Micromechanical-Rheology Model for Predicting the Complex Shear Modulus of Asphalt Mastic

The dynamic shear rheometer (DSR) was used to measure viscoelastic properties of asphalt mastic. Mechanical volume filling effects and additional interacting mechanisms within mastic systems are discussed on the basis of micromechanical-rheology model to predict the complex shear modulus of asphalt mastic from the measured mastic data. The Einstein coefficient is 3.761, and the maximum volumetric packing fraction is 0.562 for the measured asphalt mastic. The predicted G* of asphalt mastics is very close to the actual value, and the relative error is not exceeding 10%. The micromechanical-rheology model can predict the complex shear modulus of the asphalt mastic from the viscoelastic property of neat asphalt, the volumetric filler effect and an interactive effect between the filler and the asphalt.

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Research on Interaction between Asphalt and Filler Based on DSR Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.723.480 ◽

2013 ◽

Vol 723 ◽

pp. 480-487 ◽

Cited By ~ 8

Author(s):

Jiu Peng Zhang ◽

Jian Zhong Pei ◽

Yan Wei Li

Keyword(s):

Shear Modulus ◽

Volume Fraction ◽

Hydrated Lime ◽

Interaction Coefficient ◽

Complex Shear Modulus ◽

Volume Fractions ◽

Asphalt Mastic ◽

Complex Shear ◽

Asphalt Mastics ◽

Einstein Coefficient

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 Nielsens 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 Nielsens model and DSR test data, the Einstein coefficient KE 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 KE can be used to represent the interaction between asphalt binder and filler. The bigger value means the better interaction.

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Viscoelastic Analysis of Asphalt Mastic Based on Micromechanics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.266.38 ◽

2011 ◽

Vol 266 ◽

pp. 38-41

Author(s):

Jiu Peng Zhang ◽

Li Xu ◽

Jian Zhong Pei

Keyword(s):

Shear Modulus ◽

Chemical Interaction ◽

Hydrated Lime ◽

Asphalt Binders ◽

Dynamic Shear Modulus ◽

Dynamic Shear ◽

Complex Shear Modulus ◽

Asphalt Mastic ◽

Physico Chemical ◽

Complex Shear

In this study, the stiffening effect of fillers on asphalt binders was characterized through micromechanics and rheology methods. The dynamic shear rheometer (DSR) was used to measure viscoelastic properties of asphalt mastic. Mechanical volume filling effects and additional interacting mechanisms within mastic systems are discussed on the basis of micromechanics-rheology model to predict the complex shear modulus of asphalt mastic from the measured mastic data. It is observed that the phase angle ranges from 88.8o to 89.0o, does not significantly change due to limestone fillers addition. The analytical model prediction of complex shear modulus based on the dynamic shear modulus can be used. Using the nonlinear regression, the Einstein coefficient KE is 4.22, 5.09 and 7.44 for asphalt mixed with limestone, cement and hydrated lime, respectively. Beside, the SEM results explain why the mastic system with hydrated lime shows the highest KE. The behavior of hydrated lime fillers filled mastics is probably due to physico–chemical interaction, which can be validated by further research.

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