220.2(k) 220.3(a)
the Representative, at least 3 weeks before construction. Alkali -Silica remediation is not required regardless of the expansion value of the aggregates used in the mix design. Use Table A as a guideline for the mix design or submit an alternate design based on density guidelines and conforming to the strength requirements of Table A. Base the submitted mix design on an absolute volume of 1 cubic yard.
TABLE A Mix Design Properties & Criteria Type B Type C Type D Mix Design ( /CY) Cement (lbs)* Supplementa ry Cementitious Material (lbs)* Bottom ash (lbs)* or Coarse Aggregate or Fine Aggregate Air Generating Admixture* 50
300
2600
300
2600
** Slump (inches) AASHTO T 119, ASTM C136 7 min **** 7 min **** 7 min **** Density (pcf) AASHTO T 121, ASTM C136 N/A N/A 30-70 or as specified *** Water Absorption of Aggregate AASHTO T 85 -- -- 20% max Compressive Strength (psi) PTM No. 604 28 Days 125 max 800 min *Quantities may be varied or alternate designs submitted to adapt mix to conform to density and strength requirements or to adapt to specific site conditions. **Requires using a suitable lightweight aggregate or air entraining admixture. Provide a mix design that achieves the specified strength and density requirements. ***Approximate Value. Use of air entraining agent may reduce these values. ****Some applications may require containing flowable backfill by constructing dikes from the mix by using less water to produce a 3 -inch minimum slump, if approved by the Representative. Thickening of the mix in other areas is allowed if approved by the R epresentative.
Provide mix designs that conform to specific density requirements, if specified. If source of material is changed, submit a revised mix design before using material. Conduct design mix testing at the highest flowability or slump being used for the project. If applications involve exposed metal or metal coated with a layer of thin concrete (< 1/2 inch), test the design mixes for corrosion resistance as follows:
Resistivity, AASHTO T 288, 60 day cure > 2000 ohm -centimeters pH of pulverized flowable backfill 5.0 to 9.5 Chlorides of pulverized backfill after cure < 200 ppm Sulfates of pulverized backfill after cure < 1000 ppm Sulfides of pulverized backfill after cure < 200 ppm
220.3CONSTRUCTION —
backfill to contact aluminized materials or compounds. 220.3(a) 220.3(c) Initi