Experimental study of the interacting effects of loading rate and temperature on concrete fatigue behavior under compression

This paper presents a comprehensive experimental investigation into the thermo-mechanical interactions and temperature development during high-cycle and high-frequency fatigue loading in normal-strength concrete. A total of 30 tests were conducted, covering a range of loading scenarios including monotonic, pre-peak cyclic, post-peak cyclic, and fatigue tests. These tests were performed on cylindrical specimens (150 mm diameter, 300 mm height) while systematically varying two key parameters: three distinct load frequencies and two different load levels. The study provides a detailed analysis of the combined effects of loading rate and temperature on both the monotonic and fatigue behavior of concrete, offering a clear summary and interpretation of the underlying mechanisms driving these interactions. The results demonstrate that temperature growth, influenced by higher loading frequencies, plays a critical role in fatigue life, particularly in the high-cycle fatigue range. Resonance testing, with frequencies up to 55 Hz, induced significant temperature rise, which negatively affected fatigue life, whereas lower frequencies exhibited less pronounced temperature growth. The paper also provides rich experimental data, enabling the systematic calibration and validation of future thermo-mechanical, rate-dependent fatigue models that aim to capture these complex interactions in a physically sound manner. • Comprehensive study of fatigue behavior in concrete under varying loading rates. • High load levels show frequency dominance, low levels highlight temperature effects. • Less pronounced heat generation during fatigue in normal vs. high-strength concrete. • Rich data supports calibration of advanced models for better fatigue life predictions.