How do you calculate aggregate angularity?
How do you calculate aggregate angularity?
G= Specific Gravity, C= Volume (in Kg in termed water filled that volume), Angularity index= (3 Angularity number/20)+1. Angularity number = 67-(100w/CG).
What is angularity test?
Angularity number test gives an idea of how angular the aggregate is. This is based on the percentage of voids in the aggregate after compaction in a specified manner. In angularity number test, a quantity of single sized aggregate is filled into metal cylinder of 3 liter capacity.
What is fine aggregate angularity?
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 concrete angularity?
Angularity is the absence of roundness in aggregates. A more rounded aggregate particle has less angularity and vice versa. Angularity number of aggregate is the amount (a whole number) by which the percentage of volume of voids in it after compaction in a prescribed method exceeds 33.
What is the angularity number of fully rounded aggregate?
“67” is the percentage of volume of solids in a perfectly rounded aggregate. The value of angularity number generally lies between 0 & 11. In road construction angularity number of 7 – 10 is generally preferred.
Why is aggregate angularity important?
Fine aggregate angularity is important because an excess of rounded fine aggregate (often in the form of natural sand) can lead to HMA rutting. Figure 1: Fine aggregate angularity test. The FAA test estimates fine aggregate angularity by measuring the loose uncompacted void content of a fine aggregate sample.
How does angularity number influence workability of concrete mix?
Higher the angularity number, more angular and less workable is the concrete mix. In cement concrete roads (rigid pavements) rounded aggregates are preferred because of better workability and higher strength.
What is the specific gravity of coarse aggregate?
about 2.5 to 3.0
The specific gravity of aggregates normally ranges from about 2.5 to 3.0. According to ‘A. M. Neville’ (Author of the Properties of Concrete), the majority of natural aggregates have a specific gravity of between 2.6 and 2.7. However high specific gravity is considered as an indication of high strength.
What is the angularity index?
It is the absence of roundness. An aggregate particle, which is more rounded, is less angular and vice versa. ANGULARITY NUMBER. Angularity number of an aggregate is the amount (to the higher whole number) by which the percentage of voids in it after compacting in a prescribed manner exceeds 33.
What is flakiness and elongation?
Flakiness Index is the percentage by weight of particles in it, whose least dimension (i.e. thickness) is less than three-fifths of its mean dimension. Elongation Index is the percentage by weight of particles in it, whose largest dimension (i.e. length) is greater than one and four-fifths times its mean dimension.