Replacement of limestone with volcanic stone in asphalt mastic used for road pavement

Volcanic stones are a kind of natural materials, and they will occupy large amounts of land resources which brings a lot of inconvenience to local residents and traffic. Meanwhile, the annual demand for limestone in the world is about 1.2 billion tons and high-quality limestone has low natural resources and low production volume. In order to comply with the current green eco-friendly pavement concept, this paper aims to study the use of volcanic rocks in place of limestone in road pavement construction as a way of utilizing available natural mineral resource to reduce the problematic over-dependence on limestone. In this paper, asphalt mastics with different dosages of ground volcanic stone and limestone powder were produced. Combining macro and micro-methods, the applicability of volcanic stone was analyzed and evaluated from the aspects of basic performance experiments, X-ray photoelectron spectroscopy, scanning electron microscopy and infrared spectroscopy. The results clearly showed that the volcanic stone powder could get better distribution and better high-temperature performance in the asphalt mastic than limestone powder. It contained Si and much higher content of SiO₂, Al₂O₃, Fe₂O₃, Na₂O and K₂O which promoted chemical reactions with the asphalt, making it more compatible with asphalt than limestone powder. Based on the results of this study, it can be concluded that volcanic stone could effectively replace some limestone usage in the asphalt pavement field which will in return reduce the occupation of land resources and provide a new choice for the limestone.