A method for treating clay-bearing aggregates used in construction materials, comprising: introducing to clay-bearing sand aggregates, in an amount of 3% to 60% based on weight of clay treated, at least one copolymer obtained from monomer components,, and optionally, as follows: in an amount of 60-98 mol percent, a cationic monomer selected from quaternized vinyl pyridine or other cationic monomer represented by the following structures wherein R 1, R 2, and R 3 each independently represent hydrogen, -CH 3, or -COOH; R 4, R 5, R 6, R 7, and R 8 each independently represent a C 1 -C 4 alkyl group; R 9 and R 10 each independently represent hydrogen or -CH 3; Z 1 represents -O- or -NH-; Y 1 represents -CH 2 CH CH 2 - or C 1 -C 6 alkyl group; and X represents a halide, pseudohalide, or sulfate; in an amount of 2 - 40 mol percent, a hydrophobic, essentially water-insoluble monomer selected from the group consisting of vinyl acetate, acrylonitrile, methacrylonitrile, styrene and its derivatives, vinyl ethers of formula CH 2 =CH-O-R 11 in which R 11 is a linear or branched, saturated or unsaturated hydrocarbon radical from 1 to 12 carbons, esters or amides of formula H 2 C = CR 12 -CO-Z 2 -R 13 in which R 12 is hydrogen or C 1 to C 3 alkyl, Z 2 is -O- or -NH-, and R 13 is a linear or branched, saturated or unsaturated hydrocarbon radicals having from 1 to 18 carbons; and in an amount of 0 - 20 mol percent, a water-soluble monomer selected from the group consisting of acrylamide, methacrylamide, alkyl or dialkyl acrylamide of methacrylamide, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether. in an amount of 60-98 mol percent, a cationic monomer selected from quaternized vinyl pyridine or other cationic monomer represented by the following structures wherein R 1, R 2, and R 3 each independently represent hydrogen, -CH 3, or -COOH; R 4, R 5, R 6, R 7, and R 8 each independently represent a C 1 -C 4 alkyl group; R 9 and R 10 each independently represent hydrogen or -CH 3; Z 1 represents -O- or -NH-; Y 1 represents -CH 2 CH CH 2 - or C 1 -C 6 alkyl group; and X represents a halide, pseudohalide, or sulfate; R 1, R 2, and R 3 each independently represent hydrogen, -CH 3, or -COOH; R 4, R 5, R 6, R 7, and R 8 each independently represent a C 1 -C 4 alkyl group; R 9 and R 10 each independently represent hydrogen or -CH 3; Z 1 represents -O- or -NH-; Y 1 represents -CH 2 CH CH 2 - or C 1 -C 6 alkyl group; and X represents a halide, pseudohalide, or sulfate; in an amount of 2 - 40 mol percent, a hydrophobic, essentially water-insoluble monomer selected from the group consisting of vinyl acetate, acrylonitrile, methacrylonitrile, styrene and its derivatives, vinyl ethers of formula CH 2 =CH-O-R 11 in which R 11 is a linear or branched, saturated or unsaturated hydrocarbon radical from 1 to 12 carbons, esters or amides of formula H 2 C = CR 12 -CO-Z 2 -R 13 in which R 12 is hydrogen or C 1 to C 3 alkyl, Z 2 is -O- or -NH-, and R 13 is a linear or branched, saturated or unsaturated hydrocarbon radicals having from 1 to 18 carbons; and in an amount of 0 - 20 mol percent, a water-soluble monomer selected from the group consisting of acrylamide, methacrylamide, alkyl or dialkyl acrylamide of methacrylamide, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether.