Highly concentrated and powerful penetrating agents materials which is effectively react with cement to loosen the bonding strength . Best results can obtain on dry surface of cement.  RXSOL'S R & D  has developed this molecular cement dissolver

This liquid mixture specifically designed to deal with hard cases of cement cargo deposits or dry cement stains. Its proven advantage is the provision of immediate penetration and complete dissolution of cement, the result being a thorough cleaning.

Chemically Back-Set converts the positive ions in the hardened matrix into negative ions, which dissolves the cement into mud that can be rinsed away. Because it works chemically, rather than mechanically, Back-Set may be used to remove cured concrete, mortar, grout, and stucco from virtually any surface without harm.