Long-Term Surface Infiltration Monitoring of

Permeable Interlocking Concrete Pavement

Kevin Earley, Nicolock Paving Stones

PICP Case Study - Lindenhurst Library

Design

3/31/10

10% open area No. 8 Stone in Joints > 500 in/hr Surface Infiltration Rate

Let’s Look at another Project Example Before Discussing Surface Infiltration Rate Testing

PICP Case Study Material Supply Yard in Long Island

Before

Starts with Engineering

Subgrade Soil Analysis

Light Brown Coarse to fine sand with few gravel (SP)

•Appendix D NYS Stormwater Design Manual

•12” diameter pipe

• Pre-soak

• Falling head infiltration test

•Average infiltration rate > 100 in/hr.

Design

• Store 100,000 SF for 1.5” storm event=12,500 ft3 • Utilize existing drywells • Install 9,000 SF of PICP in lieu of more drywells • Allow for contributory run-on including roof

drains (~ 11 x’s permeable pavement area) • Installed in 2010

PICP avoided the installation of 22 12’ diam. drywells and provided a useful surface and recharge basin all in one

NO. 9

ASTM No. 9 Stone in Joints

Infiltration is Related to Joint Fill

Approx. Particle Size Permeability (k) in/hr

ASTM No. 8 (2-10 mm) 1,400 – 4,000

ASTM No. 9 (2-5 mm) 140 - 1,400

ASTM No. 10 (1-3 mm) 14 – 140

ASTM C 33 (sand) 1.4 to 14

Visual inspection during/after a rainstorm

Quantify using a test method

How Do We Measure Performance?

Visual Observation

Neoprene pad

300 mm dia. ring

Stone filled buckets

Research Devices

Showerhead

Surface Infiltration Testing

29

ASTM C 1781-13 Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems

ASTM C 1781 Origins

ASTM C 1701

12” Diameter Ring Constant Head Test

ASTM C1781 Procedures • 12” diameter ring with 0.4 and 0.6” marks • Plumbers Putty – Federal Spec A-A-3110 • 3 locations for up to 25,000 ft2 , one for each

additional 10,000 ft2 • Prewet with 8# of water – if < 30 sec use 40#,

otherwise use 8# • Test within 2 minutes, 2nd pour within 5

minutes of 1st

• Simple calculation: I = K*M/(D2*t)

New Test Method Modifies C 1701 1. Broaden use to includes – clay pavers, concrete

pavers, and grid pavers 2. Recommends a maximum ring height of 6” to avoid

splash effect 3. Clarifies test location selection and adds more

documentation 4. Follows same procedures and calculations as

ASTM C 1701 5. Provides a non-mandatory appendix to normalize

ring drainage area to entire pavement area to improve accuracy

How are we doing at the Library?

• No. 8 Stone in Joints • Little traffic or sediment, no maintenance • First test 20 months post-construction

Library Test Results and graph Location 1 Location 2 Location 3

(inches/hr) 20 months Post Construction 4/4/11 481 492 656

487 422 687 Location Average: 484 457 671

Site Average: 537 44 months Post Construction

4/18/2013 299 196 320 289 186 271

Location Average: 294 191 296 Site Average: 260

48 months Post Construction 8/29/2013 250 185 265

222 169 275 Location Average: 236 177 270

Site Average: 227

80% reduction may be in ~ 6 yrs

60% reduction in 4.1 yrs

10 in/hr design rate

How are we doing at the Supply Yard?

• No. 9 Stone in Joints • Lots of traffic and sediment, no maintenance • Detailed analysis underway

Location #1

Location #2

Location #3

Location of Measurements

Location 1 Location 2 Location 3

(inches/hr) Less than 1 week Post Construction 10/21/2010 206 302 358

183 350 313 Location Average: 195 326 336

Site Average: 285

6 months Post Construction 4/4/2011 321 341 336

340 327 353 Location Average: 331 334 345

Site Average: 336

13 months Post Construction 11/2/2011 250 229 242

244 232 238 Location Average: 247 231 240

Site Average: 239

Year 1 Results

Install Flush, Equilibrium???

Decreasing, But Consistent, No Patterns

Location 1 Location 2 Location 3

(inches/hr) 18 months Post Construction

4/11/2012 176 227 291

150 181 53

Location Avr. 163 204 172 Site Average: 180

30 months Post Construction

4/8/2013 78 98 153

83 94 147

Location Avr. 81 96 150 Site Average: 109

Year 2 Results

Decreasing, Location 3, Outlier

Decreasing, Pattern Develops

Location 1 Location 2 Location 3

35 months Post Construction

8/6/2013 36 113 207

74 110 140

Location Avr. 55 112 174

Site Average: 113

Year 3 Results

Stabilizing, Pattern Clear

(inches/hr)

68% reduction in 3 yrs

Predict 80% reduction in ~ 4 yrs

10 in/hr design rate

The Edge Effect

Results and picture of clogging test 5 in/hr (26 min.)

Gradation of clogged joint

Gradation of Joint Material

SIEVES collected collected

8/2/2010 8/29/2013 US sieve size Diameter, m % finer % finer 3/8" 9.5 100 100 No. 4 4.75 72.25 66.7 No. 8 2.36 15.36 24.7 No. 16 1.18 5.25 19.2 No. 30 0.6 2.67 14.6 No. 50 0.3 1.64 5.8 No. 100 0.15 1.03 2.2 No. 200 0.075 1.01 1.1

Conclusions 1. Fine sediment in permeable pavements will reduce

long-term surface infiltration rates

2. Clogging is common and biased

3. Less clogging potential with # 8 stone vs. # 9 stone

4. ASTM C 1781 is an inexpensive and simple test to

measure surface infiltration on PICP and other forms of

permeable pavement

5. Use ASTM C 1781 for acceptance and corrective action

triggers

Joint Stone Reduction 80%

clogging

# 8 60% in 4 yrs > 6 yrs

# 9 68% in 3 yrs 4 yrs

PICP Industry Recommendations 4th Edition PICP Manual

• Hydrologic design • Structural design • Construction guidelines C1701 acceptance testing Min. 100 in./hr (250 cm/hr) • Maintenance guidelines C1701 performance testing Min. 10 in./hr (25 cm/hr)

For additional information about PICP contact: Kevin Earley 631-774-6431 kearley@nicolock.com