terms of sintering.