Canada's “Rock to Road” Magazine

November/December 2007 Issue

• Roadbuilder of the Year
• Canada's first perpetual pavement built to last
• The Red Hill Valley Parkway - A perpetual pavement
• Warm asphalt gains traction
• Screen media provides fine screening solution, boosts productivity
• Hard markers give loaders high marks
• Fuel efficiency pays for loader owner
• Liebherr fuel test parameters

For a copy of the issue that contains these articles with colour photos, click here.

Roadbuilder of the Year

By Andy Bateman, Engineering Editor

Roadbuilder of the Year is a new feature in Aggregates & Roadbuilding to recognise companies that are making a major contribution to the development of Canada’s road network. We are proud to nominate Peter Kiewit Sons Co. as our first Roadbuilder of the Year and this article looks at just some of the nation’s major roadbuilding projects, past, present and future, involving the Kiewit organization.

     Peter Kiewit Sons Co. began as Kiewit Brothers, an Omaha, Nebraska-based masonry contracting partnership formed by Peter and Andrew Kiewit in 1884. The company has since grown into one of the largest employee owned companies in North America with over 1700 US and Canada employee stockholders. In Western Canada, the company is a leading heavy construction contractor and, since the early 1940s, has been building projects from British Columbia to Manitoba and the Northwest Territories. Kiewit’s Eastern Canada District conducts its operations though Construction Kiewit Cie and Peter Kiewit Sons Co., both subsidiaries of the Kiewit Corporation. Kiewit Energy Canada Corp., also a subsidiary of the Kiewit Corporation, is a major industrial contractor based in Calgary, Alberta.

Autoroute 25 extension - Montreal, Quebec
     In Quebec, Kiewit is a key member of Concession A25 S.E.C., the consortium selected by the provincial government to design, build, finance, operate and maintain the Autoroute 25 extension in the Montreal metropolitan area. Project director Jacques Lacombe explains that the completed extension will connect Montreal with Laval and so establish a direct physical link in the eastern sector of Montreal between Laval in the North, Montreal and the South Shore of Montreal. Goals for the extension also include improved public transportation between Montreal and the North Shore and an alternate route for freight transportation. The 7.2-km extension between Henri-Bourassa Boulevard in Montreal and Autoroute 440 in Laval includes a 1.2-km toll bridge across the Rivière des Prairies.
     The design concept proposed by Concession A25 S.E.C. consists of a four-lane highway with a six-lane cable-stayed bridge over the Rivière des Prairies. It will also include a multifunctional path for cyclists and pedestrians, and a reserved public transit lane.
     Concession A25 S.E.C is comprised of MIP Quebec Holdings, L.P. and Concession A25 Funding 2 Ltd; Macquarie Bank Ltd., Construction Kiewit Cie, Ciment St-Laurent Inc., Parsons Overseas Company of Canada Ltd., Genivar Société en Commandite, and Miller Paving Ltd. The partnership agreement entered into between the province and Concession A25 S.E.C. outlines the terms of the 35-year concession for the Autoroute 25 extension. For this project, Kiewit will partner with Parsons to oversee the firms that will design and build the various components required to complete the project. Kiewit’s design and construction activities are ISO 9001-certified and its activities related to the protection of the environment during the construction phase of the project are ISO 14001-certified. Kiewit is among the first construction companies in Quebec to receive an ISO 14001 certification. Construction is scheduled to begin in March 2008 with bridge construction on the Laval side of the Rivière des Prairies and highway construction in Laval. The project is scheduled for completion in July 2011 with final highway construction in Laval and Montreal.

Crowchild Trail Corridor - Calgary, Alberta
     The Crowchild Trail Corridor, Calgary’s first design-build transportation project, was completed in Spring 2007 after Kiewit Management Co., a subsidiary of Kiewit Corporation, was awarded the $59 million widening, interchange, and corridor upgrade contract. The 31.5-km long Crowchild Trail Corridor carries 60,000 vehicles per day and connects downtown with northwestern Calgary. The scope of work included widening a 4.2-km long corridor section from two to three lanes in each direction, constructing three interchanges, upgrading the utility infrastructure, erecting sound and retaining walls, and preparing a 2.9-km section for a future light rail extension. After completing drainage and utility upgrades, work began on three major interchanges, which included a total of seven overpass and underpass structures. Paving operations included over 200 000 tonnes of base and sub-base, more than 8000 m2 of foam insulation, 45 000 tonnes of asphalt, and 12 km of curb and gutter. Crews constructed 1400 m2 of sound attenuation walls and placed more than 1900 m3 of concrete on twenty three separate retaining walls. The completed project has significantly improved traffic flow through the corridor.

Garden River Project - Sault Ste. Marie, Ontario
     In 2000 the Ontario Ministry of Transportation awarded Garden River Constructors, a joint venture between Peter Kiewit Sons Co. and the Garden River First Nations, the contract to build 16 km of new divided highway through the Garden River First Nation just east of Sault Ste. Marie. Project director Gary Karjala explains that the work included the construction of eleven bridges and overpasses the excavation of approximately two million m3 of common excavation, and the processing and placement of approximately one million m3 of granular materials. The work was complicated by the presence of sensitive clays underneath portions of the highway alignment, necessitating the use of preload and lightweight fill to preconsolidate the subsoils and minimize future settlement of the roadway. Preload durations of up to five years were required and in certain areas up to 1.5 m of settlement was observed. All of the granular materials were processed from pits located adjacent to the highway.
     Karjala adds that the project passes through First Nations Lands and has provided an excellent opportunity for the local community. It was completed one year ahead of schedule and is an important improvement in the transportation infrastructure in Northern Ontario.

York Region Rapid Transit Viva- Phase I Quick Start – York, Ontario
     The York Region Rapid Transit Viva is the first rapid transit system of its kind in the Greater Toronto area. The project was awarded through a custom developed, design-build contract negotiated between a joint venture led by Peter Kiewit Sons Co., and York Region Rapid Transit Corporation. The design-build team developed innovative design solutions to meet the project’s technological challenges, including real-time electronic bus arrival displays, transit signal priority to adjust signal timing for buses behind schedule and a computer-aided dispatch transit control center with GPS. Heritage versions of the shelters and fare equipment were designed to preserve the integrity of historic districts. Phase I of the first rapid transit system had to be designed, procured, tested, commissioned and integrated with existing transit components in less than 18 months. Valued at $72.5 million, the project was awarded the 2006 Design-Build Excellence award (transportation over $50 million) by the Design-Build Institute of America and the Public Works Project for 2006 award (transportation over $10 million) by the Ontario Public Works Association.

Calgary Trail, Ellerslie Road Interchange - Edmonton, Alberta
     The Calgary Trail and Ellerslie Road interchange is situated on the south side of Edmonton, Alberta. This $10.5 million interchange project involved the construction of two large bridge structures and more than 6 km of roadway. Here, crews used an innovative phased construction method to construct the first bridge, which measured 127 m long and 27 m wide. The bridge was cast-in-place at grade, post-tensioned and then excavated to expose the completed structure. A second bridge, measuring 38 m by 15 m, was constructed using a single-span precast method. The east and west retaining walls were more than 700 m long and supported by drilled cast-in-place concrete piles. Crews constructed more than 6 km of roadway including 65 000 m3 of excavation, 112 000 m3 of native fill, 66 000 tonnes of road base and 23 000 tonnes of asphalt.

Yoho Bridge Replacement and Approaches – Golden, British Columbia
     This $24 million project, completed for the British Columbia Ministry of Transportation, included replacing the existing Yoho Bridge and rebuilding 1.5 km of roadway approaches along the Trans-Canada Highway through the deep and narrow Kicking Horse Canyon. The highway is a major thoroughfare, carrying more than 14,000 daily vehicles in the peak summer months. Peter Kiewit Sons Co. widened the existing two-lane roadway to four lanes to reduce curves and minimize grades, and replaced the single bridge with two, two-lane bridges over the Kicking Horse River. Work also involved three mechanically stabilized earth (MSE) walls, a 500 m long rock catchment wall with more than 300 double corrosion protection soil anchors, 25 000 m3 of rock excavation and 80 000 m3 of common excavation. Construction of the project was phased to allow for two lanes to be open to traffic at all times. An innovative detour scheme eliminated a planned total closure of the Trans Canada Highway that was anticipated during demolition of the existing structure.

Sea-to-Sky Highway Improvement Project - British Columbia
     The Sea-to-Sky Highway Improvement Project was first featured in the August 2006 issue of Aggregates & Roadbuilding and, in a recent update, senior engineering manager David Wallace reports that the project’s 230 week construction program is on time and on budget. Kiewit is currently working over the entire 100 km project length between West Vancouver and Whistler and it is anticipated that the majority of the heavy civil works will be completed by the end of 2008. Paving, landscaping and other finishing activities will carry on into 2009. Work in progress includes bridge construction, Mechani-cally Stabilized Earth (MSE) downslope wall construction, rock excavation, highway embankment and asphalt paving. Wallace adds that good progress is being made on the construction of the project’s 31 bridges and over 10 km of MSE downslope retaining wall structures.
     Newly completed sections include Furry Creek to Britannia Beach (DB5N & DB6) and North Cheakamus Canyon to Rubble Creek (DB12S), to be followed in the next few months by sections from Britannia Beach to South Squamish and Furry Creek to North of Lions Bay. Major bulk material quantities include over 3 million tonnes of MSE backfill, asphalt aggregates, subbase and base aggregates, 37 000 m3 of concrete aggregates and asphalt reclamation for mixing into new subbase.
     This roadbuilding project has received close public attention, particularly on environmental and traffic control issues, due to its unique location and role in the 2010 Winter Olympics. Wallace notes that the project’s Environmental Assessment Certificate included a Table of Commitments for which accountability and compliance has been achieved to date, despite close proximity to the Pacific Ocean (Howe Sound), many sensitive fish bearing streams and heavy rains in both 2006 and 2007. Together, the attention to the environment and the systems that have been developed (compliant with EAC requirements using an ISO 14000:2004 program) represent the leading edge in Canadian heavy infrastructure construction environmental compliance.
     Wallace adds that the highway improvement project has very limited greenfield construction as most of the improvements are along existing alignments. Project land acquisition is done by the Province, with less land taken than had been originally envisaged. Historical and archaeological features such as culturally modified trees from early First Nations have been identified and safeguarded during the construction process, together with extensive consultation and involvement with the Squamish and Lil’Wat First Nations.
     Measures have also been introduced to help protect at risk and endangered wildlife species. For tailed and red legged frogs, for instance, measures include habitat preservation, enhancement and the installation of sub-highway crossing features. In addition, typical fish bearing streams and salmon runs were accounted for in the construction planning, while protection for the area’s extensive bird population included no blasting during nesting season and the installation of solar powered video cameras to monitor nest activity. Environmental monitoring has been done according to Agency requirements and Kiewit developed comprehensive training programs for its field engineers, environment coordinators and supervisors to enhance awareness and abilities on environmental issues.
     All Work Plans, detailing how each item of work is to be executed, included the standard safety, quality, environmental and construction requirements. The special section on environmental requirements was reviewed by a Kiewit staff of registered professional biologists who would assist the field engineers and construction personnel with training, and correct implementation of the proper measures to mitigate adverse impacts on the environment.
     On traffic control, Wallace reports that the challenge to keep traffic moving through the construction site has been met by careful planning and subdivision of the project into numerous phased work areas and smaller work task increments. As a result, heavy mobile equipment has been floated to new locations between day and night shifts to facilitate continuous work operations throughout the highway corridor. A good safety record has been maintained despite the hazards of steep terrain and moving traffic, again thanks to work planning and completion of difficult work elements during the day with maximum light conditions and keeping the simpler tasks for night to maximise the use of regularly scheduled traffic closures.
     Kiewit trained and developed its own traffic engineering and management capabilities so that this group would be closely connected to the design and construction groups. The company also made use of Intelligent Traffic Systems providing lane counts, traffic density and calculated travel times compared to established baselines, as well as remotely controlled variable traffic message signs.
     In addition to these measures, the traffic control supervisors and manager received specialized training to deal with the particular nature of working in the mountainous Sea-to-Sky corridor. For the travelling public, this collective effort has paid off with actual traffic closures only about 60 per cent of the anticipated number as well as a predictable closure schedule to assist commuters.
     The sea-to-sky project is a public-private-partnership (P3) availability style project and under this approach payment by the province for ten payment sections begins as each is substantially completed and ready to carry traffic. According to Wallace, benefits of this project approach include a construction period some three years shorter than a traditional bid-build delivery method.
     The extensive list of mobile equipment involved in the project has included at least 350 items and some $52 million worth of new equipment. Major pieces of mobile equipment include six Caterpillar dozers (D3C, two D6R XLs, two D8Ts and D9R DS), a Caterpillar 426B and two John Deere 710Gs backhoe/loaders, two Caterpillar graders (14G and 14H), 13 Caterpillar excavators (225CL, 320B, 330B, three 450C LCs, four 330CLs, 330C LC, 365CL and 385CL), a John Deere 135C RTS excavator, a Komatsu PC1250LC-7 excavator, two Ingersoll-Rand SD150D compactors, five Caterpillar compactors (CP323C, CP563D, CS323C, CS563E, CS583E), a Dynapac CA151D compactor, a Link-Belt HC-218 and three Grove (RT-745 RT-750, TTS870B) mobile cranes, 17 articulated trucks (five Volvo A35Ds and four each of Caterpillar 730, 735 and 740 models), four Caterpillar 769D rigid frame haulers, an Ingersoll-Rand ECM -350 air track drill, ten Sandvik drills (two 550 Tiger drills and eight Ranger 800 drills), three Traxxon excavator mounted hydraulic drills on a Caterpillar 330 carrier, three Ford 8000 tankers, 16 Kenworth tri-drive trucks complete with pups, five Freightliner International 7400 SBA trucks, sixteen tridem pony trailers and 175 Ford light trucks, SUV’s and cars.
     In addition, rental equipment has included nine John Deere excavators (135, 200, 225, 330 and 450 models), three Komatsu excavators (PC200, PC-78 MR6 and PC300LL), as well as nine articulated trucks; a Komatsu HM300, two Caterpillar 735s and six Volvo A30s.
     Portable material plants dedicated to the job include Erie Strayer, Ross and CON-E-CO dry batch concrete plants, while the Raynier quarry is home to the Astec asphalt plant of BA Blacktop. Aggregate processing plants includes portable Pioneer track jaw and Terex track jaw crushers, in addition to aggregate processing at Raynier, Garibaldi and a subcontractor’s plant washing concrete aggregates.
By any measure, the Sea-to-Sky Highway Improvement Project is one of Canada’s outstanding roadbuilding projects.

Other projects
     Turning to other projects in Kiewit’s portfolio, Wallace notes that work is well underway on the $175 million Pitt River cable stayed bridge project between Port Coquitlam and Pitt Meadows in B.C. while Kiewit was also recently awarded a $185 million project in Edmonton AB for the 23rd St. At the time of writing, a decision was pending on the Coast Meridian CPR Overpass Project in Coquitlam B.C. valued at over $100 million. Still in B.C., Kiewit is also part of the ConnectBC development group putting together the RFP response to the Province for the $1.7 billion (includes $400 million of property) Port Mann / Highway 1 widening project for construction between 2009 and 2013. This is a 40-year tolling concession with one point of tolling on the Port Mann Bridge.
     Overall, Kiewit’s project approach demonstrates an ongoing commitment to innovative engineering, safety, environmental awareness and efficient project delivery.

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Canada's first perpetual pavement built to last

By Andy Bateman, Engineering Editor

     Billed as Canada’s first highway to have been designed and completed as a perpetual pavement, Ontario’s Red Hill Valley Parkway incorporates the latest thinking in durable pavement design.

    Popularly known as the Red Hill Creek Expressway and valued at over $400 million, the 7.5-km long, four-lane Red Hill Valley Parkway runs south of downtown Hamilton to connect the Lincoln M. Alexander Parkway with the Queen Elizabeth Way (QEW). After a long and controversial development history spanning two decades and several changes of government, the new freeway is expected to be open to traffic in November 2007, with remaining works such as noise mitigation scheduled for completion between 2008 and 2012. For the owner, The City of Hamilton, the project represents a practical application of the concept of perpetual pavement sustainability. The Parkway has certainly been designed and built to last. Its structures have a design life of 100 years, while the pavement itself has a design life of 50 years with periodic resurfacing at intervals of 15 to 20 years. (See sidebar on Perpetual Pavements.)
     The substantial perpetual pavement cross section includes two granular and four asphalt layers, generally starting with Granular B and Granular A lifts of 420 mm and 100 mm respectively. These are followed by an 80 mm thick layer of asphalt-rich mix known as Rich Bottom Mix (RBM). In this case, the RBM is a Superpave SP19 mix with 0.5 per cent additional asphalt cement and is designed to protect against the initiation of load induced fatigue (bottom-up) cracking. Above the RBM, a 70 mm lower binder layer of SP 25 and a 50 mm upper binder layer of SP19 complete the permanent structural portion of the pavement and provide excellent rut resistance. Finally, the pavement’s durable surface course is a 40 mm layer of SMA 12.5 to provide superior rutting resistance, fatigue endurance, durability and improved skid resistance, as well as some noise reduction when compared with conventional hot-mix asphalt mixes.
     Dufferin Construction Company won the mainline paving contract PW-06-243 RHV last year with a bid of $30.3 million. Work extended from the Mud St. Interchange to the QEW Interchange and included the placing of granular, hot mix paving, curb and gutter, barriers, electrical, structures, illumination, signage, restoration of recreational features and some landscaping. Bulk asphalt mix quantities included 42 000 tonnes of RBM, 36 000 tonnes of SP25, 39 000 tonnes of SP 19, 9500 tonnes of SP12.5 and 16 000 tonnes of SMA. Paving began in May 2007 and was completed on the highway by the end of August 2007.
     James Wharrie, project engineer for Dufferin Construction, explains that the pavement sections for ramps and shoulders are somewhat different to the mainline itself. Ramps still have the four asphalt layers for their full width, but with a 40 mm lift of SP12.5FC2 replacing the SMA. The mainline shoulders have two lifts of asphalt with a 50 mm lift of SP19 and a 40 mm surface lift of HL3 HS.
     Wharrie adds that, during site operations, most of the hot mix asphalt for the contract was supplied from the company’s portable CMI plant set up at Dartnell Rd. On site, Dufferin’s paving train included a Roadtec SB2500 Shuttle Buggy, Caterpillar AP-1055C and AP-655C pavers, with both pavers fitted with hoppers and usually working in echelon. For the most mixes, the compaction set up included a Bomag BW205 compactor in the breakdown position with a Caterpillar CB634D in support and also making finishing passes as required. A Dynapac CP271 pneumatic machine worked in the secondary position.
     This compaction set up worked well most of the time to achieve target compaction densities, including the 97 per cent density of the RBM. The exception was the SMA due to rapid cooling of the open graded mix. Wharrie explains: “the SMA mix was produced at 165OC and we typically found that it had already cooled to 125OC behind the paver screed. Only 10 m behind the paver, the mix temperature had dropped a further 10OC to 115OC, with further cooling of about 10OC for every additional 10 m from the paver. This meant that our compactors had to get on the mat right away. We found that four compactors, all steel drum, were about the limit we could place on the mat at any one time without undue congestion. The SMA compaction fleet included the Bomag BW205 as well as two Caterpillar CB634D’s and one CB534D. Even with this compaction fleet, the overall pace of the paving train was set by the compaction process when paving SMA.”
     The pavement on the new freeway incorporates sophisticated performance and monitoring systems. In the driving (slow) northbound lane, performance sensors will measure pressure and moisture content in the subgrade, temperatures in all pavement lifts and both longitudinal and transverse horizontal strains in various lifts. In the northbound and southbound lanes, sensors and loops of a weight in motion system will allow traffic count, and the monitoring or traffic speed, wheel loads as well as stresses applied to the pavement.
     Crediting individuals on a project of this size is always risky, but most would agree that Gary Moore, Director of Engineering for the City of Hamilton has been a prime mover of the project and instrumental in turning concept into reality. Dr. Ludomir Uzarowski, pavement and materials specialist with Golder Associates, has also been closely involved, completing the project’s feasibility study, perpetual pavement design and developing its asphalt paving specifications. Among the Dufferin Construction team, Peter Gamble, plant equipment and technology manager and David Hainer, project superintendent, are recognised for their significant contributions to a successful project.

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The Red Hill Valley Parkway - A perpetual pavement

     The City of Hamilton decided that, “given the projected traffic volumes (which will be as high as 100,000 vehicles per day), the conventional wisdom of designing a deep strength pavement for a 20-year life may not be acceptable. The advanced asphalt technology and materials used in the perpetual pavement design will allow the pavement structure to last 50 years with only periodic surface course replacements and without any major pavement rehabilitation. The associated benefits of delivering a highly durable and safe pavement surface and avoiding major shut-downs of the expressway (the surface course replacements can be completed during single lane closures at night), are in keeping with the City’s desire to be a leader in the application of sustainable design solutions for public infrastructure.”
     The paper also includes details of a Life Cycle Costing Analysis (LCCA), which compares the cost of a perpetual pavement design for the mainline to a conventional deep strength asphalt pavement alternative. The analysis concluded that the perpetual pavement offers net savings of about $1.5 million over the 50 year period. Expressed in present worth, the $1.5 million higher initial construction costs of the perpetual pavement are more than offset by some $3 million of future savings in maintenance and rehabilitation costs as well as reduced user delay costs:
     Later in the paper, further analysis estimates that the perpetual pavement will also use less construction materials: “It is anticipated that over the 50-year analysis period, the perpetual pavement will require about 30 000 tonnes less hot-mix asphalt, 22 000 tonnes less granular base and 95 000 tonnes less granular subbase material:
     The paper concludes, among other things, that “better materials and improved analytical techniques now allow asphalt pavements to be designed to last 50 or more years. These long lasting (perpetual) asphalt pavements have lower impact on the environment over their entire service lives in terms of use of materials, energy consumption, greenhouse gas emissions, and impact on road users and on local neighbourhoods.”
     Extracts from Sustainable Pavements – Making The Case For Longer Design Lives For Flexible Pavements by Michael Maher, Ph.D., P.Eng. Principal, Golder Associates Ltd., Ludomir Uzarowski, (then) M.Sc., P.Eng. Associate, Golder Associates Ltd., Gary Moore, P.Eng. Manager, Design and Construction, Red Hill Valley Project, City of Hamilton and Vince Aurilio, P.Eng. Ontario District Representative for Bitumar Inc.

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Warm asphalt gains traction

     Garth St. in Hamilton, is one of the city’s principal four lane routes and, with northbound and southbound lanes separated by a median, provided city engineers an ideal opportunity to compare the long-term field performance of hot and warm asphalt mixtures. The southbound lanes were resurfaced with hot mix asphalt, while the northbound lanes were resurfaced with warm mix asphalt utilising one of four warm asphalt technologies currently in development in North America. Evotherm is a chemical additive package used at 0.5 per cent to 1.5 per cent by weight of asphalt and delivered as a high residue emulsion. Benefits of this technology are said to include a 50 per cent reduction in fuel consumption together with a decrease in plant and jobsite emissions by 40 to 60 per cent compared to a hot mix asphalt control mix.
     Generally speaking, warm mix asphalt can be produced, hauled and paved with existing equipment. In this case, paving contractor King Paving & Materials, a division of KPM Industries Ltd., produced the warm asphalt for the job using the company’s Cedarapids 2.7-tonne capacity batch plant. The asphalt emulsion for the warm mix was pumped directly into the plant’s pug mill from an emulsion tanker and the resulting mixture shipped 20 km to site in King’s fleet of Flow Boy live bottom trailers. On site, the mixture was fed directly to a pair of Barber Greene BG-245 pavers working in echelon and compacted by a Bomag fleet including two BW164AD dual steel drum units and a BW11R rubber tired machine. Site weather conditions were good with no rain and temperatures in the mid-20°C for the two-day paving job.
     King Paving’s vice president of operations John Hutter points out that the cooler temperatures involved in the warm mix production process save energy in both aggregate drying and oil heating. At King’s plant, the exit temperature of the aggregates from the dryer was 105°C compared to 165°C for the hot mix. In addition, the emulsion was maintained at a temperature of 90°C, also some 60°C cooler than the typical 150°C storage temperature for hot mix asphalt cement. Hutter does add a note of caution with respect to warm mix asphalt production and placement. At the plant, a considerable amount of steam is generated in the pug mill when the hot aggregate makes contact with the asphalt emulsion. This steam can mix with airborne dust, forming a cake that can block valves and gates. To avoid this situation, operators should ensure the mill is well vented before mixing begins. On site, paving crews report that handwork with the more tacky warm mix is somewhat harder than a conventional mix. Still on site, the mixture was also found to pick up a little on rollers, although this was easily remedied by the addition of soap to the roller water.
     Keith Davidson, director of technical services for McAsphalt Industries, explains that the mix used for Garth St.’s two southbound lanes were paved utilising a SP 12.5FC1 mixture containing five per cent PGAC 64-28 asphalt cement. The two northbound lanes were paved with the same mix apart from the Evotherm 64-28 emulsion, with the asphalt emulsion content increased to seven per cent to reflect the 30 per cent water content of the emulsion. Both mixes utilised 50 per cent HL1 steel slag and 50 per cent high stability sand from the Dundas quarry of Lafarge Canada Inc. The Garth St. job is one of seven warm asphalt projects involving McAsphalt Industries in 2007, for a total of eleven since the first was completed in 2005. Experience to date indicates energy cost savings of at least 35-40 per cent for gas or oil fired plants and these numbers seem to be consistent with the results of perhaps 50 projects that have now been completed globally.

     According to supplier MeadWestvaco, the Evotherm additive significantly reduces temperatures at which asphalt pavements are produced and applied without compromising the durability of the paving material. Company data adds that the additive can be used in any traditional hot mix application, from binder course to surface course, with the asphalt laid at temperatures 50-75°C lower than the equivalent hot mix asphalt mixture. The range of applications is said to include surface, binder, polymer-modified and rap mixes, as well as stiffer mixes, thin lift and ultra thin lift mixes, stone-mastic asphalt (SMA) mixes, open-graded friction courses and cooler weather mixes, all while utilising existing HMA job mix formulas.
The reduction in temperature is said to extend haul distances and so allow the service area of an asphalt plant to increase without compromising quality. In addition, the new technology does not require a change in equipment and can be used in existing plants. Claimed advantages of Evotherm include energy savings and decreased emissions at the hot-mix plant, no odour, increased throughput, reduced dust generation, less plant wear, reduced job site fumes, quicker return to traffic, longer binder life and an extended operating season.
     The data also compares stack emissions at the asphalt plant for an Evotherm mix at 93°C to a HMA control mix at 154°C, with the HMA emissions normalised to 100 per cent. This data indicates that carbon dioxide emissions are reduced by 46 per cent, carbon monoxide by 63 per cent, sulphur dioxide by 81 per cent, nitrogen oxides by 58 per cent and total particulate matter (TPM) by 34 per cent, all at the same time as fuel consumption is reduced by 55 per cent. An additional analysis for site fume emissions indicates that total organics are reduced by 41 per cent while benzene solubles are below detectable limits.

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Screen media provides fine screening solution, boosts productivity

     An Ontario lime producer reports increased screening efficiency and productivity after installing flexible screens in a challenging application.

     Leke Fadiya is Mine Engineer at the Carmeuse Lime Beachville operation near Ingersoll, Ont. Fadiya explains that part of the production process at Beachville involves the separation of crushed limestone to provide feed material for the operation’s kiln and pulverised stone plants. Granular 22 mm minus material is screened into three sizes: 22 mm x 13 mm, minus 13 mm x 6.3 mm and minus 6.3 mm. The 22 mm x 13 mm is used as kiln feed while the minus 6.3 mm is utilised as feed for the operation’s pulverised stone plant and also as feed for AG75 product. Occasionally, the minus 13 mm x 6.3 mm fraction is blended back into the pulverised stone feed to improve material flow.
     Under normal operating conditions, the 22 mm minus feed material is fed at a total rate of 300 tonnes/h to a pair of 5x14 double- deck screens. These screens were previously fitted with slotted woven wire screen cloths having 9.5 mm x 76 mm and 4.8 mm x 76 mm openings on the top and bottom decks respectively. With that screen media set up, screening efficiency was reasonable in dry or very cold weather, but rapidly deteriorated when the feed material was wet due to rain or snow. The bottom deck frequently became blinded, resulting in carry over of 6.3 mm minus material into the 13 mm x 6.3 mm fraction. In extreme situations, both top and bottom decks became blinded and little feed material separation occurred at all, so risking contamination of the kiln feed with minus 13 mm x 0 material.
     In these situations, plant operators often had little choice but to stop the screening operation and attempt to manually scrape or lever off the caked material that had built up on the screen cloths. Operators even resorted to the use of propane torches to dry and remove wet material, but that process provided only temporary improvements and the combined effects of impact and local heat did nothing for screen life. Maintenance records retrieved by the reliability engineer at Carmeuse, Arsenio Flora, show that broken screen cloths were a regular event, necessitating replacement as often as six times a year.
     To address this situation, Flex-Mat “S” type screen cloths were installed on the upper and lower decks of one of the 5x14 screens in 2006, with the existing slotted cloths left in place on the other screen for comparison purposes. Fadiya reports an immediate improvement in screening efficiency and the installation of the Flex-Mat screen cloths on the second screen soon afterwards. For this application, each side tensioned Flex Mat screen cloth panel is 1.486 m wide and 1.422 m long for a total of three panels in the 4.267 m long deck. The Flex-Mat screens have been in service for sixteen months, with Fadiya reporting significantly improved productivity and no sizing, maintenance or repair issues to date.
     According to manufacturer Major Wire Industries Ltd., the Flex-Mat “S” type cloths utilised in this application are designed to remove fines for cleaner retained product. One of the key differences between all Flex-Mat designs and conventional woven screen media designs is the absence of cross wires. A special formulation of polyurethane bonded with individual screen wires eliminates the need for traditional woven cross wires, thereby eliminating high spots inherent in a woven design and the consequent opportunity for premature failure due to high spot wear. Polyurethane strips, centered on each screen deck crown bar support, allow individual wires to vibrate independently at different frequencies, preventing material from accumulating between wires as it typically does with woven wire.
     The current range of Flex-Mat screens is designated Flex-Mat 3 as the third generation in product development, with each type targeting different screening challenges. The Series D has a diamond pattern and is designed for precise sizing of passing material and most standard applications. In this pattern, crimped individual wires present diamond-shaped openings to the feed material, with available size opening ranging from 1.5 mm to 101.6 mm. The Series S has a wave pattern to remove fines, with size openings in this design ranging from 1.5 mm to 50.8 mm. Additional applications for the Series S are said to include replacement of any existing slotted screens and also those situations where specification product is required utilising natural round material. The Series T heavy-duty screen has a triangular pattern for larger sizes and is reinforced for heavy loads or high impact materials. Its use is recommended when 25 per cent of material is four or more times larger than screen cloth openings and its size openings range from 2.0 mm to 50.8 mm.

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Hard markers give loaders high marks

Aggregates & Roadbuilding recently visited some aggregate operations to obtain operator feedback on one manufacturer’s wheel loaders with generally positive results.

     While matching a new piece of mobile equipment to its intended application is a relatively straightforward exercise, pleasing its operators is a much tougher job.
     Mobile equipment manufacturers make many claims for their products and potential owners are faced with a dizzying array of machine sizes, options and performance promises. Conspicuous by its absence however, is any guarantee that any particular machine will be well received by its operators. Those same operators are not generally bashful about voicing their opinions, favourable or otherwise, knowing that a machine’s strengths and weaknesses will become all too familiar over thousands of hours of operation. Fortunately, most equipment manufacturers and owners recognise the importance of this feedback and carefully consider operator viewpoints when building or buying mobile equipment.
     To see the loaders in action, Aggregates & Roadbuilding visited Ontario producers Tri City Materials and St Marys CBM. Tri City Materials Ltd., named after the three Ontario cities of Waterloo, Kitchener and Cambridge, has five sand and gravel operations and a ready mix division with two concrete plants. The far larger St. Marys CBM, the building materials division of St. Marys Cement Inc., is a major aggregate producer with twelve sand and gravel operations and quarries, plus 40 ready mix concrete plants. St Mary’s Cement is in turn part of Votorantim Cimentos, an international cement manufacturer based in Sao Paulo, Brazil.
     Tri City Materials is currently operating three John Deere 844J wheel loaders and one 824J machine, while a new 544J loader has gone into service with Tri City Ready Mix Ltd. The John Deere 844J at the St Marys CBM David Pit is reportedly the company’s first John Deere loader, although there are other Deere products in the mobile fleet.
     Operators at both companies gave positive feedback on these loaders, noting smooth shifting, fast hoist speeds, good power under load and good visibility, while minor grumbles included varying bucket roll position. The 844J wheel loader is a relatively new arrival on the large loader scene having first been available in November 2005 and, at least based on these comments, seems to have a bright future.
     At Tri City Material’s Kitchener pit, a John Deere 824J wheel loader with a standard 4.59 m3 bucket was on load and carry duty feeding granular base material to an aggregate screening and washing set up. This loader maintained a feed rate of 300 tonnes/h to the wash plant and appeared well matched to the duty, with steady wash plant production and little waiting time during the load and dump cycle. In the same pit, one of Tri City Materials larger loaders, a John Deere 844J equipped with a standard 5.55 m3 bucket, was on split duty loading highway trucks and handling bulk materials within the pit. Operations manager Greg Ramseyer pointed out that this machine was also well matched to its duty, loading a tri-axle truck in two passes or a tractor trailer unit in five passes. On the same day at Tri City Materials’ Amulree pit, one of the company’s other 844J wheel loaders was feeding pit run to a Powerscreen Warrior 1800 screen plant. This harder duty cycle involved loading pit run containing pieces up to 600 mm and hauling it some 150 m. Despite the longer haul and poor weather, this loader and screen duo was well-matched and making three products from the pit run at a reasonable rate.
     At the David pit of St Marys CBM near Cambridge Ont., equipment manager Howard Wheeler explained that the John Deere 844J wheel loader based here is dedicated to loading highway trucks from product stockpiles. For this duty, the loader has been fitted with Deere’s 6.2 m3 bucket, the largest rated bucket available for this machine. Operator Sam Carrothers reports that this bucket enables the 884J to load about 10 tonnes of sand or about 9.5 tonnes of coarse aggregate with each pass, depending on the moisture content of the material. Most of the time Carrothers utilises the loader’s steering wheel, more from familiarity as much as anything else, but has occasionally used the joystick control and found it to be user friendly and intuitive. The loader is reportedly delivering fast cycle times, thanks to a combination of smooth shifting, fast bucket hoist speeds and good power availability, especially when travelling loaded up a steep grade. Such situations can occur when the loader is travelling uphill to a waiting truck or driving up the feed hopper ramp of a processing plant.
     Although in a different place at different times, the feedback from Tri City operators Wes Esbaugh and Marv Stere was very similar. Here, favourable comments were made with respect to the loader’s high breakout force and fast bucket hoist rate. Characteristics such as the loader’s ability to travel loaded up a steep grade, smooth shifting and easy to use joystick control were likewise noted here.
     Turning to options and accessories chosen by the machine’s owners, the general purpose buckets on Tri City’s loaders have several ground engaging tools including bolt on edges, teeth and segments as well as the John Deere Jagz system. Manufacturer’s literature describes Jagz as a versatile angled dovetail design from which users can custom build a wear surface on loader buckets or scraper bowls. It is said to be guaranteed against breakage, self-sharpening, reversible and interchangeable and will fit any model or make of loader.
     The St Marys CBM loader is equipped with a Microload 310 loader scale to facilitate accurate loading and minimise overloads. It is routinely used to make small adjustments to the last bucket load, with material being trickled off to ensure that the truck is loaded as closely as possible to its target payload. Information from scale manufacturer Thermo Fisher Scientific, Inc., adds that the scale can be set to target mode which counts down as loading progresses, or totalising mode which maintains a running total on the screen for use in applications such as hopper or ship loading. Load records are stored on cartridges for periodic data retrieval and analysis if required. In terms of accuracy, the manufacturer claims typical static accuracy of plus or minus one per cent of full load while dynamic accuracy (weighing with the machine on the move) is rated at plus or minus 1.5 per cent of the local reference scale.
     The 844J loader has a net rated power of 330 hp at the rated engine speed of 2100 rpm. There are four forward speed ranges and three reverse speed ranges with maximum speeds of 37.7 and 27.4 km/h respectively. The bucket range is 4.6 - 6.2 m3. Specifications based on the standard bucket size of 5.55 m3 with no counterweight indicate straight and full turn tipping loads of 24.1 tonnes and 20.8 tonnes. Dump clearance at 45 degrees is 3.36 m and the loader’s operating weight is 31 tonnes.
     The 824J Z-Bar wheel loader has net rated power of 275 hp at 2000 rpm. It also has four forward speed ranges and three reverse speed ranges with maximum speeds of 39.4 and 31.1 km/h respectively. The bucket range is 4.4 - 5.2 m3. Its specifications, based on the standard bucket size of 4.59 m3 with no counterweight, indicate straight and full turn tipping loads of 19.3 tonnes and 16.2 tonnes. Dump clearance at 45 degrees is 3.23 m and the 824J’s operating weight is 26 tonnes.

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Fuel efficiency pays for loader owner

     Residents and race fans in the Kanata and Carp area west of Ottawa will most likely associate Rick Rump with the Capital City Speedway, where Rump is a regular competitor in the late model class. Less well known perhaps is the fact that Rump is also the principal of Rick Rump Excavation, an established topsoil business based in Carp.
     Each year, some 25 000 m3 of dredged sand is mixed with 60 000 m3 of screened top soil at Rump’s Carp Road pit, with some 90 per cent of production going to commercial landscapers.
     Topsoil screening is completed by a Roto-Screen RS-65 trommel screen, while Rump’s excavation and dirtmoving equipment fleet includes a Caterpillar 330BL excavator, 215LC excavator, D7 dozer and John Deere 450 dozer. Trommel feeding, materials handling and truck loading are completed by a Liebherr L544 2+2 wheel loader which replaced a competitor’s machine of similar size. Rump has found that the fuel efficiency of the L544 2+2 compares favourably to its predecessor and makes a measurable contribution to the bottom line.
     Daily loader duties include sand load and carry, maintaining topsoil feed to a portable trommel screen and loading product onto a fleet of International tri-axle highway trucks. In this application, Rump reports that the L544 2+2 consumes an average of 150 litres of diesel fuel during each 10-hour shift, or 80 litres less than the 230 litres consumed by the previous machine. With coloured diesel currently running at about 80 cents/litre, the L544’s fuel efficiency translates into monthly cost savings of about $1,300 or nearly $9,000 over the business’s typical seven month operating season.

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Liebherr fuel test parameters

     Manufacturer’s literature for the Liebherr range of wheel loaders includes a description of the company’s “Norm Test”, or “Standard Consumption Test”. Said to be easy to reproduce and practical, the test provides a way of comparing the fuel consumption of wheel loaders in a controlled working cycle: “conducted on customer’s premises, the customer determines the number of loading cycles than can be completed with 5 litres of diesel fuel. Material is taken from pile A and carried over a distance of 20 m to pile B. Discharge at point B should take place from a height of 2.5 m and the time required for each complete working cycle should be 35 seconds. The working cycle is repeated until the five litres of fuel in the external measuring tank have been used up. The loader’s fuel consumption in litres per hour is calculated by dividing the number 400 by the number of loading cycles completed during the test.”
     For the L544 2+2 loader with a standard 3.0 m3 capacity bucket, the result of the Norm Test indicates fuel consumption of 11.4 litres/h, equivalent to 2.6 litres per 100 tonnes of material moved For the Liebherr L550 2+2, successor machine to the L544 2+2, the Norm Test indicates slightly higher fuel consumption of 12.9 litres/h but the same productivity of 2.6 litres per 100 tonnes of material moved. This apparent anomaly is explained by the larger 3.2 m3 loading bucket capacity of the L550 compared to the 3.0 m3 loading bucket capacity on the L544. In other words, the two machines consume about the same amount of fuel to do the same amount of work, as the greater payload of the L550 offsets its slightly higher fuel consumption.
     Another Liebherr analysis compares the fuel consumption of its loaders to competitor’s machines in the same class. In the case of the L550, the average fuel consumption of competitor’s machines is quoted at 16.7 litres/h. The L550 therefore uses 3.8 fewer litres/h, and, based on a diesel price of $0.90/litre and 2000 operating hours per year, will save its owner $6,840 each year in fuel costs relative to competitor’s machines performing the same duty. The analysis then considers these fuel cost savings, totalling $34,200 over five years of operation, as an offset to the L550’s list price of $230,000 for a “Comparative Cost” of $195,800.
     Similar calculations are made for other wheel loaders in the Liebherr range. According to this analysis, five-year fuel cost savings range from $36,000 for the L538 up to $68,400 for the L586 loader. The analysis adds that “further operating cost savings can be expected from reduced brake wear and tire wear as the loader is constantly breaking hydraulically, rendering the service brake as a secondary function. The standard traction control also allows the operator to adjust for various working surfaces, thereby significantly reducing stress and wear probabilities on tires. These reductions in brake and tire wear could result in additional savings of $40,000 over the initial five year period.”

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November-December 2007 issue

Aggregates and Roadbuilding Magazine
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