Low-Temperature Cracking and Aging Performance of Modified Asphalt Concrete Specimens

Author(s):  
Richard Fortier ◽  
Ted S. Vinson

The thermal stress restrained specimen test (TSRST) was used to evaluate the low-temperature cracking resistance and aging performance of modified asphalt concrete (AC) specimens. One aggregate, two asphalt cements (AAA-1 and AAB-1), five modifiers (latex polymer, ethylene acrylate copolymer, rubber powder, elastomer, and a blend of polypropylene and Kevlar fibers), and four 85°C oven aging levels (0, 5, 25, and 50 days) were considered. The results of the bending beam rheometer test (BBRT) on binders at −20°C showed that AAA-1 displayed a smaller creep stiffness than AAB-1. Only two modifiers increased the deflection and softness of AAB-1. The additives in AAA-1 did not improve its lowtemperature rheological behavior. These results served as the basis for comparison with those from the TSRST. The fracture strength and temperature of AC specimens are sensitive to asphalt type (4.11 MPa and −32.2°C for AAA-1, 3.28 MPa and −25.4°C for AAB-1) and degree of aging (from 4.11 to 2.04 MPa and from −32.2 to −21.2°C for AAA-1 for aging levels from 0 to 50 days at 85°C). Only one modifier in AAB-1 (among the two candidates identified with the BBRT) improved the low-temperature performance of the AC specimens. After 50 days of aging, no improvement was observed. The modified AAA-1 AC specimens displayed an optimum improvement in performance for aging levels of 25 and 50 days. Several modified AC specimens displayed a low-temperature failure without apparent fracture. This behavior would appear to be advantageous for the performance of pavements in cold regions.

Author(s):  
Hannele K. Zubeck ◽  
Ted S. Vinson

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.


2017 ◽  
Vol 5 (12) ◽  
pp. 7797-7801 ◽  
Author(s):  
Safaa Moubark ◽  
Farag Khodary ◽  
Ayman Othman

It is noticeable that the increase of road traffic during the last two decades in addition to the insufficient degree of maintenance caused an accelerated deterioration of road structure. These roads show early signs of distress such as rutting, cracking, low temperature cracking, ageing and stripping. Heavier loads and higher traffic volume demand higher performance of pavement.  Excellent performance of pavement requires bitumen that is less susceptible to high temperature, rutting or low temperature cracking. Several additives are used to increase the performance of bitumen and the quality of the produced mixtures. Polymers are considered the most widely used additives in asphalt modification that give better performance. The performance of the Polymer-modified asphalt depends on the type and the level of modification the used polymer. The choice of modification level and t modification type depends on the physical properties of the polymer, and its compatibility with bitumen. The polymer can be loosely classified into two categories, Plastomers and Elastomers. The results indicated that, the addition of polypropylene generally improved the mechanical properties of the mixture regardless of the percentage of polymers that added and (PP) content of 5%. it can be noticed that  the performance of PP-modified asphalt mixtures is better  compared with unmodified asphalt concrete mixtures  modifier because it has the highest Marshall Stiffness, indirect tensile strength and unconfined compressive strength


Author(s):  
Hannele K. Zubeck ◽  
Huayang Zeng ◽  
Ted S. Vinson ◽  
Vincent C. Janoo

Construction histories, cracking observations, and temperature data were collected for five test roads in Alaska, Pennsylvania, and Finland. A full-scale and fully controlled low-temperature cracking test program was conducted at the U.S. Army Cold Regions Research and Engineering Laboratory. Specimens were fabricated in the laboratory with original asphalt cements and aggregates from the test roads. The thermal stress restrained specimen test (TSRST) results obtained for these samples were correlated with the field observations. On the basis of a statistical analysis of the data, the TSRST fracture temperature is associated with the field cracking temperature and crack frequency for the test roads where mixture properties dominated low-temperature cracking. It was concluded that the TSRST can be used to simulate low-temperature cracking of asphalt concrete mixtures.


2018 ◽  
Vol 163 ◽  
pp. 05012
Author(s):  
Amal Abdelaziz ◽  
Chun-Hsing Ho ◽  
Matthew Snyder

Low temperature cracking is one of the most common distress types in asphalt concrete pavements, particularly in cold regions. Many factors influence the behaviour of asphalt concrete pavements at low temperatures, such as the applied traffic load, environmental conditions and material characteristics. Asphalt binders are one of the primary factors that influence material properties. The purpose of this study is to compare the performance of two types of asphalt binders: styrene-butadiene-styrene (SBS) modified asphalt binder and unmodified asphalt binder in resisting low temperature cracking. The study was conducted in Flagstaff, located at the area of Northern Arizona, in the United States. Asphalt samples were collected from the paving sections and were compacted and trimmed into small beams. Bending Beam Rheometer tests were performed, using the trimmed specimens at temperatures of -6°C, -12°C and -18°C. Based on the results of the study, it was concluded that, SBS modified asphalt binder performs better in resisting low temperature cracking, compared to the unmodified binder. Based on the study outcomes, it is recommended to use SBS polymer modified polymers in areas subjected to severe cold weather events to maximize the life span of asphalt concrete pavements.


2011 ◽  
Vol 374-377 ◽  
pp. 1385-1390
Author(s):  
Rui Xia Li ◽  
Pei Wen Hao ◽  
Chun Wang

With the experiments of dynamic shear rheometer(DSR), bending beam rheometer(BBR) and Brookfield rotary viscometer, the rheological performance of Buton Rock Asphalt (BRA) modified asphalt is tested and analyzed. The results indicate that the high temperature PG grades, the anti-rutting indicator and the viscosity are all increased, the high temperature stability is enhanced greatly and the temperature sensitivity is reduced after the addition of BRA modifier. Furthermore, the change rate increases with the increase of the additive; the creep stiffness modulus increases and low-temperature performance decreases at a low temperature, so the dosage of BRA should be appropriately considered in the process of application.


2018 ◽  
Vol 45 (6) ◽  
pp. 469-477 ◽  
Author(s):  
Sevil Köfteci ◽  
Perviz Ahmedzade ◽  
Taylan Günay

The aim of this paper is to examine the effects of ground plastic pipe wastes on bitumen. For this purpose, three modified bitumen samples with modifier contents of 2%, 4%, and 6% along with pure bitumen were prepared and tested. To understand the effect of modifier on bitumen, conventional bitumen tests, rotational viscosity tests at 135 °C and 165 °C, dynamic shear rheometer tests at three different frequencies that represent three different traffic speeds, and bending beam rheometer (BBR) test were performed. The BBR test results showed that resistance of pure bitumen to low-temperature cracking increased by using additives up to 4%. Based on the results of this study, it can be said that waste plastic pipes can be used as modifier for the bitumen binder. The 4% additive showed the best performance.


2014 ◽  
Vol 505-506 ◽  
pp. 35-38 ◽  
Author(s):  
Chun Mei Gao ◽  
Shuo Han ◽  
Shuang Chen ◽  
He Li

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% .


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Wenhui Zhao ◽  
Xiangbing Xie ◽  
Guanghui Li ◽  
Jiuguang Geng ◽  
Meng Bao ◽  
...  

To expand the application range of modified asphalt and mixtures and effectively reduce the aggregation of nanomaterials in asphalt, nanocarbon/styrene butadiene styrene (SBS)/rubber powder composite-modified asphalt is proposed. This paper presents a laboratory study on the performance of nanocarbon/copolymer SBS/rubber powder composite-modified asphalt, and nanocarbon particles modified by titanate coupling agents as modifiers are selected. The nanocarbon/copolymer SBS/rubber powder composite-modified asphalt was prepared by a high-speed shearing method. The physical properties and rheological performance were assessed using ductility tests, softening point tests, penetration tests, dynamic shear rheometer (DSR) tests, and bending beam rheometer (BBR) tests. Furthermore, the mixture properties, including the high-temperature stability, low-temperature cracking resistance, moisture stability, and freeze-thaw splitting, were evaluated in the laboratory. The micromorphology of the base asphalt and composite-modified asphalt was examined by scanning electron microscopy (SEM), and the reactions between the modifiers and AH-70 base asphalt were studied by Fourier transform infrared spectroscopy (FTIR). The results reveal that the surface-modified nanocarbon and rubber powder additives substantially increased the softening point and penetration index of the base asphalt, with little obvious influence on the low-temperature performance. In addition, when nanocarbon/copolymer SBS/rubber powder composite-modified asphalt was used, the high-temperature stability and low-temperature cracking resistance of the nanocarbon/copolymer SBS/rubber powder composite-modified asphalt mixture were approximately 1.3 times those of the nanocarbon/rubber powder asphalt mixture. In terms of the micromorphology and reaction, the addition of the nanocarbon can increase the compatibility between the base asphalt and rubber powder, and then the addition of copolymer SBS can improve the structure of nanocarbon (after surface modification)/rubber powder-modified asphalt to form a stable network. Moreover, the physical reaction plays the dominant role in the modification process for the rubber powder and base asphalt, and chemical reactions occur in the modification process for the surface-modified nanocarbon and base asphalt.


2021 ◽  
Vol 891 ◽  
pp. 211-217
Author(s):  
Huan He

This paper studied the aging effect of the rolling thin film oven test (RTFOT) , pressurized aging vessel (PAV) and natural ultraviolet radiation aging method on AH-90 and PG70-28 asphalts. penetration degree , penetration degree index,softening point and ductility tests were used to evaluate the high temperature stability, low temperature split and temperature susceptibility of the two aged asphalts , it is pointed that the aging damaged the low temperature performance of the asphalts, improved the high temperature stability and the temperature susceptibility of the asphalts. Compared with the AH-90 asphalt, PG70-28 modified asphalt has better aging performance. The antiaging property and temperature susceptibility of two asphalts after ultraviolet photooxidation and thermal oxidation , were investigated by testing their viscosity index , antiaging index. which indicated that the viscosity index is correlative nearly with the penetration degree index and the influence of 10.5 kJ·cm-2 ultraviolet photooxidation on asphalt performance is more serious than PAV thermal oxidation. The results indicate that ultraviolet photooxidation research on asphalt is necessary in the intensive ultraviolet radiation region of Neimeng.


Sign in / Sign up

Export Citation Format

Share Document