A damage model for concrete under delayed ettringite formation

Damage in concrete due to delayed ettringite formation (DEF) has become a major concern in many civil engineering constructions. Damage is defined as the change of the elastic modulus of a material. The objective of this research is to determine the state of damage in a concrete specimen subjected to DEF under laboratory conditions by measuring the expansion caused by the phenomenon. The theory of continuum damage mechanics, including creep damage, is used to establish a model able to predict the amount of damage in concrete. The model takes into consideration the variable stress nature of the phenomenon. Experimental results obtained in the laboratory are used to corroborate the obtained formulation. Material parameters, with physical meaning, are determined from these laboratory results. The model is finally incorporated in a worksheet in order to obtain the objective of this investigation.