Development of a New Dynamic Modulus Predictive Model Based on Binder Viscosity for the Superpave Mixtures of New Mexico

2016 ◽  
Author(s):  
A. S. M. Asifur Rahman ◽  
Rafiqul A. Tarefder
Keyword(s):  
New Mexico ◽  
Predictive Model ◽  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Design Method ◽  
Superposition Principle ◽  
Asphalt Binder ◽  
Accurate Estimation ◽  
Sigmoid Function ◽  
Uniformity Coefficient

The newly developed mechanistic-empirical pavement design method uses the dynamic modulus as one of the crucial input parameters for the asphalt pavement to be designed or analyzed. This study proposes a new regression-based predictive model to estimate dynamic modulus of asphalt concrete from the viscosity of the asphalt binder used in the asphalt-aggregate mixture. Other parameters related to the aggregate gradation, such as, fineness modulus, and uniformity coefficient and the parameters related to the mixture volumetric are also incorporated in this model. A total of 21 asphalt concrete mixtures with asphalt binders having different performance grades and Superpave gradations were collected from different mixing plants and paving sites at various regions of New Mexico. The collected mixtures were then compacted, cored and sawed to cylindrical specimens. The asphalt concrete specimens were then tested for dynamic modulus at different temperatures and loading frequencies. The time-temperature superposition principle was then applied to develop dynamic modulus mastercurves at 70 °F (21.1 °C) reference temperature. The mastercurves were then fitted by the sigmoid function. The parameters of the sigmoid function were then correlated to the physical attributes of the asphalt concrete samples. Finally, a predictive model is developed to estimate the dynamic modulus of the AC mixtures typically used in New Mexico. Statistical evaluation showed that a fairly accurate estimation of dynamic modulus can be found by using this new dynamic modulus predictive model.

Dynamic Modulus Predictive Model Based on Artificial Neural Network for the Superpave Asphalt Mixtures of New Mexico

2017 ◽  
Author(s):  
A. S. M. Asifur Rahman ◽  
Rafiqul A. Tarefder
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
New Mexico ◽  
Predictive Model ◽  
Dynamic Modulus ◽  
Accurate Estimation ◽  
Different Temperatures ◽  
Artificial Neural ◽  
Phase Angles ◽  
Cylindrical Test

In this study, a new dynamic modulus predictive model for the Superpave asphalt-aggregate mixtures of New Mexico is developed based on the artificial neural network methodology. A total of 54 plant-produced asphalt-aggregate mixtures from all over the state were collected, compacted, cored, and sawed to cylindrical test specimens in the laboratory to conduct dynamic modulus testing at different temperatures and loading frequencies. A database containing 1,620 dynamic moduli with phase angles was then used to develop this artificial neural network based predictive model. A neural architecture with 2 twelve-node hidden layers was found to be remarkably suitable for predicting the dynamic modulus and phase angle of asphalt concrete. Statistical evaluation showed that a fairly accurate estimation of dynamic modulus can be attained by using this model.

Effect of Fineness Modulus and Uniformity Coefficient on the Complex Modulus Function of Asphalt Concrete

2017 ◽  
Author(s):  
A. S. M. Asifur Rahman ◽  
Rafiqul A. Tarefder
Keyword(s):  
Asphalt Concrete ◽  
Complex Modulus ◽  
Superposition Principle ◽  
Asphalt Binders ◽  
Modulus Function ◽  
Aggregate Gradation ◽  
Factors Affecting ◽  
Uniformity Coefficient ◽  
Time Temperature Superposition Principle ◽  
Fineness Modulus

Different material attributes such as mix volumetrics, aggregate gradations, and binder characteristics are the factors affecting viscoelastic material functions of asphalt concrete. In this study, the effects of aggregate gradation on the complex modulus function of asphalt concrete are determined. The two distinct properties of the aggregate blend considered in this study are the fineness modulus and the uniformity coefficient. A total of 54, plant produced, asphalt concrete mixtures with asphalt binders having various performance grades and sources were collected from the manufacturing plants. The asphalt-aggregate mixtures were then compacted, cored, and sawed to cylindrical specimens. Three cylindrical specimens from each of the asphalt-aggregate mixtures were prepared and tested in the laboratory for complex or dynamic modulus. After that, average mastercurves of complex modulus and phase angle were generated by applying time-temperature superposition principle. Study showed that the complex modulus function of asphalt concrete is significantly related to the fineness modulus and uniformity coefficient of the aggregate blends used in the asphalt-aggregate mixture.

Effect of Progressive Aging on the Viscoelastic Material Functions of Asphalt Concrete and its Binder

2017 ◽  
Author(s):  
A. S. M. Asifur Rahman ◽  
Hasan M. Faisal ◽  
Rafiqul A. Tarefder
Keyword(s):  
Shear Modulus ◽  
Viscoelastic Material ◽  
Asphalt Concrete ◽  
Complex Modulus ◽  
Superposition Principle ◽  
Asphalt Binder ◽  
Relaxation Modulus ◽  
Concrete Specimen ◽  
Material Functions ◽  
Four Levels

In this study, field collected loose asphalt-aggregate mixtures were used to prepare cylindrical asphalt concrete specimen using a Superpave gyratory compactor and samples were subjected to four levels of aging. Unaged and aged samples were then tested for complex modulus, relaxation modulus, and creep compliance in the laboratory at different temperatures and loading conditions. To determine broadband characteristics, mastercurves of related viscoelastic material functions were determined by applying time-temperature superposition principle. A comparison study showed that increasing levels of aging have significant effect on viscoelastic functions of asphalt concrete. In addition, liquid asphalt binder corresponding to the asphalt-aggregate mixture was tested for complex shear modulus at various levels of aged conditions, using a dynamic shear rheometer. Results showed that even though the binder shear modulus increases significantly with aging, asphalt concrete modulus does not necessarily show similar increment.

scholarly journals Backcalculated Modulus of Asphalt Concrete

2019 ◽  
Vol 8 (4) ◽  
pp. 127-136
Author(s):  
Md Rashadul Islam ◽  
Rafiqul Tarefder ◽  
Mesbah U. Ahmed
Keyword(s):  
New Mexico ◽  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Asphalt Pavement ◽  
Homogeneous Material ◽  
Loading Frequency ◽  
Falling Weight Deflectometer ◽  
Different Temperatures ◽  
Wheel Loading ◽  
Falling Weight

Asphalt Concrete (AC) is considered a spatially homogeneous material when analyzing and designing asphalt pavement. However, the modulus of AC along the wheel path and the middle of the wheel path may not be the same considering the continuous compaction by wheel loading. This study conducted monthly Falling Weight Deflectometer (FWD) tests to determine the AC modulus of a pavement section on Interstate 40 (I-40) in the state of New Mexico, USA from 2013 to 2015. The AC moduli on the wheel path, on the middle of the wheel path, on the shoulder with friction course, and on the shoulder without friction course are determined. It is mentionable that the driving lane and the shoulder have the same geometry, materials, and compaction effort. Results show that the modulus along the wheel path is almost the same as that of along the middle of the wheel path. The shoulder without friction course has a modulus greater than that of the lane AC modulus and the shoulder with the friction course. In addition, FWD backcalculated moduli at different temperatures are compared with the dynamic modulus values of the AC layer. It is found that the dynamic modulus at a loading frequency of 5 Hz is 1.7 to 1.9 times the backcalculated AC modulus.

An efficient and robust method for predicting asphalt concrete dynamic modulus

2021 ◽  
pp. 1-12
Author(s):  
Hongren Gong ◽  
Yiren Sun ◽  
Yuanshuai Dong ◽  
Wei Hu ◽  
Bingye Han ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
Dynamic Modulus ◽  
Robust Method

Dynamic Viscoelastic Properties of SBS Modified Asphalt Based on DSR Testing

2012 ◽  
Vol 598 ◽  
pp. 473-476 ◽  
Author(s):  
Yong Mei Guo ◽  
Wei Chen
Keyword(s):  
Complex Modulus ◽  
Superposition Principle ◽  
Asphalt Binder ◽  
Asphalt Binders ◽  
Frequency Range ◽  
Master Curves ◽  
Temperature Property ◽  
Low Frequencies ◽  
High Temperature Property ◽  
Frequency Sweeps

Five SBS modified asphalts and one base asphalt were selected to carry out frequency sweeps over a wider frequency range using the dynamic shear rheometer (DSR). Six asphalt binders were subjected to sinusoidal loading at 30°C-90°C within the linear viscoelastic limits, and master curves of complex modulus (G*) and phase angle (δ) could be constructed by means of the time-temperature superposition principle (TTSP). The results show that the G* values of SBS modified asphalts are significantly greater than those of base asphalt at low frequencies, but are slightly smaller at high frequencies. Compared with the base asphalt, SBS modified asphalts have narrower master curves of complex modulus, and their phase angles are much smaller within the whole frequency range. This indicates that various properties of SBS modified asphalts, such as high-temperature property, low-temperature property, temperature susceptibility and elastic recoverability, are superior to those of the base asphalt. The G* values of the rolling thin-film oven (RTFO) aged asphalt are larger than those of the unaged asphalt in the whole range of frequencies, demonstrating that the anti-rutting performance of asphalt binder is improved after short-term aging.

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