Assessing Fatigue Life of Superpave Asphalt Concrete

2014 ◽  
Vol 1 (4) ◽  
pp. 88 ◽  
Author(s):  
Saad Issa Sarsam ◽  
Ali Hussein Alwan
Author(s):  
Md Mehedi Hasan ◽  
Hasan M. Faisal ◽  
Biswajit K. Bairgi ◽  
A. S. M. Rahman ◽  
Rafiqul Tarefder

Asphalt concrete’s dynamic modulus (|E*|) is one of the key input parameters for structural design of flexible pavement according to the Mechanistic Empirical Pavement Design Guide (MEPDG). Till this day, pavement industry uses |E*| to predict pavement performance whether the material is hot mix asphalt (HMA) or warm mx asphalt or Reclaimed Asphalt Pavement (RAP) mixed HMA. However, it is necessary to investigate the correlation of |E*| with laboratory performance testing. In this study, laboratory dynamic modulus test was conducted on four different asphalt concrete mixtures collected from different construction sites in the state of New Mexico and mastercurves were obtained to evaluate dynamic modulus (|E*|) for a wide range of frequency. In addition, fatigue performance of these mixtures was predicted from the mastercurves and compared with the laboratory fatigue performance testing. Fatigue performance of these mixtures was evaluated from the four point beam fatigue test. The laboratory results show a good agreement with the predicted value from mastercurves. It is also observed from this study that the fatigue life of the asphalt concrete materials decreases with increase in |E*| value.


Author(s):  
Waleed Abdelaziz Zeiada ◽  
Padmini P. Gudipudi ◽  
B. Shane Underwood ◽  
Mena I. Souliman

Fatigue cracking is one of the most critical types of distress in asphalt pavements and is due to actions of repetitive traffic loading over time. The fatigue life of asphalt concrete is often estimated from laboratory experiments where the performance depends directly on the test method, loading conditions, temperature, rest period, and aging in addition to the composition and properties of the mixture itself. The uniaxial fatigue test has become a popular method for developing constitutive models that describe the fatigue behavior of asphalt concrete mixture owing to the uniform states of stress across the specimen section. This study investigates the effect of the loading waveform (sinusoidal versus haversine) and rest period (continuous versus intermittent) on the laboratory fatigue life of asphalt concrete mixtures. The fatigue analysis was performed using the simplified viscoelastic continuum damage (S-VECD) approach where the damage characteristic (C-S) curves were established for all the cases, and then used to estimate the fatigue laws through simulated predictions. The proposed uniaxial fatigue test and analysis method were able to determine the fatigue life relationships of asphalt concrete mixture at different waveform and rest period conditions with a reduced testing time compared to other traditional testing and analysis methods. Overall, both rest period and waveform pattern were found to affect the laboratory fatigue life of asphalt concrete mixture. Model predictions show that pulse-rest loading yields an equivalent fatigue life to continuous loading at strain values that are approximately four times greater.


2011 ◽  
Vol 306-307 ◽  
pp. 888-893 ◽  
Author(s):  
Shi Lin Yan ◽  
Wen Tao Li ◽  
Shao Peng Wu ◽  
Ling Pang

The research on the conductive asphalt concrete(CAC) is to melt snow and ice on the pavement and improve the property of skid resistance. However, research at present mainly focuses on the electrical property not on the fatigue behavior which is also important to the application of CAC in the future. The specific rheological model is developed and the relation between creep and fatigue is investigated in this paper. By the single axial static creep test, the existed rheological model (Burgers model) and method of regression, the creep deformation of asphalt concrete is measured with time and parameters of the model are obtained. The results indicate that strain increases quickly with increasing time at initial loading phase, and then the change of strain tend to a stable value in a constant load. At unloading phase, strain decreases immediately and then keep another stable value which was greater than zero. The addition of conductive fillers improves the elastic properties and has no significant influence to the viscosity of asphalt concrete. In addition, the fatigue life can be predicted by the parameters of the Burgers model. The addition of conductive fillers improves energy dissipated, which leads to shorter fatigue life of conductive asphalt concrete compared to the control at levels of longer fatigue life.


2019 ◽  
Vol 5 (12) ◽  
pp. 2727-2737
Author(s):  
Amjad H. Albayati ◽  
Waleed Arrak Turkey

Sustainability is very important in this world at this time. One of the best materials used for sustainability in asphalt concrete pavements is the warm mix asphalt (WMA) as well as the reclaimed asphalt pavement (RAP). WMA technology has the ability to reduce production temperature to reduce the fuel usage and emissions. RAP is the old concrete asphalt mixture that is out of service and using it again leads to preservation of the virgin material. This search studied the viability of using WMA with different percentages of RAP (10%, 30%, and 50%) and compared them with control hot mix asphalt (HMA) and WMA. The Marshall properties, Tensile strength ratio (TSR), rut depth and fatigue life were determined in this work. The results showed that the tensile strength ratio (TSR) for HMA was better than that for WMA by 6%, rut depth for HMA was (4.37 mm) lower than that for WMA was (6.5mm), better fatigue life was obtained for WMA was (700 cycle) as compared to HMA was (500 cycle). In case of WMA with RAP (WMA-RAP), when the percentage of RAP increased with WMA, the moisture damage resistance improved by 2.5%, 13.3% and 15.4% for G1, G3 and G5 respectively, also the rutting resistance improved by 34.6%, 48% and 62.3% for G1, G3 and G5 respectively, but deteriorated of fatigue life by 45.8%, 74% and 88.5% for G1, G3 and G5 respectively.


2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Saad Issa Sarsam

The fatigue life of asphalt concrete is often related to environmental condition, loading condition, ageing, material composition and  properties. This work investigates the influence of short and long term ageing of laboratory beam specimens, asphalt content, and testing temperature on fatigue life of asphalt concrete wearing course. Slab samples of (30 x 40x 6) cm have been prepared, beam specimens of (40x 5x 6) cm were cut from the asphalt concrete slab samples. Beam specimens were tested for fatigue life under the influence of three levels of micro strain (250, 400, and [3]750) at (5, 20, and 30) °C before and after practicing long-term aging. It was observed that the fatigue life decreases by (85 and 97) %, (87.5 and 97.4) %, (71.4 and 95.2) % after increasing the applied microstrain from (250 to 400 and 750) μƐ for control mixture and for mixtures subjected to short-and long-term ageing processes respectively. The fatigue life increases by (142.8 and 257.1) %, (34.4 and 57.8) % and (10 and 30) % when the asphalt content increases from (4.4 to 4.9 and 5.4) % for specimens practicing the applied microstrain of (250, 400 and 750) μƐ respectively. It was concluded that the fatigue life increases by a range of (two to fifteen) folds when the testing temperature increases from (5 to 20 and 30)°C respectively.


Author(s):  
Saad I. Sarsam

Implementation of additives to the asphalt binder can enhance the overall physical properties of the modified asphalt concrete. In the present assessment, an attempt has been made to use 2 % of silica fumes and 4 % of fly ash class F for modification of asphalt binder in wet process. Asphalt concrete wearing course mixtures have been prepared and compacted by roller in the laboratory. The beam specimens of 400 mm length and 50 mm height and 63 mm width were extracted from the slab samples. The specimens were subjected to the four-point repeated flexural bending beam test. The flexural stiffness was calculated under three constant micro strain levels of (250, 400, and 750). The fatigue life was monitored in terms the number of load repetitions to reach the required reduction in stiffness. It was concluded that the flexural stiffness increases by (11, and 15) %, (17.7, and 63.6) %, (57.2, and 65) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 microstrain levels respectively. However, the fatigue life of asphalt concrete beam specimens increases by (40, and 72.8) %, (115, and 220.6) %, (46, and 94.6) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 microstrain levels respectively. It is recommended to use modified binder with fly ash and silica fumes in asphalt concrete to enhance the fatigue life and stiffness.


Author(s):  
Jorge B. Sousa ◽  
Jorge C. Pais ◽  
Manuel Prates ◽  
Rui Barros ◽  
Pierre Langlois ◽  
...  

Four-point bending fatigue tests following the Strategic Highway Research Program (SHRP) M009 test protocol were executed to investigate to what extent gradation has an effect on fatigue performance of asphalt aggregate mixes. Gradations and mixes were selected that would satisfy all volumetric Superpave designs passing below the restricted zone. Other mixes were prepared with gradations passing through and above the restricted zone. The measured fatigue lives of 130 actual laboratory tests were compared with predictions by the Shell, Asphalt Institute, and SHRP-A003A fatigue-predictive equations.


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