NONDESTRUCTIVE TESTING OF CONCRETES: NEW ASPECTS

Abstract Non-linearity of deformation diagrams of concretes are an integral structure-sensible characteristic, which contains information on strength, frost-resistance, internal energy loss, structural defects of the material as well as giving evidence of fundamental interrelationship between the processes of deformation and destruction. The present research introduces theory, which is based upon analysis of the non-linear ‘stress-strain’ function and kinetic nature of strength characteristics, which have wide fields of application. Three methods using measurements of non-linear parameters were developed: spectral, phase and frequency. This work shows that it is possible to use non-linear ultrasonic methods for evaluation of the following characteristics: short-term strength, long-term strength, dynamic durability coefficient, endurance and frost resistance.