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Core Research

Established in 2000, the ICPI Foundation for Education & Research provides funding to address key research questions enabling manufacturers, designers and contractors to make, design, build and maintain better segmental concrete pavements. The updates to follow demonstrate a wide range of projects and studies the Foundation supports.

Landscape Architecture Foundation Performance Series Case Studies

The LA Foundation has assembled a tremendous collection of case studies documenting economic, environmental and social performance of specific projects and landscape systems. This information is important to an increasing number of practicing landscape architects who use performance metrics on various landscape systems for clients. One of those systems evaluated in various high-profile landscape architecture projects is segmental concrete pavements. An ICPI-curated collection of concrete paver projects published by the LA Foundation can be found at www.landscapeperformance.org/collections/segmental-pavement. Check this site in the coming months for a learning module on performance of segmental concrete paving. This presentation reviews tools to measure economic, environmental and societal performance benefits of segmental concrete paving.

Full-scale Load Testing of Paving Slabs and Planks

Modeled truckloads on slabs and planks will be validated with full-scale load testing.

An increasing number of companies are manufacturing, designing and installing paving slabs and planks. While these products can take a modest amount of vehicular traffic, a core question for the industry and designers is how much? To help answer this question, the ICPI Foundation funded finite-element computer modeling in 2015 that simulated truck tire loads on a range of paving slabs and planks on various bases and subgrade strengths. This resulted in draft structural design tables and procedures now under review by the ICPI Technical Committee for use by the industry and designers. To support this review, the Foundation funded validation of selected slab and plank shapes, base materials and thicknesses. Construction of a test area occurred at the end of June that will receive a significant number of heavy truckloads. With a start date later this summer, this full-scale load testing will likely take two years.

PICP Life Cycle Cost Analyses (LCCA), Tools and Training

This project includes developing an LCCA Excel tool that compares costs of permeable interlocking concrete pavement (PICP) to interlocking concrete pavement (ICP), as well as to conventional asphalt and concrete pavements. The tool is accompanied by a report that provides rationale on accounting for costs and benefits not directly related to PICP. Among several benefits, these can include land not used for detention ponds and reduced expenses to process stormwater and sanitary sewage from older combined sewer systems. When offsite savings are counted over decades, PICP can be less expensive than conventional pavements. Managed by Applied Research Associates, Inc., the project also includes a survey of selected PICP projects, conducting LCCAs and reporting on influencing costs and monetized benefits. Applied Research Associates will also conduct ICPI training sessions in the use of the LCCA tool.

Winter Operational and Maintenance Best Management Practices (BMPs) for Permeable Interlocking Concrete Pavers

The ICPI Foundation is leveraging about half a million dollars invested in PICP research conducted over the past few years by the Wisconsin DNR.

Construction of PICP test areas is anticipated in August 2017 at the Toronto and Region Conservation Authority in Vaughan, Ontario, Canada. Construction of the test area will be by ICPI member Ross Yantzi’s Pavestone Plus. This project evaluates the effectiveness of different cleaning equipment and winter deicer use compared to conventional pavement. Matching contributions from the ICPI Foundation and members will be from Canada’s Natural Sciences and Engineering Research Council. Oaks Concrete Products is donating permeable pavers and Lafarge is donating ready-mix concrete and aggregates for the PICP. The project will help address the primary PICP question: maintenance practices and cleaning equipment effectiveness. Results will amend ICPI Tech Spec 23 on PICP maintenance available on www.icpi.org.

Sidewalk Surface Smoothness Evaluation

Pathvu, Inc. (www.pathvu.com) will measure and determine the roughness index for 15 ICP and 15 PICP sites each in three cities. Sites have been identified in Pittsburgh, Philadelphia and Washington, D.C. Roughness data will be compared to roughness criteria from the U.S. Access Board originally developed by the University of Pittsburgh. Pathway roughness measurements are taken in anticipation of advisory material on wheelchair-pavement interaction being published by the U.S. Access Board in the next few years. The data should better position the industry by using the ASTM E3028 test method which will likely be referenced by the U.S. Access Board.

Wisconsin Department of Natural Resources

This grant supports two years of laboratory water quality analyses of outflows from a full-scale PICP no-infiltration design that has been previously monitored for several years, supported by ICPI members and Foundation contributors. The research fills the need for pollutant-reduction data on no-infiltration PICP designs. Located in a parking lot in Madison, WI, favorable pollutant reductions can qualify for credits mandated by the DNR. The industry is seeing wider use of no-infiltration PICP directly next to building foundations, over extremely weak subgrades and over high bedrock.

Road Map for Permeable Pavements

The ICPI Foundation, the National Ready Mixed Concrete Association and the National Asphalt Pavement Association collectively funded an invitation-only national conference November 14-15, 2017, organized by and located at the University of California at Davis. The deliverables will provide ways to overcome institutional barriers to wider acceptance of permeable pavements by stormwater agencies, municipal and state road departments and civil engineers.

Howard Road near Modesto, CA, will be systematically monitored for three years to determine how well it survives continuous truck traffic.

Interlocking Concrete Pavement Road Monitoring

This magzine’s Winter 2016 cover story reviewed mile-long Howard Road in Westley, CA. The unique aspect of this road is the heavy truck traffic. The ICPI Foundation funded three years of condition surveys per ASTM E2840, plus falling weight deflectometer testing to estimate its structural capacity and remaining life. The road’s owner, the Stanislaus County Public Works Department, will share the cost of the monitoring study to be conducted by Applied Research Associates, Inc. The outcome of this study will likely influence the use of ICP on other roads.

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Community Catalyst

Located a short boat ride from Peanut Island and the Palm Beach Inlet, the Riviera Beach Marina features 140,000 sf of interlocking concrete pavers, of which 105,000 sf are permeable. Winner of a 2016 Hardscape North America Honorable Mention Award, the $35 million Riviera Beach Marina redevelopment, completed in March 2016, concluded phase one of a multiphase revitalization project planned for the entire 26-acre Riviera Beach Marina District.

To attract the interest of private developers necessary for future phases of the revitalization master plan, the City of Riviera Beach and the Riviera Beach Community Redevelopment Agency (RBCRA) set their sights on the marina and the surrounding public land as the best site for phase one. The project was jointly funded with the City contributing one-third of the cost and RBCRA the rest.

“It was very important to the city council that this infrastructure investment project accomplish two things,” said Scott Evans, interim executive director of RBCRA. “Create a great waterfront public space for residents and visitors and attract future development from the private market.”


Photos courtesy of Coastal, an Oldcastle Company and Precise Paving, Inc.


PERMIT PROCUREMENT

Given the scope and scale of the Riviera Beach Marina District revitalization master plan, RBCRA had to apply for an Environmental Resource Permit (ERP) from the South Florida Water Management District. An ERP is required for development or construction activities to prevent flooding, protect the water quality of lakes and streams from stormwater pollution, and protect wetlands and other surface waters.

“Permeable [interlocking concrete] pavers were presented to us by the engineering design team as an environmentally positive method of construction,” said Mr. Evans. In addition to satisfying the ERP requirements for onsite stormwater capture and treatment, the permeable pavement was chosen for aesthetics, sustainability and lower cost.

“Using permeable concrete pavers in the parking lots and on the upper promenade was more cost effective than a traditional underground drainage system,” said Jill Lanigan, Director of Business Development at Song + Associates, the architectural design firm for the Riviera Beach Marina project.

“The soils in coastal municipalities are well suited for the use of permeable pavers,” said Patrick Figurella, P.E., Director of Engineering at Calvin, Giordano, and Associates. Based on the success his firm has had with other permeable paver projects in the region, Mr. Figurella said, “We are always looking for opportunities to use permeable pavers in other locations because of the advantages permeable systems afford with regard to reduction of runoff and providing water storage.”

The permeable paver system with standard exfiltration trenches allows the less than 14-acre marina site to provide 75% of the drainage for the entire Marina District, Mr. Figurella said. The Riviera Beach Marina site not only met the ERP’s present requirements, it established a sustainable site for future vertical development and related impervious surfaces.

In the interim, while RBCRA negotiates with a private developer for phase two construction, the public space created during phase one will be utilized for community programs to attract more visitors. Outdoor music festivals, a weekly green market and movies in the park are just a few of the events planned for the new space to serve the community and entice private developers to join the revitalization effort.

DESIGN AND CONSTRUCTION

Initial ocean-themed design concepts for the paver fields considered curvilinear patterns to emulate waves, but through several variations evolved toward an orthogonal design, explained Ms. Lanigan. The waves became geometric, with the varying widths of the fields and the varying lengths of the bands representing a stylized interpretation of waves rolling in and out from the shore. Ultimately, the final design responded better to the marina layout with an added benefit of streamlining the installation process, she said.

To reduce the heat island, the design team chose for the permeable paver fields lighter, natural colors, SRI>29 labelled Amaretto and Napoli. For the bands, they selected darker, contrasting slate to complement the other colors. With the large area of permeable pavers in the upper promenade and parking lots, the 25,000 sf lower promenade along the waterfront instead used standard 2 3/8 in. thick concrete pavers.

Except for 30,000 sf of roadway that was machine-installed, the majority of the pavers were hand installed, according to Rob Goossens, Vice President of Precise Paving. The standard paver section along the dock was installed first and was completed by December 2015. Construction delays compressed the paving schedule for the remaining portion of the project, but Precise Paving successfully installed 105,000 sf of permeable pavers in three months to meet the deadline.

“It was hectic, we had to double up our crews on this job,” Mr. Goossens said. “One good thing with permeable pavers, when you screed the No. 89 bedding aggregate, you don’t have to worry as much about rain causing bedding displacement as you do with regular sand-set pavers.” This allowed his first crew to be more aggressive, screeding up to 10,000 sf sections at a time while the second crew followed behind laying the pavers.


Video courtesy of Precise Paving, Inc.


DEADLINES AND DETAILS

The unique design of the upper promenade with variable field widths and darker bands between prevented machine installation and were installed by hand. For the permeable paver cross section, 14 in. of ASTM No. 4 stone was placed first, then 5 in. of No. 57 stone, followed by 2 in. of No. 89 stone for a total water storage depth of 19 in. beneath the 4 x 8 x 3 1/8 in. thick permeable pavers.

For the roadway, the only section of the project that could be machine installed, the paver manufacturer worked with Precise Paving to optimize mold configuration and determine the best way to palletize the product in order to achieve maximum speed and efficiency.

“Most of it went according to plan,” Mr. Goossens said. “The speed tables in the roadway were probably the biggest challenge.” The original design planned for the speed tables to be poured concrete, but Mr. Goossens convinced the design team to use permeable pavers instead, which saved time and cost by eliminating the concrete for these four 20-foot wide sections. This modification also maintained the continuity of the paver roadway from one end to the other. “It saved the project time, money, and at the end of the day, I think it’s a better product,” Mr. Goossens said.

“It’s not too difficult of a task, but you do have to account for the slopes and the elevations you need to hit,” Mr. Goossens said. “That starts of course with the base and also our screeding.” The elevation change of 6 in. brought the speed tables up flush with the curbs and pedestrian walkways from the parking lot to the event center so they could serve the dual purpose of being crosswalks as well. White pavers were used to demarcate the crosswalks and also for arrows on either side of the tables to alert drivers. Red stripes of ADA-compliant pavers were placed on both sides of each crosswalk.

“This was the first time we used permeable pavers in this manner and they worked beautifully,” said Mr. Figurella.

THE SUPERIOR OPTION

Permeable interlocking concrete pavements (PICP) have become more efficient from a structural and water management perspective. The biggest change agent advancing PICP toward greater use is their cost-effectiveness, especially for redevelopment projects such as the Riviera Beach Marina where every parcel is premium property. Sacrificing land to a detention pond or paying the high cost of installing underground storage vaults can’t compete with the volume and pollutant reduction efficiency, minimal maintenance, longevity, and aesthetic quality of PICP.

Another factor advancing growth is studies by various universities confirming PICP performance. Last but not least, mandates from the U.S. Environmental Protection Agency for onsite stormwater detention, treatment and infiltration make PICP a superior management option. From a life-cycle cost standpoint, the paver surface will last 40 to 50 years without replacement. In contrast, an asphalt surface cracks, requiring routine and unsightly patching, and eventual milling and repaving two or three times over 50 years.

REACTIONS AND RESULTS

Over a year has passed since phase one completion of the Riviera Beach Marina. “We’ve seen a large boost in the number of visitors, thousands of people,” Mr. Evans said. “And our waterfront businesses have had increased traffic as well.” Feedback from the community has been positive. “People really love the public spaces we’ve created.”

Despite initial trepidation by some, Mr. Evans said, concerns have been laid to rest on using permeable pavers for such a large area. “Performance has been positive and the system is working as designed. We’re extremely happy with it.”

Regarding maintenance, RBCRA has conducted occasional spot cleaning and sweeping, but hasn’t had any major issues, Mr. Evans said. “We’ve installed a few monument signs recently and there was concern that the process would be more challenging, but it went smoothly. We were able to take up the pavers, make some changes for the signs, and then put them back successfully.”

“It really turned out to be a great project,” Mr. Goossens said. “We had a demonstration there in June, brought in a fire truck and doused an area with 200 gallons per minute for 10 minutes. Walking over the area after they shut off the hose, there was no standing water and you could actually hear all the water filtering down through the aggregates. It’s impressive.”

“This marks the first time we’ve used permeable pavers for a city street,” Mr. Figurella said. “Riviera Beach is leading other municipalities to consider the utilization of permeable pavers for public roadways or alleyways.”

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Cooler than the Conventional

An estimated 3 to 4 million square feet of concrete grid paving units pave intermittently used parking lots, fire lanes, ditches, slopes, and boat ramps each year in the U.S. and Canada.

ICPI publishes a Tech Spec technical bulletin (No. 8, see www.icpi.org) on this product typically used to help reduce stormwater runoff while accommodating vehicles by reinforcing grass with concrete. Unlike plastic grids, concrete grids have an ASTM product standard, C1319-17 Standard Specification for Concrete Grid Paving Units. This standard defines a concrete grid and provides requirements for compressive strength, absorption and freeze-thaw durability.

Grids have maximum dimensions of 24 x 24 in. and a minimum thickness of 3 1/8 in. The percent solid recently has been updated in C1319 to range from 45% to 75%. This enables grids to conform to the minimum 50% unbound (non-solid) requirement in LEED version 4, Sustainable Sites. An Urban Heat Island Reduction credit is earned when an open-grid pavement system is used. This credit is included in LEED because grids can reduce microclimate temperatures by as much as 4° C compared to conventional pavements.

Grid pavements allow a cooler surface by combining the durability of concrete with grass.

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HNA 2017 Highlights

Contractor briefing session

Last October, contractors and dealers from across the U.S. and Canada attended HNA. This year, HNA will take place on Oct. 18–20, at the Kentucky Exposition Center in Louisville. Registration for HNA 2017 is already surging ahead of last year’s record crowd.

CONTRACTOR BRIEFING SESSIONS

Seven FREE Contractor Briefing Sessions will take place in the Trade Show Floor Classroom, including:

  • Five Ways to Future-Proof Your Hardscape Business
  • The Biz-Builder Blueprint for Contractors
  • OSHA’s New Crystalline Silica Regulation
  • ICPI Installer Certification, Advanced Designations, and Their Value
  • Opportunities for Permeable Pavers in Residential and Commercial Marketing

HARDSCAPE DEMONSTRATIONS IN THE HNA OUTDOOR ARENA

Nationally renowned instructor Bill Gardocki, owner of Interstate Landscape Co., Inc., will lead a live continuous two-day build that will highlight interlocking concrete pavement, SRW and permeable interlocking concrete installation best practices. The build will also include one-hour sessions on tools of the trade, hardscape lighting and outdoor kitchens.

EXHIBIT FLOOR

850 companies will exhibit indoors and out, including more than 170 hardscape exhibitors. The trade show floor will feature top paver manufacturers and leading suppliers of materials, equipment and services to the concrete paver industry. You will also gain access to the largest hands-on outdoor exhibit area through both HNA and the GIE+EXPO (Green Industry Equipment EXPO), included in your trade show admission.

HNA CONFERENCE SESSIONS

Conference sessions will provide attendees with a broad range of important education for their businesses, including:

  • Estimate Accurate Job Costs to Always Make a Profit
  • Emerging Online Lead Generation Trends for Residential Hardscape Businesses
  • Strategies to Win More Profitable Contracts and Overcome The Low Bid Process
  • Setting Up Your Hardscape Crews with the Right Technology to Increase Profits and Efficiency

DEALER ACTIVITIES

HNA Awards

The HNA Dealer Program, in its seventh year, is designed to help dealers accomplish two objectives: overcome the challenges in their market in order to grow their companies and identify what works and what doesn’t in a company’s unique market area—urban and rural. The program will feature Alan Beaulieu, one of the nation’s most informed economists examining the prevailing challenges confronting business. In addition, Dealer Day activities give dealers a one-of-a-kind networking opportunity and a first look at the trade show floor before it opens to everyone.

INSTALLER COURSES FOR CERTIFICATION AND DESIGNATION

Pre-show courses at the downtown Hyatt Regency Hotel in Louisville give HNA participants an opportunity to earn credentials to help differentiate themselves from their competitors. ICPI courses include the Concrete Paver Installer, Advanced Residential Paver Technician, Commercial Paver Technician and Permeable Interlocking Concrete Pavement Specialist. Three additional NCMA segmental retaining wall system installer courses are also offered.

HNA INSTALLER CHAMPIONSHIP

Installer championship

Twenty-four of the most talented installer teams will compete for the coveted championship. The competition will test and recognize the skill, dedication and passion of hardscape contractors from Canada, the U.S. and Mexico. The Grand Prize package is valued at over $10,000!

HNA AWARDS

Award-winning projects from throughout the U.S. and Canada will be on display and honored. The HNA Awards recognize outstanding hardscape projects by contractors building residential and commercial walkways, patios, driveways, commercial plazas, parking lots, streets and more. Project categories include concrete paver, clay paver, segmental retaining walls, combination of hardscape products and, brand new for 2017, the porcelain paver category.

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Success from Failures

Most progress in pavement design comes from failure. For accurate and predictable pavement design, pavements must be damaged and eventually rendered useless by repeated truck wheel loads to understand where that point lies. In fact, modern highway pavement design was originally based on load testing from trucks conducted by the American Association of State Highway Officials in the 1950s. The notion of an 18,000 lb (80 kN) equivalent single axle load as the basis for loading in pavement design emerged from these tests. Among many things, this testing discovered Miner’s Law, i.e., doubling wheel loads increases pavement damage to the fourth power. This exponential relationship between wheel loads and pavement damage is why truck owners pay high road use taxes—trucks do the most damage.

Since the 1950s, machines were invented that quickly apply truck wheel loads (or greater) without drivers. These large machines go by different names—accelerated load facility, heavy vehicle simulator, etc.—but all render 20 years of wheel loads in a matter of months. Often housed at universities or state departments of transportation, these machines have tested thousands of asphalt and concrete pavements. This research via load testing is the norm for conventional pavements. Testing, most of it funded by tax dollars, led to longer-lasting designs. Such research superbly uses tax resources because of the huge ROI: accelerated load testing costs millions; road networks cost billions.

For permeable interlocking concrete pavements (PICP), accelerated load testing validated ICPI design tables for subbase thicknesses published in 2011. Load testing was conducted in 2014 by the University of California Pavement Research Center in Davis (see picture). The design tables developed by the Center, with help from mechanistic modeling, provide for slightly thinner bases in some situations than those in the ICPI design tables. Accelerated load testing doesn’t come cheap: the testing at Davis cost about $400,000, co-funded by the ICPI Foundation, California paver manufacturers and the Cement Association of California and Nevada.

Institutionalization from this industry investment include Caltrans PICP design tables in their pervious pavement literature, and in the ASCE national PICP standard to be released later this year. While the testing certainly confirmed that heavy trucks can repeatedly traverse PICP, additional accelerated load testing is needed using stronger subbases, thereby expanding PICP use to busy urban streets (while storing and infiltrating stormwater).

While there has been accelerated load testing (mostly in the 1980s) of interlocking concrete pavements (ICP) here and overseas, they have taken mostly an experiential, empirical path toward validation of their structural capacity. Validation has come from millions of square feet used in airfield and port applications withstanding wheel loads as much as 10 times greater than trucks. For road applications, some of the busiest downtowns have seen repeated bus and truck traffic. Downtown North Bay, Ontario, and San Antonio, Texas, are examples. Built in 1983, North Bay is likely approaching 4 million standard axle loads and San Antonio around 3 million, built in 1986.

While experience is informative, the interlocking concrete pavement industry might consider systematic full-scale load testing to undergird current structural design methods. A multimillion dollar investment will put ICP in the same testing league that refined conventional asphalt and concrete pavements over the past several decades. ICP accelerated load testing will instill immeasurable confidence in designers, boost the industry’s technical credibility, and help lead to institutionalization by government road agencies and civil engineers. Like the PICP load testing, funds for ICP load testing will likely come from industry and not tax dollars, since there aren’t yet hundreds of miles of ICP roadways owned by municipal or state transportation agencies.

Success in expanding ICP road applications will come from taking ICP to the point of failure via accelerated load testing. Testing to failure is the sine qua non of pavement research and design. This can add further fuel to justifying lower life-cycle costs from investing in ICP.

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Enforcement Postponed

The U.S. Department of Labor’s Occupation Safety and Health Administration (OSHA) recently postponed enforcement of new, stricter rules regarding worker exposure to silica dust on job sites. Originally scheduled to begin June 23, 2017, enforcement of the new rules will now begin Sept. 23, 2017. Current rules will be changed this fall to reflect substantial reductions in exposure to airborne dust on job sites. A key rule change is a reduction in the 8-hour exposure limit from 100 to 50 micrograms per cubic meter of air averaged over an eight-hour day. Determining exposure to these small concentrations is typically done by workers wearing lightweight, portable air monitoring equipment that captures dust while on the job site.

Current rules require a written exposure control plan with specific tasks to protect workers. This is implemented by a designated, competent person who articulates housekeeping practices that reduce exposure with feasible alternatives. Employers must offer medical exams including chest x-rays and lung function tests to employees. These must be done every three years for workers who wear a respirator for 30 or more days annually. There must be ongoing worker training in saw cutting and other operations that result in silica exposure with instruction in ways to limit exposure. Finally, employers must keep records of workers’ silica exposure and medical exams.

OSHA’s new silica exposure rules are delayed to give more time for construction companies to comply. Silica dust on job sites requires control measures via wet (or dry) saw cutting with a vacuum system and worker protection equipment. The pavers shown here are among 5 million square feet in container yards at the Port of Oakland, CA.

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Holistic Design

As the car pulls into the driveway at the end of a long workday, worries about schedules, traffic, politics, rising prices and other everyday concerns suddenly begin melting away. Stepping out of the car, the driver immediately is embraced by a stylish, welcoming environment promising joy, relaxation, family warmth and good company.

A rapidly growing number of stressed-out homeowners nationwide experience this transformation daily. Thanks to innovative contractors building imaginative designs with interlocking concrete pavers, dull driveways are transformed and cliché backyard patios become relaxing, resort-caliber environments.

“For both new homes and remodels, people are looking to create beautiful extensions of their homes,” said Joe Raboine, Director of Research and Development at Atlanta-based Belgard Design Studio & Elements. “They’re furnishing and putting in fireplaces, outdoor kitchens, lighting and music. They want to create a cohesive and beautiful space with a uniform look throughout their whole property.”

From Driveway to Patio

For people looking to give their property visually and functionally integrated styling and luxurious amenities of a high-end resort, pavers are the best way to go, said David Park, CEO of Landmark Pavers in Temecula, CA. “When they hear about the benefits, they’ll often contemplate, for the sake of uniformity more than anything else, doing all of their hardscapes at once, including their driveway, walkway and patio, using interlocking pavers for the whole project, front and back.”

Mr. Raboine believes that more homeowners are transforming their exterior home space into a welcoming, engaging environment as a dedicated effort to re-connect with family and friends. “It may sound a little bit sappy, but I think that as we become more connected and electronic, we’re actually becoming more disconnected than ever before in face-to-face interactions,” he said. “These types of spaces help bring people together.”



It’s not only homeowners in warm climates such as Southern California, Arizona and Florida that want to upgrade their homes’ surroundings. “In Colorado, we have four seasons,” observed Tim Lindgren, president of Lindgren Landscape & Irrigation in Fort Collins, CO. “Our winter season is not always warm enough for us to get outside, but the shoulder seasons can be extended when we build these areas and put in fireplaces and fire pits, outdoor heating elements, infrared heaters and fans.”

Mr. Raboine agreed, noting that there’s also a strong demand for visually and functionally integrated home environments in many northern areas. “In the Midwest, Northeast and Eastern Canada, their seasons are so much shorter that people want to spend every possible minute outside when it’s nice.”

Rising home prices also play an important role in motivating people to upgrade their current properties, rather than simply picking up and moving to a larger property. “In some markets, real estate sells at a premium, especially in many major cities,” Mr. Raboine says. “Land is becoming increasingly expensive and harder to find. Our market here in San Diego has really changed within the last 10 years, from pavers as a replacement of concrete, to pavers as part-and-parcel of a large, all encompassing project,” Mr. Park said. “The very successful paver installers in our area have been able to change with the market and offer a full landscape design option for the customer.”

Environmental conditions sometimes make pavers the only logical choice for a major exterior space project. “In Northern Colorado, we have very expansive soils and a freeze/thaw process unlike anywhere else that I’m aware of,” Mr. Lindgren said. In January, it’s not uncommon for daily temperatures to reach 70 degrees or higher. A few days later, lows may bottom out at sub-zero levels. “So the ground freezes, and then it thaws, then it freezes, and thaws, and it expands and it contracts,” Mr. Lindgren said. “That’s devastating on concrete, especially decorative concrete or stamped concrete—the finish doesn’t hold up.”

Designing and Planning

Not surprisingly, major, complex projects, such as a complete exterior space remodeling, require much thought and planning. “We have five designers in house, and we try to find the best designer for the scope of work that we understand the client wants to do,” Mr. Lindgren said. “Some designers have strength in hardscape, some have strength in plant material, some have strength in retrofits and others have strengths in new construction.”

The next step is an onsite consultation. “We sit down with the homeowners and listen to their wish list for the property and their goals,” Mr. Lindgren said. “We walk the site with them, give them a little insight on what we think the site is capable of and by the end of the meeting we have a proposal ready for them.”

Mr. Park said convincing homeowners to use pavers isn’t all that difficult. “People generally love the look of pavers, but when they find out the benefits—the structural integrity and the other benefits of pavers—they really are very happy with that.”

Addressing Challenges

The scope and scale of an integrated home environment project can be intimidating, even for an experienced contractor. Suddenly, the contractor finds itself responsible for an array of tasks extending far beyond paver work, including landscaping, electrical and plumbing installation and, in some cases, even long-term maintenance services. And the client always wants the job completed yesterday—or sooner.

Mr. Lindgren said contractors should be realistic about their capabilities and to outsource work they don’t feel comfortable tackling. “We, as a general contractor, will hire the electrician, framer, plumber and mason—whatever trade we need that we don’t do in house,” he said. “We handle the pavers, we do the landscaping and many other things, but we still have to coordinate with a handful of subcontractors to complete most projects.”

Finishing a project on time and on budget requires a great deal of planning and coordination with subcontractors. “The biggest challenge is trying to make sure that everything is thoroughly thought out from beginning to end,” Mr. Raboine said. “When you start talking about things like adding electrical, plumbing, gas lines, music and lighting, all of those things can take several to perhaps a half-dozen subcontractors to create.” Mr. Raboine noted that it’s important to plan tasks with as much detail as possible and to make sure that subcontractors are meeting all of their work and schedule obligations, including following local codes.

“Lighting and all other fixtures must be decided and planned before a shovel ever touches the ground,” Mr. Lindgren said. “The gas line, its size, who’s doing the installation, electrical switch and outlet locations, model numbers and so on all need to be spelled out before starting work.”

Attracted to the Flame

An increasingly popular patio centerpiece is a fireplace or fire pit, available in either kit form or custom built. “Manufacturers offer really neat kits that can be put together with predesigned segmental units,” Mr. Park said. “They’re much more cost-effective to build.”

Palletized kits can be assembled on-site with very little planning or work, Mr. Lindgren said. “I think they’re great, especially when you have an inexperienced contractor that doesn’t have the industry knowledge necessary to do custom work.” Mr. Lindgren noted that to the untrained eye, a kit is virtually indistinguishable from a conventional installation.

Kits also save a great deal of manpower. “Fire pits go together without any mortar—they’re all free stacking,” Mr. Lindgren explained. “You don’t have to build a foundation, do any mortaring or veneering on the stone or put a masonry cap on top—it’s basically a puzzle that you put together.”

However, fire pit and fireplace kits have their limits. “They have their place, and they work great, but if you have a custom site where the homeowner wants the installation to match the house’s stone or capstones, and everything needs to tie in, then kits don’t work,” Mr. Lindgren said. Fireplaces require concrete foundations due to their weight and these are generally hidden from view by the fireplace.

Another downside to kits is the relatively limited number of design options. “You kind of get what you get with a kit,” Mr. Park said. “Typically, if someone doesn’t like the look of a unit that’s prefabricated, you don’t have any alternative as a contractor other than to build something with a custom design, which, of course, costs more.”

Mr. Lindgren also recommended against mixing fireplace/fire pit kits and paver brands. “It’s nice to stick with a single manufacturer when picking products so that the colors and styles match,” he said. He suggested using the same manufacturer for pavers, fireplaces/fire pit kits, vertical elements, retaining walls, bench seating and most other key project elements.

Kit and custom-built fireplaces/fire pits generally require the same amount of maintenance. “If they’re designed to use gas, there’s very little maintenance,” Mr. Lindgren said. If they’re wood burning, there can be a lot or work.” Park says his San Diego customers rarely ask for wood-burning installations. “They’re worried about casting off embers and starting a fire in an arid climate,” he said.

Moving Forward

The growing demand for visually and functionally integrated home environments is taking paver installers into areas where many have little or no prior experience. “The trend for the traditional paver installer is going to be one of offering more all-inclusive landscape designs,” Mr. Park said. “Not only installing pavers, but also doing landscaping, synthetic turf, patio covers and offering a wide variety of other products.”

As contractors cope with new customer demands, they also face the challenge of rising prices. “The cost of materials is going up,” Mr. Lindgren said. “The cost of labor is also going up, and labor in our industry is so hard to find.” Mr. Park, however, is optimistic that most contractors will be able to adjust to the new challenges and to continue operating profitably in the years ahead. “The bottom line is that as long as the job market in a region is strong, and the housing market is strong, the hardscape market will also be strong,” he said.

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Retrospective: Dayton, Ohio

As the birthplace of aviation and key manufacturing industries, Dayton, Ohio (2013 pop. 143,355) is also the birthplace of the first machine-assisted municipal street with interlocking concrete pavement. Built in November 1985, the repaving project likely never generated much cocktail chatter among Dayton’s historical society, but it was part of the city’s multimillion-dollar investment to help revitalize several historic districts. The city supported millions in private investment by urban pioneers during the 1970s and 1980s. Such funding renewed vintage late-1800s homes and brought physical and social stability to old neighborhoods.

After 20 years, this magazine issued an interim report in 2005 on the 11,000 sf Tecumseh Street in Dayton’s Oregon Historic District. When constructed in 1985, it was considered a demonstration project by the City, an expression of support for a rundown neighborhood being revitalized with a consistent infusion of restorative sweat equity by residents. While a lightly trafficked pavement in a residential neighborhood, the editor again visited the 31-year-old street last year to inspect the project. Since the editor was responsible for building the project for the City in 1985, the visit was more like listening to an old friend.

From a functional perspective, there were only a few cracked interlocking concrete pavers. Most pavement cracking occurred within the deteriorated concrete collars set around manholes and shutoff valves. By comparison, the pavers will certainly outlast the cast-in-place collars.

Tecumseh_StreetThe decades-old road base is a 7-inch thick mix of cement and aggregates, a hardened slurry that once supported a macadam surface, a thin layer of asphalt mixed with sand. This base had roughly 20% of it removed and replaced in 1985 due to deteriorated areas. As part of the renovation, the macadam, an early version of today’s asphalt surfacing, and the top of the concrete base were ground out and removed to receive an inch of bedding sand and 3 1/8-inch thick concrete pavers. These were machine-set in a 90-degree herringbone pattern in three days.

The aging base shows in a few areas where the paver surface has settled. Had the surface been asphalt, they would have been potholes. The pavers accommodate such movements while continuing to provide service to passing vehicles.

The pavement structure has at least another decade of remaining life. The pavers will almost certainly outlast the base. The strongest indicator of a need for repairs will happen when the base settles in places that eventually set off neighborhood driver complaints. That is unlikely as vehicle speeds are generally below 20 mph.

From a life-cycle cost analysis (LCCA) perspective, Tecumseh Street asks the question, what’s the long-term expense to Dayton’s taxpayers compared to asphalt or concrete? Would more street pavers ultimately save the City money? Since 1985, asphalt prices have fluctuated while interlocking concrete pavement has not. For residential streets in northern states, resurfacing (shave and pave) can be reasonably set at 17 to 20 years. An LCCA favorable to interlocking concrete pavement would compare costs for periodic asphalt pavement resurfacing. Such resurfacing during higher priced markets could likely register a savings by using concrete pavers.

The larger question asked by the street is institutional in nature. Just about every city has organized design, specifications, construction and maintenance equipment, and labor around asphalt and, to a lesser degree, concrete pavements. From a certain perspective, cities’ street maintenance departments are committed to asphalt because it’s cheap. Rather than a single street in pavers, what if Dayton had an entire neighborhood, district, or city with them? While an investment in a third pavement is an additional expense, would interlocking concrete pavement be less expensive to maintain from a city budget perspective if it was the majority pavement, replacing asphalt?

Cost comparisons could be modeled using pavement management software that most cities use to project maintenance costs. One aspect is for certain, departmental investment in construction and maintenance equipment, as well as labor and materials, would be significantly lower for concrete pavers than that required for asphalt. If deemed a cost savings, a shift by any city street maintenance department to pavers would require phasing out asphalt in low-speed streets. There would likely be a commensurate increase in property values due to enhanced neighborhood character. Whether a historic district or not, such enhancements benefit the City and property owners alike.

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Industry Outlook

Gross sales for segmental concrete pavement contractors in the U.S. and Canada increased by 8.8% in 2016, according to a new report recently released by the Interlocking Concrete Pavement Institute (ICPI). In all, 218 contractors from all-sized companies participated in the 2017 ICPI Contractor Industry Survey conducted during January for ICPI by Industry Insights of Columbus, OH. Three-quarters of the companies responding to the survey pave residential projects and the remainder place commercial pavements, including housing and publicly funded works.

Most of the respondents to the survey were company owners, presidents or executives. Most companies have been in business 10 years or longer and almost half had annual sales of $1 million or greater with 10 or more employees. Most companies provide on-the-job training on installation best practices as well as on worksite safety and equipment maintenance. 69.1% of contractors required crews to review and participate in formal, documented safety programs, an increase of 4.1% from 2015.

Over half of the companies use wet saws for cutting, dust masks and/or respirators to reduce silica inhalation on job sites. Over two-thirds use wet saws for cutting with a vacuum dust collection system. Almost one-fourth use dry saws for cutting with a vacuum system.

The strengthening economy is making reliable labor harder to find, as reported by almost three-quarters of the respondents. The next most challenging aspect of running their businesses is increasing overhead costs. Almost all respondents have at least one ICPI Certified Concrete Paver Installer on their payroll. Average wages/salaries increased by 3.0% in 2016 and are forecasted to increase again in 2017 by 3.2%.

Man cutting pavers at jobsite.

Since new OSHA rules on reduced exposure to silica dust start in June 2017, the ICPI contractor survey specifically addressed how employees avoid dust exposure when cutting pavers at jobsites.

While all companies install interlocking concrete pavements, the largest companies install most of the segmental paving slabs, likely in commercial projects. The average annual total installed area of pavers is 71,000 sf. Larger companies installed as many as 300,000 sf in 2016.

About three-quarters of all projects are sand-set and 12% are permeable interlocking concrete pavements. To support sales, ICPI Tech Specs are the most often used resource, with ICPI guide specifications a close second. ICPI’s detail drawings are the third most used resource.

While about 13% of all jobs in 2016 required an ICPI certified installer, almost half of the respondents agreed or strongly agreed that ICPI certification helps increase business.

Marketing expenses constitute 4% to 5% of revenue and most leads come from referrals, jobsite and vehicle signs, dealers or general contractors.

The report also includes respondent answers about length of construction season, gross sales, salaries and wages, number of employees during the construction season and more. The detailed study provides deeper insight into an industry that installed over half-a-billion square feet of concrete pavers, slabs, and grids in 2016, as well as other paving and wall products. The complete 59-page report is available for purchase for $100 at www.icpi.org/shop. ICPI members can purchase it at the member discounted price of $25. Shipping and handling are extra.

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ICPI Releases Technical Bulletin on PICP Maintenance

Available at icpi.org, this 12-page bulletin with 33 figures walks the reader through a range of maintenance practices mostly to prevent sediment from collecting on the surface, or remove it should it remain.

The bulletin covers practices supporting surface infiltration, such as not using sand in the surface or within the pavement assembly, conducting effective erosion control during and after construction, and maintaining joints filled with aggregate so sediment can be more easily removed from the surface.

The text then moves on to surface infiltration inspection and testing, which includes inspection points before and after a rainstorm, as well as surface infiltration testing per ASTM C1781 Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems. A tool at icpi.org for calculating surface infiltration using this ASTM standard is referenced to facilitate better surface infiltration monitoring.

Tech Spec 23.

Tech Spec 23 published Feb. 2017.

The document explains routine and restorative surface cleaning. Routine means periodic preventive cleaning, i.e., keeping the surface water infiltrating. Restorative cleaning is often required when cleaning is neglected. This often results in water ponding on the surface. Sediment must be drawn out of the joints with the help of equipment to increase surface infiltration.

Advice then moves into preventive maintenance equipment options for maintaining various sized PICP applications. This section provides a range of technologies for cleaning, from a simple broom to sophisticated vacuum truck equipment. For clogged PICP with low overall surface infiltration, restorative infiltration maintenance techniques for small and large clogged surfaces are also covered.

An inspection list is provided for maintaining surface infiltration as well as a checklist for addressing distresses such as settlement or rutting. Guidance on winter maintenance is included as well as directions on how to reinstate PICP over underground utilities. This information supports cities that use PICP in highly urbanized areas.