Method ensuring relatively long time of cement mixture settling down and subsequent quick settling down reduction, additive for this method as well as use of such additive

摘要

In the present invention there is disclosed a modification method of concrete or mortar mixture settling down by addition in different time intervals a water-soluble poly(alkylene oxide) and beta-naphthalenesulfonate formaldehyde condensate and a softening agent or an associated softening agent being selected from a group comprising lignosulfonates, melaminesulfonate-formaldehyde condensation products, carboxylate and selected copolymers based on styrene and maleic acid anhydride. The poly(alkylene oxide) can be preferably substituted up to the amount of 50 percent by weight with (hydroxy)alkyl cellulose. The invented method is preferably used for application of gunite. In the present invention there is also claimed the additive for the above described method as well as the use of this additive.