Research Progress on Skid Resistance of Basic Oxygen Furnace (BOF) Slag Asphalt Mixtures

In order to ensure the safety of traffic, asphalt pavement is commonly required to utilize aggregates with excellent anti-abrasion property. This results in the lack of high-quality aggregates. The incorporation of solid waste in the aggregates is regarded as a high potential alternative for solving this problem. Since its material properties, such as rough surface, high Polished Stone Value (PSV) and the excellent adhesion property of asphalt, Basic Oxygen Furnace (BOF) slag can effectively improve the skid resistance of asphalt mixtures. First, the material properties of BOF slag are reviewed in this study. Then, the skid resistance of asphalt mixtures and aggregates are commendably evaluated by the Polished Stone Value test, Wehner/Schulze Tester, Aachen Polishing Machine, British Pendulum Test and Sand Patch test. The physical and mechanical properties of BOF slag play a key role in asphalt mixtures. This review found that the skid resistance mechanism of the BOF slag asphalt mixture is governed by factors such as BOF slag properties, incorporation methods and gradation types. Finally, the economic and environmental benefits of BOF slag asphalt mixtures were discussed. In addition, the function of gas catalysis and the melting of ice and snow can be added to the BOF slag asphalt mixture for a cleaner development in engineering. Furthermore, the existing problems, research directions and corresponding measures in this field are directed towards more durable and functional asphalt pavement construction.

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Evaluation of the Cooling and Pavement Performance of Basic Oxygen Furnaces Slag Used in Asphalt Mixture

10.20944/preprints201709.0083.v1 ◽

2017 ◽

Author(s):

Long-Sheng Huang

Keyword(s):

Asphalt Mixture ◽

Road Construction ◽

Basic Oxygen Furnace ◽

Asphalt Mixtures ◽

Partial Substitution ◽

Basic Oxygen ◽

Stone Mastic Asphalt ◽

Bof Slag ◽

Natural Aggregates ◽

The Stability

The basic oxygen furnace slag (BOF) was wide used in road construction, but there was a lack of characteristics in different asphalt mixtures. This study investigates the properties of hot-mixed asphalt (HMA) containing stone mastic asphalt (SMA), porous asphalt (PA) and dense-graded BOF as a partial substitution for natural aggregates. The purpose of this study is to evaluate various BOF slag contents in the asphalt mixtures would affect the cooling behavior after compaction. Asphalt mixture specimens contained 0%, 20%, 40% and 60% BOF slag, respectively, as coarse aggregate. Test results showed that BOF slag has a lipophilic property, so it can be adsorbed by asphalt cement, thereby reducing the cost of asphalt. The stability value of all asphalt mixtures increases with the proportion of BOF slag replacement. In addition, the voids in the mineral aggregate (VMA) value variable exhibited significant differences among asphalt mixtures, and could determine the deviation of the cooling trend of asphalt mixtures. Furthermore; it was found that the cooling procedure of the BOF slag used in dense-graded asphalt mixture takes about 100 min, and that the temperature tends to be moderate; however, it took about 120 min of cooling the SMA and PA mixture with BOF slag. In addition, the voids distribution of dense asphalt mixture was not uniform. It would result in various locations of thermal energy temperature on asphalt mixtures that were inconsistent.

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

European Journal of Engineering Science and Technology ◽

10.33422/ejest.v3i1.161 ◽

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.

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Morphological Discrepancy of Various Basic Oxygen Furnace Steel Slags and Road Performance of Corresponding Asphalt Mixtures

Materials ◽

10.3390/ma12142322 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2322 ◽

Cited By ~ 4

Author(s):

Yong Ye ◽

Shaopeng Wu ◽

Chao Li ◽

Dezhi Kong ◽

Benan Shu

Keyword(s):

Steel Slag ◽

Asphalt Mixture ◽

Basic Oxygen Furnace ◽

Asphalt Mixtures ◽

Basic Oxygen ◽

The Road ◽

Treatment Processes ◽

Road Performance ◽

The Difference ◽

The Stability

Due to the difference of cooling and treatment processes (rolling method, hot braised method, layer pouring method), basic oxygen furnace (BOF) steel slag can be mainly classified as roller steel slag (RSS), hot braised steel slag (HBSS) and layer pouring steel slag (LPSS). Treatment difference directly results in the performance variations of different BOF steel slag and corresponding asphalt mixtures. The primary purpose of this research was to examine the effects of different cooling and treatment processes on the morphological discrepancy of different BOF steel slag. Also, the road performances of corresponding asphalt mixtures, and mechanism between steel slag performance and road performance were studied. The results show that LPSS owns the largest variability of angular index and texture index, and RSS has the most balanced morphological parameters. The structure of RSS asphalt mixture is advantageous for improving the ability of the asphalt mixture to resist the deformation and enhancing the stability of structure. Higher content of CaO and lower content of SiO2 make the acid-base reaction of RSS asphalt mixture most intense, which contribute to the best road performance of it.

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Evaluation of the Volume Stability and Resource Benefit of Basic Oxygen Furnace Slag and Its Asphalt Mixture Based on Field Application

Advances in Civil Engineering ◽

10.1155/2021/6676154 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Yuechao Zhao ◽

Jiangkai Song ◽

Jun Xie ◽

Fusong Wang ◽

Meizhu Chen ◽

...

Keyword(s):

Calcium Oxide ◽

Steel Slag ◽

Asphalt Mixture ◽

Basic Oxygen Furnace ◽

Free Calcium ◽

Oxide Content ◽

Basic Oxygen ◽

Volume Stability ◽

Bof Slag ◽

Natural Aggregates

Applying basic oxygen furnace (BOF) slag as aggregate in asphalt mixture is continuously investigated due to the increasing shortage of natural aggregate in recent years. However, the negative effect of BOF’s expansion in water greatly limits its further application in pavement construction. To address this problem, this paper studied the volume stability of BOF, and its asphalt mixture relied on actual engineering. The asphalt mixtures contained BOF aggregate was designed by the Marshall method with three different gradation types (AC-16, AC-20, and ATB-25). Besides, both laboratory samples and the core samples from field drilling were investigated in volume expansion rate after curing in a water bath. The economic and resource benefits of BOF replacement of natural aggregates were also analyzed. The results showed that the free calcium oxide content of BOF slag is positively related to the particle sizes. Nevertheless, the expansion rates of both the BOF aggregate and its asphalt mixture were less than 1%, which meant the BOF aggregate applied to the asphalt mixture meets the practical engineering requirements. The maximum allowable free calcium oxide content for large-grain size of steel slag is the smallest; it is also recommended that the expansibility of large-grain steel slag should be the first concern in the application. The resource assessment indicated that the use of steel slag for the construction of a trial section of one kilometer of single lane can save 967 tons of natural aggregates. The economic evaluation showed that the use of steel slag instead of natural aggregates for surface course construction could reduce the investment by 16.87%. The experimental methods and conclusions mentioned in this article provide stable references to enhance the development of sustainable pavement by recycling metallurgical slag in highway construction.

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Characteristics of Different Types of Basic Oxygen Furnace Slag Filler and its Influence on Properties of Asphalt Mastic

Materials ◽

10.3390/ma12244034 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4034 ◽

Cited By ~ 2

Author(s):

Dezhi Kong ◽

Shaopeng Wu ◽

Meizhu Chen ◽

Meiling Zhao ◽

Benan Shu

Keyword(s):

Chemical Composition ◽

Asphalt Mixture ◽

Basic Oxygen Furnace ◽

Stiffness Modulus ◽

Limestone Filler ◽

Basic Oxygen ◽

Asphalt Mastic ◽

Different Types ◽

Bof Slag ◽

Basic Oxygen Furnace Slag

The fillers of ordinary and pyrolytic basic oxygen furnace (BOF) slag were selected to investigate the properties of their asphalt mastic. XRF (X-Ray Fluorescence) was used to analyze chemical composition of fillers. Meanwhile, SEM (Scanning Electron Microscope) and AIMS (Aggregate Image Measurement System) were utilized to explore meso-morphology, angularity and sphericity. Penetration, softening point and viscosity of asphalt mastic were discussed, while the rheological properties of asphalt mastic were studied by means of DSR (dynamic shear rheometer) and BBR (bending beam rheometer) tests. The experimental results show that chemical composition of different types of BOF slag is similar. The grinding energy consumption of pyrolytic BOF slag is higher than that of limestone and ordinary BOF slag. It is not recommended that pyrolytic BOF slag filler is produced by grinding process. The micro-texture structure of ordinary BOF slag filler is more abundant and their angularity index is about 15% higher than that of limestone filler. The stiffness modulus and rutting factor of asphalt mastic with ordinary BOF slag filler is higher than that of limestone filler. Meanwhile the incorporation of BOF slag filler will further reduce the low-temperature flow performance of asphalt mastic. The effect of pyrolytic BOF slag filler on the performance of asphalt mastic is less than that of ordinary BOF slag. Ordinary BOF slag filler can effectively improve high temperature anti-rutting stability of asphalt mixture. Ordinary BOF slag has a useful application prospect as filler in asphalt mixture.

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Time-Dependent Strength Behavior, Expansion, Microstructural Properties, and Environmental Impact of Basic Oxygen Furnace Slag-Treated Marine-Dredged Clay in South Korea

Sustainability ◽

10.3390/su13095026 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5026

Author(s):

Gyeong-o Kang ◽

Jung-goo Kang ◽

Jin-young Kim ◽

Young-sang Kim

Keyword(s):

Particle Size ◽

Environmental Impact ◽

South Korea ◽

Mechanical Characteristics ◽

Basic Oxygen Furnace ◽

Microstructural Properties ◽

Compression Tests ◽

Basic Oxygen ◽

Strength Behavior ◽

Bof Slag

The aim of this study was to investigate the mechanical characteristics, microstructural properties, and environmental impact of basic oxygen furnace (BOF) slag-treated clay in South Korea. Mechanical characteristics were determined via the expansion, vane shear, and unconfined compression tests according to various curing times. Scanning electron microscopy was conducted to analyze microstructural properties. Furthermore, environmental impacts were evaluated by the leaching test and pH measurements. According to the results, at the early curing stage (within 15 h), the free lime (F-CaO) content of the BOF slag is a significant factor for developing the strength of the adopted sample. However, the particle size of the BOF slag influences the increase in the strength at subsequent curing times. It was inferred that the strength behavior of the sample exhibits three phases depending on various incremental strength ratios. The expansion magnitude of the adopted samples is influenced by the F-CaO content and also the particle size of the BOF slag. Regarding the microstructural properties, the presence of reticulation structures in the amorphous gels with intergrowths of rod-like ettringite formation was verified inside the sample. Finally, the pH values and heavy metal leachates of the samples were determined within the compatible ranges of the threshold effect levels in the marine sediments of the marine environment standard of the Republic of Korea.

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Component Modification of Basic Oxygen Furnace Slag with C4AF as Target Mineral and Application

Sustainability ◽

10.3390/su13126536 ◽

2021 ◽

Vol 13 (12) ◽

pp. 6536

Author(s):

Yanrong Zhao ◽

Pengliang Sun ◽

Ping Chen ◽

Xiaomin Guan ◽

Yuanhao Wang ◽

...

Keyword(s):

Intermediate Phase ◽

Raw Materials ◽

Activity Index ◽

Basic Oxygen Furnace ◽

Hydration Products ◽

Basic Oxygen ◽

Bof Slag ◽

Mineral Compositions ◽

Slag Component ◽

Basic Oxygen Furnace Slag

In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C4AF, C2S and C3S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C4AF and C2S through reasonable batching calculation and the amount of regulating agent. The formation of C4AF and C2S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C3S is not detected. With the increase in the CaO/SiO2 ratio in raw materials, the CaO/SiO2 ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na2SO4 solution and the improvement of the structure densification of the hydration products.

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Simulated Experiment Study of Factors Influencing the Hydration Activity of f-CaO in Basic Oxygen Furnace Slag

Advances in Materials Science and Engineering ◽

10.1155/2016/7529382 ◽

2016 ◽

Vol 2016 ◽

pp. 1-15 ◽

Cited By ~ 4

Author(s):

Ruiquan Jia ◽

Jiaxiang Liu

Keyword(s):

Solid Solutions ◽

Volume Expansion ◽

Basic Oxygen Furnace ◽

Hydration Reaction ◽

Basic Oxygen ◽

Activity Sequence ◽

Bof Slag ◽

Iron Phase ◽

Calcium Iron ◽

Iron Manganese

The compositions and formation process of f-CaO in BOF slag were revealed and simulated to understand its expansion rules and why its hydration activity is low. BSE showed the compositions of f-CaO, which included calcium iron phase and calcium iron manganese phase, were diverse. The hydration activity sequence was Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; only Ca2Fe2O5 and Ca3Fe1.5Mn1.5O8 were hard to hydrate, and the volume expansion rates of the tricomponent f-CaO varied with different compositions. Inductively, in BOF slag, the hydration activity sequence was solid solutions CaO-FeOx and CaO-FeOx-MnOy in tricomponent f-CaO < CaO in tricomponent f-CaO < monocomponent f-CaO; the volume expansion rates of tricomponent f-CaO changed with different compositions, and CaO-FeOx and CaO-FeOx-MnOy were difficult to hydrate. The reason why solid solutions CaO-FeOx and CaO-FeOx-MnOy were hard to hydrate was that their hydration reaction driving force, which is the absolute value of standard molar reaction Gibbs functions, decreased.

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Determining Optimum Carbon Nanotubes Content for Asphalt Mixture in Road Pavements

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1023.121 ◽

2021 ◽

Vol 1023 ◽

pp. 121-126

Author(s):

Van Bach Le ◽

Van Phuc Le

Keyword(s):

Carbon Nanotubes ◽

Asphalt Pavement ◽

Asphalt Binder ◽

Asphalt Mixture ◽

Construction Cost ◽

Asphalt Mixtures ◽

Static Modulus ◽

Pavement Construction ◽

Modified Binder ◽

Marshall Stability

Although small amount of binder in asphalt concrete mixture may commonly range from 3.5 to 5.5% of total mixture as per many international specifications, it has a significant impact on the total cost of pavement construction. Therefore, this paper investigated the effects of five carbon nanotubes contents of 0.05%, 0.1%, 0.15%, 0.2%, 0.25% by asphalt weight as an additive material for binder on performance characteristics of asphalt mixtures. Performance properties of CNTs modified asphalt mixtures were investigated through the Marshall stability (MS) test, indirect tensile (IDT) test, static modulus (SM) test, wheel tracking (WT) test. The results indicated that asphalt mixtures with CNT modified binder can improve both the rutting performance, IDT strength and marshall stability of tested asphalt mixtures significantly at higher percentages of carbon nanotubes. However, the issue that should be considered is the construction cost of asphalt pavement. Based on the asphalt pavement structural analysis and construction cost, it can be concluded that an optimum CNT content of 0.1% by asphalt weight may be used as additive for asphalt binder in asphalt mixtures.

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