703Coarse Aggregate

Coarse aggregate shall consist of crushed stone, washed gravel (crushed or uncrushed), crushed slag, or any combination thereof, conforming to the requirements of these Specifications. 703.1-CRUSHED STONE: 703.1.1-General Requirements: Crushed stone shall consist of particles of clean, hard, tough, durable rock free from adherent coatings and shall contain only the rock type declared by the producer/supplier. Aggregates that do not meet these requirements are subject to being restricted to limited application. Limited application is defined as material that is only approved for use in applications covered by Section 704. The approval process for coarse aggregates is governed by MP 700.00.56. 703.1.2-Deleterious Substances: Deleterious substances shall not exceed the limits set forth below: MATERIAL PERCENT BY WEIGHT Thin or elongated pieces (determined by MP 703.00.25) 5 Shale (determined by MP 703.00.27) 1 Coal and other lightweight deleterious material (determined by MP 702.01.20) 1.5 Friable particles (determined by MP 703.01.20) 0.25 703.1.3-Percentage of Wear (AASHTO T 96 or ASTM C535): Crushed stone shall have a percentage of wear not to exceed 40. 703.1.4-Soundness (Determined by MP 703.00.22): When subjected to five cycles of the sodium sulphate test, the weighted percentage of loss shall be not more than twelve. 703.1.5-Limestone Anti-Skid Aggregates: 703.1.5.1 Limestone: When produced for anti -skid, limestone shall be sampled from the stockpile by the Division. The stockpile shall meet the requirements for Section 703.1, with the addition of MP 703.00.29. Limestone shall contain a minimum of 10% quartz retained on the #200 (75µm) sieve. 703.1.5.2-Dolomite Limestone: When produced for anti -skid, shall be sampled from the stockpile by the Division. The stockpile shall meet the requirements for Section 703.1, with the addition of ASTM C1271 and ASTM C1301. Dolomite shall contain a minimum of 10% elemental magnesium. 778 703.2-GRAVEL: 703.2.1-General Requirements: Gravel shall be composed of particles of hard, durable rock, thoroughly clean and well graded in size. Gravel shall meet the requirements of 703.1.2, 703.1.3 and 703.1.4. 703.2.2-Crushed Particles: The following minimum requirements for percent of crushed particles (determined by MP 703.00.21) for the type of construction indicated shall govern: Crushed Particles Minimum Percent by Weight of the Gravel or Blends Retained on No. 4 (4.75 mm) Sieve Fracture Type Of Construction One Face Two Face Asphalt Pavements - Base 1 80 0 Asphalt Pavement - Wearing, Patching and Leveling , Base 2, Prime, Tack, Chip Sealsand aggregates No. 7 and smaller in penetration macadam and Road Mix Asphalt Pavements ------- 80 Asphalt Pavements - Surfaces or Wearing Courses on all projects requiring specific skid resistant qualities ------- 80 703.2.3-Pea Gravel: Pea gravel shall consist of clean uncrushed river gravel conforming to the requirements of subsections 703.1.3, 703.1.4, total deleterious substances shall not be greater than five percent (5%), and shall meet the following grading requirements for perce nt passing: ½ in. (12.5 mm) 100 No. 16 (1.18 mm) 703.3-SLAG: Slag shall be air cooled blast-furnace slag, reasonably uniform in density and quality, and free from dirt and other objectionable matter. When tested in accordance with AASHTO T 19 and when standard sizes are combined in the proportions used in the job mix formula, the slag shall not weigh less than 70 lb. per cu. ft. when used in Portland cement concrete or hot -laid asphalt surface courses, and not less than 60 lb. per cu. ft. when used in other applications. Blast furnace slag shall meet the requirements of subsection 703.1.2 and 703.1.4. In addition to air cooled blast furnace slag, other slags which meet the applicable physical requirements may be used with the approval of the Engineer. All other slag shall meet the requirements of subsections 703.1.2, 703.1.3 and 703.1.4. 703.3.1-Steel Slag: Steel slag, from the production of steel, includes open hearth, electric furnace, and basic oxygen furnace slag. Steel slag is differentiated from air cooled blast - furnace slag which is from the production of iron. For items where steel slag is used, it must be cru shed to its intended item gradation, maintained in a constant wet condition for a period of at least 6 months, and must be rendered sufficiently inert to minimize potential expansion and the discharge of deleterious effluent. The aging period shall begin at the completion of stockpiling and shall be strictly monitored 779 by the supplier. The stockpile shall be isolated with no additional material being added during the aging period. Should additional material be added, the aging period shall start over from the date of the addition. When aging, stockpiles should be kept at a maximum height of ten (10) feet to allow adequate moisture penetration throughout the pile. To evaluate the effectiveness of the aging process expansion tests shall be conducted at the end of the 6-month aging period. The selection of samples for expansion testing shall be on a stratified random basis vertically with at least one sample from each top one-third, middle one- third, and bottom one -third of the stockpile. Samples shall be obtained in accordance with MP 700.00.06, Aggregate Sampling Procedures. Expansion values shall not be greater than 0.50 percent (0.5%) at seven days when tested in accordance with applicable portions of ASTM D4792. If one or more of the samples do not meet the 0.50 percent (0.5%) expansion limit after the 6 month aging period, the stockpile shall be kept moist and aged an additional two months, after which expansion tests shall again be conducted in the manner described above. This process shall conti nue prior to use until the steel slag conforms to the expansion limit. When the stockpile has shown compliance to the expansion test requirements, it may be used in items as directed by the Engineer. When steel slag is to be used in Hot -Mix Asphalt (H MA), the expansion tests shall be waived. Steel slag, when used in HMA, shall not exceed 50 percent (50%) by weight of the coarse fraction of the mix, and in no case shall steel slag be used as a coarse aggregate fraction and a fine aggregate fraction within a single mix. When steel slag is to be used in items where thickness and quantities are limited and the slag is not confined, such as aggregate shoulders, road stabilization, snow and ice control, etc., the expansion tests may be waived as directed by the Engineer. In addition to other requirements specified elsewhere in the Contract Documents, for the particular item, acceptance of the material shall be on the basis of the Division’s evaluation of the supplier’s written certification that the afo rementioned aging, moisture, and expansion requirements (where applicable) have been accomplished, and that the level or degree of expansion exhibited meets the expansion criteria. The certification shall include all test data when applicable. Steel slag shall not be used in any item where expansion might be detrimental. Such items include, but not necessarily limited to, the following: aggregate for Portland cement concrete, backfill around drainage structures, piers, abutments, walls, etc. 703.3.1.1-Wearing III (Sand Mix): When fine aggregate steel slag is used in a sand mix all the requirements specified in Section 703.3.1 for coarse aggregate steel slag when used in HMA shall apply with the following exceptions: fine aggregate steel slag shall meet the quality requirements of subsections 702.1.2 and 702.1.3, and shall not exceed 25 percent (25%) by weight of the total fine aggregate used in the mix. 703.3.2-Electrometallurgical Slag: Electrometallurgical slag is from the production of metal alloys as differentiated from the production of steel. Electrometallurgical slag may not be used as a Portland cement concrete aggregate. When electrometallurgical slag is used as an aggregate in asphalt construction and payment is on a tonnag e basis, proper allowance will be made for the difference in weight per cubic foot. 703.3.3-Power Plant Slag: Power plant slag consists of Wet Bottom Boiler Slag (shiny, black, glassy material) formed when molten ash from the burning of coal drops into water and 780 shatters at the bottom of the boiler, and Bottom Ash formed when ash particles from the burning of pulverized coal is allowed to air cool at the bottom of the furnace. Power plant slag may not be used as a Portland cement concrete aggregate. 703.4-GRADING OF COARSE AGGREGATES: Coarse aggregate shall be uniformly graded to conform to the requirements of Table 703.4. The gradations for coarse aggregates required by AASHTO M 43 shall be determined in accordance with AASHTO T 27. The gradation of coarse aggregates in the production of concrete shall be controlled by the Ā value as specified in 501.3 and 601.3. In addition, coarse aggregates to be used in Portland cement concrete shall have no more than one percent (1%) by weight passing the No. 200 (75 μm) sieve, except that this percentage may be increased to 1.5 in the case of crushed aggregate if the material finer than the No. 200 (75 μm) sieve consists of the dust of fracture, essentially free from clay or shale. The gradation shall be determined in accordance with AASHTO T 27 and T 11. When the coarse aggregate is to be used in Portland cement concrete, larger percentages passing the No. 200 (75 μm) sieve in the coarse aggregate fraction will be permitted if the percent passing the No. 200 (75 μm) sieve in the fine aggregate fraction (702.1) is less than the specified maximum. In no event, however, shall the percent passing the No. 200 (75 μm) sieve in the total concrete aggre gate be greater than an amount which would exist if both aggregate fractions contained their specified maximum percentage passing the No. 200 (75 μm) sieve. 703.5-LIGHTWEIGHT COARSE AGGREGATE FOR STRUCTURAL CONCRETE: Lightweight coarse aggregate for structural concrete shall meet the requirements of ASTM C330. 781 TABLE 703.4 STANDARD SIZES OF COARSE AGGREGATES (AASHTO M 43) Size No. Nominal Size Square Openings (1) Amounts Finer Than Each Laboratory Sieve (Square Openings), Percent By Weight 4 in --- 100 mm 3½ in --- 90 mm 3 in --- 75 mm 2½ in --- 63 mm 2 in. --- 50 mm 1½ in --- 37.5 mm 1 in --- 25.0 mm 3/4 in --- 19.0 mm 1/2 in --- 12.5 mm 3/8 in --- 9.5 mm No. 4 --- 4.75 mm No. 8 --- 2.36 mm No. 16 --- 1.18 mm No. 50 --- 300 μm No. 100 --- 150 μm 3½ to 1½ in ------ 90 to 37.5 mm 100 90 to 100 25 to 60 0 to 15 0 to 5 2½ to 1½ in ------ 63 to 37.5 mm 100 90 to 100 35 to 70 0 to 15 0 to 5 2½ to ¾ in ------ 63 to 19.0 mm 100 90 to 100 25 to 60 0 to 10 0 to 5 2 to 1 in ------ 50 to 25.0 mm 100 90 to 100 35 to 70 0 to 15 0 to 5 357 2 in to No. 4 ------ 50 to 4.75 mm 100 95 to 100 35 to 70 10 to 30 0 to 5 1½ to 3/4 in ------ 37.5 to 19.0 mm 100 90 to 100 20 to 55 0 to 15 0 to 5 467 1½ in to No 4 ------ 37.5 to 4.75 mm 100 95 to 100 35 to 70 10 to 30 0 to 5 1 to 1/2 in ------ 25.0 to 12.5 mm 100 90 to 100 20 to 55 0 to 10 0 to 5 56 1 to 3/8 in ------ 25.0 to 9.5 mm 100 90 to 100 40 to 85 10 to 0 to 15 0 to 5 57 1 in. to No 4 ------ 25.0 to 4.75 mm 100 95 to 100 25 to 60 0 to 10 0 to 5 3/4 to 3/8 in ------ 19.0 to 9.5 mm 100 90 to 100 20 to 55 0 to 15 0 to 5 67 3/4 in to No 4 ------ 19.0 to 4.75 mm 100 90 to 100 20 to 55 0 to 10 0 to 5 68 3/4 in to No 8 ------ 19.0 to 2.36 mm 100 90 to 100 30 to 65 5 to 0 to 10 0 to 5 1/2 in to No 4 ------ 12.5 to 4.75 mm 100 90 to 100 40 to 70 0 to 15 0 to 5 78 1/2 in to No 8 ------ 12.5 to 2.36 mm 100 90 to 100 40 to 75 5 to 0 to 10 0 to 5 3/8 in to No 8 ------ 9.5 to 2.36 mm 100 85 to 100 10 to 0 to 10 0 to 5 89 3/8 in to No 16 ------ 9.5 to 1.18 mm 100 90 to 100 20 to 55 5 to 30 0 to 10 0 to 5 No. 4 to No. 16 ------ 4.75 to 1.18 mm 100 85 to 100 10 to 40 0 to 10 0 to 5 No. 4 to 0 (2) ------ 4.75 mm to 0 (2) 100 85 to 100 10 to 30

Where standard size of coarse aggregate designated by two or three digit numbers are specified, obtain the specified gradation by combining the appropriate single digit standard size aggregates by a suitable proportioning device where has a separate compartment for each coarse aggregate combined. Performed the blending as directed by the Laboratory. 782