Research on Interaction between Asphalt and Filler Based on DSR Test

摘要

To explain the interactive effect between asphalt and fillers in the asphalt mastic, it is probably to start with an assessment of the rheology properties, since asphalt mastics are viscoelastic materials. In this study, firstly prepare the asphalt mastics with different dosage of limestone filler, and the volume fractions of fillers were 0, 14, 24, 32, 39 and 45%. And then, the same asphalt is mixed with different fillers, such as cement and hydrated lime, and the volume fractions of fillers were 18, 23, 28and 33%. DSR test was conducted on all of the asphalt mastic specimens to measure the complex shear modulus G* at different temperature. The volume filling effects and interaction between asphalt and filler are discussed on the analysis of complex shear modulus coefficient and Nielsen's model model. It is obviously that G* of asphalt mastics decrease with the test temperature, but increase with the volume fraction of filler. A function relation between complex shear modulus coefficient and volume fraction of fillers is established, and the interaction coefficient α is proposed. For limestone, cement and hydrated lime filler, the interaction coefficient α values are 0.301, 0.317 and 0.429 respectively. Based on Nielsen's model and DSR test data, the Einstein coefficient K_E is calculated, and Einstein coefficients are 3.761, 5.09 and 7.44 for asphalt-limestone mastic, asphalt-cement mastic and asphalt- hydrated lime mastic respectively. Both the interaction coefficient α and Einstein coefficient K_E can be used to represent the interaction between asphalt binder and filler. The bigger value means the better interaction.