How do you find fine aggregate angularity?
Uncompacted void content is calculated as the difference between the volume of the cylindrical measure and the absolute volume of the fine aggregate collected in the measure expressed as a percentage of the volume of the measure. This value is also known as the Fine Aggregate Angularity or FAA.
How is angularity number calculated?
Determination of angularity number from the voids point of view:
- Find the mean weight (W) of the aggregate filling cylinder.
- Find the specific gravity (Gs) of aggregates.
- Find the volume of cylinder (C) by completely filling measured quantity of water in the cylinder.
What is fine aggregate angularity?
Scope. The fine aggregate angularity test determines the loose uncompacted void content of a fine aggregate material. The void content information derived from this test gives you an indication of the effect fine aggregate will have on stability and voids in the mineral aggregate.
What is coarse aggregate angularity?
Overview. The coarse aggregate angularity (CAA) test is a method of determining the angularity of coarse aggregate (Figure 1). Coarse aggregate angularity is important to ensure adequate aggregate interlock and prevent excessive HMA deformation under load (rutting).
What are fine aggregates?
Fine aggregates are essentially any natural sand particles won from the land through the mining process. Fine aggregates consist of natural sand or any crushed stone particles that are ¼” or smaller. Frequently referred to as washed concrete sand or manufactured sand, C33 refers to the grading or size of the material.
What is aggregate crushing test?
The strength of coarse aggregates is assessed by aggregates crushing test. The aggregate crushing value provides a relative measure of resistance to crushing under a gradually applied compressive load. The aggregate passing 12.5mm IS sieve and retained on 10mm IS sieve is selected for standard test.
Can angularity number be negative?
Importance of Angularity Number The normal aggregate which are suitable for making concrete may have angularity number anything from 0 to 11.
What is range of angularity number?
The value of angularity number generally lies between 0 & 11. In road construction angularity number of 7 – 10 is generally preferred.
How do you calculate aggregate void?
VMA = Voids in mineral aggregate, in percent of bulk volume, Gsb = Bulk specific gravity of the aggregate, Gmb = Bulk specific gravity of compacted mix, Ps = Aggregate, percent by total weight of mix. Where: P1 = Percent by weight of aggregate 1, etc., G1 = Bulk specific gravity of aggregate 1, etc.
How do you calculate aggregate crushing value?
Calculation: The aggregate crushing value is defined, as a ratio of the weight of fines passing the specified IS sieve to the total weight of the sample expressed as a percentage. Where, W1 = Total weight of dry sample. W2 = Weight of the portion of crushed material passing 2.36mm IS sieve.
Why is the fine aggregate angularity test important?
The fine aggregate angularity (FAA) test (Figure 1) is an indirect method of assessing the angularity of fine aggregate. Fine aggregate angularity is important because an excess of rounded fine aggregate (often in the form of natural sand) can lead to HMA rutting.
How are uncompacted voids affected by fine aggregate?
The measured uncompacted voids are affected by the shape, angularity and texture of the fine aggregate, the aggregate grading and specific gravity. FAA can indicate the effect of the fine aggregate portion of the mixture on the overall properties of the mixture.
What does as received mean for fine aggregate?
The fine aggregate is tested in an “as received” condition, meaning its gradation remains in tact. Therefore, test results not only account for form, angularity and texture, but they also account for fine aggregate gradation.
How is the mass of fine aggregate determined?
A nominal 100 mL calibrated cylindrical measure is filled with fine aggregate of definite grading by allowing the sample to flow through a funnel from a fixed height into the measure. The aggregate is then struck off and its mass is calculated by weighing.
