Patent ID: 8404041

Claim:
A method for controlling release of an admixture in a cement-based composition comprising first intercalating the admixture into a layered double hydroxide or mixture thereof to form a controlled release formulation and then adding the controlled release formulation to a cement-based material, the layered double hydroxide having formula (I): [M 2+ 1−x M 3+ x (OH) 2 ] x+ [A n− x/n .mH 2 O] x− (I) where M 2+ is Ca 2+ , M 3+ is a trivalent metal cation, A n− is NO 3 − , Cl − , SO 4 2− or a mixture thereof, x is a number from 0 to 1 but not 0, n is a number 1 or greater, and m is a number 0 or greater.