Influence of organo-montmorillonites on fatigue properties of bitumen and mortar

This study investigated the influence of organo-montmorillonites on fatigue properties of bitumen and mortar. Two organo-montmorillonites, Mt1 and Mt2 with octadecyl trimethyl ammonium and with benzyl dimethyl hexadecyl ammonium surfactants were used to modify one base bitumen with a content of 4 wt.%, respectively. Mt2 was also used to prepare the mortar which consisted of bitumen, filler and sand at a weight ratio of 0.34:0.30:0.36. The dispersion state of montmorillonite in bitumen was determined by the X-ray diffraction. A cone and plate device was designed to perform the fatigue test on bitumen. A column specimen before and after a short time aging was prepared for the fatigue test of mortar. An intercalated morphology for both montmorillonites was observed in bitumen. Results indicated that the addition of organo-montmorillonites can change the fatigue properties of bitumen under a stress control mode. This change was influenced by the type of the surfactant which determined the interfacial interaction between the bitumen and the montmorillonite. The mortar with modified bitumen showed better fatigue resistance and aging resistance than one with base bitumen. Therefore, the organo-montmorillonite would be an alternative to modifiers used in the bitumen to improve the lifetime of asphalt pavements.