Patent ID: 8864905

Claim:
A method for preparing mortar or concrete comprising adding a carboxymethylchitosan as a flocculating additive and a setting accelerator to a construction useable binder composition wherein the carboxymethylchitosan has the general formula (I): where: R1 and R2 independently of one another represent H or CH 2 COOX; R3 and R4 independently of one another represent H, CH 2 COOX, CH 2 CH 2 Y, CH 2 CH 2 COOZ, COCH 3 , or CH(CH 3 )CH 2 CH 2 COOX; X represents a H, Na, Li or K, Y is selected from one of the following groups: Z is selected from H, CH 2 CH 3 , Na and K; n represents a number between 35 and 6000; and at least one from among R1, R2, R3 and R4 is a CH 2 COOX group.