A method for abruptly reducing the flowability of a pumpable cement-containing mixture

摘要

A process for modifying the slump of a concrete or mortar by the addition at different times of a water-soluble poly(alkylene oxide) and a beta -naphthalene sulphonate-formaldehyde condensate, a plasticizer or superplasticizer which is selected from lignosulphonates, melamine sulphonate formaldehyde condensates, carboxylates and selected styrene-maleic anhydride copolymers. The poly(alkylene oxide) is preferably partially replaced by a (hydroxy)alkyl cellulose. The process is advantageously used in shotcreting.