Reduction mechanisms of fatigue strength of concrete under compression due to permeation of liquids

Reduction mechanisms due to liquid permeation are studied on the fatigue strength of concrete under compression. Referring to the nucleation of micro-cracks, deformation and energy consumption characteristics of specimens are investigated. Reduction of the interfacial energy between solid and liquid plays a major role for the decrease in the strength of fatigued concrete under compression permeated by liquids. By suitable setting of the K value in the S–N curve equation considering the lower-limit stress ratio, it is possible to predict the fatigue life of concrete permeated by liquids with the reasonable accuracy.

► Fatigue process of concrete under compression is examined.
► K value in S–N equation declines depending on surface tension of permeating liquid.
► Fatigue life (cycles to failure) of concrete is highly affected by strain rate.
► Liquid permeation lowers interfacial energy to nucleate micro-cracks.
► Strain rate increase due to liquid permeation results in fatigue strength decrease.