Sieve Analysis. Concrete Mix Design Technician School. Terms and Definitions. Aggregate. An inert filler material, such as crushed stone, gravel, and sand which is mixed with cement and water to make concrete. Coarse Aggregate.
Concrete Mix Design Technician School
An inert filler material, such as crushed stone, gravel, and sand which is mixed with cement and water to make concrete.
Generally aggregate larger than 1/2" in diameter, referred to as stone or gravel.
A natural silica or manufactured aggregate smaller than 1/4" in diameter, normally referred to as sand.
A process in which an aggregate is separated into its various sizes by passing it through screens of various size openings for the purpose of determining the distribution of the quantities separated.
Gradation of an Aggregate
The relative amounts of aggregate particles of consecutively larger and smaller sizes.
Maximum Size of Aggregate
The smallest sieve opening through which the entire amount of the aggregate is required to pass.
Nominal Maximum Size of Aggregate
The smallest sieve opening through which the entire amount of the aggregate is permitted to pass.
6", 3", 1 1/2", 3/4", 3/8", and No.4
Nos. 4, 8, 16, 30, 50, and 100
One 1- in cube of aggregate. Surface area = 6 x 1 x 1 = 6 sq in
27 1/3 - in cubes of aggregate. Surface area = 6 x 1/3 x 1/3 x 27
=18 sq in.
Take a representative sample.
Reduce to proper size for testing.
North Carolina Department of Transportation
Coarse Aggregate Gradation
When tested during production the amount passing the No. 200 sieve may be no greater than 0.6% by weight.
When tested at the job site prior to use , the amount of material passing the No. 200 sieve shall not be greater than 1.5% by weight.
If a stockpile at the job site is found to contain in excess of 1.5% passing the No.200 sieve prior to use, the engineer may approve its use provided the total % by weight passing the the no 200 sieve in the combined coarse and fine aggregate does not exceed 2%, & no increase in W/C ratio is required by the use of this aggregate.
Aggregate Gradation of Fine Aggregate
When tested during production the amount of material passing the No.200 sieve shall not be greater than 8%.
When tested at the job site prior to use, the amount of material passing the No. 200 sieve shall not be greater than 10%.
Percent passing No. 200 sieve =
Total dry wt – wt after washing x 100 Total dry wt
Total dry wt 514.0 grams
Wt after washing 504.9 grams
Gram mat’l passing 200 9.1 grams
9.1 grams x 100 = 1.8% passing
Fine Modulus – An index to the coarseness or fineness of an aggregate.
Fineness Modulus (FM) – Defined mathematically as the sum of the cumulative percentages retained on the standard sieves divided by 100.
FM of fine aggregate should not be less than 2.30 or more than 3.10, nor vary by more than 0.20 from batch to batch.
Coarse Sand 2.80 - 3.10
Medium 2.50 - 2.80
Fine Sand 2.30 - 2.50
1 ½ in
Fine agg. range 3/8 - #100
Coarse agg. range 6 in - #8
Nominal Maximum Size
Water Reducing Agent
HOLD ON A MINUTE AND LET ME MARK THOSE IN THE BACK OF MY BOOK!!