Influence of Variable Stress State of Concrete on its Frost Resistance
Test results of concrete under the conditions of simultaneous action of multiply repeated loads of axial compression and cyclic freezing at different temperatures are given. It is established that such variable stress state of concrete under the condition σmax<R0T (where σmax is the maximum stress of the loading cycle and R0T is the stress level determining the lower boundary of the microcrack formation region of concrete) can increase its frost resistance. This is only true if the degree of water saturation of gel pores and pore capillaries of concrete does not exceed a critical value – more than 90% by volume. The results of the investigations of the structural and technological characteristics of concrete (water-cement ratio, moisture content, differential porosity, ice content, determined by calorimetric and ultrasonic methods), frozen to temperatures down to minus 70 °C, confirm the validity of the conclusions about the effect of the variable stressed state of concrete on its frost resistance.
Dr. Denis Solovev
N.I. Karpenko et al., "Influence of Variable Stress State of Concrete on its Frost Resistance", Materials Science Forum, Vol. 945, pp. 169-175, 2019