A new evaluation of the fatigue design criteria of roller compacted concrete (RCC) pavements

Abstract

Although mechanical fatigue loading can generally cause critical stresses in pavement systems, there have been few studies that specifically investigate fatigue behavior of roller-compacted concrete (RCC). Possible reasons for this lack include the complexity and time-consuming nature of fatigue tests as well as difficulties in producing RCC prismatic specimens because of stiff consistency in their fresh state. In this experimental study, to simulate actual field-compaction procedures, three RCC mixes of different performance categories were compacted in a plate mold by first applying a vibratory plate compactor, followed by a small-scale vibratory hand roller. Fatigue behavior of RCC mixtures was investigated by applying fatigue loads at five different stress ratios on beam specimens taken from the compacted plates. The average fatigue strength of RCC corresponding to 2 million loading cycles was found to be about 62.5% of the ultimate static strength, showing that RCC performs better than conventional concrete under fatigue. Using a Weibull distribution, the failure probabilities of these mixtures were also determined and expressed as an S-N-P curve. The relationships between RCC fatigue life and mixture design parameters showed that the degree of compaction of a specimen significantly affects the fatigue performance of RCC. A fatigue-life model considering the mixture parameters was also developed, providing a more realistic and novel solution than other RCC fatigue life-estimation models found in the literature that consider only stress ratios. This model is less conservative than those currently used in pavement design.