Specifying Pervious Concrete ... Pervious Concrete Design. Pervious Concrete Mix. 9. Properties of Portland

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  • Presented By: National Ready Mixed Concrete Association

    Specifying Pervious Concrete

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    National Ready Mixed Concrete Association

    • National Trade Association – Established in 1930 • HQ in Alexandria, VA • 1,400+ Member Companies • NRMCA Represents ~75% of North American Ready Mixed Production • Mission - Serve Industry and Partners Through:

    • Compliance and Operations • Engineering • Government Affairs • Local Paving: Pave Ahead™ Initiative • Structures and Sustainability: Build With Strength™ Initiative

    Interested in becoming a member? Visit: www.nrmca.org/membership/

    https://paveahead.com/ https://buildwithstrength.com/ https://www.nrmca.org/membership/

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    Thank you to the NRMCA 2020 Super Sponsors

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    NRMCA Disclaimer • This presentation has been prepared solely for information purposes. It is intended

    solely for the use of professional personnel, competent to evaluate the significance and limitations of its content, and who will accept full responsibility for the application of the material it contains. The National Ready Mixed Concrete Association and any other organizations cooperating in the preparation of this presentation strive for accuracy but disclaim any and all responsibility for application of the stated principles or for the accuracy of the content or sources and shall not be liable for any loss or damage arising from reliance on or use of any content or principles contained in this presentation.

    • Unless otherwise indicated, all materials in this presentation are copyrighted to the National Ready Mixed Concrete Association. All rights reserved. Therefore reproduction, modification or retransmission in any form is strictly prohibited without the prior written permission of the National Ready Mixed Concrete Association.

    • ©2015 National Ready Mixed Concrete Association.

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    Instructions

    • Webinar is being recorded and posted at paveahead.com/education/.

    • Everyone is muted.

    • Type questions in the question box.

    • Download the handouts in the GoToWebinar control panel.

    • Credit for course: – Based on attendance.

    – Survey (Quiz) – In follow-up e-mail, not required, but encouraged.

    – Attendance Certificate – In follow-up e-mail 1 hour after webinar.

    – AIA members – Attendance registered with AIA-CES if AIA number provided.

    https://paveahead.com/education/

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    About the Course

    Learning Units (LU) or Professional Development Hours (PDH)

    • AIA-CES DSP102: 1.0 LU/Elective (1.0 Hour) or 1.0 PDH for Engineers

    • Learning Objectives:

    – Understand principles behind proper pervious concrete mix design

    – Familiarity with ACI 522R-10: Report on Pervious Concrete and ACI 522.1-13: Specification for Pervious Concrete Pavements

    – Understand necessity for pervious concrete contractor certification

    – Understand appropriate acceptance testing procedures for pervious concrete

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    Today’s Presenter

    • Phil Kresge –Senior Vice President – East Central –Ready Mix Producer –PA Concrete Promotion Council – Exec. Director –NRMCA since 2004

    More information at paveahead.com/experts/

    https://paveahead.com/experts/

  • Pervious Concrete Design

    Pervious Concrete Mix

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    Properties of Portland Cement Pervious Concrete

    • 15% to 25% air void content

    • 120 to 135 lbs/ft3 unit weight

    • 500 to 3,000 psi strength – Introduction of small amount of fine aggregate (sand) can increase strength

    – BUT compressive strength typically NOT USED as acceptance criteria.

    – Air void structure and unit weight are used for acceptance instead.

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    Mix Design – The Old Way

    • 550 - 650 lbs. Portland Cement

    • 27 ft3 Coarse Aggregate

    • 0.25 – 0.30 W/C Ratio

    • Admixtures

    – High Range Water Reducer

    – Viscosity Modifier

    – Hydration Stabilizer

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    Mix Design – What We’ve Learned

    • Maximum 500-550 lbs. cementitious – 5% Silica Fume optional

    • 27 ft3 Coarse Aggregate • 0.32 – 0.37 W/C Ratio

    – Sufficient water to display a wet, metallic sheen on the aggregate

    • Admixtures – Specifically for Pervious Concrete – Mix Water Conditioner

    • 550-650 lbs. Portland Cement

    • 27 ft3 Coarse Aggregate • 0.25 – 0.30 W/C Ratio

    • Admixtures – High Range Water Reducer – Viscosity Modifier – Hydration Stabilizer

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    Typical Portland Cement Pervious Concrete Mix Design

    • ADMIXTURES

    –Hydration Stabilizer • 10 to 16 ounces per 100 weight

    • Ounces depend on temperature – add more on hotter days

    –Viscosity Modifier • Ounces depend on % passing the 30 & 50 sieve

    • 2 to 6 ounces per 100 wt – add VMA for more fines

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    Permeability and Porosity

    • Permeability – rate at which water can flow

    • Function of interconnected voids

    • Porosity – the amount of voids

    • Increase in porosity increases permeability

    • Some voids are entrapped during the placement and compaction process

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    Aggregate

    • Texture and Porosity Affected by:

    –Aggregate Size

    –Aggregate Grading

    –Aggregate Angularity

    –Paving Equipment

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    Strength

    • Add sand into mix • 5% up to 25% • Adds up to 1,000 psi • Sacrifice porosity for strength

    • Synthetic Fibers • Larger Aggregate Size

    • For areas where high heels & wheelchairs are not a concern

    • VAE Polymers • Increase density • Increased resistance to de-icing chemicals

    • Thicker sections

  • Pervious Concrete Specification

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    ACI 522 – Pervious Concrete

    • ACI 522R – 10 – Provides technical information on

    pervious concrete’s application, properties, and construction methods

    • ACI 522.1 – 13 – Specification for Pervious

    Concrete Pavements

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    ACI 522.1 - 13: Specification for Pervious Concrete Pavements

    • Provides Guidelines for

    – Quality Assurance

    • Materials

    • Testing - Acceptance

    – Placement

    • Does not provide recipe for pervious concrete mix design

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    Density

    • Two types of density – Fresh Density

    – Hardened Density

    • Density increases as Void decreases

    • Measured to determine acceptability – Fresh density for concrete mixture

    – Hardened density for installation

    • Assess whether void content is achieved

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    Density of Fresh Concrete

    • Measured in accordance with ASTM C1688

    • Varies with: – type/quantity of materials – void content

    • Void calculated from measured density

    • Fresh density used for acceptance at delivery – +/- 5 lb/ft3 of approved mix design

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    Density of Hardened Concrete

    • Measured in accordance with ASTM C1754

    • +/- 5% of hardened density results from test panels

    • Differs from density of the fresh concrete

    – Vary with compaction process

    – Change in moisture content

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    Acceptance Criteria – ACI 522

    • ACI 522 recognizes difference between – Density of fresh mixture

    – Density of compacted pavement

    • Neither fresh nor hardened density should be specified

    • Void content specified by designer – Applies to fresh concrete

    – Typically 15% to 25%

    – Acceptance range typically +/- 5%

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    Specification Recommendations

    “Target void content of 15% to 25% as measured by ASTM C1688*”

    Suggested text - Not taken from ACI 522.1-13

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    Section 2.2 - Products

    • 2.2.2 Aggregates - Nominal maximum aggregate size shall not exceed 1”, unless otherwise specified.

    • 2.2.4 Admixtures - Chemical admixtures shall comply with ASTM C260/C260M, ASTM C494/C494M, or ASTM C1017/C1017M unless otherwise specified.

    • 2.2.5 Fibers - Fibers shall comply with ASTM C1116/C1116M, 4.1.3 or 4.1.4. Fibers may be used in pervious concrete mixtures when permitted by the Architect/Engineer.

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    Section 1.5: Quality Control

    •1.5.1.1 Contractor qualification - Unless otherwise approved by Architect/Engineer, Contractor shall provide evidence of employment of one (1) NRMCA certified Pervious Concrete Craftsman who must be on site, overseeing each placement crew, during all concrete placement, or the contractor shall provide evidence of employment of three (3) NRMCA certified Pervious Concrete Installers who have received hands-on training in the construction of pervious concrete pavements, and who must be on site, working as members of each placement crew, during all concrete placement, or, with the approval of Architect/Engineer, contractor may provide written evidence of project experienc