Flat and Elongated Particles Overview The flat and elongated particle test is used to determine the dimensional ratios for aggregate particles of specific sieve sizes. This characterization is used in the Superpave specification to identify aggregate that may have a tendency to impede compaction or have difficulty meeting VMA specifications due to aggregate degradation. Flat or elongated particles Figure 1 tend to lock up more readily rather than reorient during compaction making compaction more difficult. They also have a tendency to fracture during compaction along their weak, narrow dimension, which can effectively make aggregate gradation finer and possibly cause lower-than-expected VMA. Figure 1: Flat particles left and elongated particles right.
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Tegrel The standard flat and elongated particles in coarse aggregate test is: Flat and elongated requirements do not apply. The mass of all flaky particles passing appropriate slots as percent of the sample is the flakiness index. Particle d elongated when its length longest dimension is more than 1.
This characterization is used in the Superpave specification to identify aggregate that may have a tendency to impede compaction or have difficulty meeting VMA specifications due to aggregate degradation. Periodically, inspect to width greater than a specific value. Comments to this Manuals Your Name. Aggregate Blending 0 20 40 60 80 10 1 0. Figure 1 indicates that 37 percent of the states surveyed have some requirement to control flat and elongated particles, but only a very few states measure flat and elongated particles separately.
Method A is a reflection of the original procedure as developed prior to Superpave and is intended for all non-Superpave applications. Elongated particles are undesirable because they have a tendency to break during construction and under zstm.
Coarse aggregate shall be aggregate retained on the No. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
Division of Engineering Services:: The user should set the larger opening of the Caliper. Use GDT to analyze these materials. Scratch Hardness Tester— H Scratch Hardness Tester determines quantity of soft particles in coarse aggregates on basis of scratch hardness. The complete procedure for determination of relative shape characteristics of coarse aggregates using the Four- Station Caliper is described in ASTM D Link to Active This link will always route to the current Active version of the standard.
Standard Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate This test method covers the determination of the percentages of flat particles, elongated particles, or flat and elongated particles in coarse aggregates.
This characterization is used in the Superpave specifiion to identify aggregate that may have a tendency to impede compaction or have difficulty meeting VMA specifiions due to aggregate degradation. Elongated, it is classified as Neither Flat nor Elongated. Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregates Background Flat or elongated aggregate particles xstm, if present in sufficient number, 1 impede compaction or 2 affect HMA behavior by fracturing during compaction.
For each of the v selected, SMA mix designs were conducted and Cantabro abrasion loss for cohesion and resistance to ravelingmoisture susceptibility, and rutting performance were evaluated. Two procedures, Method A and Method B, are presented in this standard. VMA the volume of intergranular void space between the aggregate particles of a compacted paving mixture that includes the air voids and the effective binder content expressed as d ….
This test method covers the determination of the percentages of flat particles, elongated particles, or flat and elongated particles in coarse aggregates. Two procedures, Method A and Astk B, are presented in this standard. Link to Active This link will always route to the current Active version of the standard. Flat and Elongated Particles shall be determined on the aggregate blend. This test method provides a means for checking compliance with specifiions that limit such particles or to determine the relative shape characteristics of coarse aggregates.
Coarse aggregate angularity requirements do not apply. GMC All rights reserved. The complete procedure for determination of relative. Balance, accurate to 0. Find out why Close. The particle is flat and elongated if the flattest portion of the particle can be satm through the smaller opening. Evaluation of the Specification for Flat and Elongated The data for comparison, as well as the results of the 5: Cubical particles are desirable, with a limited amount of flat or thin and elongated particles.
Flat and elongated particles have long been considered undesirable in hot mix asphalt HMA mixes due to their tendency to break down during construction and traffic. The particles shape of course aggregates influences the properties of some construction materials and may affect their placement and consolidation.
Ratio desired is obtained by d one of four adjustable positions: Related Posts
Zulkinris A pressuremeter test is an in-situ stress-strain test performed on the wall of a borehole using a cylindrical probe that is expanded radially. Note 2—Strain-controlled tests also can be performed, whereby the probe volume is increased at a constant rate and corresponding pressures are measured. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1—A standard for the self-boring pressuremeter is scheduled to be developed separately. This test method is limited to the pressuremeter which is inserted into predrilled boreholes or, under certain circumstances, is inserted by driving. A pressuremeter test is an in situ stress-strain test performed on the wall of a borehole using a cylindrical probe that is expanded radially. Work Item s — proposed revisions of this standard.
Flat and Elongated Particles
Shape characteristics of coarse aggregates are important when determining the performance of materials or mixes. Units are constructed of durable plated steel, precision tooled for accuracy. For shape determination of flat particle sizing, set the width of a particle in the larger end of the Caliper, then tighten the pivot screw. Without adjusting the Caliper, check the same particle in the smaller measuring end of the Caliper. If the particle fits within the smaller gap, it is considered flat. Elongated particle determination follows the same steps.
ASTM D4791 PDF