CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

Pervious Concrete:1. What is Pervious?

A. DefinitionB. HistoryC. Applications

2. Stormwater ManagementA. BenefitsB. Recommended SpecificationsC. Hydrologic Analysis

3. Mix Design

CONCRETE APPLICATIONS I

CIMT 210

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

1. What is Pervious?

A. DEFINITION (SEE VIDEO ON PERVIOUS CONCRETE)

http://youtube.com/watch?v=G6BOJ6AFhls

1. It allows rainfall to be captured and to percolate into the ground.2. It reduces stormwater runoff3. It recharges groundwater4. It supports sustainable construction

http://asusmart.com/blog/news/asu-art-museum-pervious-parking-lot

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1. What is Pervious?

B. HISTORY

http://www.perviouspavement.org/?gclid=CLG3wNr-so8CFQ4SQQodmStrMQ

1. Its not a new technology (first used in 1852)

2. Federal Clean Water legislation (promotes it.)

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1. What is Pervious?C. APPLICATION

http://www.perviouspavement.org/?gclid=CLG3wNr-so8CFQ4SQQodmStrMQ

1. Its high porosity provides is thermally insulating (i.e in walls of buildings)

2. It has good acoustical properties (for sound barrier walls).

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

1. What is Pervious?C. APPLICATIONTable . Applications for Pervious Concrete

Low-volume pavements

Residential roads, alleys, and driveways

Sidewalks and pathways

Parking areas

Low water crossings

Tennis courts

Subbase for conventional concrete pavements

Patios

Artificial reefs

Slope stabilization

Well linings

Tree grates in sidewalks

Foundations / floors for greenhouses, fish hatcheries, aquatic amusement centers, and zoos

Hydraulic structures

Swimming pool decks

Pavement edge drains

Groins and seawalls

Noise barriers

Walls (including load-bearing)

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2. STORMWATER MANAGEMENT

A. BENEFITS

1. Its subbase may provide enough water storage capacity to eliminate the need for retention ponds, swales, and other precipitation runoff containment strategies. 2. Its drainage media for hydraulic structures, parking lots, tennis courts, and greenhouses.

3. It helps owners comply with EPA stormwater regulations

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

2. STORMWATER MANAGEMENTB. Recommended Specifications

 1. Recommended Concrete working time is usually, one hour between mixing and placing.2.Using retarders and hydration stabilizers can extend the working time by as much as 1.5 hours  (Density and Porosity)

.A pavement 5 inches (125 mm) thick with 20% voids will be able to store 1 inch (25 mm) of a sustained rainstorm in its voids.

It covers the majority of rainfall events in the U.S. 6-inch thick subbase of open-graded gravel increases it to as much as 3” of precipitation                                                                  

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

2. STORMWATER MANAGEMENTB. Recommended Specifications

  (Permeability)  Typical flow rates through pervious concrete are 3 to 8 gal/ft²/min, rates of up to 17 gal/ft²/min  (Compressive Strength) Compressive strengths ( 500 to 4000 psi)Typical values are about 2500 psiDrilled cores best measures in-place strengthsCompaction differences make cast cylinders less representative of field concrete. (Flexural Strength) Flexural strength (150 psi to 550 psi ). Flexural strength is affected by compaction, porosity, and the aggregate-to-cement (A/C) ratio.Pervious concrete does not require the measurement of flexural strength for design. 

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

2. STORMWATER MANAGEMENTB. Recommended Specifications

Freeze –Thaw (continued)Research indicates that entrained air in the paste dramatically improves freeze-thaw protection  Sulfate ResistanceAggressive chemicals in soils or water, such as acids and sulfates, are a concern to conventional concrete and pervious concrete Abrasion Resistance Because of the rougher surface texture and open structure of pervious concrete, abrasion and raveling of aggregate particles can be a problem, particularly where snowplows are used to clear pavements.

Highways are generally not suitable for pervious concretes. However, anecdotal evidence indicates that pervious concrete pavements allow snow to melt faster, requiring less plowing.

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3. MIX DESIGNA. STRUCTURAL DESIGN

Cementitious materials Portland Cements (ASTM C 150, C 1157) Blended cements (ASTM C 595, C 1157)Fly Ash, pozzolans (ASTM C 618)Ground-granulated blast furnace slag (ASTM C 989)

 Supplementary cementitious materials (SCMs) Fly ash, pozzolans, and Slag These influence concrete performance, setting time, rate of strength development, porosity, permeability, etc. Silica fume, Fly ash, and Blast furnace slag all increase durability by decreasing permeability and cracking

CONCRETE INDUSTRY MANAGEMENT TECHNOLOGY

3. MIX DESIGNA. STRUCTURAL DESIGN

Silica fume is a byproduct of silicone production. It consists of superfine spherical particles Used frequently for high-rise buildingsIt produces concrete that exceeds 20,000 psi Silica fume can replace 5-12% cement

Fly ash is the waste byproduct of burning coal in electrical power plants;it used to be landfilledThis material can be used to replace 5-65% of the Portland cement

Blast furnace slag is the waste byproduct of steel manufacturing. It imparts added strength and durability to concrete, and can replace 20-70%of the cement in the mix.