New Class of Reactive Polymer Modifiers for Asphalt: Mitigation of Low-Temperature Damage

2000 ◽  
Vol 1728 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Glen A. Crossley ◽  
Simon A. M. Hesp
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Polymerization Process ◽  
Stable Mode ◽  
Reactive Polymer ◽  
New Class ◽  
Specimen Test ◽  
Temperature Damage ◽  
Styrene Butadiene ◽  
Polymer Modifiers

Results from the low-temperature performance evaluation of a new class of reactive polymer modifiers designed to improve binder-aggregate adhesion in asphalt concrete are discussed. A living free radical polymerization process was used to prepare polyisoprene (PI) with short blocks of reactive silane-functional monomer at one end of the polymer chain. Performance was evaluated with the thermal stress restrained specimen test at a cooling rate of-10°C/h. The results obtained were compared with those for unmodified and styrene-butadiene (SB)-modified mixes. When added at 3 and 6 percent by weight of the binder, SB reduced the fracture temperature of the asphalt concrete by 6°C and 9°C, respectively. Similar results were obtained with the reactive polymers. However, although all the SB-modified samples failed in a catastrophic mode, none of the samples containing the silane-functional PI did. It is hypothesized that these polymers toughened the asphalt to an extent that cracks were only able to grow in a stable mode as opposed to an unstable mode or that localized yielding occurred. The method for obtaining the desired toughening effect is flexible; lower-cost monomers, such as butadiene, and more common polymerization methods, such as emulsion or anionic polymerization techniques, could be used equally well to produce polymers with similar or better performance characteristics. An added benefit is that the tested polymers were able to improve the stripping resistance of the mix significantly.

New Class of Reactive Polymer Modifiers for Asphalt: Mitigation of Moisture Damage

2000 ◽  
Vol 1728 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Glen Crossley ◽  
Simon Hesp
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Asphalt Concrete ◽  
Lower Cost ◽  
Water Immersion ◽  
Polymerization Process ◽  
Reactive Polymer ◽  
New Class ◽  
Added Benefit ◽  
Polymer Modifiers

A new class of reactive polymer modifiers designed to improve binder-aggregate adhesion in asphalt concrete was evaluated. Using a controlled free radical polymerization process, polyisoprene was prepared with short blocks of reactive amino- or silane-functional monomer at one end of the polymer chain. The reactive polymers so synthesized were tested with a modified version of the Tunnicliff-Root method (ASTM D4867) for measuring retained tensile strengths after water immersion moisture conditioning at 60°C for 24 h. It was found that the retained tensile strength of the unmodified samples was 53 percent, and the retained tensile strength of the regular polyisoprene-modified control samples was between 57 and 69 percent, depending on the polymer molecular weight and content. The best retained tensile strengths of 86 and 90 percent, respectively, were obtained with samples modified with 3 and 5 percent by weight of the higher-molecular-weight silane-functional polyisoprene. The method for obtaining the desired effect is flexible; lower-cost monomers, such as butadiene, and more common polymerization methods, such as emulsion or anionic polymerization techniques, may be used equally well to produce polymers with similar or better performance characteristics. An added benefit is that the tested polymers imparted significant improvements in low-temperature performance measured with the thermal stress restrained cooling test.

Fracture toughness of polymer-modified asphalt concrete at low temperatures

2003 ◽  
Vol 30 (2) ◽  
pp. 406-413 ◽  
Author(s):  
Kwang W Kim ◽  
Seung Jun Kweon ◽  
Young S Doh ◽  
Tae-Soon Park
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Asphalt Concrete ◽  
Low Temperatures ◽  
Asphalt Binder ◽  
Polymer Modification ◽  
Modified Asphalt ◽  
Temperature Damage ◽  
Polymer Modified Asphalt ◽  
Styrene Butadiene

The fracture toughness of asphalt concrete increases at low temperature and then decreases at temperatures below a certain level. Some polymers are known to have the property of improving the temperature susceptibility of asphalt binder at low temperatures. Therefore, this study evaluated the fracture toughness (KIC) of some polymer-modified asphalt concretes. Low-density polyethylene (LDPE), styrene–butadiene–styrene (SBS), and a mixed polymer of LDPE and SBS were used in this study. The fracture toughness KIC of normal asphalt concrete was compared with that of polymer-modified asphalt (PMA) concrete, and the effectiveness of polymer modification against falling values of KIC was evaluated at low temperatures. The results showed that PMA concretes, in general, showed better KIC than normal asphalt concretes, and the temperature at which the highest KIC was obtained was lower than that in the case of normal asphalt concrete. Therefore, the PMA concretes evaluated in this study had better fracture resistance than normal asphalt at low temperatures.Key words: asphalt concrete, polymer-modified asphalt, PMA, fracture toughness, differential thermal contraction, low-temperature damage.

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.

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

1998 ◽  
Vol 1630 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Richard Fortier ◽  
Ted S. Vinson
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Bending Beam Rheometer ◽  
Modified Asphalt ◽  
Acrylate Copolymer ◽  
Specimen Test ◽  
Low Temperature Cracking ◽  
Creep Stiffness ◽  
Rheometer Test ◽  
Aging Performance

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.

Field Validation of Thermal Stress Restrained Specimen Test: Six Case Histories

1996 ◽  
Vol 1545 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Hannele K. Zubeck ◽  
Huayang Zeng ◽  
Ted S. Vinson ◽  
Vincent C. Janoo
Keyword(s):  
Thermal Stress ◽  
Low Temperature ◽  
Asphalt Concrete ◽  
Temperature Data ◽  
Field Validation ◽  
Case Histories ◽  
Test Program ◽  
Concrete Mixtures ◽  
Specimen Test ◽  
Low Temperature Cracking

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.

scholarly journals Evaluation of Properties and Micro-Characteristics of Waste Polyurethane/Styrene-Butadiene-Styrene Composite Modified Asphalt

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2249
Author(s):  
Bei Chen ◽  
Fuqiang Dong ◽  
Xin Yu ◽  
Changjiang Zheng
Keyword(s):  
Low Temperature ◽  
Performance Test ◽  
Permanent Deformation ◽  
Modified Asphalt ◽  
Basic Performance ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Sbs Modified Asphalt ◽  
And Storage ◽  
Butadiene Styrene

In order to solve the problems caused by asphalt diseases and prolong the life cycle of asphalt pavement, many studies on the properties of modified asphalt have been conducted, especially polyurethane (PU) modified asphalt. This study is to replace part of the styrene-butadiene-styrene (SBS) modifier with waste polyurethane (WP), for preparing WP/SBS composite modified asphalt, as well as exploring its properties and microstructure. On this basis, this paper studied the basic performance of WP/SBS composite modified asphalt with a conventional performance test, to analyze the high- and low-temperature rheological properties, permanent deformation resistance and storage stability of WP/SBS composite modified asphalt by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The microstructure of WP/SBS composite modified asphalt was also observed by fluorescence microscope (FM) and Fourier transform infrared spectroscopy (FTIR), as well as the reaction between WP and asphalt. According to the results of this study, WP can replace SBS as a modifier to prepare WP/SBS composite modified asphalt with good low-temperature resistance, whose high-temperature performance will be lower than that of SBS modified asphalt. After comprehensive consideration, 4% SBS content and 15% WPU content (4 S/15 W) are determined as the suitable types of WPU/SBS composite modified asphalt.

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