scholarly journals Significance of Fines in Hot Mix Asphalt Synthesis

2017 ◽  
Vol 6 (1) ◽  
pp. 30-42
Author(s):  
Elvira Kalaitzaki ◽  
George Kollaros ◽  
Antonia Athanasopoulou

Abstract According to their size, aggregates are classified in coarse grained, fine grained, and fines. The determination of fines content in aggregate materials is very simple and is performed through the aggregate washing during the sieving procedure to define the gradation curve. The very fine material consists of grains having a size lower than 63 μm. The presence of fines directly influences the composition and performance of concrete and asphalt mixtures (e.g. asphalt content, elasticity, fracture). The strength and load carrying capacity of hot mix asphalt (HMA) results from the aggregate framework created through particle-particle contact and interlock. Fines or mineral filler have a role in HMA. The coarse aggregate framework is filled by the sand-sized material and finally by the mineral filler. At some point, the smallest particles lose contact becoming suspended in the binder not having the particle-particle contact that is created by the larger particles. The overall effect of mineral filler in hot mix asphalt specimens has been investigated through a series of laboratory tests. It is clear that a behaviour influenced by the adherence of fines to asphalt film has been developed. The optimum bitumen content requirement in case of stone filler is almost the same as that for fly ash. It has been found that the percentage of fly ash filler is crucial if it exceeds approximately a value of 4%.

Author(s):  
Bhalchandra S. Pujari ◽  
Snehal Shekatkar

The ongoing pandemic of 2019-nCov (COVID-19) coronavirus has made reliable epidemiological modeling an urgent necessity. Unfortunately, most of the existing models are either too fine-grained to be efficient or too coarse-grained to be reliable. Here we propose a computationally efficient hybrid approach that uses SIR model for individual cities which are in turn coupled via empirical transportation networks that facilitate migration among them. The treatment presented here differs from existing models in two crucial ways: first, self-consistent determination of coupling parameters so as to maintain the populations of individual cities, and second, the incorporation of distance dependent temporal delays in migration. We apply our model to Indian aviation as well as railway networks taking into account populations of more than 300 cities. Our results project that through the domestic transportation, the significant population is poised to be exposed within 90 days of the onset of epidemic. Thus, serious supervision of domestic transport networks is warranted even after restricting international migration.


2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Alexander Thomas ◽  
Michael Rückauer ◽  
Jürgen Becker

Since the introduction of the first reconfigurable devices in 1985 the field of reconfigurable computing developed a broad variety of architectures from fine-grained to coarse-grained types. However, the main disadvantages of the reconfigurable approaches, the costs in area, and power consumption, are still present. This contribution presents a solution for application-driven adaptation of our reconfigurable architecture at register transfer level (RTL) to reduce the resource requirements and power consumption while keeping the flexibility and performance for a predefined set of applications. Furthermore, implemented runtime adaptive features like online routing and configuration sequencing will be presented and discussed. A presentation of the prototype chip of this architecture designed in 90 nm standard cell technology manufactured by TSMC will conclude this contribution.


2021 ◽  
Vol 40 (1) ◽  
pp. 28-38
Author(s):  
Pascal Ambrose ◽  
Siya Rimoy

California Bearing Ratio (CBR) laboratory testing is the conventional method for determining soaked strengths of pavement subgrades. The test requires careful preparation of soil samples followed by four days of water soaking before penetrating the samples using a standard plunger at prescribed rates to set depths. When the number of samples becomes large the determination of soaked CBR values becomes cumbersome as the test is laborious and time consuming. This study aimed at establishing an alternative way of determining soaked CBR by developing a model that would be used for estimating soaked CBR of fine- and coarse- grained soils without performing the CBR test. This has been achieved by correlating CBR values compacted at 95% Maximum Dry Density (MDD) with the soil index properties. The results show that soaked CBR values of fine-grained soils significantly correlate with specific gravity of soil (GS), Plasticity index (PI) and the grading modulus (GM) of the soil that yields a degree of determination of R2 = 0.91 and for coarse grained (A-2 type) soil, the soaked CBR values significantly correlate with specific gravity of soil and percentage of fines passing 0.075mm sieve size that yields a degree of determination of R2= 0.94.


Episteme ◽  
2020 ◽  
pp. 1-19
Author(s):  
Matthew Brandon Lee ◽  
Paul Silva

Abstract A Lockean metaphysics of belief that understands outright belief as a determinable with degrees of confidence as determinates is supposed to effect a unification of traditional coarse-grained epistemology of belief with fine-grained epistemology of confidence. But determination of belief by confidence would not by itself yield the result that norms for confidence carry over to norms for outright belief unless belief and high confidence are token identical. We argue that this token-identity thesis is incompatible with the neglected phenomenon of “mistuned knowledge” – knowledge in the absence of rational confidence. We show how partial epistemological unification can be secured, even without token identity, given determination of outright belief by degrees of confidence. Finally, we suggest a direction for the pursuit of thoroughgoing epistemological unification.


1977 ◽  
Vol 14 (3) ◽  
pp. 399-407 ◽  
Author(s):  
K. E. Robinson

This paper discusses the design and performance of a tailings dam constructed over very loose, saturated sandy silt foundation soils. A major slide in an iron tailings disposal area in 1948 resulted in liquefied tailings flowing through a valley and depositing up to 6 m of very loose tailings over glacial till. The properties of the saturated tailings foundation soils were critical to the overall dam design. The new dam will eventually reach a height of 30 m.The paper discusses consolidation and strength parameters of the foundation tailings, design considerations including the potential for foundation and stored tailings liquefaction, and the result of monitoring programs during construction of the starter dam which reached a height of about 9 m. During construction the most critical stability conditions developed during placing of the initial 1.2 m lift of pit-run gravel. After foundation pore pressures dissipated additional fill was placed with no further problems. Contrary to experience with other fine grained angular soils having few clay sized particles, the iron tailings foundation soils consolidated significantly under applied load. It was computed that consolidation under the weight of the starter dam would be sufficient to increase the relative density to a value that would remain stable under maximum anticipated earthquake loadings.


1962 ◽  
Vol S7-IV (7) ◽  
pp. 888-897
Author(s):  
Marie Jose Pavillon ◽  
Pierre Routhier

Abstract Based on their chemical and chronologic characteristics the granitic rocks of massifs are classified in two groups: syntectonic and late tectonic granites of the first phase; and extensively fractured, with coal deposition and later mineralization of the second phase. A structural analysis of the Meymac region (central French massif) is used as an example as it represents a granitic pluton, with continuous evolution resulting in a zonal distribution of the minerals and formations. The typological determination of granitic massifs requires specifically defined terminology, and metalliferous deposits must be differentiated. Examination of the granitic facies reveals four types of massifs: massifs with porphyritic granite associated with medium-grained non-porphyritic granite; massifs with porphyritic granite containing fine-grained granite bodies; massifs of coarse-grained, non-porphyritic granite; and massifs of varied facies disposed in an irregular manner. Typology seems to be a possible beginning in the study of the dynamics of deepseated petrogenesis.


2019 ◽  
Vol 28 (3) ◽  
pp. 488-499
Author(s):  
Krzysztof Michalczuk ◽  
Mirosław Lipiński ◽  
Małgorzata Wdowska

The major criteria which determine selection of tunneling technology with use of tunnel boring machine (TBM) technique concern geotechnical an hydrogeological conditions of a site. When subsoil strata does not consist of rock the soils are group in two categories, i.e. coarse grained and fine grained soils. Determination of geotechnical parameters pertinent to the problem of tunneling requires individual approach in each case. In case of slurry shield technique, calculations of pressure required for face support should account for real loading conditions. In particular, with respect to shear strength, drainage conditions should be properly accounted for. Thus determined shear strength should be assigned to properly distinguished soil layers. The proper division of soil strata into soil layers is also discussed in the paper.


2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Jakob Kraner ◽  
Tomaž Smolar ◽  
Darja Volšak ◽  
Marjana Lažeta ◽  
Robert Skrbinek ◽  
...  

In the whole manufacturing chain of aluminium products, hot rolling significantly impacts the obtaining of favourable microstructures and desired mechanical properties of final products. The determination of crucial differences between the reverse hot rolling on a single-stand mill and the tandem hot rolling on a tandem-stand mill presented a major challenge. Besides the grain-size distribution in the microstructure’s cross-section, the crystallographic textures of hot-rolled strips were also determined and compared. The alternating band areas of a coarse-grained microstructure and fine-grained microstructure due to reverse hot rolling and, especially, the appearance of extremely fine grains on the surfaces present limitations compared to the tandem hot rolling. For subsequently cold-rolled foils, classical mechanical properties were measured. Besides, the usefulness of EN AW-8021B foils with a thickness of 60 µm for pharmaceutical-packaging applications was tested with a burst test. A minor but important difference of 1 % in the elongation is shown for the convex height increased by 1 mm.


Author(s):  
Wang Zheng-fang ◽  
Z.F. Wang

The main purpose of this study highlights on the evaluation of chloride SCC resistance of the material,duplex stainless steel,OOCr18Ni5Mo3Si2 (18-5Mo) and its welded coarse grained zone(CGZ).18-5Mo is a dual phases (A+F) stainless steel with yield strength:512N/mm2 .The proportion of secondary Phase(A phase) accounts for 30-35% of the total with fine grained and homogeneously distributed A and F phases(Fig.1).After being welded by a specific welding thermal cycle to the material,i.e. Tmax=1350°C and t8/5=20s,microstructure may change from fine grained morphology to coarse grained morphology and from homogeneously distributed of A phase to a concentration of A phase(Fig.2).Meanwhile,the proportion of A phase reduced from 35% to 5-10°o.For this reason it is known as welded coarse grained zone(CGZ).In association with difference of microstructure between base metal and welded CGZ,so chloride SCC resistance also differ from each other.Test procedures:Constant load tensile test(CLTT) were performed for recording Esce-t curve by which corrosion cracking growth can be described, tf,fractured time,can also be recorded by the test which is taken as a electrochemical behavior and mechanical property for SCC resistance evaluation. Test environment:143°C boiling 42%MgCl2 solution is used.Besides, micro analysis were conducted with light microscopy(LM),SEM,TEM,and Auger energy spectrum(AES) so as to reveal the correlation between the data generated by the CLTT results and micro analysis.


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