Damage of Plain Concrete due to Thermal Incompatibility of its Phases

The present paper focuses on analytical and experimental investigation of plain concrete deterioration due to internal thermal stresses. Using fracture mechanics and micromechanics approach the crack size is defined as a function of temperature increase. In this type of material cracks appear at the interface of aggregate and cement paste because of the mismatch of the coefficients of thermal expansion. Assuming uniform distribution of cracks, analytical expression for Young's modulus as a function of temperature increase is obtained. Experimental investigation of two series of specimens confirms analytical predictions. This research challenges usually accepted assumptions that moderate temperature change doesn't affect mechanical properties of plain concrete.