scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-temperature Strength Properties

2018 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperature action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength using the Thermal Stress Restrained Specimen Test (TSRST) and the Uniaxial Tension Stress Test (UTST), flexural strength using the Bending Beam Test (BBT) and fracture toughness using the Semi-Circular Bending Test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen is a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was proved by all test methods that were used. It was also observed that the level of cooling rate influences the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT and SCB test methods.

scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2118 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength was measured using the thermal stress restrained specimen test (TSRST) and the uniaxial tension stress test (UTST), flexural strength was measured using the bending beam test (BBT), and fracture toughness was measured using the semi-circular bending test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on the strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen was a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was valid for all test methods that were used. It was also observed that the level of cooling rate influenced the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT, and SCB test methods.

Evaluation and Improvement of Asphalt Mixture’s Performance at Low Temperature

2011 ◽  
Vol 255-260 ◽  
pp. 3326-3329
Author(s):  
Yong Qiang Zhong ◽  
Xiao Ming Huang ◽  
Gong Yun Liao
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Decay Rate ◽  
Tensile Strain ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Freeze Thaw ◽  
Flexural Tensile Strength ◽  
Fiber Bridging

In order to evaluate and improve the performance of asphalt mixture at low temperature, low-temperature bending test of asphalt mixture was done at first. It was shown that flexural-tensile strength and flexural-tensile strain of different oil-stone ratios reduced under freeze-thaw condition compared to no freeze-thaw condition. The maximum decay rate of flexural-tensile strength is about 18.97% and the maximum decay rate of flexural-tensile strain is about 6.59%. Then six types of polyester fiber were added to asphalt mixture and bending test at low temperature was done. Through the experiment results comparison of fiber asphalt mixtures, it is found that ultimate flexural strain of Good Road II fiber asphalt mixture increases the largest which is up to 12.95%. Ultimate flexural strain of Dolanit AS fiber asphalt mixture increases 8.67% and other fiber asphalt mixtures increase from 3% to 6%. Fiber bridging and fiber micro-reinforced role in the mixture improves the performance of asphalt mixture at low temperature.

scholarly journals On the influence of basic thermodynamics on thermal cracking resistance of asphalt mixtures in cooling tests

2018 ◽  
Vol 3 ◽  
pp. 1-7
Author(s):  
Daniel Steiner ◽  
Bernhard Hofko
Keyword(s):  
Tensile Strength ◽  
Cooling Rate ◽  
Thermal Cracking ◽  
Radiation Condition ◽  
Asphalt Mixtures ◽  
Air Cooling ◽  
Laboratory Assessment ◽  
Cracking Resistance ◽  
Viscoelastic Parameters ◽  
The Impact

The cooling test or Thermal Stress Restrained Specimen Test (TSRST) simulates fully restrained pavements, as they occur in field for laboratory assessment of the thermal cracking resistance of asphalt mixtures. In the TSRST, cryogenic stress builds up due to cooling and prevented shrinkage until the tensile strength of the specimen is exceeded and the specimen fails by cracking. By carrying out TSRST various viscoelastic parameters, e.g. relaxation, evolution of tensile stresses, and tensile strength can be analyzed. Thus, a comprehensive view on the low temperature performance is possible. Standard TSRST is controlled by setting the cooling rate of the air within the chamber at a fixed value, e.g. -10°C/h. In thermodynamics, the actual cooling rate of objects is not only influenced by the cooling but also by external conditions like humidity, air velocity, radiation condition, etc. A current study investigates the impact of additional cooling parameters rather than just the air cooling rate. Two test machines of the same manufacturer that differ in the year of production and the setup of the climate chamber are compared. An initial wide scatter of test results from the two devices could be explained by taking thermodynamics into account and the reproducibility could be significantly enhanced.

Research on Performance of Emulsion Asphalt Cold Reclaimed Mixture with Various RAP Contents

2011 ◽  
Vol 255-260 ◽  
pp. 3432-3436
Author(s):  
Xian Yuan Tang ◽  
Jie Xiao
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Compression Test ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Beam Test ◽  
Reclaimed Asphalt ◽  
Indirect Tensile ◽  
The Impact

This paper systematically elaborates the impact upon performance of emulsion asphalt cold reclaimed asphalt mixture by different RAP contents, through a series of testing on six cold reclaimed asphalt mixtures with various RAP contents, such as single axle compression test, 15°C indirect tensile strength (ITS) test, 40°C rutting test and -10°C low-temperature bending beam test. Testing results indicate that 15°C ITS decreases from around 0.75 MPa to 0.58 MPa with the RAP content of mixture increasing from 0% to 100%. 40°C dynamic stabilities reduce considerably from around 19,000 time/mm of 0% RAP mixture to 3,600 time/mm of 100% RAP mixture. -10°C failure strains only change from 1500με to 2000με.

scholarly journals Stiffness and Fatigue of Asphalt Mixtures for Pavement Construction

2018 ◽  
Vol 26 (2) ◽  
pp. 24-29 ◽  
Author(s):  
Juraj Šrámek
Keyword(s):  
Fatigue Life ◽  
Asphalt Mixture ◽  
Construction Materials ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Deformation Properties ◽  
Pavement Construction ◽  
And Control

AbstractThe quality of a road is affected by its correct design, the appropriate use of materials, the effects of the climate, and the technological discipline. The deformation properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The assessment of deformation properties is performed by means of a dynamic impact test and the fatigue life of a particular asphalt mixture. An evaluation of the fatigue life is based on decreases in resistance or increases in deformations in different binders and mixtures. The test methods for the design and control of pavement construction materials determine the basic conditions valid for flexible matter. The Two-Point Bending Test was used for determining the deformation characteristics and the fatigue of asphalt mixtures at the Department of Construction Management in Zilina.

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.

Selecting Most Desirable Hot-Mix Asphalt Mixtures

1997 ◽  
Vol 1590 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Peter E. Sebaaly ◽  
Dan Ridolfi ◽  
Raja S. Gangavaram ◽  
Jon A. Epps
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Hot Mix Asphalt ◽  
Resilient Modulus ◽  
Permanent Deformation ◽  
Strength Properties ◽  
Load Test ◽  
Aggregate Properties ◽  
Low Temperature Cracking ◽  
And Performance

Aggregate properties and gradations have been shown to have a significant impact on the strength and performance of HMA mixtures. Strength properties, such as the resilient modulus and tensile strength, and performance properties, such as moisture sensitivity, permanent deformation, and low-temperature cracking, play a major role in the field performance of HMA mixtures. However, it is believed that by changing the aggregate gradation and the asphalt binder, a desirable hot-mix asphalt mixture can be achieved for any source of aggregate. The data and analysis of a laboratory research study that evaluated four gradations and four asphalt binders in conjunction with five sources of Nevada aggregates are summarized. The measured material properties include the Superpave binder and aggregate properties, the strength properties, and the permanent deformation and low-temperature cracking of the mixtures. The data analysis indicated that the resilient modulus and tensile strength tests can be used in lieu of the more complicated triaxial repeated-load test to ensure against rutting and that the binder property can be used to ensure against low-temperature cracking.

scholarly journals Effect of Heat Treatment on the Mechanical Properties of Two-Phase Titanium Alloy Ti6al7nb/ Wpływ Obróbki Cieplnej Na Własności Mechaniczne Dwufazowego Stopu Tytanu Ti6al7nb

2014 ◽  
Vol 59 (4) ◽  
pp. 1713-1716 ◽  
Author(s):  
R. Dąbrowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Yield Strength ◽  
Cooling Rate ◽  
Strength Properties ◽  
Two Phase ◽  
Impact Tests ◽  
Alloy Heat

Abstract Mechanical properties of the two-phase titanium alloy Ti6Al7Nb, after the heat treatment based on soaking this alloy in the α + β range, cooling in water or oil and ageing at two selected temperatures, were determined in the hereby paper. The alloy mechanical properties were determined in tensile and impact tests, supported by the fractographic analysis of fractures. In addition, its hardness was measured and the analysis of changes occurring in the microstructure was performed for all variants of the alloy heat treatment. Regardless of the applied cooling rate of the alloy, from a temperature of 970°C followed by ageing at 450 and 650°C, none essential changes were noticed in its microstructure. It was shown that applying less intensive cooling medium (oil) instead of water (before tempering) decreases strength properties indicators, i.e. tensile strength and yield strength as well as hardness (only slightly). The decrease of the above mentioned indicators is accompanied by an increase of an elongation and impacts strength. Fractures of tensile and impact tests are of a ductile character regardless of the applied heat treatment.

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