Shotcrete is often used in similar applications. The question of bending is a structural engineering question. Shotcrete is a method of placing concrete and the properties of shotcrete are similar if not the same as cast concrete. To achieve a composite wall, you must ensure that the existing surface is properly prepared to maximize the potential bond between the overlay shotcrete and the existing wall. Shotcrete placed against a properly prepared existing wall should achieve great bonding strength without the use of bonding agents. Drilled and grouted dowels also contribute to the system, working as a composite wall.