scholarly journals Investigating the Effect of Aggregate Characteristics on the Macroscopic and Microscopic Fracture Mechanisms of Asphalt Concrete at Low-Temperature

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2675 ◽  
Author(s):  
Yinshan Xu ◽  
Yingjun Jiang ◽  
Jinshun Xue ◽  
Jiaolong Ren
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Pavements ◽  
Fracture Mechanisms ◽  
Discrete Element Modeling ◽  
Aggregate Distribution ◽  
Initiation Zone ◽  
Low Temperature Cracking ◽  
Different Temperatures ◽  
Temperature Crack

The low-temperature crack of asphalt concrete is considered to be one of the main deteriorations in asphalt pavements. However, there have been few studies on the composite effects of the aggregate characteristics and fracturing modes on the low-temperature cracking of asphalt concrete. Hence, the edge cracked semi-circular bend tests and the discrete element modeling approaches are combined to investigate the effect of the aggregate contents, aggregate morphological features and aggregate distributions on the fracture behavior of asphalt concrete in different fracturing modes at different temperatures. The results show that the fracture toughness and the crack extended time reduce with the increasing aggregate orientation and flatness and the decreased aggregate content. The effect of aggregate flatness is nonlinear and its reduction trend grows gradually with the increasing flatness. The total number of failed contacts is reduced with the increasing aggregate orientation and flatness, particularly at 10 °C. The number of failed contacts that occurred in the aggregate-mastic interface in quasi mode II fracturing is slightly higher than that in other fracturing modes. The aggregate distribution in the crack initiation zone greatly influenced the crack resistance, particularly at 10 °C. The research is beneficial to better understanding the fracture mechanisms of asphalt concrete at low-temperature.

Low Temperature Cracking Evaluation of Asphalt Rubber Mixtures Using Semi-Circular Bending Test

2011 ◽  
Vol 243-249 ◽  
pp. 4201-4206 ◽  
Author(s):  
Jing Hui Liu
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Asphalt Pavements ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Low Temperature Cracking

Low temperature cracking is the main distress in asphalt pavements in winter. As asphalt rubber course is increasing, there is no standard method to characterize the resistance to cracking of asphalt rubber mixtures. This paper investigates the use of a Semi Circular Bend (SCB) test as a candidate for a low-temperature cracking specification. Based on the SCB test, this paper presents the findings of a laboratory study that aimed to evaluate the effects of recycled tire rubber on the Low temperature cracking properties of asphalt mixtures. Three mix types, a conventional hot-mix asphalt concrete, a dry process rubber modified asphalt concrete, and a wet process asphalt-rubber asphalt concrete, were included in the investigation. It is found that the asphalt mixtures produced by the wet process showed much better low temperature crack resistance, the binder effect modified by rubber was significant.

scholarly journals Performance and Microstructure of Cold Recycled Mixes Using Asphalt Emulsion with Different Contents of Cement

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2548 ◽  
Author(s):  
Yanhai Yang ◽  
Ye Yang ◽  
Baitong Qian
Keyword(s):  
Low Temperature ◽  
Temperature Stability ◽  
Hydration Products ◽  
High Temperature Stability ◽  
Asphalt Emulsion ◽  
Moisture Susceptibility ◽  
Pavement Maintenance ◽  
Maintenance And Rehabilitation ◽  
Low Temperature Cracking ◽  
Temperature Crack

Cold recycled mixes using asphalt emulsion (CRME) is an economical and environmentally-friendly technology for asphalt pavement maintenance and rehabilitation. In order to determine the optimum range of cement contents, the complex interaction between cement and asphalt emulsion and the effects of cement on performance of CRME were investigated with different contents of cement. The microstructure and chemical composition of the fracture surface of CRME with different contents of cement were analyzed in this paper as well. Results show that the high-temperature stability and moisture susceptibility of CRME increased with the contents of cement increasing. The low-temperature crack resistance ability gradually increased when the content of cement is increased from 0% to 1.5%. However, it gradually decreased when the content of cement is increased from 1.5% to 4%. Cold recycled mixes had better low-temperature cracking resistance when the contents of cement were in the range from 1% to 2%. The results of microstructure and energy spectrum analysis show that the composite structure is formed by hydration products and asphalt emulsion. The study will be significant to better know the effects of cement and promote the development of CRME.

Behaviour of recycled asphalt pavements at low temperatures

1991 ◽  
Vol 18 (3) ◽  
pp. 428-435 ◽  
Author(s):  
M. Sargious ◽  
N. Mushule
Keyword(s):  
Finite Element ◽  
Low Temperature ◽  
Thermal Stresses ◽  
Asphalt Pavements ◽  
Recycled Asphalt ◽  
Expected Performance ◽  
Different Types ◽  
Low Temperature Cracking ◽  
Proper Comparison ◽  
Better Than

This paper summarizes the results of a study conducted to evaluate the behaviour of recycled asphalt pavements with respect to low-temperature cracking. For this purpose, a recycled mix consisting of 45.2% reclaimed materials and 54.8% virgin materials as well as a virgin control mix were used in the research program. In the design of both mixes, their initial properties were kept as close as possible to each other to allow for a proper comparison between recycled and virgin asphalt pavements. Using mix properties that were determined experimentally in the laboratory, thermal stresses resulted from drop in temperature and the expected cracking temperatures were determined for both mixes. An experimental analysis based on laboratory tests that consider the pavement properties only as well as a more complete theoretical analysis based on a finite element computer program known as FETAB were included in this study. The program incorporates subgrade parameters, as well as pavement properties and thickness. Using these variables as inputs to the program, the expected performance of recycled and virgin asphalt pavements of various thicknesses and resting on different types of subgrade, with respect to low-temperature cracking, was studied. The results of the study indicated that recycled asphalt pavements would perform better than virgin asphalt pavements of similar initial properties. Key words: asphalt, finite element, low-temperature cracking, reclaimed, recycled, thermal stresses.

Research on Basalt Fiber Asphalt Concrete's Low Temperature Performance

2014 ◽  
Vol 505-506 ◽  
pp. 35-38 ◽  
Author(s):  
Chun Mei Gao ◽  
Shuo Han ◽  
Shuang Chen ◽  
He Li
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Failure Strain ◽  
Basalt Fiber ◽  
Test Method ◽  
Temperature Performance ◽  
Low Temperature Cracking ◽  
Indirect Tensile ◽  
Low Temperature Performance ◽  
Temperature Damage

Conduct experimental study on low temperature performance about asphalt concrete with 6mm basalt fiber and without basalt, 6mm fibers whose dosage is 0.12%0.15% and 0.17%, test method is the indirect tensile test,test temperature is-10±0.5°C. The results show that basalt fiber improved the strength and failure strain of asphalt concrete in low temperature damage, reduced the failure stiffness,in which the maximum increased value of breaking strength is 3.41%, the maximum increased value of failure strain is 38.83%,and the maximum reduced value of failure stiffness is 25.52%,obviously improved low temperature cracking resistance of asphalt concrete;for low temperature performance, the optimum amount of value about 6mm basalt fiber is 0.15% .

Prediction of Low-Temperature Cracking of Asphalt Concrete Mixtures with Thermal Stress Restrained Specimen Test Results

1996 ◽  
Vol 1545 (1) ◽  
pp. 50-58 ◽  
Author(s):  
Hannele K. Zubeck ◽  
Ted S. Vinson
Keyword(s):  
Thermal Stress ◽  
Low Temperature ◽  
Asphalt Concrete ◽  
Probabilistic Model ◽  
Deterministic Model ◽  
Crack Spacing ◽  
Test Results ◽  
Concrete Mixtures ◽  
Specimen Test ◽  
Low Temperature Cracking

A deterministic model and a probabilistic model were developed to predict low-temperature crack spacing as a function of time using thermal stress restrained specimen test results, pavement thickness and bulk density, pavement restraint conditions, and air temperature. The effect of aging on pavement properties was incorporated in the models by predicting the field aging with long-term oven aging treatment in the laboratory. The calculation of the crack spacing is based on the theory that the pavement slab cracks when the pavement temperature reaches the cracking temperature of the mixture and the slab is fully restrained. The deterministic model predicts crack spacing with time, whereas the probabilistic model predicts crack spacing and its variation with time and yields the reliability of the design with regard to a minimum acceptable crack spacing criterion defined by road authorities. The probabilistic model is recommended for use in predicting the low-temperature cracking of asphalt concrete mixtures.

Evaluation of Carbon Nanotubes Asphalt Modification Using the Superpave Criteria

2021 ◽  
Vol 902 ◽  
pp. 135-143
Author(s):  
Mohammad Ali Khasawneh ◽  
Khalid Ghuzlan ◽  
Nada Bani Melhem
Keyword(s):  
Carbon Nanotubes ◽  
Low Temperature ◽  
Rheological Properties ◽  
Asphalt Binder ◽  
Fatigue Cracking ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Low Temperature Cracking ◽  
Asphalt Modification ◽  
Rotational Viscosity

Rutting, fatigue cracking and low temperature cracking are the most important distresses in asphalt pavements as a result of changes in rheological properties of asphalt binder. Many types of modifiers were used to enhance asphalt behavior at both low and high temperatures. In this study, carbon nanotubes (CNT) were used as one of many nanomaterials that take a large attention in the latest research related to asphalt modification against different types of distresses. Effect of CNT on rheological properties of asphalt binder was investigated by testing unmodified and CNT modified asphalt binders using two of Superpave devices: Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). Penetration, softening point, flash point and rotational viscosity (RV) tests were carried out as well. CNT was added in 0.1%, 0.5% and 1% by weight of asphalt binder. It was found that adding CNT in 0.5% and 1% increase stiffness of asphalt and consequently asphalt pavement rutting resistance. On the other hand, this increase in stiffness affected pavement behavior adversely which is not desirable for fatigue and low temperature cracking. However, Superpave specifications were still satisfied and asphalt binder’s relaxation properties were improved upon CNT modification. It was eventually found that 0.5% of CNT is the optimum percentage for the best performance.

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