Plasticizer having cationic side chains without polyether side chains

A hydraulically settable composition comprising:

• a hydraulically settable binder comprising clay in an amount of 0.1 to 15 wt % relative to the total weight of the hydraulically settable binder, and
• at least one zwitterionic comb polymer in an amount of 0.01 to 5 wt %, relative to the total weight of the hydraulically settable binder,
• wherein the zwitterionic comb polymer has a main chain and consists of
• a) at least one acid unit A of formula (I):
• wherein R1, R2 and R3, each independently represent H or an alkyl group having 1 to 5 carbon atoms,
• each R4 independently represents —COOM, —CH2COOM, —SO2—OM, —O—PO(OM)2, or —PO(OM)2;
• wherein M stands for H, an alkali metal, an alkaline earth metal, ammonium, an ammonium cation, an organic ammonium compound, or mixtures thereof;
• and
• b) at least one cationic structural unit K of formula (II)
• wherein
• R5 independently represents —CO—O—R′—, —NH—R′—, —CO—NH—R′—, —O—, R′, —O—R′—, or —R′—O—R′—, with R′ being a C1 to C20 alkylidene group, which can be branched or unbranched;
• R6 independently stands for a cationic group, and
• R7 independently stands for H or CH3.