Effect of freeze-thaw on fatigue damage characteristics of cement emulsified bitumen mastic

Cement emulsified bitumen mastic (simplified as CEBM) is a type of composite binder composed of cement, emulsified bitumen, water and various additives. Freeze-thaw cycles have an important influence on the fatigue properties of CEBM. In this paper, freeze-thaw test and fatigue test were carried out. Damage variable characterizing freeze-thaw effect and total damage variable characterizing freeze-thaw and fatigue coupling effect were established. They were based on the initial complex modulus and fatigue properties parameters of fatigue test. Effects of freeze-thaw cycles on fatigue properties and damage evolution process were analysed. This study demonstrates that, as freeze-thaw cycles increasing, fatigue life decreases, and the sensitivity of fatigue life with stress level is reduced. With the increase of freeze-thaw cycles, both freeze-thaw damage and total fatigue damage increase, and the proportion of freeze-thaw damage in total damage increases. Effect of freeze-thaw cycles on the fatigue properties of CEBM is enhanced. With the increase of bitumen content, freeze-thaw damage reduces and total damage increases. The increase of bitumen content can improve the frost resistance of CEBM and improve the sensitivity of fatigue properties to freeze-thaw cycles.

Automated summary

The study demonstrated that increasing freeze-thaw cycles decreases fatigue life of CEBM, while increasing both freeze-thaw damage and total fatigue damage. Increasing bitumen content improves frost resistance of CEBM and enhances sensitivity of fatigue properties to freeze-thaw cycles.