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Iowa 175 Test Road

Iowa 175, west of the town of Ellsworth, is a test road with sections containing portland cement concrete, and concrete panels containing partial cement replacement by Class C or Class F fly ash. These pavements, constructed about 1981, have performed very well and exhibit no evidence of vibrator trails. This location was of interest as these concretes appear to be in excellent condition, yet are slightly older than those exhibiting problems, and used similar materials, including fly ashes. The materials and properties of the specimens taken from Iowa 175 were provided by the Iowa Department of Transportation and are given in table three.

Table 3. Iowa 175, West of Ellsworth, Iowa: Materials and Properties [28]
Cement:Type I,
 2.16 % SO3,
 0.35 % equivalent alkali
 
Coarse Aggregate:Alden (Weaver) Limestone, open quarry,
 1.5 % freeze-thaw loss, 2.7 % absorption,
 LA Abr. 40 % loss, durability factor 79
 
Fine Aggregate:Ames sand
Admixtures:AEA
Fly Ash:Class C, 15 % replacement of cement
 1.65 % SO3,
 1.46 % equivalent alkali,
 0.20 % loss on ignition
 
Concrete Batch Mass / m3 (IDOT A-3 Mix)
Cement 278 kg 0.49 w/s Slump: 90 mm to30 mm, avg. 50 mm
Water161  Air: 7.8 % to 5.4 %, avg. 6.6 %
Fly Ash49   
C. Agg.973  Slipform paver - spreader used
F. Agg.844  Temperature: 32 to 7 (º C),
    no precipitation, clear
WR0   Mix Characteristics: no reported problems
AEA no value provided 27.1 MPa compressive strength
 
Cores:
No. Mile Post Location Vibrator Trail Designation Condition/Comments
2 224+95 Joint   2j Excellent Condition
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