The document summarizes a study on using macro fiber reinforcement in pervious concrete. The study tested different fiber lengths and dosages to determine their effect on pervious concrete properties. It found that fibers increased unit weight and tensile strength but decreased permeability. Freeze-thaw durability improved for mixtures with 2.25-inch fibers. The optimum fiber dosage appeared to be 5 pounds per cubic yard of 2.25-inch fibers, as it reduced raveling, improved durability, and increased tensile strength the most.

1. Macro Fiber Reinforced Pervious
Concrete
John Kevern and Dan Biddle
Pervious in Paradise 2014

2. Motivation
• Raveling and surface
durability is still prevalent
in pervious concrete
• Micro fibers have
previously shown to
improve pervious
durability
• Limited anecdotal
evidence suggested that
macro-synthetic fibers

3. Study Scope
• Determine the effect macro-synthetic fibers
have on pervious concrete properties
and
• Determine the best fiber length and dosage

4. Study Mixtures
Material Description Amount (pcy)
Coarse Agg. 3/8 in. limestone 2175
Fine Agg. C33 river sand 164
Cement Lafarge TI/II 573
Water 195
Water Reducer BASF Glenium 7500 4 oz/cwt
Air Entrainer BASF Everair Plus 2 oz/cwt
Hydration Stabilizer BASF Delvo 6 oz/cwt
FORTA Ferro-Green
1.5 in. – 2.5 pcy, 5.0 pcy, 7.5 pcy
2.25 in. – 2.5 pcy, 5.0 pcy, 7.5 pcy
*All samples individually placed to control
voids at 25%

5. Tests
• Unit weight (ASTM C1688 and ASTM
C1754) and voids (ASTM C1754)
• Plastic workability
• Strength
• Permeability and infiltration
• Abrasion
• Freeze thaw durability

6. Gyratory Workability
82
84
86
88
90
92
94
96
98
100
102
0 20 40 60 80 100
Gyrations @ 60kPa
ApparentDoC(%)
8
Workability
Energy
Index (WEI)
Compaction Densification Index (CDI)
Workability (WEI)
Explanation Range
Self-Consolidating > 640
Acceptable Workability 640>WEI>600
Poor Workability WEI<600
Compactibility (CDI)
Explanation Range
No Additional Compaction Required CDI<50
Normal Compaction Effort Required 50<CDI<450
Considerable Additional Compaction Effort
Required CDI>450

7. Abrasion (ASTM C944)

8. Abrasion (ASTM C1747)

9. Freeze-Thaw Durability (ASTM C666a)

10. Results – Fresh Properties
At 25% design void content, not much impact on
constructability
Workability (WEI)
Explanation Range
Self-Consolidating > 640
Acceptable Workability 640>WEI>600
Poor Workability WEI<600
Compactibility (CDI)
Explanation Range
No Additional Compaction Required CDI<50
Normal Compaction Effort Required 50<CDI<450
Considerable Additional Compaction Effort
Required CDI>450
Fresh Unit Weight
ASTM C1688
Avg. (pcf)
Control 121.8 659 38
2.5/1.5 119.2 670 0
5.0/1.5 121.4 660 3
7.5/1.5 124.8 646 38
2.5/2.25 124.4 662 1
5.0/2.25 125.1 651 7
7.5/2.25 125.8 647 12
WEI (DVC)
Mixture
CDI (DVC)

11. Results-Unit Weight
110
112
114
116
118
120
122
124
126
128
130
Control 2.5pcy/1.5in 5.0pcy/1.5in 7.5pcy/1.5in 2.5pcy/2.25in 5.0pcy/2.25in 7.5pcy/2.25in
UnitWeight(pcf)
ASTM C1688 Fresh Unit Weight ASTM C1754 Hardened Unit Weight

12. Results – Compressive Strength
0
500
1,000
1,500
2,000
2,500
3,000
3,500
Control 2.5pcy/1.5in 5.0pcy/1.5in 7.5pcy/1.5in 2.5pcy/2.25in 5.0pcy/2.25in 7.5pcy/2.25in
CompressiveStrength(psi)
7d 28d

13. Results – Tensile Strength
0
50
100
150
200
250
300
350
400SplittingTensileStrength(psi)

14. Results – Abrasion
0
2
4
6
8
10
12
MassLoss(g)
Mixture
Abrasion (%) Abrasion (g)
ASTMC1747 ASTM C944
Control 28.6% 11.0
2.5/1.5 24.2% 3.8
5.0/1.5 26.5% 4.8
7.5/1.5 27.1% 4.8
2.5/2.25 26.0% 5.7
5.0/2.25 24.5% 4.7
7.5/2.25 26.2% 7.7

15. Results – Freeze Thaw
Mixture
Durability
Factor
(Mass)
Durability
Factor (RDM)
Control 53 14
2.5/1.5 38 12
5.0/1.5 53 7
7.5/1.5 85 21
2.5/2.25 89 40
5.0/2.25 91 41
7.5/2.25 96 44

16. Results – Freeze Thaw
Control – 187 cycles
2.5 pcy (1.5 in.) – 133 cycles
5.0 pcy (1.5 in.) – 188 cycles

17. Results – Freeze Thaw
Control – 187 cycles
2.5 pcy (2.25 in.) – 300 cycles
7.5 pcy (2.25 in.) – 300 cycles

18. • Ferro-Green® by FORTA macro fibers function like
fine aggregate, increasing fresh unit weight of the
mixtures.
• Fiber addition decreased infiltration and
permeability. No trends were observed with
respect to dosage rate.
• Fiber addition did not affect compressive strength.
• The addition of fibers increased tensile strength
for all mixtures with increased strength
corresponding to dosage rate. Similar strength
increases were observed at each dosage rate,
independent of fiber length.
Summary and Conclusions

19. • Raveling and abrasion was reduced for all fiber
dosages.
• Freeze-thaw durability was improved for all
mixtures containing 2.25 inch length fibers. Only
the mixture containing 7.5 pcy of the 1.5 inch
fibers had improved freeze thaw durability versus
the control.
• Comparing tensile strength increase, raveling
reduction, and freeze-thaw improvement, 5.0 pcy
of the 2.25 inch fibers appears to be the optimum
dosage of the combinations tested.
Summary and Conclusions

20. Contact Information
John T. Kevern, PhD, PE, LEED AP
Associate Professor of Civil Engineering
370A Flarsheim Hall, 5110 Rockhill Rd.
University of Missouri – Kansas City
Kansas City, MO 64110
Phone: 816-235-5977
Fax: 816-235-1260
Email: kevernj@umkc.edu