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# CON 121 Session 3 - Standards and Evaluation

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### CON 121 Session 3 - Standards and Evaluation

1. 1. CON 121Concrete AggregateSession 3Fine and Coarse Concrete AggregatesStandards and Evaluation
2. 2. Range of Particle SizesRange of particle sizes found in aggregate for use in concrete
3. 3. Grading of AggregateGrading is the particle-size distribution of an aggregateas determined by a sieve analysis using wire meshsieves with square openings.ASTM C 33:Fine aggregate―7 standard sieves with openings from 0.15 mm to 9.5 mm (No. 100 to 3/8 in.)Coarse aggregate―13 sieves with openings from 1.18 mm to 100 mm (0.046 in. to 4 in.)
4. 4. Fine-Aggregate Grading Limits Sieve size Percent passing by mass 9.5 mm (3/8 in.) 100 4.75 mm (No. 4) 95 to 100 2.36 mm (No. 8) 80 to 100 1.18 mm (No. 16) 50 to 850.60mm (No. 30) 25 to 600.30mm (No. 50) 5 to 30 AASHTO 10 to 300.15mm (No. 100) 0 to 10 AASHTO 2 to 10 4
5. 5. Fineness Modulus (FM)The FM is an index of the fineness of the aggregate. The higher the FM the coarser the aggregate The FM of any shipment made during the progress of the work should not vary more than 0.20 from the initially approved value. Different aggregate grading may have the same FM
6. 6. Fineness Modulus (FM) Obtained by adding the sum of the cumulative percentages by mass of a sample aggregate retained on each of a specified series of sieves and dividing the sum by 100. The specified sieves are: 0.15 mm (No. 100), 0.30 mm (No. 50), 0.60 mm (No. 30), 1.18 mm (No. 16), 2.36 mm (No. 8), 4.75 mm (No. 4), 9.5 mm (3/8 in.), 19.0 mm (3/4 in.), 37.5 mm (1½ in.), 75 mm (3 in.), and 150 mm (6 in.).
7. 7. Sieve Analysis and Sand FM Cumulative % of individual percentage fraction retained, % passing, retained, by Sieve size by mass by mass mass9.5 mm (3/8 in.) 0 100 04.75 mm (No. 4) 2 98 22.36 mm (No. 8) 13 85 151.18 mm (No. 16) 20 65 350.60mm (No. 30) 20 45 550.30mm (No. 50) 24 21 790.15mm (No. 100) 18 3 97 Pan 3 0 —Total 100 283 7 Fineness modulus = 283 100 = 2.83
8. 8. Normal-Weight Aggregate ASTM C 33Most common aggregates Sand Gravel Crushed stone Produce normal-weight concrete 2200 to 2400 kg/m3 (140 to 150 lb/ft3)
9. 9. Lightweight Aggregate ASTM C 330 Expanded  Shale  Clay  Slate  Slag Lightweight aggregate. Expanded clay (left) and expanded shale (right). Produce structural lightweight concrete 1350 to 1850 kg/m3 (90 to 120 lb/ft3)
10. 10. Lightweight Aggregate Pumice Produce lightweight insulating Scoria concrete— 250 to 1450 kg/m3 (15 to 90 lb/ft3) Perlite Vermiculite Diatomite
11. 11. Heavyweight Aggregate ASTM C 637, C 638 (Radiation Shielding) Barite Limonite Produce high-density concrete up Magnetite to 6400 kg/m3 (400 lb/ft3) Ilmenite Hematite Iron Steel punchings or shot 11
12. 12. Coarse Aggregate Grading Size No. 57 : 1in. To No.4 % passing by Sieve size mass 37.5 mm 1½ in 100 25.0 mm 1 in. 95 to 100 12.5 mm ½ in. 25 to 60 4.75 mm No. 4 0 to 10 2.36 mm No. 8 0 to 5
13. 13. Grading Limits Curves indicate the limits specified in ASTM C 33 for fine aggregate and for one commonly used size number (grading size) of coarse aggregate.
14. 14. Maximum Size vs. Nominal Maximum Size of Aggregate Maximum size ― is the smallest sieve that all of a particular aggregate must pass through. Nominal maximum size ― is the standard sieve opening immediately smaller than the smallest through which all of the aggregate must pass. The nominal maximum-size sieve may retain 5% to 15%
15. 15. Nominal Maximum Size of Aggregate Size should not exceed ―  1/5 then narrowest dimension between sides of forms  3/4 clear spacing between rebars and between rebars and the form  1/3 depth of slabs
16. 16. Maximum Aggregate Size and Water Requirement Cement and water contents in relation to maximum size of aggregate for air- entrained and non-air- entrained concrete. Less cement and water are required in mixtures having large CA.