scholarly journals Shape Characterizing of Aggregates Produced through Different Crushing Techniques

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1199
Author(s):  
Ghulam Yaseen ◽  
Wesam Salah Alaloul ◽  
Imran Hafeez ◽  
Abdul Hannan Qureshi
Keyword(s):  
Form Factor ◽  
Aspect Ratio ◽  
Shape Factor ◽  
Asphalt Mixtures ◽  
Volumetric Properties ◽  
Shape Parameters ◽  
Jaw Crusher ◽  
Factor Form ◽  
Marshall Stability ◽  
Aggregate Shape

The aggregate shape properties produced from the different crushing techniques influence the performance properties of the asphalt mixtures. The objective of this study was to classify the aggregates into spherical, flat, elongated and flat, and elongated shapes, collected from impact crusher and jaw crusher of two sources, and to calculate the shape parameters, such as aspect ratio, shape factor, form factor, sphericity, roundness, and angularity index. In addition, this study also investigated the effects of this classification on the Marshall stability and volumetric properties of asphalt mixtures prepared from the respective shape of aggregates. The results showed that the aggregate of different fractions (passing 37.5 mm and retained on 4.75 mm) produced from the jaw crusher of Margalla quarry showed better shape parameters. The spherical aggregates collected from all crushers showed 20–30% higher Marshall stability of the blends by improving the mechanical and volumetric properties of the asphalt mixtures.

Determining Optimum Carbon Nanotubes Content for Asphalt Mixture in Road Pavements

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.

scholarly journals Laboratory Evaluation of the Use of Florida Washed Shell in Open-Graded Asphalt Mixtures

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7060
Author(s):  
Mohammad Alharthai ◽  
Qing Lu ◽  
Ahmed Elnihum ◽  
Asad Elmagarhe
Keyword(s):  
Tensile Strength ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Void Content ◽  
Coarse Aggregates ◽  
Significant Difference ◽  
Indirect Tensile ◽  
Marshall Stability

This study investigates the substitution of conventional aggregate with a Florida washed shell in open-graded asphalt mixtures and evaluates the optimal substitution percentage in aggregate gradations of various nominal maximum aggregate sizes (NMASs) (i.e., 4.75, 9.5, and 12.5 mm). Laboratory experiments were performed on open-graded asphalt mixture specimens with the coarse aggregate of sizes between 2.36 and 12.5 mm being replaced by the Florida washed shell at various percentages (0, 15, 30, 45, and 100%). Specimen properties relevant to the performance of open-graded asphalt mixtures in the field were tested, evaluated, and compared. Specifically, a Marshall stability test, Cantabro test, indirect tensile strength test, air void content test, and permeability test were conducted to evaluate the strength, resistance to raveling, cracking resistance, void content, and permeability of open-graded asphalt mixtures. The results show that there is no significant difference in the Marshall stability and indirect tensile strength when the coarse aggregates are replaced with Florida washed shell. This study also found that the optimum percentages of Florida washed shell in open-graded asphalt mixture were 15, 30, and 45% for 12.5, 9.5, and 4.75 mm NMAS gradations, respectively.

Effect of rejuvenator types and mixing procedures on volumetric properties of asphalt mixtures with 50% RAP

2019 ◽  
Vol 218 ◽  
pp. 457-464 ◽  
Author(s):  
Zhaoxing Xie ◽  
Hashim Rizvi ◽  
Caitlin Purdy ◽  
Ayman Ali ◽  
Yusuf Mehta
Keyword(s):  
Asphalt Mixtures ◽  
Volumetric Properties

scholarly journals Evaluasi Kinerja Campuran Beraspal dengan Bitumen Hasil Ekstraksi Penuh dari Asbuton

2018 ◽  
Vol 24 (1) ◽  
pp. 62
Author(s):  
Nyoman Suaryana ◽  
Iwan Susanto ◽  
Yohannes Ronny ◽  
Ida Rumkita Sembayang
Keyword(s):  
Tensile Strain ◽  
Asphalt Mixtures ◽  
Rolled Sheet ◽  
Asphaltic Concrete ◽  
Natural Rock ◽  
Asphalt Mix ◽  
Marshall Stability ◽  
Oil Penetration ◽  
Hot Rolled ◽  
Large Deposits

Asbuton is a natural rock asphalt that can be found on the island of Buton in Southeast Sulawesi province, has a large deposits but not yet well utilized. This research aims to find out the performance of asphalt mixtures AC-WC (Asphaltic Concrete Wearing Course) and HRS-WC (Hot Rolled Sheet Wearing Course) using bitumen results from full extraction of asbuton. The research was done by experimental methods through laboratory tests then its performance was compared to convensional mixtures using asphalt oil with penetration grade of 60. The results obtained showed that the bitumen of asbuton did not meet the specification of bitumen based on penetration grade. Characteristics of hot mixture asphalt using bitumen of asbuton showed better performance in terms of the Marshall stability namely 1871 kg higher than the convensional hotmixture of asphalt, with 1100 kg for AC-WC and 1241.9 kg compared with 1094 kg for HRS-WC. In addition, the results of deformation resistance tests showed asphalt mix with pure asbuton  more resistant to rutting shown by higher dynamic stability value namely 4200 track/mm compared with 492 track/mm for AC-WC and 2739 track/mm compared with 325 track/mm. The modulus resilient value of mix with pure asbuton is also higher at temperature of 25°C and relatively the sameat temperatures of 35°C and 45°C. While the resistance of  fatigue for AC-WC and HRS-WC on the test tensile strain of 150 µs were relatively the same as hotmix asphalt using asphalt oil penetration grade of 60, but on test of  a larger tensile strain has worse fatigue resistance, especially for AC-WC.

scholarly journals Investigation of Moisture Sensitivity and Conductivity Properties of Inductive Asphalt Mixtures Containing Steel Wool Fiber

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Seyed Mohsen Hosseinian ◽  
Vahid Najafi Moghaddam Gilani ◽  
Peyman Mehraban Joobani ◽  
Mahyar Arabani
Keyword(s):  
Electrical Conductivity ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
Asphalt Mixtures ◽  
Dynamic Resistance ◽  
Moisture Resistance ◽  
Steel Wool ◽  
Moisture Sensitivity ◽  
Optimal Amount ◽  
Marshall Stability

The construction of suitable roads in rainy areas has created problems in the construction process due to the low resistance of asphalt to moisture. To solve this problem, materials are commonly used that make mixtures resistant to moisture; however, these materials may reduce the dynamic resistance of asphalt. Therefore, materials should be used that, in addition to increasing the dynamic resistance, also increase the moisture resistance of asphalt mixtures. One of these materials used in this research is steel wool fiber (SWF), which in addition to creating conductive roads also could have a significant effect on moisture resistance. In this study, the impact of 2%, 4%, 6%, 8%, and 10% SWF on the Marshall stability and moisture sensitivity of mixtures was investigated using the Marshall stability and indirect tensile strength (ITS) tests, respectively. Moreover, using SWF as a conductive fiber, the conductivity properties of asphalt mixtures were explored to find the optimal amount of electrical conductivity. The results of the Marshall stability test indicated that by increasing SWF contents, the stability of mixtures increased, compared with the base sample, and greater amounts of 6% SWF resulted in the reduction of the Marshall stability. The results of ITS showed that modification of bitumen by SWF increased ITS and tensile strength ratio (TSR) amounts of mixtures. 6% SWF was the optimal amount for enhancing the resistance of asphalt mixtures to moisture sensitivity. The results of the electrical resistivity test showed that the resistivity had three phases: high resistivity, transit, and low resistivity. Mixtures containing less than 4% SWF illustrated an insulating behavior, with electrical resistivity greater than 7.62  ×  108  Ω . m . At the transit phase, the resistivity of mixtures had a sharp reduction from 7.62  ×  108  Ω . m to 6.17  ×  104  Ω . m . Finally, 8% SWF was known as the optimal content for the electrical conductivity of mixtures.

Mitochondrial network complexity and pathological decrease in complex I activity are tightly correlated in isolated human complex I deficiency

2005 ◽  
Vol 289 (4) ◽  
pp. C881-C890 ◽  
Author(s):  
Werner J. H. Koopman ◽  
Henk-Jan Visch ◽  
Sjoerd Verkaart ◽  
Lambertus W. P. J. van den Heuvel ◽  
Jan A. M. Smeitink ◽  
...  
Keyword(s):  
Form Factor ◽  
Aspect Ratio ◽  
Complex I ◽  
Mitochondrial Morphology ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Network ◽  
Mitochondrial Structure ◽  
Complex I Deficiency ◽  
Complex I Activity ◽  
Human Complex

Complex I (NADH:ubiquinone oxidoreductase) is the largest multisubunit assembly of the oxidative phosphorylation system, and its malfunction is associated with a wide variety of clinical syndromes ranging from highly progressive, often early lethal, encephalopathies to neurodegenerative disorders in adult life. The changes in mitochondrial structure and function that are at the basis of the clinical symptoms are poorly understood. Video-rate confocal microscopy of cells pulse-loaded with mitochondria-specific rhodamine 123 followed by automated analysis of form factor (combined measure of length and degree of branching), aspect ratio (measure of length), and number of revealed marked differences between primary cultures of skin fibroblasts from 13 patients with an isolated complex I deficiency. These differences were independent of the affected subunit, but plotting of the activity of complex I, normalized to that of complex IV, against the ratio of either form factor or aspect ratio to number revealed a linear relationship. Relatively small reductions in activity appeared to be associated with an increase in form factor and never with a decrease in number, whereas relatively large reductions occurred in association with a decrease in form factor and/or an increase in number. These results demonstrate that complex I activity and mitochondrial structure are tightly coupled in human isolated complex I deficiency. To further prove the relationship between aberrations in mitochondrial morphology and pathological condition, fibroblasts from two patients with a different mutation but a highly fragmented mitochondrial phenotype were fused. Full restoration of the mitochondrial network demonstrated that this change in mitochondrial morphology was indeed associated with human complex I deficiency.

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