15. Concrete Mix Design (Local Aggregate).pdf
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- Attached to
- Repair Electrical Distribution Lines, Feeder 5, Ascension Auxiliary Airfield (AAAF), South Atlantic Ocean
- Solicitation number
- FA252123B0008
About this file
This document contains two concrete mix designs and details regarding a federal contract opportunity for electrical distribution line repair on Ascension Island.
The concrete mix designs provide specifications for two types of structural concrete using local aggregates and imported materials. Mix Design 1 uses Type IL cement for a 4,000 psi concrete. Mix Design 2 uses Type II cement and a maximum 0.50 water-cement ratio for similar concrete. Both accounts for absorption of the saturated surface dry aggregates and allowances for additional mixing water. The opportunity notice is for repair of Feeder Line 5 on the auxiliary airfield via replacement of overhead lines and poles, removal and installation of electrical equipment, and underground duct work. The work must be performed according to the project specifications and drawings in Section J. The Department of the Air Force Space Command is the contracting agency.
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Text version
Concrete Mix Design Structural Concrete (TYPE IL)
Materials Portland Cement: Type IL Corse Aggregate: #57 Stone Local. From Ascension Island Rock Crusher (Government Owned) Fine Aggregate: Not Applicable. (Availability of local crusher fines is limited on Ascension Island) Sand: Imported Standard Silica Sand Water: Local Potable Air Content: 2% Entrapped Air Assumed Admixtures: Not Applicable.
Specified Strength:
4,000 PSI at 28 Days
Mix Proportions
Item Material Weight
(LBS)
Estimated Volume
(CF)
1 Water. (40 Gallons Per Cubic Yard) 334 5.35
2 Portland Cement. Type IL (8 Bags Per Cubic Yard)
752 8.00
3 #57 Stone. Ascension Island Rock Crusher 1261 8.08
4 Sand 1550 9.44
5 Air (Entrapped) 0.54
TOTALS 3897 31.41
Design Notes Slump = 4” +/- 1.5” Air Content = 2% Entrapped Water-Cement Ratio = .44 Lb
General Notes Concrete design is based on aggregate being saturated surface dry (SSD). Allowance is made for additional water for absorption by the aggregates based on 2% for the coarse aggregate and 6% for the fines/sand. Additional allowance made for adding up to 15 Gallons per CY based on current weather conditions (rain).
Due to limitations of the Government batch plant, the cement must be placed on top of the aggregate as it travels up the conveyor into the mixer truck.
The additional water needed for absorption is added with the balance of the water per the concrete design.
Up to 1.5 Gallons of water per CY may be added at final pour site to achieve desire slump.
Concrete Mix Design Structural Concrete (TYPE II)
Materials Portland Cement: Type II Corse Aggregate: #57 Stone Local. From Ascension Island Rock Crusher (Government Owned) Fine Aggregate: Not Applicable. (Availability of local crusher fines is limited on Ascension Island) Sand: Imported Standard Silica Sand Water: Local Potable Water Air Content: 2% Entrapped Air Assumed Admixtures: Not Applicable.
Specified Strength:
4,000 PSI at 28 Days
Item Material Weight
(LBS)
Estimated Volume
(CF)
1 Water. (40 Gallons Per Cubic Yard) 334 5.35
2 Portland Cement. Type II (7.5 Bags Per Cubic Yard)
705 3.59
3 #57 Stone. Ascension Island Rock Crusher 1261 8.08
4 Imported Sand 1550 9.44
5 Air (Entrapped) 0 0.54
TOTALS 3850 27.00
Design Notes Slump = 4” +/- 1.5” Air Content = 2% Entrapped Water-Cement Ratio = .47 Lb (Maximum Allowable Ratio = .50)
General Notes Concrete design is based on aggregate being saturated surface dry (SSD).
In general no more than 1 Gallon per CY of mix batching water should be added to the mix or the maximum water cement ratio would be exceeded and adversely affect the both the concrete strength and its long term durability.
Because of wind and humidity conditions, the aggregate may be dry prior to start of mixing operations.
Any water added for absorption should be added and pre-mixed a minimum of 15 minutes before adding in any cement or mix water may be on the order of 1.5 Gallons per CY.
Due to limitations of the Government batch plant, the cement must be placed on top of the aggregate as it travels up the conveyor into the mixer truck.
File details come from the government source that posted it. Updated .