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PERVIOUS CONCRETE PAVEMENTS 6/24/22 Department of civil engineering, T.K.M.C.E 1

Pervious concrete

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Page 1: Pervious concrete

May 2, 2023 Department of civil engineering, T.K.M.C.E

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PERVIOUS CONCRETE PAVEMENTS

Page 2: Pervious concrete

May 2, 2023 Department of civil engineering, T.K.M.C.E

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INTRODUCTION

Pervious concrete - high porosity concrete- due to highly interconnected void content

Has little or no fine aggregate

Allows water to pass directly through-reduces the runoff and recharges ground water

Used in parking areas with light traffic, residential streets, pedestrian walkways, and greenhouses

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PERVIOUS CONCRETE PAVEMETS

A mixture of coarse aggregate, Portland cement, water and little or no sand

Controlled amounts of water and cementitious materials creates a paste that forms a thick coating around aggregate particles without flowing off during mixing and placing

Has a 15-25% void structure, hence lightweight

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PERVIOUS VS IMPERVIOUS PAVEMENT

Pervious concrete pavement

Impervious concrete pavement

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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MATERIALS

Portland cement

Coarse aggregate

Water

Cementitious materials

Admixtures

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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Material Proportions (kg/)Cementitious materials 270-415Narrowly graded aggregate (gravel/crushed stone)

1190-1480

w/c ratio 0.28-0.35 (with chemical admixtures)0.34-0.40 (without chemical admixtures)

Cementitious materials/Aggregate ratio

1:0.21-1:0.25

Fine aggregate: Coarse aggregate ratio

0 to 1:1

Polypropylene fiber (optional when no fine aggregate is present)

0.1% by volume or 0.9 kg/

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PROPERTIES

1. COMPRESSIVE STRENGTH

Falls in the range of 3.5 MPa to 28 Mpa . Typical values are about 17 MPa

2. FLEXURAL STRENGTH

Ranges between about 1 and 3.8 MPa

Influenced by degree of compaction, porosity, and the aggregate-to-cement (A/C) ratio

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May 2, 20238

PROPERTIES (CONTD….)

Department of civil engineering, T.K.M.C.E

3. DENSITY

Depends on - The properties and proportions of the materials used - Compaction procedures used in the placement

In-place densities in the order of 1600 to 2000 kg/m^3 –falls in upper range of lightweight concretes

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PROPERTIES (CONTD….)

4. DURABILITY : FREEZE-THAW RESISTANCE

It depend on the saturation level of the voids in the concrete at the time of freezing

Voids are saturated, complete freezing can cause severe damage

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PROPERTIES (CONTD….)

5. ABRASION RESISTANCE

Open and rough structure- abrasion and raveling of aggregate on the surface can be a problem

Hence Highways are generally not suitable for pervious concretes

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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DESIGN

Designed to support the intended traffic load and manage storm water strategy

Should meet the hydrological and structural requirement

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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CONSTRUCTION

Subgrade –can be native material or imported fill

Properly compacted- Density 90-95%, surface - Uniform and stable

Sub-base – clean gravel or crushed stone, if insufficient percolation rate in the compacted site fill

Subgrade and sub-base - moistened before placement of pervious concrete layer

Final layer –compacted by manually operated roller

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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MIXING AND TRANSPORTATION

Conventional concrete mixing equipment is used - mixing times may be extended

Cement may be replaced by about 10-30% of fly ash, 20-50% of blast furnace slag and 5% of silica fume

Fine aggregate will decrease the porosity and increase strength

Discharged completely within one hour after initial mixing

Retarding admixtures - increase the discharge time

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PLACEMENT

Placement - continuous, spreading - rapid

Strike off about 15 to 20 mm above the forms

Commonly used- mechanical vibrating screed, manual screeds

Vibrating ScreedManual Screed

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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CONSOLIDATION

Consolidation-by rolling over the concrete with a steel roller

Because of rapid hardening and high evaporation rates, delays in consolidation can cause problems

Steel Roller

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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CURING

As pervious concrete pavements do not bleed, they have a high tendency for plastic shrinkage cracking

Recommended curing procedure -fog misting followed by plastic sheeting for 7 days

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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MAINTENANCE

Consists of prevention of clogging and surface raveling

Raveling

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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MAINTENANCE(CONTD…)

Cleaning byPower blowing

Pressure washing

Broom sweeping Broom sweeping

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ENVIRONMENTAL BENEFITS

Reduces storm water runoff

Replenishes water tables and aquifers

Eliminates - detention ponds - other costly storm water management practices

Allows for more efficient land development

Prevents warm and polluted water from entering streams

Department of civil engineering, T.K.M.C.E

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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SAFETY BENEFITS

Minimizes flash flooding and standing water

Skidding is reduced

Light reflectivity is higher than asphalt surfaces, hence reduce heat island effect

Glare from wet pavement is virtually eliminated

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PERVIOUS CONCRETE PROJECTS

Parking for prime outlets mall in Williamsburg, Virginia (7.6 acres)

Walkway in Beijing, China built for 2008 Olympics

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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PERVIOUS CONCRETE PROJECTS (CONTD…)

Green alleys in Chicago

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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DISADVANTAGES

Runoff from adjacent areas onto pervious concrete needs to be prevented

If reinforcement is required, epoxy coated bars should be used

Concrete is variable in permeability; over vibration significantly reduces permeability

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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APPLICATIONS

Pervious pavement for

Parking lots

Alleys and driveways

Trees gates in sidewalk

Tennis court

Greenhouse floors

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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CONCLUSION

Pervious concrete pavement construction is an exceptionally good method to improve sustainability of construction. It effectively recharges the ground water and also helps in control of urban heat island effect. Even though compression strength is low, it can be used for light traffic roads, pavements, parking lots, and paving the front of houses.

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May 2, 2023 Department of civil engineering, T.K.M.C.E

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REFERENCES

S.O. Ajamu, A.A. Jimoh, J.R. Oluremi, “Evaluation of Structural Performance of Pervious Concrete in Construction”, International Journal of Engineering and Technology Volume 2 No. 5, May, 2012.

Karthik Obla, “Pervious concrete overview”, The Indian Concrete Journal,2012

Dan, B. : “Pervious Concrete Pavement” A Win-Win System, Holcim (US) Inc. Retrieved March 24, 2010 from

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THANK YOU

LOVE THE NATURECARE THE NATURE

BE WITH THE NATURE

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