Porous Asphalt Pavements ppt.pdf

8/18/2019 Porous Asphalt Pavements ppt.pdf

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OHIO RIDES ON US

OHIO RIDES ON US

Porous Asphalt Pavement

Design, Construction andMaintenance


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AMERICA RIDES ON US

AMERICA RIDES ON US

What are Porous Pavements?


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OHIO RIDES ON US

OHIO RIDES ON US

Porous Asphalt


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AMERICA RIDES ON US

AMERICA RIDES ON US

Why Porous Pavement?

• New stormwater regulations – Reduce total volume (not just peak flow) – Limiting impervious area – Improve runoff quality – Taxing runoff

• Sustainability• Build lot flat,• no puddles 0

1

2

3

4

0 400 800 1200 1600 2000 2400Time

F l o w

( c f s )

Post-Dev. InflowInfiltration Bed DischargePre-Development Runoff Detention Basin Discharge


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AMERICA RIDES ON US

AMERICA RIDES ON US

Porous Asphalt Pavement Development

•Concepts developed by the Franklin Instituteunder US EPA grant – 1972•Tested in pilot projects during 1970’s •Franklin Institute Press – Porous Pavement byThelen and Howe - 1978•Development of geotextiles in 1979•Current design since 1980

•Cahill Associates (now CH2MHill) has builtover 150 projects since 1980•Outstanding engineering project - 2000


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OHIO RIDES ON US

OHIO RIDES ON US

Porous Asphalt Use – Light DutyParking Facility


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OHIO RIDES ON USOHIO RIDES ON US

Porous Asphalt Use – Light DutyParking Facility


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Porous Asphalt Use – Light DutyRoadway


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POROUSPAVEMENT FORSTORMWATER

CONTROL

• Design• Construction• Maintenance


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POROUS PAVEMENTDesign, Construction, Maintenance

• Components of a porous pavementsystem

• Performance• Design considerations• Constructing a porous pavement system

• Ensuring long life through propermaintenance


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Highly permeableasphalt surface


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Air Voids: 17%

Permeability: 352 to 6000ft/day (soil: 6 in/hr)

AASHTO no. 8 sizeaggregate (1/2 inch max)

100% crushed stone forstrength & stability

Polymer modified asphaltbinder (6% min)

Layer thickness: 4 to 6inches

Modeled after ODOT SS803(open graded frictioncourse)


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Stone rechargebed / reservoir


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Stone rechargebed / reservoir

Purpose: Stormwaterstorage and discharge

Depth/thickness of reservoir

will depend on design stormevent and soil permeability.

Air Voids: 40%

AASHTO no. 2 sizeaggregate (1 ½ - 2 ½ inch)

100% crushed stone ensuresstability

Ensure void structureprovides long-termpermeability


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Source: Ohio Aggregates and IndustrialMinerals Association

Aggregate Size Voids (Average %)No, 2 Limestone 41No. 4 Limestone 41No. 57 Limestone 41No. 8 Limestone 42No. 7 Limestone 42Limestone sand 36


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Stabilizing layer


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Stabilizing layer

Purpose: Lock up surface ofstone recharge bed /reservoir in preparation forpaving

Thickness: approx. 2 inches

AASHTO no. 57 sizeaggregate (3/4 inch)

100% crushed stone ensuresstability


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Geotextile fabric


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Geotextile fabric

Purpose: Prevent migrationof fines from subgrade orexcavation into the pavementstructure.

Material: ODOT 712.09, TypeB


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Uncompactedsubgrade


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Uncompactedsubgrade

Purpose: retain soilpermeability

Avoid any activities that

would result in compactedsubgrade

Use excavation equipmentthat leaves a light footprint.

If necessary, reestablish

permeability by scarifying.


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Stormwater Quantity Control


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Pollutant Removal

-20

0

20

40

60

80

100

120

T o

t a l

P h o s p

h o r u

s

S o

l u a

b l e

P h o s p

h o r u

s

T o

t a l

N i t r o g e n

N i t r a t e

Z i n

k

T S S M

e d i a n

P o

l u t a n

t R

e m o v a

l E f f i c i e n c y

Infiltration Wetlands Wet Ponds Filtering Swales Dry Ponds


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TSS Removal Efficiencies

100

90

80

70

60

5040

30

20

100

T S S %

R e m o v a

l E f f i c i e n c y

Source: University of New Hampshire Storm Water Center


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Pavement Longevity


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Pavement Longevity

Porous Pavement – No maintenance treatments

Dense-graded Pavement – Two maintenance treatments


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Design Considerations• Porous pavements can be designed as

infiltration OR detention systems• UNHSC research indicates some

infiltration will occur even in low-permeability, clay-like soils. – TANK project confirms infiltration occurs in

poor draining soil

– Build in failsafe (e.g. underdrains,catchbasins, etc)


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Failsafe


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Failsafe


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Design Considerations• Soil bed must be designed to be flat to

maximize infiltration area. Step pavementto assure flat surface.


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Design Considerations

• Provide a pavement structure that willcarry paving equipment without distorting. – Avoid thick courses (> 3 inches) of single size

aggregate such as no. 57


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Constructing a Porous PavementSystem

• Build porous pavement last – Protect from construction debris – Protect from debris laden runoff

• Protect site from heavy equipment – Avoid compaction of subgrade by construction

equipment

• Excavate to subgrade using soft footprint


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• Place filter fabric, ensuring fabric extendsabove excavation to protect pavementuntil vegetation is established


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• Compaction ofasphalt mixes iscrucial toperformance

• Asphalt bindercontent is 6.0min. Source:

University ofNew

HampshireStorm Water

Center


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Regularly sweep, vacuum or blowpavement to remove leaves, needlesor other debris that can clog.


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Regularly sweep, vacuum or blowpavement to remove leaves, needlesor other debris that can clog.


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Snow & IceWeighted Skid Resistance (BPN)

01020304050

60708090

100

100 50 25 0

% Salt Application

S k i d R e s i s t a n c e ( B P N )

Dense Mix Asphalt

Porous Asphalt

0102030405060708090

100

100 50 25 0

% I c

e C o v e r

% Salt Application

% Ice Cover

Dense Mix Asphalt

Porous AsphaltConventionaldense-graded mix

PorousasphaltSource: University of New

Hampshire Storm Water

Center


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Resources


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Resourceshttp://www.flexiblepavements.org

Porous Asphalt Use – Light Duty


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Porous Asphalt Use Light DutyParking Facility


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Porous Asphalt Parking Facility atMunroe Falls Metro Park

Contractor: Perrin Asphalt

Porous Asphalt Use – Light Duty


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Porous Asphalt Use Light DutyParking Facility

Munroe Falls Metro Park – Perrin Asphalt


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Porous Asphalt Pavements ppt.pdf