Discrete Element Method (DEM) Analyses of Hot-Mix Asphalt (HMA) Mixtures Compaction and Internal Structure

2013 ◽  
Vol 639-640 ◽  
pp. 1287-1294 ◽  
Author(s):  
Jing Song Chen ◽  
Lei Zeng ◽  
Jian Yin
Keyword(s):  
Discrete Element Method ◽  
Hot Mix Asphalt ◽  
Coarse Aggregate ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Point Of View ◽  
Compaction Process ◽  
Dem Simulation ◽  
Air Voids ◽  
Superpave Gyratory Compactor

Asphalt mixture compaction is an important procedure of asphalt mixture construction and can significantly affect the performance of asphalt pavement. In this paper, an open source DEM code was applied to simulate the compaction of hot-mix asphalt (HMA) with the Superpave gyratory compactor. The asphalt mixture compaction process, air voids distribution, internal coarse aggregate structure, and the effect of CA ratio were investigated from a microscopic point of view. The analysis results show that DEM simulation is an economical and effective approach to the research of asphalt mixture compaction, and has tremendous potential for asphalt mixture design.

Laboratory Investigation of Mixing Hot-Mix Asphalt with Reclaimed Asphalt Pavement

2005 ◽  
Vol 1929 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Baoshan Huang ◽  
Guoqiang Li ◽  
Dragan Vukosavljevic ◽  
Xiang Shu ◽  
Brian K. Egan
Keyword(s):  
Layered Structure ◽  
Hot Mix Asphalt ◽  
Coarse Aggregate ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Reclaimed Asphalt Pavement ◽  
Controlled Experiments ◽  
Reclaimed Asphalt ◽  
Aged Asphalt ◽  
Blending Process

This paper presents a laboratory study in which the blending process of reclaimed asphalt pavement (RAP) with virgin mixture was analyzed through controlled experiments. One type of screened RAP was blended with virgin (new) coarse aggregate at different percentages. A blended mixture containing 20% of screened RAP was subjected to staged extraction and recovery. The result from this experiment indicated that only a small portion of aged asphalt in RAP actually participated in the remixing process; other portions formed a stiff coating around RAP aggregates, and RAP functionally acted as “composite black rock.” The resulting composite layered structure was desirable to improve the performance of the hot-mix asphalt mixture.

scholarly journals Effect of Adding Crushed Glass to Asphalt Mix

2016 ◽  
Vol 62 (2) ◽  
pp. 35-44 ◽  
Author(s):  
Y. Issa
Keyword(s):  
Specific Gravity ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Waste Glass ◽  
Maintenance Cost ◽  
Original Sample ◽  
Air Voids ◽  
The World ◽  
Asphalt Mix

Abstract The need to modify conventional pavement rises due to high maintenance cost of the highway systems. With the continuously increased consumption, a large amount of waste glass materials is generated annually in the world. This paper aims to study the performance of pavement asphalt in which a fractional aggregate is replaced with crushed glass. In this paper, some important properties of asphalt mix, including stability, flow, specific gravity and air voids are investigated. The original sample is prepared without adding glass for different percentages of bitumen. Other samples are prepared by adding crushed glass to the mix with 5%, 10%, and 15% by aggregate weight. The results show that the properties of glass-asphalt mixture are improved in comparison with normal asphalt pavement. It is concluded that the use of waste glass in asphalt pavement is desirable.

Compaction Quality of Bitumen Mixtures Based on Ultrasonic Methods

2007 ◽  
Vol 353-358 ◽  
pp. 2341-2344
Author(s):  
Tao Xie ◽  
Yan Jun Qiu ◽  
Ze Zhong Jiang ◽  
Bo Lan
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Concrete Pavements ◽  
Destructive Testing ◽  
Air Voids ◽  
Highway Engineering ◽  
Ultrasonic Methods ◽  
Pavement Engineering ◽  
Excellent Method

Water damage of asphalt concrete pavements has been one of the major distresses in highway engineering. Engineering experiences and research results indicate that this damage is due to the extortionate air voids of bitumen mixtures. Paranormal porosity of asphalt mixture is largely the result of the poor controlling of compact degree during paving process. The quality of asphalt pavement is subjected to the controlling methods of compacting of bitumen mixtures. Ultrasonic is an excellent method for non-destructive testing used in various engineering fields. It is also a potentially effective tool to be applied in the control and evaluation of the compaction quality of bitumen mixtures. This paper presents the results of a study aimed at the applicability of ultrasonic technology for evaluation of porosity and compaction quality of bitumen mixtures. It is shown that this technology, which has been successfully used for many years for evaluation of Portland concrete structures, might be used in asphalt pavement engineering to provide a simple, quick, and objective methodology for control and evaluation of the compact quality of bitumen mixtures. The results of laboratory testing demonstrate the potential of this technology.

Multicharacteristic Performance-Related Specification for Hot-Mix Asphalt Pavement: Complete Development Process

2003 ◽  
Vol 1861 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Richard M. Weed
Keyword(s):  
Development Process ◽  
Hot Mix Asphalt ◽  
Asphalt Pavement ◽  
Performance Model ◽  
Department Of Transportation ◽  
Air Voids ◽  
Complete Development ◽  
Multiple Quality Characteristics ◽  
Engineering Mathematics ◽  
Sufficient Detail

At a time when there is great interest in developing performance-related specifications incorporating multiple quality characteristics and several highly complex approaches are under development, it is questioned whether these procedures will be capable of providing the degree of practicality and ease of application sought by most practitioners. Alternatively, it is claimed that there is a simple, straightforward procedure that is suitable for most practical purposes. The components of this procedure have been successfully applied by the New Jersey Department of Transportation over a period of many years, and it is argued that additional complexity is rarely necessary or beneficial. An example is presented illustrating how readily obtainable data can be used, first to develop the performance model and then to develop the acceptance procedure for a specification for in-place air voids, thickness, and smoothness of hot-mix asphalt pavement. The example is presented in sufficient detail to demonstrate the ease with which this procedure can be learned and applied by individuals with only a basic background in engineering mathematics.

scholarly journals Investigation of Impact of Aggregate Coating by Bitumen on Change of Micro Texture Values

1970 ◽  
Vol 3 (1) ◽  
pp. 52-61
Author(s):  
Zuzana Florkova ◽  
Jana Pastorkova ◽  
Matus Farbak ◽  
Zuzana Kolkova ◽  
Peter Hrabovsky
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Point Of View ◽  
Skid Resistance ◽  
Analysis Method ◽  
Texture Change ◽  
Bitumen Content ◽  
The Individual ◽  
The Impact

Asphalt pavement micro texture values primarily depend on aggregate properties used in asphalt pavement mixture and by aggregate surfaces is secured the basic contact medium with vehicle tires. It often happens that new asphalt surfaces have not required skid resistance properties and is needed a certain period of time to eliminate film of bitumen binder which is coating the aggregate grain on the surface of pavement by action of vehicles. In most cases, the investigation of the aggregate micro texture impact on the pavement skid resistance properties is carried out under laboratory conditions and generally relates only to measurements on natural aggregate samples (without bitumen). However, due to coating of aggregate by bitumen binder, valleys between the individual peaks of aggregate are filled. Obviously, it can be supposed that the usage of high amount of bitumen content can leads to decreasing of aggregate micro texture values. From this point of view, it can be expected that change in micro texture values depends on the content of binder in the asphalt mixture. Particular aggregate grains were taken from asphalt mixtures samples (AC 8, AC 11 and SMA 11) produced in the laboratory, in order to determine the impact of aggregate coating by bitumen binder on micro texture change. Each usage asphalt mixture was produced with three different bitumen binder contents. Digital image analysis method was used for subsequent evaluation. Changes in the micro texture values depending on the amount of used bitumen binder and also on the calculated theoretical bitumen film thickness are investigated in the conclusion.

Evaluation of Superpave Gyratory Compaction of Hot-Mix Asphalt

1996 ◽  
Vol 1543 (1) ◽  
pp. 145-150
Author(s):  
E. R. Brown ◽  
D. I. Hanson ◽  
Rajib B. Mallick
Keyword(s):  
Hot Mix Asphalt ◽  
Current Data ◽  
Average Difference ◽  
Density Data ◽  
Air Voids ◽  
Superpave Gyratory Compactor ◽  
Gyratory Compaction ◽  
Pavement Temperature

To achieve 4.0 percent air voids in laboratory-compacted hot-mix asphalt with the Superpave gyratory compactor, different gyration levels are currently specified in the Superpave manual, each applicable to a particular combination of traffic and maximum pavement temperature. Two 1-year-old and four 2-year-old in-place densities were compared to those obtained from Superpave compaction of laboratory-prepared specimens and from compaction of reheated plant-produced mixtures. The gyration numbers corresponding to in-place density fell below 100 for all the mixes. At similar gyration levels, density of compacted, reheated, and laboratory-prepared specimens indicated an average difference of about 1 percent. Current data show that the Ndesign, Ninitial, and Nmax gyration levels may be too high, at least for lower traffic. Evaluation of the currently specified Ndesign values will be refined when the 3-year in-place density data become available.

A New Method of Gradation Design about Rutting Resistance of Asphalt Pavement

2010 ◽  
Vol 168-170 ◽  
pp. 2397-2401
Author(s):  
Bao Lin Zhu ◽  
Xin Huang ◽  
Yan Ping Jing
Keyword(s):  
Particle Size ◽  
Prediction Model ◽  
Packing Density ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Aggregate Size ◽  
Air Voids ◽  
Aggregate Packing ◽  
Continuous Particle ◽  
The Relationship

The article derived the formula of continuous particle size of asphalt aggregate packing density based on the Stovall model; according to the relationship between porosity and rutting, rutting prediction model was established; by experiment to determine the parameters in the formula to be determined , and the applicability of the formula was verified, the results showed that: the formula can calculate air voids and dynamic stability of asphalt mixture by aggregate size distribution and the aggregate ratio .

scholarly journals Effect of Gradation Variability on Volume Parameter and Key Performances of HMA

2021 ◽  
Vol 7 ◽  
Author(s):  
Shutang Liu ◽  
Lin Zhu ◽  
Huiqin Zhang ◽  
Tao Liu ◽  
Ping Ji ◽  
...  
Keyword(s):  
Design Theory ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Fine Aggregate ◽  
Aggregate Gradation ◽  
Mineral Aggregate ◽  
Air Voids ◽  
Pavement Engineering ◽  
Asphalt Content ◽  
Main Component

The graded mineral aggregate composed of coarse aggregate, fine aggregate, and mineral powder is the main component of hot asphalt mixture (HMA), and it occupies a mass ratio of more than 95% in HMA. The gradation variability of mineral aggregate is frequently an unavoidable problem in the construction of asphalt pavement engineering. In order to investigate the effect of gradation variability on the volume parameters and key performances of HMA, the asphalt concrete with a nominal maximum particle size of 20 mm (AC20) was selected as the research carrier. Firstly, a benchmark mineral aggregate gradation (BMAG) was designed based on the theory of dense skeleton gradation presented in the paper. Secondly, six types of HMA (that is, AC20) with variable gradations were also determined and all the specimens were prepared by rotary compaction process with the same optimum asphalt content (gradation varies but asphalt content remains the same), and finally based on asphalt pavement analyzer, the performances of all the specimens of each gradation were tested. The results show that, compared with the BMAG-HMA, the volume parameters such as air voids, voids in mineral aggregate, and voids filled with asphalt of the variable-graded HMA change in different directions, but the water stability and high-temperature performance both degrade greatly. The experimental results also show the feasibility and effectiveness of the dense skeleton gradation design theory adopted in this study.

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