Porous Pavement in Cold Climates

8/13/2019 Porous Pavement in Cold Climates

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Porous Pavement in Cold ClimatesPart: Performance and Cost

Onondaga Environmental Institute

17 March 2011

Thomas Ballestero, PhD, PE, PH, CGWP, PG,Robert Roseen, PE, PhD, D.WRE,

James Houle, CPSWQUniversity of New Hampshire Stormwater Center

Department of Civil Engineering, University of New Hampshire


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State of the Practice

Water quality performance is strong to

excellent depending on design

Hydraulic performance is excellent

Cold climate performance is strongWinter maintenance has tremendous

potential for salt reduction

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Concerns On Performance

Little removal of nitrogen

No removal of many common ionic forms

However, a large number of installations

STILL continue to be sub-standard

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Porous Pavement Design Overview

Porous pavements for new andredevelopment are a watershed-

based strategy that can bothmitigate impacts for newdevelopment and reverse impactsin areas with redevelopment.

Porous pavement (PP) systemscombine stormwater infiltration,storage, and structural pavementin a single system.

PP are a layer cake system, witheach layer possessing structuralor water quality purposes.

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Porous Asphalt Path, Grey Towers

National Historic Site, PA(Source: CH2M HILL)

Porous Asphalt Commercial Parking Lot,

Greenland Meadows, Greenland, NH(Source: UNHSC)

Porous Asphalt Section of State Highway,

South Portland, ME (Source: ME DOT)

Porous Asphalt Basketball Court,Upper Darby, PA

(Source: CH2M HILL)

Porous Asphalt Residential Lane, Pelham, NH

(Source: UNHSC)

Parking Lot with Standard Aisle and

Porous Asphalt Stalls, Morris Arboretum,

Philadelphia, PA (Source: CH2M HILL)


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Typical Porous Pavement

System Sections

8

Choker Course: 4-8 10 20 cm minimum

Pervious pavement: 4-6 (10 - 15 cm) of porous asphalt

Filter Course: 8 - 12 (20 - 30 cm) minimum thickness of subbase(aka. bank run gravel or modified 304.1)

Native materials

Filter Blanket: intermediate settin bed: 3 8 cm thickness of 3/8 1 cm ea ravel

Reservoir Course: 4 (10 cm) minimum thickness of 3/4 (2 cm) crushed stone for

frost rotection 4-6 10-15 cm diameter erforated subdrains with 2 cover

Optional-Liner for land uses where infiltration is undesirable(e.g., hazardous materials handling, sole-source aquifer protection)

Section with Filter Course for Water Quality


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Water Quality

Performance Results


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Porous Pavements and Pond Water

Quality100

90

80

70

60

50

40

30

20

10

0

%Remo

valEfficiency

Porous AsphaltPervious ConcreteRetention Pond


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TSS Removal Performance


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HydrologicPerformance Results


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Hydrrologic Performance of

Porous PavementsPervious Concrete (HSG-B)Porous Asphalt (HSG-C)


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Lag Time (kL) Peak Reduction (kP)

5 2 1 0.5 0.1

Hydraulic Performance

3/22/2011


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Curve Number

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Method 1

Q-P

Method 3

Q p

Method 3

Q p

Tbase Tpeak Tcentroid NRCS Folmar

88 7 1 1 1 28

90 1 1 1 1 5

10 15 2 2 2 37

Method 2

Lag

Mean

Median

Standar Deviation


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Porous Asphalt Surface Infiltration Rates

Low maintenance sensitivity due to excess infiltration capacity

Clogged areas can drain to adjacent unclogged areas

Even with 99% clogging the IR=10in/hr > most sands & soils

Worst case scenario, no maintenance performed for 3 yrs Certain areas have reduced IC (drive lanes) while parking areas

remain unchanged


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New England Sites

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Infiltration Capacity by Age

315

7,0454,013

2,598 2,905

54

2,354

140

4,365

10

100

1,000

10,000

100,000

URI-

PA-02

UNH-

PA-04

URI-

PA-04

Grswld-

PC-05

Frpt-

PA-06

Sski-

PA-06

SlvrLk-

PA-06

StoYo-

PA-06

UNH-

PC-07

ICv

ia

SItest(cm/h

r)

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How Do They Really Work?

43 in rainfall event in 3 minutes!


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Cold ClimatePerformance Results


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Frost Penetration

Can be related to pavement failure

Measured with a field-assembled

frost gauge (Ricard et al., 1976)

Show relationships betweenpavements and soils


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Porous Asphalt Frost Penetration


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Winter Maintenance &

Salt Reduction


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Where should reductions occur?

Sources of Salt Loading

From Vehicular Surface Deicing

(Rockingham County, NH)(NHDES 2007)

50%

3%27%

9%

11%

Parking Lots

Private Roads

Municipal Roads

State Roads

Other


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Measuring Skid Resistance w/ BPT


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Lots one-hour after plowing, -4*C (11AM on 2/3/07)

PA/DMA Snow & Ice Cover

PA DMA


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Conditions after thawing and subsequent refreezing (9AM on 3/18/07)

No black ice formation on PA

PA/DMA Snow & Ice Cover

PA DMA


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PC Snow & Ice Cover

Conditions after thawing and subsequent refreezing (1PM on 2/16/08)

No black ice formation on PC

PC Stnd. Asphalt Ref. Lot


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Shading contributes to amount of cover on PC

PC Snow & Ice Cover

PC in sun

PC in partialsunPC in shade


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PA after spring rain on snow event

DMA after spring rain on snow event


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Effective Salt Reductions

PavementType

2006-2007 2007-2008 Reductions Possible

when compared to

DMA with

100% App. RateAnti-

Icing

Apps.

Deicing

Apps.

Anti-

Icing

Apps.

Deicing

Apps. App.

Rate

Average

Mass

Reduction*

(06-08)DMA 15 14 23 22 100% 0%

PA 15 6 23 27 25% 75%

PC -

shade - - 23 31 100% -20%

PC - sun - - 23 23 100% -2%

* Reduction possible with no loss in skid resistance (safety)


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Winter Maintenance GuidanceMixed precipitation and compact snow or ice is

particularly problematic for porous surfaces. This isprevented by appropriate plowing and corrected by

application of excess deicing chemicals. In certain instances of compact snow and ice,

excess salt may be required, however loading is

offset by the overall reduced salt during routinewinter maintenance and salt reduction.

With good sun exposure some porous asphalt

installations will require no deicing. Porous asphalt provides exceptional treatment for

rain on snow events which commonly result indangerous refreezing

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Future Research Needed

Additional research is needed to examinesalting loading at high loading rates

common to commercial applications

MN Recommended application rates of

3lbs per 1000 square feet appear to beexceptionally low in comparison tocommercial rates.

Salt substitutes: water, viscous brine

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Cost of Porous Materials

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C


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Cost Information

~10-20% more for materials

2009, DMA $75-100/ton, PA $89-125/ton placed

by machine for parking and residential road anddriveways

Complicated jobs with handwork are more

expensiveDMA $2.25/sf, PA $2.80/sf, not including

subbase

Costs offset by lack of stormwater infrastructureCost break even is achieved when designing for

quantity management ~Q10-Q25


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Maintenance

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P T E t t f D b i /Cl i


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Pre-Tx Extent of Debris/Clogging

Infiltration capacity via the Pre-Tx DRI test varied from 0 to 53

cm/hr, all effectively clogged when slope is considered. 48


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Treatment Effectiveness for Clogged


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Treatment Effectiveness for Clogged

Locations

0

50

100

150

200

250

300

PW & Vac Soap, PW, & Vac

Cleaning Treatment

Mea

nIC

(cm/hr)

Pre-Tx IC

Post-Tx IC

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P i C t S lli


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Pervious Concrete Spalling

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Boulder Hills Pelham NH


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Boulder Hills, Pelham, NH 2009 Installation of 900 of

first PA private residentialroad in Northeast

Site will be nearly Zerodischarge

LID subdivision 55+ ActiveAdult Community

Large sand deposit

Cost 25% greater per toninstalled

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But there is more


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But there is more

Salted twice, then never again (less salt to receivingstream)

Better traction than standard DMA Fire fighting storage from rooftop capture No concern about mosquitoes in the ponds

Very little site runoff (pollutant load to stream verysmall, no thermal pollution) Receiving stream geomorphic equilibrium not taxed

The project sold 2 units in 2009, and 11 units sinceJanuary 2010much easier to sell GREEN

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Porous Pavement in Cold Climates