Interlock Design - Winter 2018

THE OFFICIAL PUBLICATION OF THE INTERLOCKING CONCRETE PAVEMENT INSTITUTE

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STRONGER BASES FOR PICP ROAD MAP FOR PERMEABLE PAVEMENTS DEICER USE GUIDELINES

Concrete Header Here pavers Please connect the University Header Here Please of Tennessee campus Header Here Please volume 24 number 1

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ICP-022 ICP-038

Interlocking Concrete Pavement Institute 14801 Murdock Street, Suite 230 Chantilly, VA 20151

PRSRT STD U.S. POSTAGE PAID Madison, WI Permit 29

volume 24 number 1

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EXECUTIVE DIRECTOR: Charles McGrath, CAE

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PUBLISHING DIRECTOR: Dennis Smith EDITORIAL DIRECTOR: David R. Smith CONTRIBUTING EDITOR: Robert Bowers, P.Eng.

You Have to Think

WINTER 2018

ART DIRECTOR: Amy Liss

The permeable plaza surface next to the Student Union enabled compliance with local storm water regulations.

5 the

contents

FEATURES

Photo Credit: Belgard

A 14801 Murdock Street, Suite 230 Chantilly, VA 20151 Tel 703.657.6900 Fax 703.657.6901 Email icpi@icpi.org ICPI Canada P.O. Box 1150 Uxbridge, ON L9P 1N4 Canada SUBSCRIPTION AND MEMBERSHIP: Qualified design professionals can receive a complimentary subscription — email us at icpi@icpi.org.

For further information about this publication or about membership in ICPI, write to the appropriate address, call 703.657.6900 or fax 703.657.6901.

Send story submissions for consideration to dsmith@icpi.org.

05 SETTING A NEW STANDARD Permeable Interlocking Concrete Pavers Address Multiple Challenges at University of Tennessee

Manage your subscription at www.icpi.org.

Interlock Design is published quarterly by the members of the Interlocking Concrete Pavement Institute (ICPI) for producers, suppliers, contractors, specifiers and users of interlocking concrete pavements.

The opinions expressed in Interlock Design articles are those of the authors and do not necessarily represent the position of the editor or ICPI.

DEPARTMENTS 02 INTERLOCKUTOR

ICPI Webinar Seminars Register at: www.icpi.org/view/events

You have to think

09 ENGINEER'S VIEW

Strengthening Opengraded Aggregates in Permeable Pavements

13 KNOWLEDGE BASE

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Load Testing Begins on Paving Slabs and Planks

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Permeable Pavement Road Map Conference

23 THE MAIN EVENTS

Resisting Deicer Damage

ADVERTISING DAN HARTZOG danH@llmpubs.com | 503-445-2229

David R. Smith

s we enter the 24th year of this magazine, the industry returns to pre-recession sales levels. Residential sales dominate about threequarters of shipments, with the remainder placed in commercial (specified) applications. Permeable interlocking concrete pavements, paving slabs and planks are the high-growth products. Permeable units have been regulated into existence, whereas slabs and planks present a sleek, modern aesthetic that visually and emotionally connects pedestrians to residential and commercial settings.

While the economy charges forward and pulls construction with it, we continually remind users that segmental concrete pavement products are elements or components within larger pavement systems. The systems con-

sist of hundreds of possible combinations of elements: paving units, patterns, colors, bedding and base materials.

Traffic and soils often drive the right combinations. Like any other pavement or building system, finding the right combination of elements for an application is the key to ease of construction and minimal maintenance.

understand the interaction of pavement materials under different loads and in various climates. In a fee-driven, hurry-up design and construction world, clear thinking about segmental pavement can get overlooked.

Some decision tools are needed to bring clarity to design thought processes.

One segmental paving expert ICPI provides a large stable of who provided an integrated detail drawings and specifica- decision tool for many aptions on www.icpi.org to help plications is Professor John designers choose the best Knapton on www.sept.org/ combination of elements. techpapers/1098.pdf. Entitled, Twenty-three ICPI Tech Specs “A Total Quality Approach to offer design, construction Pavement Specification,” the and maintenance advice on a paper was written 17 years range of assemblies. However, ago and provides a structure they don’t cover absolutely for decision-making regarding every design situation. There- selecting the right pavement fore, some thinking is required structure components. Anto find the assembly that fits other summary of structural the application while avoidperformance and system asing cut-and-paste solutions. semblies are presented below More importantly, thought as a guideline. We hope these and study are required to clarify your thinking.

STRUCTURAL PERFORMANCE LIMITS

continued on page 3

PAUL VOLLMER paul@llmpubs.com | 503-445-2222 DESIGN AMY LISS amy@llmpubs.com | 503-445-2238 ISSN 1087-9862 The acceptance of advertising in Interlock Design magazine does not constitute or imply the endorsement or recommendation by ICPI or its members, staff, editors or the publishers of any product or service mentioned, referenced or advertised in the publication.

ICPI accepts no responsibility for any claims made in any advertisement. ICPI further reserves the right to refuse to accept any advertisement.

Canada Post Agreement No. 41567031

*ESALs = 18,000 lb equivalent single axle loads

©2018 Interlocking Concrete Pavement Institute. Visit our website at www.icpi.org.

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WINTER 2018

Assembly Selection Guide Surface & Bedding Options Interlocking

Min. Unit Thickness Pedestrian, In. (mm) 2 3/8 (60)

Vehicular Base Options

3 1/8 (80) DGA*

DGA, cement or asphalt stabalied, asphalt or concrete

Sand-bitumen ¾ in. (15 mm)

Asphalt or concrete

Asphalt or concrete

Mortar

Concrete

N/A

2 3/8 (60)

ASTM No. 8 stone 2 in. (50 mm) No. 8, 89 or 9 injoints

3 1/8 (80) Open-graded aggregate, asphalt or cement treated permeable bases

Open-graded aggregate

Slabs

2 (50)

3 1/8 (80)

Sand 1 in. (25mm)

DGA* or concrete

Concrete or asphalt

Sand-bitumen ¾ in. (15 mm)

Concrete or asphalt

Concrete or asphalt

Mortar

Concrete

N/A

Planks

3 1/8 (80)

4 (100)

Sand 1 in. (25 mm)

DGA* or concrete

Concrete or asphalt

Sand-bitumen ¾ in. (15 mm)

Concrete or asphalt

Concrete or asphalt

Mortar

Concrete

N/A

Grids

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Min. Unit Thickness Vehicular, in. (mm)

Sand 1 in. (25 mm)

Permeable Interlocking

3 1/8 (80)

Sand ½ - 1 in.

(13 - 25 mm)

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Pedestrian Base Options

3 1/8 (80) DGA*

DGA*

*DGA = Dense-graded aggregate road base conforming to state or local road agency specifications or to ASTM D2940.

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 COVER STORY

setting a new standard

WINTER 2018

Sheryl S. Jackson

PERMEABLE INTERLOCKING CONCRETE PAVERS ADDRESS MULTIPLE CHALLENGES AT UNIVERSITY OF TENNESSEE

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The University of Tennessee at Knoxville incorporated permeable interlocking concrete pavement into a campus center upgrade.

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hen 28,000–plus students, some 10,000 faculty and staff members, and 102,000 football fans head to a game at Neyland Stadium at the University of Tennessee, Knoxville, they enjoy a new concrete paver walkway and pedestrian bridge that connects the east and west sides of campus. The plaza, walkway, and bridge feature an intricately designed permeable paver system that sets the standard for other pedestrian areas throughout the campus.

Originally built in 1952 and renovated in 1967, the university center was ready for an

upgrade. This resulted in a multi-year, $167 million construction project that features a new Student Union building with approximately 50% more space for the bookstore, dining establishments, auditorium space, and meeting rooms for university organizations. In addition to enhanced services in the building, students and visitors enjoy a renovated exterior plaza and pedestrian walkway and bridge that safely takes users over a busy street. The $65 million first phase included a new building, road modifications, a parking lot, landscaping with a plaza, and pedestrian walkway.

“We closed an existing road as part of the new construction, which made it possible to create a student plaza and align our major east-west pedestrian corridor,” explained Dan Smith, P.E., Project Manager at University of Tennessee, Knoxville. The plaza and some of the walkway are built over the lower portion of part of the Student Union, and the pedestrian bridge extends over a busy street to improve access between the residential and academic sections of the campus. “The new walkway also gave us the opportunity to improve compliance with the Americans with Disabilities Act

by eliminating a number of grade changes of the previous road and creating a steady grade along the walkway.”

The University wanted a paving system that was visually pleasing and addressed stormwater drainage. “Our campus is close to the Tennessee River, so we have to mitigate stormwater runoff before it gets to the river,” Mr. Smith said. “Permeable interlocking concrete pavers met our requirements.”

Figure 1 illustrates the plaza which also detains stormwater.

Figure 1.

The permeable plaza surface next to the Student Union enabled compliance with local storm water regulations.

Cover Story continued on page 7

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COVER STORY WINTER 2018

PROJECT CREDITS



setting a new standard

OWNER: UNIVERSITY OF TENNESSEE

Cover Story continued from page 6

The final design for the pedestrian area was a basket weave paver pattern comprised of four different colors provided an ICPI member. “We know that it is advisable to keep the geometry simple when using pavers, but the more complicated design was important to this project,” said Kelly L. Headden, AIA, Senior Vice President of BarberMcMurry architects in Knoxville, Tennessee. The design was a joint venture with BarberMcMurry and another Knoxville, Tennessee-based architecture firm, McCarty Holsaple McCarty. The intricate, final design included a complex paver design with a variety of colors, graced by shade trees and other landscaping to create a livable, welcoming space.

Over 30,000 sf (2,787 m2) of pavers were installed in the first phase of the construction project. When completed in spring 2018, a total of 56,500 sf ($5,249 m2) of pavers will be placed. The cost for pavers, base and labor when both phases of the project are complete will be $725,000, Mr. Pierce said.

Although Hickory Hardscapes of Knoxville specializes in installation of permeable pavers, the university’s walkway and pedestrian bridge were a departure from the typical projects handled by the company, said Joe Pierce, owner and president of the company. Not only did the paving system have to be permeable, but it also had to be durable enough to handle some vehicular traffic. “Small utility vehicles will use the walkway for maintenance and landscaping activities,” he explained.

“All of the pavers had to be installed by hand due to the basket weave pattern, the number of colors and the detailed cuts to create the design,” Mr. Pierce said. “There was no border between designs, so everything had to match up exactly.”

The portion of the walkway built over the lower floors of the Student Union diverts water to the gutters that are part of the building’s roof while the pavers on the pedestrian bridge divert water to drains in the bridge structure. Pavers throughout other areas of the walkway and plaza have a catch basin system to manage storm

water drainage. Walkways were constructed with 3.125 in. (80 mm) thick permeable interlocking concrete pavers that sloped to catch basins and drains. The pavers were placed over two in. of washed ASTM No. 89 stone and 6 to 9 in. of ASTM No. 57 stone base. This base layer offers up to 3 in. (75 mm) of water storage and infiltration into the soil subgrade, or about 56,000 gallons (212,000 liters) of rainfall.

Figure 3 shows a detail where the perme­ able pavement section rests on a concrete base which serves as the underground roof for a portion of the Student Union building.

“

We had two weeks to complete work that would normally require 60 days.”

—Joe Pierce Owner and President of HIckery Hardscapes of Knoxville

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Figure 3. A section detail of the pavement illustrating the concrete base which was also the roof for the underground portion of the Student Union building.

The greatest challenge to complete the pedestrian walkway and bridge was the timetable. “We are almost always one of the last subcontractors on the project, which means that we are at the deadline end of the project, but we had only two weeks to complete the largest part of the paving system,” Mr. Pierce explained. “We had two weeks to complete work that would normally require 60 days.”

Although Hickory Hardscapes typically handles mechanical installation of permeable pavers for parking lots, there was no difficulty tackling a project that requires manual installation, said Mr. Pierce. “Most of the people in my company have been with me for a long time, so they have the experience and skill needed for this project.”

The walkway is a high traffic area for faculty, staff and students to travel across campus, plus football fans. With classes and the football season starting in late August, there was no leeway in the deadline.

To meet the tight deadline, Mr. Pierce scheduled four crews instead of the typical single crew. “Our entire company worked 65 to 70 hours, Monday through Friday, for two weeks to complete the project and allow the university to open the area in time for new students and football fans,” he said.

The University previously used interlocking concrete pavers in smaller projects around campus, but the expanse of the area surrounding the Student Union, and the positive reception to the intricate color and design scheme, has led to creation of standards that require future projects using pavers to match the same specifications, Mr. Smith explained. “These standards ensure a uniform aesthetic throughout

campus and help us plan maintenance and future renovations,” he said. “Having specific standards also makes it easier to replace pavers if they are damaged.”

The location of the plaza, walkway and pedestrian bridge make it a natural spot for special events, live reports from various news media representatives and informal gatherings of faculty, staff, students and family members throughout the week. The design and craftsmanship that went into the construction of the paving system will stay in the spotlight as the University continues to host special events—including ESPN GameDay broadcasts—on the plaza in the future.

ARCHITECT: McCARTY HOLSAPLE McCARTY/BARBER MCMURRY ARCHITECTS CONTRACTOR/CM: RENTENBACH CONTRACTOR/INSTALLER: HICKORY HARDSCAPES, KNOXVILLE, TENNESSEE COVER PHOTO: DENISE RETALLACK, KNOXVILLE, TENNESSEE PAGES 6 & 7: BRUCE MCCAMISH, KNOXVILLE, TENNESSEE

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Figure 4. The strength of the paver design is the strong visual connection between the two sides of the campus.

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WINTER 2018

ENGINEER’S view

By David Smith

Strengthening Open-graded Aggregates in Permeable Pavements

P

ermeable pavements use open‑graded aggregates that provide two roles, supporting vehicles and storing water.

Permeable interlocking concrete pavements for vehicular traffic typically use a 2 in. (50 mm) thick layer of ASTM No. 8 stone over a base or choker layer of 4 in. (100 mm) thick No. 57 or similar size aggregate. The latter is compacted on a subbase consisting of ASTM No. 2, 3 or 4 stone. Crushed rock is recommended for all three layers to help maximize interlock among the aggregate. Figure 1 shows a cross section used for vehicular applications. While not shown, this section can include a perforated underdrain.

When loaded by vehicles, open-graded aggregates behave somewhat differently than dense-graded aggregates typically used under asphalt and beneath (non-permeable) concrete pavers interlocked with jointing and bedding sand. Opengraded aggregates don’t have small particles mixed with larger particles to help confine the larger ones. Compacted, opengraded aggregates usually have 35% to 40% open space due to the absence of small particles. Compaction with a heavy plate or roller compactor helps open-graded aggregates find tighter positioning which results in better interlock among their neighbors.

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Figure 1.

Typical open-graded aggregate layers in permeable interlocking concrete pavement.

Engineer's View continued on page 11

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continued from page 9

WINTER 2018

ENGINEER’S VIEW

Engineers View

Figure 2.

A geogrid engaging open-graded aggregate.

Photo credit: Formpave

Like dense-graded aggregates, opengraded materials eventually rut when repeatedly loaded by vehicles. Given the same wheel loads and structural design, open-graded aggregates tend to rut faster than dense-graded aggregates.

Designers have some options to slow the rate of rutting in open-graded aggregates. All options confine or constrain the aggregates and help reduce their tendency to move and rut under repeated vehicular loads.

Placing geogrids within the aggregate—Like dense-graded bases, open-graded bases can be anchored within geogrid via ‘strike through,’ i.e., aggregates lodged into and through the grid openings which creates an anchor. See Figure 2. Geogrids resist pulling from compaction and bear up well under repeated loads. The extent to which geogrids can stiffen densegraded aggregate is illustrated in a 2009 study by the Montana Department of Transportation was about 26%. Similar efficiencies would be likely for geogrids placed within open-graded bases.

are slightly overfilled with aggregates and then compacted. The plastic cells confine sideways movement of the aggregate when subject to wheel loads. In doing so, the manufacturers of the cells note that the aggregate stiffness is increased by up to two times compared to unconfined, compacted aggregates. Geocell installation is rapid and the mats can be easily trimmed to accommodate pavement protrusions and layouts. Figure 3 illustrates geocells over a geogrid to gain the structural benefit of each.

Add cement or asphalt to the aggregates—Provincial and state departments of transportation construction specifications often call these treated or stabilized permeable bases. The aggregates are stabilized with asphalt or cement which binds the aggregates together. The stones are mixed with either binder and compacted on the job site while remaining permeable. Depending on the mix, stabilized permeable bases can increase the stiffness or resistance to load by two to three times. However, the larger the aggregates, the greater the porosity and lower number of binder contact points among aggregates. This results in decreased efficiency in binder use and stiffness.

these three options. Using any of these options should be decided by a qualified pavement engineer. These engineered options present potentials for reduced subbase thicknesses, or reinforced sections that can accept additional wheel loads while minimizing rutting and reducing costs. Each option should be evaluated based on available materials, contractor expertise, and labor costs.

Figure 4. Pervious concrete as a type of cementstabilized base under permeable pavers provides additional structural support.

Figure 3.

Geocells with open-graded aggregate.

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For example, given equal thicknesses, a cement- or asphalt-stabilized ASTM No. 8 aggregate with 3/8 in. (10 mm) top size stones would provide a higher stiffness than a No. 57 stone with a top size of ¾ in. (19 mm). Made with a 3/8 in. top size aggregates, this gradation qualifies pervious concrete as a base for permeable interlocking concrete pavements (See Figure 4). A key to the Place and compact the aggregates into costs of this or similar cement-treated or three-dimensional geocells underlaid asphalt-treated permeable bases is that mixing plants likely require a minimum with a geogrid—Geocells are typically number of tons in an order to deliver an flat, flexible plastic “accordions” that unfold to rectangular mats at the job site. entire batch.

The mats are supplied in 4 in. (100 mm) In summary, strengthening openor 8 in. (200 mm) depths. The openings graded aggregates is possible with

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

Permeable Pavement Road Map Conference PROVIDES INSIGHT INTO DIVERGENT AGENCY GOALS AND NEEDED INSTITUTIONAL CHANGES

While presentations proceeded, the audience wrote questions for discussion. This resulted in 76 questions covering the topics listed below. The second day of the conference consisted of breakout groups generating answers to these questions. Here are the salient questions and answers. All responses are found at www.ucprc.ucdavis.edu/permPvmt.

Costing & cost decision support—Unlike approaches for traditional pavements, life cycle costs analyses must include offsite benefits. Continued initial and maintenance costs must be monitored and collected.

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Material & pavement performance—More pilot projects, specifically street and road shoulder demonstration projects are needed. Pervious concrete and porous asphalt durability needs to be improved.

Education & training—Besides in-service training for design professionals and decision-makers, there needs to be university curriculum on permeable pavements. Can design professional training also include certification?

Civil engineers need to learn how to design permeable pavements in saturated subgrades as this isn’t taught in

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university curriculum. Hence, the reluctance to use permeable pavements. This is a core institutional concern.

Communication among industries and users—Can there be an information clearinghouse?

Project-level design concerns—There is a need for more design details, standard methods for soil investigations, and structural design tables developed from full-scale load testing include hybrid designs. Tested proof of structural performance is needed to raise user confidence. This will promote full-width street applications and convince more municipalities to adopt permeable pavements into their catalogs of standard specs and drawings.

Watershed & flood control design concerns—Permeable pavements have the potential to reduce flooding and contribute to a more resilient infrastructure. What research, modeling, and case studies are needed to demonstrate this? What are the economic benefits? Cities such as Atlanta and New Orleans are using permeable pavement to control flooding, i.e., the road system is also the runoff storage and conveyance system.

Designing for additional benefits & impacts—Permeable pavements have many benefits beyond stormwater management. They need to be quantified and some need to be measured through environmental life cycle assessment analyses.

Construction standards & issues—Continued contractor training and construction QC/QA are essential, as well as refinement of specifications, and adoption into state and local specifications.

Knowledge base continued on page 15

You Asked. We Listened.

Now you have TIME to see it ALL! WWW.HARDSCAPENA.COM

ed by Dr. John Harvey, Director of the UC Pavement Research Center at UC Davis, experts convened last November to identify barriers to permeable pavements and how to overcome them. The conference began with presentations by industry representatives, plus federal, state, and municipal officials, academics, and consultants. While most participants came from areas within storm water management, others came with a pavements background.

Funding for research, development, and implementation— Funding sources for quantifying stormwater management have been from industry, municipal, state and federal sources.

More research is needed on structural performance and on watershed flood control. Should there be a university center for this?

Planning & development codes —Opportunities abound for updating municipal codes, LID, and complete street guidelines for road agencies. Greater confidence by such agencies in performance and designs for low maintenance will help gain acceptance and reduce stormwater versus road agency bifurcation of interests and priorities. Resilience may be key to getting road agencies to adopt permeable pavements, as stormwater management doesn’t hold a top priority or a compelling interest for adoption by many road agencies.

Over 50 persons recently gathered in Davis, California, to remove barriers to wider use of permeable pavements.

L

Asset management—This is an emerging field. There needs to be condition survey tools that include stormwater/infiltration performance as well as structural performance to include permeable pavements in pavement asset management software programs used by municipalities. Standard O&M guides need to be created and standardized.

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WINTER 2018

KNOWLEDGE base

Maintenance—Systematic collection of maintenance data and costs is needed, especially on surface cleaning, as well utility repair guidelines and costs.

HARDSCAPE NORTH AMERICA AN ICPI EVENT

SAVE THE DATE

NEW THREE-DAY FORMAT IN 2018!

WEDNESDAY, THURSDAY & FRIDAY • OCTOBER 17-19, 2018 KENTUCKY EXPOSITION CENTER - LOUISVILLE, KENTUCKY

NEW 3-Day Format for all Attendees Keynote Speaker you won’t want to miss New VIP Pass

OCT 17-19 2018

KEC

Redesigned Outdoor Demos New Dealer Program Format ICPI & NCMA Certification Installer Courses

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KNOWLEDGE BASE

Knowledge base continued from page 14

WINTER 2018

Load Testing Begins on Paving Slabs and Planks FULL-SCALE LOAD TESTING BEGINS ON PAVING SLABS AND PLANKS IN FREDERICK, MARYLAND

Likely the first experiment of its kind in the U.S., full-scale load testing began on paving slabs and planks in December 2017 at an ICPI member’s manufacturing facility in Frederick, Maryland. Funded by the ICPI Foundation for Education and Research, the pavement test area was constructed to help validate performance of selected slab and planks, base materials and thicknesses developed from finite element modeling. The modeling led to creation of draft design tables up to 75,000 ESALs. One ESAL is an 18,000 lb equivalent single axle load.

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Likely the first experiment of its kind in the U.S., full-scale load testing began on paving slabs and planks in December 2017 at an ICPI member’s manufacturing facility in Frederick, Maryland.”

The test area includes slabs and planks on an inch of bedding sand over compacted aggregate alone, and on a 4 in. (100 mm) thick concrete base over compacted aggregate. Both assemblies are identical to those modeled and provided in the draft design tables.

The pavement structures will be subject to heavily loaded truck traffic for one to two years, typical to that shown in the photos. Besides load monitoring, performance and failure will be documented based on the extent of cracked or severely displaced paving units.

Knowledge base continued on page 17

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WINTER 2018

KNOWLEDGE BASE

Knowledge base continued from page 16

Resisting Deicer Damage THE FIRST STEP TO DEICER USE IS KNOWING WHAT’S BEING APPLIED.

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Now that a cold winter is upon many of us, some guidelines follow on deicer use for concrete pavers.

As a first step, always check the content of deicers sold. If the types of chemicals are not stated, the deicer company’s website should be visited as it typically includes material safety sheets with content descriptions.

Never the friend of any type of concrete, deicer damage can be minimized because the high density of pavers and slabs can limit absorption of deicers. In addition, a high cement content helps paving units resist damage from the stress of expanding ice on and inside them. Research and experience have highlighted factors affecting the winter durability of concrete pavers, including the utilization of:

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yy Aggregates with low absorption that will not degrade when subject to freezing and thawing with deicing materials yy Proper aggregate gradation that enables high density from compaction during manufacturing yy Sufficient cement paste to coat the aggregate and reduce capillary pores yy Sufficient compaction during manufacturing to ensure maximum density and uniformity ASTM C936 Standard Specification for Solid Concrete Interlocking Paving Units includes freeze-thaw durability criteria for assessing the freeze-thaw durability and resistance to deicing salts. C936 references the test method ASTM C1645 Standard Test Method for Freeze-thaw and De-icing Salt Durability

of Solid Concrete Interlocking Paving Units. C936 includes an optional lower freezing temperature to use in test method C1645 for regions of the U.S. that experience severe freezing conditions based on a climatic zone map. The optional testing in 3% saline for these regions is equivalent to the testing required in the Canadian concrete paver standard, CSA A231.2 Precast Concrete Pavers. To obtain a copy of ASTM C936 or ASTM C1645 visit www.astm.org. The CSA standard is available from www.csagroup.org.

A literature review prepared for the Utah Department of Transportation* in 2013 found that concrete exposed to sodium chloride experienced only minor, if any, adverse effects, while specimens exposed to calcium chloride, magnesium chloride, or calcium magnesium acetate (CMA)

Always check for the types of chemicals in deicers. This one is magnesium chloride.

experienced significant deterioration, including scaling, cracking, mass loss and compressive strength loss. The report recommends that engineers responsible for winter maintenance of concrete pavements utilize sodium chloride whenever possible, instead of calcium chloride, magnesium chloride or CMA, and apply only the amount necessary to ensure safety of the traveling public. While the literature review did not specifically address segmental concrete paving, the findings support ICPI’s guidelines for deicing salt exposure. *Physical and Chemical effects of Deicers on Concrete Pavement: Literature Review, Report No. UT-13.09 Prepared for Utah Department of Transportation Research Division by Brigham Young University, July 2013.

Knowledge base continued on page 19

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KNOWLEDGE BASE WINTER 2018

Guidelines for Limiting Deicing Chemical Exposure A key to successfully using deicing materials on segmental concrete paving (or any concrete) is using only as much as needed to do the job. This will maximize benefits while minimizing concrete and surrounding environment damage. The following guidelines can help limit the exposure of deicing chemicals while maintaining a safer environment: yy Apply sand first to increase traction, then apply deicers as needed. Sand should not be applied to permeable interlocking concrete pavements. yy Rock salt (sodium chloride or NaCl) is the least damaging to concrete materials and should be used whenever possible. yy If a more effective, quicker acting deicer is necessary, consider the judicial use of calcium chloride. yy The use of magnesium chloride and CMA is not recommended because they can chemically degrade all types of concrete, significantly increasing potential damage. The potential for damage from CMA increases with the amount of magnesium in the formulation. yy Do not over-apply deicing chemicals; follow the recommended dosage.

yy Protect vegetation and metal from contact with deicing chemicals as most can impair vegetation and corrode metals.

In addition, use ICPI-recommended jointing and bedding sand materials to minimize water penetration into the pavers. This can also help reduce deicers from entering and accumulating in the jointing and bedding sand that may eventually degrade the pavers. ICPI also recommends adequate pavement slopes (typically a minimum of 2%) to facilitate surface water drainage and help remove deicing materials. While not essential, reduction of water entering jointing sand can be further enhanced with joint sand stabilization materials and/or sealers.

Deicer

Effective* Temperature ºF / ºC1

Potential Freeze Thaw Degradation of Concrete

Additional Potential of Chemical Degradation of Concrete

Comments

NaCl Sodium Chloride

15 / -9

Least Among Deicing Salts

Minimal

Least damaging deicer; use whenever possible.

CaCl2 Calcium Chloride

-2 / -19

Minimal to Moderate

Moderate

Use judicially if a more effective, quicker acting deicer is needed.

CMA Calcium Magnesium Acetate

19 / -7

Moderate

Moderate to Significant

Not recommended. Potential for damage increases with the amount of magnesium in the formulation.

MgCl2 Magnesium Chloride

-8 / -22

Moderate to Significant

Significant

Not recommended. Highest potential for damage.

*Effective temperature is lowest practical temperature of the deicer defined as the lowest temperature at which the relative melting potential (MP) is 0.7 as calculated in reference 1 below.

1 Information adapted from National Cooperative Highway Research Program Report 577 “Guidelines for the Selection of Snow and Ice Control Materials to Mitigate Environmental Impacts” ©2007 Transportation Research Board.

The following chart compares common deicing chemicals with respect to their effective temperature, plus their impact on the potential freeze-thaw degradation and on chemical degradation of the concrete

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yy Do not use deicing chemicals in place of snow removal, but reserve them for melting ice formed by freezing precipitation or freezing snow melt.

yy Once loosened, snow, ice, and excess deicing salts should be promptly removed by plow or shovel to avoid an increasing concentration of deicing chemical(s).

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THE MAIN EVENTS

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WINTER 2018

the MAIN events EVENT LOCATION JAN

FEB

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MAR

SEPT OCT MAR

22-23

Concrete Paver Installer Course – County Materials Corporation

Oconomowoc, WI

23

PICP Specialist Course – Alliance for the Chesapeake Bay

Washington, DC

23-24

Concrete Paver Installer Course at 2018 World of Concrete

Las Vegas, NV

24

PICP Specialist Course – Greendell Landscape Solutions

Noblesville, IN

24

PICP Specialist Course – County Materials Corporation

Oconomowoc, WI

24

PICP Specialist Course – Nicolock

Manassas, VA

24-25

Concrete Paver Installer Course – Zimmerman Mulch Products, LLC

Lebanon, PA

24-25

Concrete Paver Installer Course – Belgard

Southern Pines, NC

30-31

Concrete Paver Installer Course – Lowcountry Paver

Hardeeville, SC

31- FEB 1

Concrete Paver Installer Course (Spanish) – Nicolock and Sisler Stone

Falls Church, VA

1

PICP Specialist Course – Lowcountry Paver

Hardeeville, SC

1

PICP Specialist Course – Master Builders Association

Bellevue, WA

1-2

Concrete Paver Installer Course – Master Builders Association

Bellevue, WA

5-6

Concrete Paver Installer Course – SiteOne Landscape Supply

Wichita, KS

6-7

Concrete Paver Installer Course – Oberfields

Columbus, OH

6-7

Concrete Paver Installer Course – Belgard

Salt Lake City, UT

9-10

2018 ICON EXPO

Indianapolis, IN

9-13

2018 ICPI Annual Meeting

Indianapolis, IN

13-14

Concrete Paver Installer Course – Dunning Stone and Supply Co.

Farmington, CT

13-14

Concrete Paver Installer Course – MidAmerica Green Industry Council (MAGIC)

Kansas City, MO

14-15

Concrete Paver Installer Course – Watkins Concrete Block

Omaha, NE

21-22

Concrete Paver Installer Course – Nicolock

Lindenhurst, NY

23

PICP Specialist Course – Nicolock

Lindenhurst, NY

27

PICP Specialist Course – Newline Hardscapes

Falls Church, VA

27-28

Concrete Paver Installer Course – Belgard

Minnetonka, MN

6-7

Concrete Paver Installer Course – Belgard

Clackamas, OR

7-8

Concrete Paver Installer Course – Nicolock

Albany, NY

12-13

Concrete Paver Installer Course – New England Concrete Manufacturers Association

Providence, RI

13

PICP Special Course – New England Concrete Manufacturers Association

Providence, RI

14-15

2018 Northeast Hardscape Expo

Providence, RI

28-29

ICPI Commercial Sales Course

Baltimore, MD

10-13

2018 ICPI Summer Meeting

Vancouver, BC

16-19

2018 International Conference on Concrete Block Pavement

Seoul, South Korea

BP Pro

17-19

2018 Hardscape North America Trade Show

Louisville, KY

Columbia Machine, Inc.

3-6

ICPI 25th Annual Meeting (2019)

Charleston, SC

ICPI WEBINAR SEMINARS DATE

WEBINAR TOPIC/SPEAKER

TIME

January 22

Win the Job and Increase Profits: Using ICPI Certification to Differentiate Yourself from the Competition

1 pm EST

(Members Only) – Carl Peterson, Nicolock February 6

Effective Use of Geosynthetic Materials in Hardscape Construction for Long-Term Performance – Robert

1 pm EST

Bowers, P. Eng., ICPI Director of Engineering February 22

Modern Day Marketing of Contractors: Using Social Media and Tools like Drones, YouTube and Apps – Tom

1 pm EST

Gardocki, Interstate Landscape Co., Inc. March 13

How to Present a Lunch and Learn (Members Only) – Mark Dooley, Basalite and Dan Moreland, Anchor, an

1 pm EST

Oldcastle Company April 17

7 Key Principles (Everyone Should Know) for Sales Success (Members Only) – Randy Anderson, E3

1 pm EST

Professional Trainers May 8

ICPI Foundation Projects Update (Members Only) – David Smith, ICPI Technical Director and Robert Bowers,

1 pm EST

P. Eng., ICPI Director of Engineering

ADVERTISERS IN THIS ISSUE

Alabama Pallets Alliance Design Products, Inc.

14 4

Inside Front Cover, 11 22

Kobra Molds, LLC Pave Tech

18 9,12,20

Slab Innovation, Inc.

19

Solomon Colors, Inc.

16

Pavers by Ideal

14

Techniseal, Inc. Outside Back Cover

SEK, Inc.

22

Topwerk American, LTD

10

(2019)

23

InterlockDesign.org

24