Characteristics of calcareous sand filler and its influence on physical and rheological properties of asphalt mastic

Abstract

The composition and properties of asphalt mastic (filler and asphalt composition) play a decisive role in the performance of the asphalt mixture. This paper aims to investigate the feasibility of using fine calcareous sand as mineral filler to prepare asphalt mixture. Calcareous sand was ground into powder with particle size less than 0.075 mm by planetary ball mill. The physical and chemical properties of calcareous sand filler was then examined and compared to that of the limestone filler, including Scanning Electron Microscope, Energy Dispersive Spectrometer, X-ray fluorescence, X-ray diffraction, and laser particle size analyzer. The penetration, softening point and viscosity of asphalt mastics containing calcareous sand filler were then investigated, and rheological properties were studied by dynamic shear rheometer (DSR). The test results indicated that calcareous sand owns similar physical properties and chemical composition to that of the limestone. The penetration and dynamic viscosity of asphalt mastics with calcareous sand filler are slightly lower than that of asphalt mastics with limestone filler. The high-temperature stability of asphalt mastics with calcareous sand filler is slightly lower than that of asphalt mastics with limestone filler, while the low-temperature performance is comparable. Overall, calcareous sand can be used as an appropriate substitute for limestone filler in asphalt mixture.