A flat piece is one in which the maximum width is greater than 5 times the maximum thickness. An elongated piece is one in which the maximum length is greater than 5 times the maximum width.
Flat and elongated particle ratio is a shape characteristic for coarse aggregates used in pavements. The ASTM D 4791 is the standard test method to determine flat and elongated coarse aggregate particles in asphalt mixes.
The problem with this approach is that particles tend to lay or fall flat, consequently it is elongation that is measured, rather than the more critical flatness or flat and elongation.
Method B is used to separate particles into two groups: flat and elongated (comparing maximum length to maximum thickness), or not flat and elongated.
Semantic Scholar extracted view of "Image-based methods for automatic identification of elongated and flat aggregate particles" by Zeqi Chen et al.
The mass (or count) of coarse aggregate particles meeting the fractured face specification is compared to the total coarse aggregate sample mass (or particle count) and converted to a percentage.
In addition, compared to the elongated aggregate particles, the flat aggregate particles make the relative movement between the aggregates easier; this has a greater impact on the compaction performance of the asphalt mixture. Miao et al. used DEM to study the influence of elongated and flat aggregate particles on a mixture [7].
The Flakiness Index measures the concentration of flat and elongated particles in a sample, while the Elongation Index measures the concentration of elongated particles.
Soundness of Aggregate by Use of Magnesium Sulphate Percent Flat and Elongated Particles in Coarse Aggregate Petrographic Analysis of Coarse Aggregate Organic Impurities in Sands for Concrete Determination of Insoluble Residue of Carbonate Aggregates Freezing and Thawing of Coarse Aggregate Determination of Potential Alkali …
With the increase of the flat and elongated particles content in mixture, the aspect ratio expectation of particles-AR1, AR2 and angularity expectation increases, and the cross section area of ...
Abstract: Granular shear flows of flat disks and elongated rods are simulated using the Discrete Element Method. The effects of particle shape, interparticle friction, coefficient of restitution, and Young's modulus on the flow behavior and solid phase stresses have been investigated. Without friction, the stresses decrease as the particles ...
However, these methods require inspectors to individually measure the aggregate particles, which is labor-intensive and inefficient. Hence, it is necessary to develop an automatic identification method for elongated and flat aggregates.
The design procedures for Superpave and stone-matrix asphalt mixtures emphasize the importance of aggregate shape. The current test procedure for characterization of aggregate shape, ASTM D4791, lacks a precision statement and is extremely time-consuming. A round-robin analysis was conducted with 15 laboratories, …
Flat and Elongated Particles -2. 20-yr ESALs1 (millions) Maximum Flat & Elongated (%) < 0.3.
It has long been believed that coarse aggregates that have a flat and elongated (F&E) shape are detrimental to the properties of hot-mix asphalt. Several attempts have been made to establish a relationship between these aggregate particles and performance.
Each fraction spread out on clean, large flat surface to allow for inspection of individual particles?.......... _______
Some states have recommended changing the definition of flat and elongated aggregates from 5:1 to 3:1 and an increase in the maximum allowable percentage of flat and elongated (F&E) particles to 20% or higher in …
6.2 After calculating the number of flat and elongated particles in each size group, take an average of the percentages. This will be the percentage of flat and elongated particles.
Study with Quizlet and memorize flashcards containing terms like The cracking of pavements caused by freeze-thaw deterioration of the aggregate is called _____., If an aggregate is less than SSD, it will contribute to the mixing water of a concrete batch., The bulk density of aggregate used in normal-weight concrete ranges from _____ pounds per …
Particles in Coarse Aggregate, ASTM D4791. (Flat and Elongated Test, Method B –
Flat and elongated aggregate particles can lock together to hamper the compaction of asphalt pavement mixtures and make the mix unstable if a significant number of particles fracture. Concrete mixes with these particles are difficult to place, resist consolidation, and are hard work to finish.
Flat and/or elongated aggregate particles are susceptible to breakage when a load is applied perpendicular to the flat side or to the longest axis of the particle. Therefore, flat and/or elongated particles are more easily broken than the more cubical aggregates during handling and mixing at the plant, placement, compaction, and even …
Granular shear flows of flat disks and elongated rods are simulated using the Discrete Element Method. The effects of particle shape, interparticle friction, coefficient of restitution, and Young's modulus on the flow behavior and solid phase stresses have been investigated. Without friction, the stresses decrease as the particles become flatter or …
Semantic Scholar extracted view of "A detection method of elongated and flat aggregate particles based on multi-view shape features with a single camera" by Weijun Fan et al.
Use this test method to determine the percentage of flat and elongated particles in coarse aggregates. Flat and elongated aggregate particles interfere with compaction and can result in harsh, difficult to place materials. They also break under load and prevent development of an adequate aggregate skeleton.
3.1.2 flat and elongated particles of aggregate—those particles having a ratio of length to thickness greater than a. specified value. 3.1.3 length—maximum dimension of the particle. 3.1.4 width—maximum dimension in the plane perpendicular to the length. 3.1.5 thickness—maximum dimension perpendicular to the.
Study with Quizlet and memorize flashcards containing terms like Why are flat and elongated particles undesirable in road construction?, This procedure shall be run on what sized material?, Reduce your sample to the sizes …
Flat and elongated particles in coarse aggregates, for some construction uses, may interfere with consolidation and be difficult to place.
Other good information on this test can be found here: https://pavementinteractive/reference-desk/testing/aggregate-tests/flat-and-elongated-particles/
Flat and Elongated – Set the larger opening equal to the length of the Particle. The particle is flat and elongated if the particles least dimensional requirement (thickness) can pass completely through the smaller opening of
The Elongation Index focuses on the presence of elongated particles, while the Flakiness Index considers both flat and elongated particles. This means that the Flakiness Index provides a broader assessment of particle shape, taking into account a wider range of potential shape-related issues. Another difference lies in the specific sieve sizes ...
