Summary Surface repairs must be dimensionally and mechanically compatible with the existing concrete substrate to minimize cracking and ensure that the repair and existing structure act monolithically. To achieve repairs that comply with these requirements@ the magnitude of the repair material modulus of elasticity with respect to that of the substrate needs to be taken into account.
ACI 364.5T-2010 history
2010ACI 364.5T-2010 Importance of Modulus of Elasticity in Surface Repair Materials