Post on 21-Apr-2017
May 2, 2023 Department of civil engineering, T.K.M.C.E
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PERVIOUS CONCRETE PAVEMENTS
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
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
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
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
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/
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
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
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
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
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
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
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
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
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
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
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
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
May 2, 2023
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
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
May 2, 2023 Department of civil engineering, T.K.M.C.E
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PERVIOUS CONCRETE PROJECTS (CONTD…)
Green alleys in Chicago
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
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
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.
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
May 2, 2023 Department of civil engineering, T.K.M.C.E
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THANK YOU
LOVE THE NATURECARE THE NATURE
BE WITH THE NATURE
May 2, 2023 Department of civil engineering, T.K.M.C.E
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