Precision of the Dynamic Modulus and Flow Number Tests Conducted with the Asphalt Mixture Performance Tester

2011 ◽  
Author(s):  
◽  
◽  
Author(s):  
Hassan Malekzehtab ◽  
Hamid Nikraz

The dynamic modulus of the asphalt mixtures is an important factor in designing or analyzing an asphalt concrete pavement, but it is expensive and time consuming to measure. Therefore, it is important to develop a model to predict this value. In this regard, the Hirsch model is a popular model, however, it is developed based on a range of U.S. asphalt mixtures and standards. Therefore, it is not certain that it can be used for asphalt mixtures based on materials and codes other than U.S. This article investigated whether this model performs satisfactorily with two typical asphalt mixtures in Western Australia (WA) containing 0, 10, 20, and 30% of recycled asphalt pavement. To do so, cylindrical samples were made with materials and locally established standards in Western Australia and then tested in Asphalt Mixture Performance Tester (AMPT) machine to acquire their dynamic modulus and phase angle values in different loading frequencies (0.01 to 10 Hz) and temperatures (4 to 40°C). Meanwhile, the results are estimated by the Hirsch model using some properties of the mixture and binder. The properties of the binder in different test conditions are obtained using a dynamic shear rheometer. The comparison of the results showed that the dynamic modulus underestimation or overestimation error can reach to 50 and 280% respectively. Generally, this model did not perform well in this study.


2008 ◽  
Vol 35 (10) ◽  
pp. 1114-1119 ◽  
Author(s):  
Shu Wei Goh ◽  
Zhanping You

This paper shows a preliminary study of asphalt mixtures containing bottom ash with a primary focus on the permanent deformation. The objectives of this study are (i) perform literature reviews on the mechanical properties of asphalt mixtures containing bottom ash; (ii) evaluate the effects of using bottom ash as the mineral filler for the asphalt mixture through the flow number and dynamic modulus tests; and (iii) use the test results to evaluate the pavement permanent deformation using the Mechanistic–empirical pavement design guide (MEPDG) analysis. It was found that the asphalt mixture using bottom ash uses higher asphalt content due to the higher absorption. The replacement with bottom ash in the asphalt mixture generates a lower dynamic modulus as compared to the control mixtures. Additionally, results from MEPDG analysis show mixtures with bottom ash have higher rutting potential.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chaohui Wang ◽  
Songyuan Tan ◽  
Qian Chen ◽  
Jiguo Han ◽  
Liang Song ◽  
...  

Dynamic modulus is a key evaluation index of the high-modulus asphalt mixture, but it is relatively difficult to test and collect its data. The purpose is to achieve the accurate prediction of the dynamic modulus of the high-modulus asphalt mixture and further optimize the design process of the high-modulus asphalt mixture. Five high-temperature performance indexes of high-modulus asphalt and its mixture were selected. The correlation between the above five indexes and the dynamic modulus of the high-modulus asphalt mixture was analyzed. On this basis, the dynamic modulus prediction models of the high-modulus asphalt mixture based on small sample data were established by multiple regression, general regression neural network (GRNN), and support vector machine (SVM) neural network. According to parameter adjustment and cross-validation, the output stability and accuracy of different prediction models were compared and evaluated. The most effective prediction model was recommended. The results show that the SVM model has more significant prediction accuracy and output stability than the multiple regression model and the GRNN model. Its prediction error was 0.98–9.71%. Compared with the other two models, the prediction error of the SVM model declined by 0.50–11.96% and 3.76–13.44%. The SVM neural network was recommended as the dynamic modulus prediction model of the high-modulus asphalt mixture.


2011 ◽  
Vol 243-249 ◽  
pp. 4220-4225
Author(s):  
Rui Bo Ren ◽  
Li Tao Geng ◽  
Li Zhi Wang ◽  
Peng Wang

To study the mechanical properties of high modulus asphalt mixtures, dynamic modulus and phase angle of these two mixtures are tested with Simple Performance Testing System under different temperatures, loading frequencies and confining pressures. Testing results show the superiority of high modulus asphalt mixture in aspect of high temperature performance. Furthermore, the changing rules of dynamic modulus and phase angle are also discussed.


2011 ◽  
Vol 287-290 ◽  
pp. 1155-1163
Author(s):  
Shao Long Huang ◽  
Fan Shen ◽  
Qing Jun Ding

In this paper, recycled PE was added directly to the asphalt mixture to prepare high modulus asphalt mixture. To study the influence of the dosage and molecular weight of recycled PE on the performance of asphalt mixture, three kinds of recycled PE with different molecular weight and three asphalt binders (Conventional, SBS Modified and PE Modified) were used to prepare eight kinds of asphalt mixture. Various tests, including dynamic modulus, wheel tracking and Lottman test, were conducted to evaluate the performance of them. The results showed that 1) the dynamic modulus of asphalt mixture modified by recycled PE is higher than the normal mixture and mixture prepared with SBS modified asphalt binder; 2) adding recycled PE directly into the asphalt mixture during mixing is more effective than preparing asphalt mixture with PE modified asphalt binder in making high modulus asphalt mixture; 3) the recycled PE used to produce high modulus asphalt mixture should have certain big molecular weight, more than 27,000, and the dosage of recycled PE should be no less than 0.4% of the total weight of asphalt mixture. The performance tests indicted the good high temperature deformation resistance property of asphalt mixture modified by recycled PE.


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