Effect of cement paste on drinking water

When water conduits are made of concrete or are lined with cement mortar, t he cement paste can be leached by water. This occurs to a significant degre e if the water remains in prolonged contact with the cement paste. The cons equences of leaching are an increase in pH and in the content of CaCO3. Rec ent rules of the European Union endeavour to deal with this problem. As the tolerable amount of leachate depends on the original properties of t he water, tests are not easy to perform. The use of admixtures and of high- alumina cement are discussed. The actual levels of various chemical species in different waters in service and of tolerable quantities of these specie s need to be established so that a safe use of cement in conduits can be as sured.