Test Method for Evaluation of Asphalt Mixture Cracking Resistance using the Semi-Circular Bend Test (SCB) at Intermediate Temperatures

Author(s):  
2018 ◽  
Vol 2018 (11) ◽  
pp. 49-59
Author(s):  
Piotr Jaskula ◽  
Cezary Szydlowski ◽  
Marcin Stienss

Cracking is one of the predominant distresses occurring in flexible pavements, especially in old pavements that were rehabilitated with an asphalt overlay. In such cases asphalt mixtures should be designed to ensure high resistance to reflective cracking because new asphalt layers are exposed to existing cracks of the old pavement. The nature of these cracks can be various (transverse, longitudinal as well as crazy cracking). One factor that minimizes this type of distress is the proper mix design process, which should involve selection of specific bitumen binder and mineral mix gradation. However, still there is no universally adopted laboratory test method that would allow to clearly assess resistance of asphalt mixtures to reflective cracking. This paper describes the usage of one of the devices developed to test asphalt mixtures in terms of such distress – Texas Overlay Tester. For this test, samples prepared in laboratory conditions (i.e. compacted with the use of Superpave Gyratory Compactor) as well as obtained in the field (by core drilling) can be used. The results are obtained not only quickly and easily, but also with sufficient repeatability. The described method characterizes both crack initiation and crack propagation properties of asphalt mixtures. In this work one type of mineral mixture was tested with 4 different types of bitumen (one neat bitumen, two ordinary polymer-modified and one polymer-modified with high polymer content). For selected cases extra additives (rubber and loose fibres) were also tested. In total, six asphalt mixtures were tested. A ranking of the used binders was created on the basis of the results in order to conclude which bitumen would ensure the best performance characteristics in terms of reflective cracking. The results have clearly shown that deliberate choice of the binder used in the asphalt mixture for the overlay will significantly improve its reflective cracking resistance or even fatigue resistance.


2021 ◽  
Vol 3 (3) ◽  
pp. 69-75
Author(s):  
Cindy Pasilaputri ◽  
Alpius ◽  
Louise Elizabeth Radjawane

Several factors that can affect road damage are excessive traffic load, temperature (weather), water, and pavement construction that does not meet the technical requirements. The durability of an asphalt mixture is the resistance of the mixture to the effects of water, water vapor, and temperature. A mixture with a high durability value provides a good mix quality and long-term use. The purpose of this study was to determine the durability of the AC-BC mixture using Mount Baba stone. The general specifications of Bina Marga in 2018 are the reference in this study. By using the standard Marshall test method, the results obtained through the Marshall AC-BC mixture immersion test with a duration of immersion time of 0.5 hours, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours with a durability value of 95.49% - 86.99%. The increase in immersion time causes a decrease in the durability of the mixture.


2012 ◽  
Vol 446-449 ◽  
pp. 2590-2594
Author(s):  
Tuo Huang ◽  
Guo Ping Qian ◽  
Jian Long Zheng

2019 ◽  
Vol 10 (1) ◽  
pp. 130
Author(s):  
Tan Tan ◽  
Zepeng Fan ◽  
Chao Xing ◽  
Yiqiu Tan ◽  
Huining Xu ◽  
...  

It has long been recognized that fine aggregate (FA) plays a crucial role in the performance of asphalt mixture, especially for the viscoelastic behavior. In this research, 13 types of FA (1 natural sand, 5 stone chips, and 7 machine-made sands) were selected for investigation. Three indirect indicators (uncompact void content test, flow time test, and standard test method for index of aggregate particle shape and texture ASTM D3398) and three types of direct indicators (form, angularity, and texture) were employed to evaluate the geometric characteristics of FA and conduct comprehensive studies on the indicator system. Meanwhile, the effects of FA geometrical properties on the viscoelastic behavior of asphalt mortar were investigated. The results show that only the form indicator ratio of equivalent ellipse axis (E) and angularity indicator surface parameter (SP) can effectively distinguish different types of fine aggregates. The correlation analysis reveals that the parameters of the four elements in the Burgers model are negatively related to the form index (E) but positively related to the angularity index (SP), while the parameter retardation time ( τ r ) exhibits the opposite. This indicates that the use of less flat-elongated and more angular FA can increase both the overall stiffness and elastic component of asphalt mortar.


2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Jun Xie ◽  
Yougang Yang

In order to analyze the torsional shear process of asphalt mixtures in a microscopic view, the numerical simulation of a torsional shear test of an asphalt mixture was carried out by discrete element method. Based on the defects of existing algorithms, the method of random reconstruction of the existing 3D model of the asphalt mixture was improved, and a new reconstruction method was proposed. A 3D numerical model of the asphalt mixture contained irregular-shaped coarse aggregate, mineral gradation, and asphalt mortar; furthermore, the particle algorithm established the air void distribution. Then, the numerical simulation of the asphalt mixture’s torsional shear was completed; in addition, the stress, displacement, and contact of the specimens at each stage were analyzed. The results showed that the stress and displacement in different stages changed greatly with the loading, i.e., the crack generated from a weak point on the surface and then spread to the ends with an oblique angle of about 45°. At the same time, the shear failure process of the asphalt mixture was studied. The virtual test method could accomplish the implementation of the numerical simulation of torsional shear; it also provided a good research method for analysis of the asphalt mixture’s shear failure process.


2012 ◽  
Vol 5 ◽  
pp. 352-357 ◽  
Author(s):  
Ming Hao Hou ◽  
Yi Qiu Tan ◽  
Bin Hu

This paper introduces dynamic water effect into the test, develops a laboratory test device for simulating the dynamic water effect on asphalt pavement, and puts forward a test method of dynamic water effect working together with load, water and temperature. Based on this method, the high temperature stability of seven kinds of asphalt mixtures with the factors of asphalt grade, gradation and air voids are studied. The research shows that the effect of dynamic water can take adverse effect for the high temperature stability of asphalt mixture. The effect degree is different under different factors. It is the most disadvantaged when the air voids of the mixture is near 10%, the skeleton structure gradation of mixture is better than the suspended structure at the most disadvantage air voids, and the mixture made of high viscosity asphalt is more affected when the temperature is higher.


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