scholarly journals Determination of temperature regimes of producing of mastic asphalt concrete mixtures on bitumen binders of different consistency

Author(s):  
Serhii Oksak

Abstract. Problem. The temperature of mastic as-phalts mixing is significantly higher than the one for hot asphalt mixtures. It is due using of high viscous bitumens as a mixture component and realizing the main advantage of mastic asphalt – its ability to flow and compact with its own weight at high tempera-ture. There is no uniform way to assign the process temperatures for mastic asphalt. Goal. To find the process temperatures for mastic asphalt with bitumen binders differ by viscosity as a researching on tem-perature influence and influence of binder concentra-tion on properties of mastic asphalt is a goal of this research work. Methodology. The mastic asphalt mixtures and asphalt concrete with conventional pavement bitumen 70/100 (penetration is 85 dmm) and high viscous bitumen (penetration is 38 dmm) are chosen for research. The mineral aggregates contain 42 % of crushed granite 5-10 mm, 33 % of granite screening and 33 % of limestone powder. The properties of mastic asphalts are evaluated with EN 12697-20:2003, SOU 42.1-37641918-106:2013 and DSTU EN 13108-6:2018. Results. It was found a significant influence of amount and viscosity of bitu-men and a temperature on workability of mastic as-phalt mixture and on properties of mastic asphalt concrete. Originality. The comparative analysis of workability of mastic asphalt mixture and properties of mastic asphalt concrete with bitumens differ in viscosity is a scientific originality of presented re-search. Practical value. Due to research results it is not reasonable to assign the temperature that sup-plies viscosity of 0.5 Pa•s as a temperature of mixing of mastic asphalt. The temperature conditions of mastic asphalt mixing are much higher (200 – 240 °C). To evaluate workability and find a minimal acceptable temperature of mixture it is possible to use the thickness of the mixture layer after spreading as an indicator. With this the acceptable workability of the mastic asphalt mixture can be characterized by thickness of its layer 30 mm or less after spreading.

2015 ◽  
Vol 76 (14) ◽  
Author(s):  
Norhidayah Abdul Hassan ◽  
Nor Asniza Mohamed Abdullah ◽  
Nurul Athma Mohd Shukry ◽  
Mohd Zul Hanif Mahmud ◽  
Nur Zurairahetty Mohd Yunus ◽  
...  

Porous asphalt mixture is one of the alternative solutions to increase pervious surface area due to urbanization. The uniqueness of porous asphalt surface textures and internal structures allows the mixture to become a temporary storm-water retention and capable to channel excessive storm water. However, one of the major problems that affect the performance of porous asphalt mixtures is the clogging. Therefore, this study aims to determine the effect of clogging towards the permeability of porous asphalt. A total of 30 gyratory compacted samples were fabricated according to aggregate gradation recommended by Malaysia Public Works Department. The clogging materials were collected from two different location, residential area and major highway. The composition and characteristics of the clogging materials were investigated using Plastic Limit, Liquid Limit and Scanning Electron Microscope (SEM). The permeability test was conducted to investigate the permeability rate of the compacted samples based on different clogging material types, clogging concentrations and clogging cycles. In addition, the compacted samples were scanned using X-ray Computed Tomography to obtain the air voids distribution throughout the samples for comparison. It was found that higher concentration of clogging materials and clogging cycles reduced the rate of permeability. Clogging material collected from residential area has higher tendency to clog the void spaces compared to the one obtained from highway.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4496
Author(s):  
Jiahao Tian ◽  
Sang Luo ◽  
Ziming Liu ◽  
Xu Yang ◽  
Qing Lu

To address the severe distresses of asphalt pavement, a new type of pavement maintenance treatment, porous ultra-thin overlay (PUTO) with small particle size was proposed. The PUTO has a thickness of 1.5–2.5 cm and a large void ratio of 18–25%. As a newly asphalt mixture, the structure characteristics differ from poor traditional pavement. Therefore, it is necessary to investigate the fabrication schemes in laboratory and on-site, respectively. In this study, the optimal fabrication schemes, including compaction temperature and number of blows of PUTO were determined based on Cantabro test and volumetric parameters. Then, the corresponding relationship between laboratory and on-site compaction work was then established based on the energy equivalent principle. On this basis, the numbers of on-site rolling passes and the combination method were calculated. The results show that increased compaction temperature and number of blows reduce the height and enhance the compaction of the Marshall sample. With the same temperature and number of blows, the raveling resistance of coarse gradation, Pavement Asphalt Concrete-1 (PAC-1) is better than that of fine gradation, Pavement Asphalt Concrete-2 (PAC-2), and the increased asphalt viscosity significantly improves the raveling resistance of the asphalt mixture. To ensure the scattering resistance and volumetric characteristic, the initial compaction temperature of the PAC-1 and PAC-2 should not be lower than 150 °C and 165 °C, respectively. Then, the laboratory compaction work and on-site compaction work were calculated and converted based on the principle of energy equivalence. Consequently, the on-site compaction combination of rolling machines for four asphalt mixtures was determined. According to the volumetric parameters, the paving test section proved that the construction temperature and the on-site rolling combination determined by laboratory tests are reasonable, and ultra-thin overlay has good structural stability, drainage, and skid resistance.


2012 ◽  
Vol 238 ◽  
pp. 22-25 ◽  
Author(s):  
Yuan Zhao Chen ◽  
Zhen Xia Li

In order to discuss the effectiveness of basalt fiber in reinforcing pavement performance of asphalt mixtures, the pavement performances of basalt fiber asphalt mixtures were investigated by tests of high temperature stability, water stability and low temperature crack resistance, and compared with the pavement performance of asphalt mixtures with polyester fiber and xylogen fiber, and that of reference mixture. The results show that pavement performance of fiber asphalt mixture are improved and optimized comparing with reference asphalt mixture, the performance of asphalt mixture with basalt fiber are excelled than those with polyester fiber and xylogen fiber while the dosage of fibers is keeping at the optimum.


2012 ◽  
Vol 58 (4) ◽  
pp. 521-534 ◽  
Author(s):  
W. Gardziejczyk ◽  
M. Wasilewska

AbstractThe aggregate applied for the wearing course has a significant influence on skid resistance of road surfaces. However, it is difficult to evaluate the behaviour of road surface in use on the basis of the Polished Stone Value (PSV) determined for the aggregate according to the so called ‘British method’. The British method, which is currently used in many countries, does not allow to determine the influence of neither the grain size of the aggregate nor the type of the wearing course on skid resistance of road surface. The present paper suggests a method for evaluation of the British Pendulum Number (BPN) for road surfaces in laboratory conditions. The authors assumed the BPN for polished slabs, made from asphalt mixtures, as the criterion. The index was measured with the British Pendulum Tester. The simulation of the process was conducted on research stand (called slab polisher) built at Bialystok University of Technology (BUT). The results of laboratory tests indicate that surfaces from asphalt concrete (AC) have slightly higher values of BPN in comparison with the values determined for surfaces made from stone mastic asphalt (SMA).


2015 ◽  
Vol 10 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Xinsheng Li ◽  
Zhaoxing Xie ◽  
Wenzhong Fan ◽  
Lili Wang ◽  
Junan Shen

The objective of this research was to select the most effective warm asphalt additives for mix practice based on a series of laboratory testing programs such as density, Marshall stability, freeze-thaw splitting strength, dynamic stability, and bending beam strain. The experimental design of warm mix asphalt included the use of three commonlyused additives, two typical aggregate gradations, one crushed aggregate, and one modified asphalt. Results showed that: (1) the bulk specific gravity and air voids of all the mix specimens were similar to those of controls; (2) the Marshall stability and flow values of the warm stone mastic asphalt were 6.8%–26.6% and 3.5%–10.3%% higher than those of controls, respectively, and those of the warm asphalt concrete were 6.1%–15.6% and 6.5%–9.7% higher than those of controls, respectively; (3) the indirect tensile strength of two types of mixtures was 1.7%–14.4% lower than that of controls, and the average tensile strength ratio of the warm stone mastic asphalt and asphalt concrete was 4.3% and 1.3% higher than that of controls, respectively; (4) the dynamic stability of warm mix specimens was 10.8%–16.6% lower than that of the controls; (5) the average bending failure strain of warm stone mastic asphalt was 7.6% higher than that of the controls, and that of warm asphalt concrete was 12.8% lower than that of the controls; (6) Overall, warm asphalt mixtures with Sasobit and Rediset had relatively best performances required in Southeast China, where rutting and stripping are the main failures of asphalt pavements.


Author(s):  
Taesoon Park ◽  
Brian J. Coree ◽  
C. W. Lovell

The viability of using pyrolized carbon black (CBp) derived from waste tires as a reinforcing agent in asphalt mixtures was evaluated. Commercial carbon black (CB) has been previously shown to reduce the rutting resistance, temperature susceptibility, and cracking propagation potential of asphalt concrete. It was believed that CBp could produce similar benefits; this belief has been confirmed by this study. Different ratios of CBp and CB (5, 10, 15, and 20 percent by weight of asphalt) were blended with two grades of asphalt (AC-10 and AC-20). The Marshall method, the gyratory testing machine, the dynamic creep testing (confined), the indirect tensile testing, and the resilient modulus test were performed. The test results of CBp mixtures were compared with results of CB and conventional mixtures. The analyses of test results show that the typical performance of CBp-modified asphalt mixtures is improved with respect to commercial CB and conventional mixtures. The rutting potential and the temperature susceptibility can be reduced by the inclusion of CBp in the asphalt mixture. A CBp content of 10 to 15 percent by weight of asphalt is recommended for improvement of asphalt concrete.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1481 ◽  
Author(s):  
Xiaoliang Zhang ◽  
Ben Zhang ◽  
Huaxin Chen ◽  
Dongliang Kuang

Road construction consumes great amounts of high-grade natural resources. Using low-grade natural rocks or some solid wastes as substitute materials is a hot topic. Considering this, the feasibility of using low-grade granite aggregate, solid waste-based filler (desulphurization gypsum residues, DGR) and binder (waste tire rubber modified asphalt, RMA) simultaneously in asphalt mixtures has been fully investigated in this research. The commonly used base asphalt and limestone powder (LP) filler were control groups. Material characteristics of raw materials mainly including micro-morphology, functional group, mineral phase, chemical composition and thermal stability were first evaluated in order to recognize them. Four asphalt mixtures (two asphalt binder and two filler) were then designed by standard Superpave method. Finally, a detailed investigation into the pavement performance of asphalt mixtures was carried out. The moisture damage resistance and low-temperature crack resistance were detected by the changing rules of stability, strength and fracture energy, and the high-temperature stability and fatigue performance were determined by wheel tracking test and indirect tensile (IDT) fatigue test, respectively. Results suggested that RMA and DGR both showed positive effects on the low-temperature crack resistance and fatigue property of the granite asphalt mixture. DGR also strengthened moisture stability. The contribution of RMA on high-temperature deformation resistance of the granite asphalt mixture was compelling. It can offset the insufficiency in high-temperature stability made by DGR. A conclusion can be made that asphalt mixture prepared with granite, DGR and RMA possesses satisfactory pavement performances.


Author(s):  
Boris Radovskiy

Recently, several researchers have proposed asphalt film thickness as a criterion for ensuring the durability of asphalt mixtures. However, they suggested that the standard film thickness equation, which dates back to the 1940s, needs to be examined by modern technology and improved. A presumable background on which the Asphalt Institute surface area factors are based was recovered and analyzed in detail. A fundamentally sound model for film thickness calculation was developed using a model of asphalt concrete in which the aggregates are spherical but have an arbitrary size distribution. A recent result from statistical geometry is applied to determine the film thickness for any volume fraction of aggregates and any volume fraction of effective asphalt. The analytical formulas are presented, the details of the calculation are summarized, and examples are provided.


2016 ◽  
Vol 2 (10) ◽  
pp. 538-545 ◽  
Author(s):  
Ramin Bayat ◽  
Siamak Talatahari

Engineers are constantly trying to improve the performance of the flexible pavements. The main surface distress types which cause maintenance and disruption are rutting and fatigue cracking. For solving these problems, many studies have been carried out until now, ranged from changing gradation to adding polymers and fibers to asphalt mixture. In this study, polypropylene additive was selected as fiber additive because of low costing and having good correlation with asphalt pavement. Three type of polypropylene additive in the length 6, 12 and 19 mm were selected and used at five different percentages in the asphalt concrete mixture. Asphalt specimens were analysed by Marshall Analysis and finally tested by Marshall Stability apparatus. Adding polypropylene increased Marshall Stability (38%), and decreased Flow (39%). These results show that polypropylene can be helpful for increasing pavement life.


2021 ◽  
Author(s):  
Jan Valentin ◽  
Majda Belhaj ◽  
Pavla Vacková

High modulus asphalt concrete (HMAC) presents a concept of an asphalt mixture with advanced performance which is suitable mainly for heavy loaded pavement structures. The mix concept was developed more than 25 years ago in France and became a standard in many countries. In the Czech Republic this type of asphalt mixtures is used since the early years of this millennium, when original technical requirements have been set. After almost 20 years a volunteer technical assessment started to validate whether the technical requirement set mainly for stiffness values and partly also for flexural strength or resistance to crack propagation are still up-to-date or if some reasonable modification is needed like was done several years ago in France when high modulus asphalt concrete of so called EME II or GP5 generation were brought to the practice. Based on this a study with focus on stiffness determination for more than 40 different HMACs was started. The stiffness was tested at different temperatures. At the same time virgin and aged asphalt mixtures were compared. Results from this study are presented by the paper.


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