Pervious Concrete and its application

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Welcome to the Future in Concrete!!

O

A

O

A

ENVIRONMENTAL FRIENDLY

PERVIOUS CONCRETE

Guided by

Guided by Presented byPresented by

Guided by

Guided by Presented byPresented by

Dr.

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What is Pervious Concrete ?

••

A performance

A performance --engineered structural

engineered structural

material using the usual constituents of

gg

conventional PCC, only with little or no

sand in the mixture , allowing for a 15

sand in the mixture , allowing for a 15--30

30 t i

id f t

t i

id f t

percent air void factor.

••

It allows 3

It allows 3--8 gallons of water/min to pass

8 gallons of water/min to pass

through 1

through 1 sq ft

sq ft of the material

of the material

through 1

through 1 sq.ft

sq.ft. of the material.

. of the material.

••

It is an open

It is an open--cell structure with an

cell structure with an

appearance sometimes described as that of

a “

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Pervious Concrete Is Not a New Material :

 First known use in 1852 on isle of Wright for 12 to 14 in. thick walls for homes

 Before and after WWII wide spread use in resident and construction in the UK  Before and after WWII, wide spread use in resident and construction in the UK

and Europe .

 One British firm constructed over 250,000 homes .,  Mid 1960s, experimental road in England

-- 8--in conventional concrete in conventional concrete

- 2-in pervious concrete bonded overlay in pervious concrete bonded overlay  First use for pavements in U.S. In early 1970s in Florida .

 Most of the activity has been in the southeast – primarily Georgia,

Florida and now “Enhanced Porous Concrete ”pavement is in Mexico,Texas, Oklahoma Wisconsin Oregon Pennsylvania & California Pennsylvania &

Oklahoma, Wisconsin, Oregon, Pennsylvania & California. Pennsylvania & California.

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GENERAL BACKGROUND OF PERVIOUS

CONCRETE

•• Materials for Pervious Materials for Pervious Concrete Production:

Concrete

Production:--••

CementitiousCementitious material:material:-- Portland & Portland & blended cements,

blended cements, flyashflyash, , pozzolanas,GGFS

pozzolanas,GGFS..

•• Coarse aggregate: Coarse aggregate: -- 3/4in. 3/4in. –– 1in., A/C 1in., A/C ratio= 4

ratio= 4 –– 4.5 by mass.4.5 by mass.

•• Water :Water :–– water/water/cementitiouscementitious ratios = ratios = 0.27

0.27--0.30.3

•• Admixtures.Admixtures.

Pervious concrete is made with a narrow aggregate gradation,but different f t t b bt i d th h th f diff t i

surface textures can be obtained through the use of different maximum sizes. The concrete in the box contained a 1⁄4-in. (6.5-mm) top size, while that below used a larger topsize, 3/4 in. (20 mm)

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Mix Proportion of Pervious Concrete: Mix Proportion of Pervious

Concrete:--Carefully controlled amounts of water &

Carefully controlled amounts of water & cementitiouscementitious materials are materials are used to create a paste that form a thick coating around aggregate used to create a paste that form a thick coating around aggregate used to create a paste that form a thick coating around aggregate used to create a paste that form a thick coating around aggregate particles without flowing off during mixing & placing.

particles without flowing off during mixing & placing.

(b) proper

amount of water,

(a) too little water

(c) too much water.

Samples of pervious concrete with different water contents, formed into a ball: ( )

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Three major groups of pervious concrete

Three major groups of pervious concrete..

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ENGINEERING PROPERTIES

1. FRESH PROPERTIES:

1. FRESH PROPERTIES: -- mixture is stiff compared to traditional concrete

2. HARDENED PROPERTIES: 2. HARDENED PROPERTIES:



 Density & Porosity : 1600Density & Porosity : 1600--2000 Kg/m2000 Kg/m33 

 Flexural Strength : 1MpaFlexural Strength : 1Mpa--3.8Mpa 3.8Mpa



 66



 Shrinkage : about 200 x 10Shrinkage : about 200 x 10--66

3. DURABILITY: 3. DURABILITY:--  PermeabilityPermeability : 0.2: 0.2 –– 0.54 cm/s.0.54 cm/s.   Permeability : 0.2 Permeability : 0.2 0.54 cm/s.0.54 cm/s. 

 Compressive Strength : 4.5Mpa Compressive Strength : 4.5Mpa –– 28Mpa28Mpa

–– Compressive strength typically Compressive strength typically notnot used as acceptance criteria.used as acceptance criteria. –– Air void structure and density are used instead.Air void structure and density are used instead.



 FreezeFreeze--Thaw Resistance Thaw Resistance



 Sulfate resistance : laid over 6in. Layer of 1 in. maxSulfate resistance : laid over 6in. Layer of 1 in. maxmm _{size top aggregates}_{size top aggregates} 

 AbAb ii i ti t



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Pervious Concrete Pavement

E

i

t l Ad

t

E

i

t l Ad

t

Environmental Advantages

••

Percolation Recharges Percolation Recharges Groundwater

Groundwater

••

Water Resources are ConservedWater Resources are Conserved

••

Less Need for IrrigationLess Need for Irrigation

••

Adjacent Trees and VegetationAdjacent Trees and Vegetation

••

Adjacent Trees and Vegetation Adjacent Trees and Vegetation are

are allowed More Rainwaterallowed More Rainwater

••

Runoff to Streams and Lakes is Runoff to Streams and Lakes is Reduced

Reduced Reduced Reduced

••

Cooler Surface Has Less Impact Cooler Surface Has Less Impact on Air Temperature

on Air Temperature -- Urban Heat Urban Heat l d ff

l d ff Island Effect Island Effect

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Pervious Concrete Pavements

Model Natural Ground Cover

and Can be Used as Part of a System

Designed to Meet Requirements for:

g

q



Stormwater Quality



Stormwater Quality



Sustainability



Impervious Area Zoning

Requirements

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Solution to Stormwater

Management

_{STORMWATER IN} PERVIOUS CONCRETE PAVEMENT PAVEMENT AGGREGATE BASE STORMWATER OUT SUBGRADE SUBGRADE

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Sustainability

••

Low

Low--Impact Development

Impact Development

••

Pollution Treatment

••

Recharging Groundwater

••

Tree Protection

••

Tree Protection

••

LEED Requirements

••

Cool Communities (Urban Heat Island

Effect)

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Low Impact Development

Pre-Development Post-Development Low-Impact

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Pollution Treatment

_{=> Porous}

••

About 90% of the surface About 90% of the surface

ll t t i d ff b

Allow many mega litres of

Pavement

pollutants are carried off by pollutants are carried off by the first ½

the first ½--inch to 1inch to 1--inch inch of rainfall (first flush)

of rainfall (first flush)

good fresh water to become contaminated ( ) ( )

••

First flush passes through First flush passes through pavement into soil

pavement into soil

S il fil d S il fil d contaminated by the pollutants on our streets

••

Soil filters and treats Soil filters and treats rainfall

rainfall

••

Rainfall is spread overRainfall is spread over

and pollute coastal waterways

Rainfall is spread over Rainfall is spread over

entire parking area (instead entire parking area (instead of detention pond)

of detention pond) Capture and

cleanse the Or

c ea se e water for our use?

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Recharging Groundwater and

g g

Aquifer

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Protects Trees

Can pave within the drip line Water and air filters to roots

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Meets LEED Requirements

••

Re

duce

duce stormwater

stormwater

runoff

••

Use Recycled

Materials

••

Use Regional

Materials

••

Reduce urban heat

islands

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Typical Structure Design

yp

g

(cross section diagram)

Pervious Concrete Pervious Concrete Compacted Sub

Compacted Sub--basebase

(#57/#67 Stone) (#57/#67 Stone)

Filter Fabric Filter Fabric Compacted Sub

Compacted Sub--gradegrade

m um m um _{o pa}_{o pa} _{d ub}_{d ub g ad}_{g ad} (92% max) (92% max) Water Table Water Table 2 f eet mini m 2 f eet mini m Water Table Water Table (wet season level) (wet season level)

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BASIC INSTALLATION RECOMMENDATIONS

for Pervious Pavement

Z

l

i GOOD!

Z

l

i GOOD!

••

Zero slump is GOOD!

••

Set forms with screed strips

••

Use vibratory truss or rollers to spread

••

Compact materials with rollers

••

No need for troweling!

••

Joint spacing: No greater than 40’

Joint spacing: No greater than 40

••

Cure w/ plastic sheeting

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Site work

Typical design mix

yp

g

 Placing

 Finishing

 C i

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Fine Grading & Compacting Base

.

A

A--frame Vibratory Screed & Rollerframe Vibratory Screed & Roller strikes off and compacts the surface

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Other Applications for Porous Concrete

•• Greenhouse Floors, fish hatcheriesGreenhouse Floors, fish hatcheries

•• Surface Course for Tennis CourtsSurface Course for Tennis Courts

•• Basketball CourtsBasketball Courts

•• Public walkwaysPublic walkways

•• Swimming pool decksSwimming pool decks kk

•• ParksParks

•• Plazas and PatiosPlazas and Patios

•• Groins & SeawallsGroins & Seawalls

•• Well liningsWell linings

•• ZoosZoos

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Architectural Pervious Concrete Architectural Pervious Concrete

Univ. of Calif.

Univ. of Calif. -- BerkeleyBerkeley

Sidewalk

Taller buildings, preserving natural areas

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NOISE BARRIER

Two mechanisms for noise abatement generally

accepted:

••

Decreased intensity Decreased intensity of sound generated of sound generated of sound generated of sound generated at the tire at the tire –– pavement interface; pavement interface; and and a d a d

•• Dissipation of the Dissipation of the generated as well as generated as well as other incident noise other incident noise within the pore

within the pore

structure of pervious structure of pervious concrete in the form concrete in the form of heat.

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Heat Island Reduction

••

High void factor and lower densityHigh void factor and lower density →less solar heat absorption and gg yy →less solar heat absorption and pp rapid cooling.

rapid cooling.

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MAINTENANCE

Can Use Vacuum, Pressure Water, Pressure Air or Combination. Have Been Unable to Find Anyone who Does Maintain other than for Normal Street

Have Been Unable to Find Anyone who Needs to Maintain… – As defined by critical reduction in capacity

– Water runs off instead of draining through Continuously Informing Staff and Publicy g

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COSTS

•

Depends on Scale and Application

•

Depends on Scale and Application

•

Materials Cost Average 20% - 40% Higher than Normal Concrete

– Due to slower discharge and loading rates

•

Construction is Simpler, Quicker than for Normal Concrete

•

Experience and Market are FactorsExperience and Market are Factors

•

Larger Projects will Usually Drive Lower Unit Costs

•

NRMCA-Certified Contractors

•

Benefit is to Avoid Losing Land to Retention Ponds and Creating more Runoff and Pollution

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Denver

Denver –– Next AM Following 12” Snow

Next AM Following 12” Snow

Sit

di

tl

t

Sit

di

tl

t

Sites directly across street

Photos: 5 min. differential max Photos: 5 min. differential max

Pervious Concrete

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CONCLUSION

•

The use of pervious concrete is among the Best Management Practices (BMP) recommended by the EPA and other agencies for the

management of storm water runoff on a regional and local basis.

•

Eliminates the need for retention ponds, swales and other storm water devices.

•

Lowers overall project costs on a first-cost basis.

•

Makes efficient use of land.

•

Good for Bicycles but Bad for Skateboards

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Concrete mix quality control continues to be difficult Porous concreteConcrete mix quality control continues to be difficult. Porous concrete is very sensitive to water and thus difficult to mix correctly.

•

Very few contractors know how to install it correctly.

still work going on how and how often to clean the porous concrete still work going on how and how often to clean the porous concrete.

•

Thus, we will see more applications and our expertise with porous materials will grow.

•

In So th Asia & Asia Pacific e need to se this technolog as

•

In South Asia & Asia Pacific, we need to use this technology as almost all types of weather conditions found here.

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REFERENCES:

•

American Concrete Institute 522R-06 on Pervious Concrete May 2006 http://www.aciint. org/PUBS/newpubs/522.htmp g p

•

National Ready Mixed Concrete Association Pervious Concrete Publicationswww.nrmca.org

•

“Freeze Thaw Resistance of Pervious Concrete,” National ReadyFreeze Thaw Resistance of Pervious Concrete, National Ready Mixed Concrete Association, May 2004. www.nrmca.org

•

“Pervious Concrete Contractor Certification,” National Ready Mixed Concrete Association, August 2005. www.nrmca.org, g g

•

City of Seattle Department of Planning and Development Client Assistance Memo #515. http://www.ci.seattle.wa.us/dclu/Publications/cam/CAM515.pdfp p

•

LID Technical Guidance Manual for Puget Sound,

http://www.psat.wa.gov/Publications/LID_tech_manual05/lid_index. htm

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