Canada's “Rock to Road” Magazine

January/February 2004 Issue

• Packed APAO Seminar highlights safety risks and remedies
• Superpave – Building for the future
  • Western Region Report
  • Eastern Region Report
• Canadian debut for portable sand plant
• Focus on Cold Planers

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

Packed APAO Seminar highlights safety risks and remedies

By Andy Bateman, Engineering Editor

    Safety topics at this year's Aggregate Producers Association of Ontario (APAO) Operations, Health and Safety Seminar included conveyors, surface rescue, material stockpiles, addiction, and increased work risks to young workers.
     A packed two-day agenda also included presentations on operational improvements, fundraising events and associate member's displays.
      The presentations began on a serious note as guest speaker Bill Whelan described a conveyor accident in 1999 that cost him his right arm, right shoulder and nearly his life. With the aid of compelling video, Whelan showed how an event lasting just a few seconds had profoundly affected not only on his own life but also the lives of those around him. Months of surgery and slow rehabilitation were followed by depression, but, even during these difficult times, Whelan recognised that he was fortunate to be around at all, based on the 5 per cent survival rate for such severe injuries. One thing Whelan has not lost is his sense of humour, noting that, "I've learned how to be left-handed and my prosthetic right arm, even at a cost of $60,000, is not as good as the original."
      In Why are we still hurting Young Workers? Fergus Kerr of the WSIB explained that young workers aged 15 to 24 are the most "at risk" group in terms of work related accidents. In Ontario there are 10 to 15 young worker fatalities and 16,000 lost time claims for young workers every year. In Canada as a whole, more young people die of workplace injuries than all other causes combined and six times more injuries happen to young people in their first month on the job. In fact, statistics show that young worker accidents in Ontario mostly occur within the first month of employment and include slips and falls, struck by, contact with hot object, lifting and pushing or pulling heavy objects. These young workers are usually in their first job, often in part-time or seasonal work and generally doing entry level jobs in fast food, retail, construction or tree planting. Over half of young workers have received no safety training.
      Some of the reasons behind the increased risk of this worker group include a sense of invincibility, lack of hazard knowledge, lack of knowledge of rights and doing hazardous work. Young people feel strong, quick, resistant and personally lucky. Teenage culture is also a factor. Many either did not know their work was unsafe, or perhaps worse, suspected a situation was unsafe but were told otherwise. Others are easily distracted, rushed, pressured to perform or reluctant to ask for fear of appearing stupid. Many did not know they could refuse unsafe work, were subject to peer pressure and were trying too hard to please. Many had no understanding of worker rights, were fearful of dismissal, often assigned physically demanding or dangerous tasks and using equipment or machinery designed for adults. Reliance on protective equipment and lack of orientation were also noted.
      To combat this situation, safety tools include the "Work Safe Work Smart" CD, the "Things you'd better know" Video, Print and media ads and Student video awards. Produced in British Columbia, the video "Lost Youth", detailed how seemingly innocent situations had rapidly become dangerous and resulted in serious permanent injuries to four young workers. Other initiatives to help raise awareness include the Young Worker Awareness Program (YWAP) in high schools, Passport to Safety, MASHA initiatives and Rob Ellis and Our Youth at Work Association. All system partners have young worker programs in 2004.
     For young workers in their first month on the job, Kerr encouraged increased orientation, spending more time explaining everything, not assuming understanding and leading by example. During training, all hazards should be identified and young workers provided with job specific training. Young workers must be aware of their rights, the importance of reporting unsafe conditions and have confidence that a supervisor will respond appropriately to any such report. In addition, coaching and mentoring are important aspects of supervision at this time. Kerr concluded that we can all be role models for young workers just starting and be a part of creating tomorrow's safe and healthy workforce.
      Staying on the safety theme, Frank Woit of MASHA presented the "Neil George" 5 Point Safety System, describing it as a practical tool for accident prevention. Woit explained that there are three sources of accidents or incidents: Conditions, Attitudes and Methods (CAM), adding that diligent workers use a safety system. The system's first point, "Check entrance and travelway to place of work", involves the inspection areas such as floors and yards for obstructions, fire or explosion risks and other hazards. The second point asks; "Are the workplace and equipment in good order?" This involves checking items such as Personal Protective Equipment (PPE), Lifting Devices, and Equipment. The third point asks; "Are employees working properly?" For instance, are employees trained for the job, using proper tools and following correct procedures? The fourth point in the system is "Do an act of safety!" This point communicates a supervisor's commitment to the safety program, and also sets out a systematic approach to safety contacts with workers.
      The final point in the system is "Can, and will workers continue to work properly?" The acronym SKATE can be helpful to help assess workers, where S = skill, K = knowledge, A = attitude, T = training and E= experience.
      Woit then explained the relationship between the 5 Point Safety System and CAM, following with examples of formal programs that incorporate the system. These include company specific forms, the protocol for completing the forms, follow-up of items recorded on the form, departmental differences, consistent application and enforcement. The benefits of a formal program include a consistent approach to help identify site issues, improved internal communications between critical workplace parties, the promotion of the Internal Responsibility System (IRS) and the provision of a practical link for compliance with OHSA & Regulations.
      In Surface Mine Rescue, Chris Bullock described emergency response procedures that have been developed by CBM Aggregates. Bullock explained that the surface mine rescue program at CBM has been developed to help close the Emergency Response Time Gap - the time between an incident and the arrival of local emergency services. It has been found that the response times from fire departments vary from 12 to 25 minutes for rural and volunteer departments and from 5 to 12 minutes for urban fire departments. Many fire departments do not have the necessary rescue equipment. Components of an emergency response plan include assigned duties, emergency posters, emergency contact numbers, written plans and equipment. Emergencies in the aggregate and mining industry include those involving being caught in machines or conveyors, falls, confined spaces, spills, fires, collapse of material and hazardous gases. In addition to the full commitment of company management, the CBM program has been developed with input from a number of safety agencies including MASHA, Mine Rescue and the Alberta Mine Safety Association's (AMSA) Surface Mine Rescue Program. The input from the latter program was particularly useful as AMSA gave permission for CBM to use the Association's 260 page training manual. The resulting three-day CBM program was developed utilising an external trainer, with teams recruited for first aid and CPR training. Rescue equipment was purchased and an emergency shoring device was fabricated. Topics covered by the program included fire safety, rope rescue techniques, and the use of emergency shoring for stockpile failures. Ongoing training consists of quarterly practices with teams involved in hands on simulations, annual evaluation by a consultant and regular inspection of rescue equipment. Additional current initiatives include working with local volunteer fire departments on training and hazard awareness, while future training initiatives may include spill response, water rescue, extrication and more confined space training. Regular contact is also being maintained with the AMSA. Overall the program's objectives are "no surprises" in terms of causes of injury or death, further closing of the emergency response time gaps and overall continuous improvement.
      CBM Aggregates made a further contribution to the seminar with Peter Graham's presentation on Stockpile Material Handling Safety. This presentation included findings from a slope stability study, operational guidelines, policies and procedures implemented at CBM. Graham pointed out that the safe stockpiling of bulk materials is not confined to the aggregates industry, but also applies to mining, industrial plants, agriculture and other industries. Company employees at risk include loader operators, quality control/assurance personnel and operations personnel, while others include commercial haulers, neighbours and contractors. Stockpile slope failures may be massive but there have also been fatal incidents involving relatively small slope failures. A review of slope failure accidents since 1995 reveal that they are the cause of about one fatality each year, involving individuals ranging from 7 to 60 years of age and including equipment operators, customers and truck drivers.
      Safety issues arise for stockpile operations when the slope is steeper than the material's natural angle of repose. Movement induced by excavating the toe of the pile, a critical area, can result cause a massive sliding of material and affect overall stockpile stability. CBM's response has included a review of stockpile policies and procedures, updates to the company's employee health and safety handbook, retraining of all employees and the commissioning of a slope stability study. The objectives of the study were to promote awareness and train personnel, gain a better understanding of the behaviour of stockpiled concrete sand, the development of stockpile operating safety guidelines and the identification of critical safety factors.
      Factors affecting stockpile stability include pile configuration, material shear strength and excavation sequence. Additional factors include vibration, groundwater and material compaction. The study examined failure of a sand pile due to toe excavation and the creation of the steep temporary slope produced during excavation, typically by a wheeled loader. The study found that slope instability leads to sliding of material and that loading typically induces failure. The higher the temporary slope, the greater tendency for the slope to fail and the greater the volume of material. CBM's stockpile operating guidelines have been completed in consultation with a cross functional team and the Ministry of Labour, the development of health and safety procedures, ongoing personnel training, and stockpile management guidelines.
      These guidelines include the maintenance of an adequate working area, limits to stockpile height, the formation of stable stockpile slopes, reduced segregation, and observance of a safe protocol for material inspection and sampling. When loading from stockpiles, site access to the loader and commercial truck is controlled, all are required to stay away at least 6m away from slopes when not in equipment, and to maintain heightened awareness. Stockpiles must have sufficient time to drain before loading. Material is to be excavated uniformly along the entire face of the slope, observing a maximum temporary slope height, with no trenching of a concave slope into the material. Potentially dangerous slopes must be flattened. Actions to mitigate existing steep slopes included the suspension of work and reduction in slope angle to the material's angle of repose. Finally, ongoing work includes the development of emergency response procedures and the periodic auditing and updating of guidelines.
      In Addiction in the Workplace, Gerry Smith of Warren Shepell Consultants quoted some sobering statistics relating to addiction in Canada, considered their implications in terms of both workplace and individual safety and recommended some appropriate responses to affected individuals. Statistics in Canada indicates that 1 in 10 addicted and 6 in 10 have had substance abuse problems. Substances include alcohol, dope, stimulants, sedatives and opioids such as heroin. In most cases (70 per cent) alcohol is involved, while other drugs, usually prescribed medications account for another 30 per cent. Opioids account for less than 1 per cent. Smith introduced the concept of mental health first aid, or the help given to someone experiencing a mental health problem before professional help is obtained. Mental health first aid does not teach people to be therapists, but rather teaches people how to recognize symptoms of mental health problems, provide initial help and guides people towards appropriate professional help.
      Mental health problems are common but still have associated stigma and many people are not well informed. With respect to substance abuse, it is important to recognise that the use of alcohol or drugs does not in itself mean that a person has a substance abuse disorder. Substance abuse disorders involve dependence, problems at work and at home, and damage to health. Substance abuse symptoms include tolerance, problems in withdrawal, use of larger amounts over longer periods than intended and problems in cutting down and controlling use. In addition, lots of time is typically spent in the process of getting, using and recovering from the substance. The person involved gives up work and social activities and continues to use the substance, despite suffering from its effects. For men, substance abuse can lead to anxiety and depression. For women, however, the sequence is generally reversed, with anxiety potentially leading to depression and substance abuse.
      Turning to causes of addiction, people use substances because, at least at first, they produce feelings of pleasure and may also decrease feelings of distress. Smith also discussed some of the differences between depression and anxiety. If a person is clinically depressed they would have at least two of the following symptoms for at least three to four weeks; unusual sad mood that does not go away, loss of enjoyment and interest in activities that used to be enjoyable, tiredness and lack of energy.
      Other characteristics of depression include loss of confidence and self esteem, feelings of guilt when there is no fault, wishing they were dead, difficulty concentrating, moving slowly, becoming agitated, sleep difficulties and changes in appetite to extremes. Anxiety, on the other hand, can help a person to avoid danger and motivates to solve everyday problems. However, as a disorder, anxiety is a type of uneasiness or panic that can be severe, long lasting and interferes with work as well as relationships. Physical symptoms of anxiety can be cardiovascular, respiratory, neurological, gastrointestinal or musculoskeletal while psychological symptoms are behavioural. Anxiety is caused mostly by perceived threats in the environment, with some people more prone than others to react to life situations with anxiety.

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Superpave – Building for the future

By Andy Bateman, Engineering Editor

     Canada's road network is estimated at 901 902 km, of which 318 371 km is paved, including 16 571 km of expressways, and 583 531 km unpaved. Of the country's paved network, an estimated 95 per cent is paved with hot mix asphalt. Given these numbers, the potential benefits of implementing the Superpave system are huge. Superpave is reportedly able to extend the life of a typical asphalt pavement from 15 to 20 years before major maintenance is needed. (1)
      Nationally, perhaps the biggest current contrast in Superpave implementation is between Ontario and Alberta, the two biggest provinces in terms of hot mix asphalt volume. In Ontario, where some 14 million tonnes of asphalt is produced annually, Superpave implementation is increasing rapidly. The province's ministry of transportation (MTO) is targeting 2005 for full Superpave implementation and had awarded 28 contracts by December 2003 incorporating over 1.5 million tonnes of Superpave asphalt mixes. In addition, a number of the province's cities have completed Superpave projects in recent years and the trend is set for further increases.
      In Alberta, on the other hand, the implementation of Superpave by Alberta Transportation & Utilities (AT&U) is in a holding pattern, pending the review of about 1.5 million tonnes of existing Superpave mixtures placed on the provinces highways. AT&U was among the first highway agencies in North America to implement the Superpave system for its primary highways, with two 1 km test sections laid as early as 1995. AT&U's Superpave tonnage has fallen off sharply in recent years, with 28 000 tonnes in 2002, followed by none during 2003. Projections for 2004 and future years were unknown near the end of 2003. Some Alberta municipalities are following AT&U's lead, while others are steadily increasing their use of Superpave.
      Many provinces have adopted Performance Grade Asphalt Cement (PGAC) as a step in implementation. Some members of the Western User Producer Group report some outstanding binder specification issues and are reviewing existing binders in terms of their performance grade equivalent. Superpave implementation in British Columbia appears to be well established at the provincial level and increasing steadily in a number of municipal public works departments.
      Quebec's unique system has some parallels with Superpave, including the use of a gyratory compactor, but also includes additional requirements such as the use of fractionated aggregates and performance testing of mixes in a wheel rut tester before being placed. Here, the system is said to be fully implemented, with gyratory designed mixes utilised to the extent practicable.
      A number of provinces have conducted parallel studies to see how aggregates and Marshall mix design would be assessed under Superpave while Ontario is also assessing how some Superpave mixes would test for air voids and stability using Marshall mix design criteria.
      In general, those provinces that are generally satisfied with the performance of their existing Marshall design mixes are not rapidly implementing Superpave. For those agencies making the transition to Superpave mixes, the percentage of manufactured sand in existing mixes seems to be a factor, with those agencies already specifying all or nearly all manufactured primary aggregates having the easier transition. Performance modelling, one of the three originally identified elements of Superpave, appears to be largely still under development.
      Looking further east, New Brunswick is the most active province in terms of implementation while others are in relatively early stages of adopting PGAC, conducting trial projects or comparing the existing mixes against Superpave, concluding in most cases that the existing Marshall mixes are performing well.
      In terms of responsibility for mix design, Quality Assurance (QA) and Quality Control (QC), the owner historically handled these functions and this is still the case in some agencies. The current trend is towards transferring mix design and QC responsibility from the owner to the contractor. The owner performs QA, with referee laboratories often utilised to resolve differences in test results.
      On the question of the cost effectiveness of Superpave, a commonly expressed view is that Superpave mixes are slightly more expensive than conventional mixes but are expected to deliver some performance improvement. For many it is a case of "so far so good", with reduced rutting and tight joints. In addition, at least two agencies report that PGAC characterization has delivered noticeable reductions in low temperature cracking. Others however, are not convinced of the cost effectiveness of Superpave. AT&U, for instance, reports that a combination of additional costs and little observed benefits have resulted in a more wait and see approach.
(1) Ontario Hot Mix Producer's Association (OHMPA) Superpave backgrounder, May 2003

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Western Region Report

By Andy Bateman, Engineering Editor

British Columbia
      Mike Oliver of British Columbia's Transportation Ministry reports that Superpave implementation is increasing slowly but steadily, with an estimated provincial tonnage of Superpave mixes of 53 000 tonnes in 2002, increasing to some 60 000 tonnes for 2003. The figure for 2004 is projected to rise to 63 000 tonnes, representing approximately from 5 to 10 per cent of the provincial asphalt paving program. Most mix designs are still completed according the Marshall method.
      With respect to asphalt binders, Oliver reports that Canadian General Standards Board (CGSB) specifications are used in the main with a soft conversion to Performance Grade binders. Gyratory compactors are being used for Superpave mix design only and Oliver estimates that six gyratory compactors are in common use within the province. Trends in testing include QC and QA testing with End Product Specifications.
      QA is being done by the Agency, where binder QA is not performed using Superpave PG grading, but reverts to CGSB. QA is actually performed testing asphalt cement content to ensure consistency, but testing of asphalt cement type is done in accordance with CGSB. Contractors are completing QC, with contractors have a choice of completing this work in house or utilizing consultants. Performance modelling is not being done at this time. In terms of Superpave performance, Oliver reports a case of so far so good, with reduced rutting on the Burnaby Freeway cited as an example.
      When asked to identify barriers to Superpave implementation, Oliver reports no barriers with respect to binder, aggregates, equipment costs or equipment availability, adding that no additional costs of Superpave mixes are incurred when compared to conventional mixes. However, Oliver adds there are some issues with respect to binder performance grading and the Western User Producer Exchange (WUPE) is doing a good job in bringing these issues out in the open. PG grading is reportedly difficult in that QA is not an easy item to check, equipment is expensive and QC from the contractor would not be acceptable without some QA by the agency. QA would require some QC from the binder supplier and some better method of analysing AC type. Additional issues include the potential introduction of split binder grades and the reduction of existing CGSB grades selection by PG grading.

City of Vancouver
      E.C. (Ted) Batty, Materials Engineer for the city of Vancouver, reports that the city switched over to Superpave for most city paving in 1998. In 2002, the city of Vancouver placed 107 000 tonnes of Superpave mixes and about 25,000 tonnes of other maintenance mixes such as patching mix from the city's own plant. In addition, city street paving by contractors resulted in an additional 5000 tonnes of Superpave mix being laid. For 2003, about 85 000 tonnes of Superpave mixes and about 20 000 tonnes of other maintenance mixes were laid. Looking forward, Batty expects Superpave tonnages for 2004 and future years to be in the same range as 2002 to 2003 at about 80 per cent of the city's total hot mix asphalt tonnage. Marshall mix designs are still used in some temporary patching and cold mix pavements. In terms of binder specification, Batty reports that the city presently specifies in accordance with CAN/CGSB- 16.3 Æ M90 specification CGSB Grade 80 Æ 100, Group A (which is equivalent to PG 64-22 for Imperial and PG 64 Æ 28 for Husky). Superpave volumetric mix design has been implemented since 1998, with a gyratory compactor in common use since that time. No Performance modelling is in place. The City's materials laboratory carries out both QC and QA functions as the City produces most of its own mix.
      Overall, Batty reports that there has been noticeable improvement in rutting resistance. The performance of Superpave placed on Knight Street, a major arterial carrying heavy truck and bus traffic, has been monitored and it has been performing well in resisting rutting for the last five years.
     Batty also provides some insights into the costs of implementing Superpave. Looking first at material costs, Batty reports that the city has equivalent PG grade binder available from the suppliers, with Superpave providing a reduced cost due to lower percentage of asphalt binder required. In terms of aggregates, good product is available although there is a slight premium for the extra angularity required. Overall the aggregate and binder costs approximately balance out. Turning to laboratory equipment, Batty estimates that the gyratory compactor for mix design and an asphalt content ignition oven, resulted in approximately $65,000 in additional costs. As for the binder, the city tests for penetration in accordance with specifications and has a viscometer. Batty notes that the city does not have any of the PG grade verification test equipment as the binder is still specified according to CGSB, although it meets the required Superpave PG requirement. Batty adds that Superpave did not require any changes to the City's asphalt plant or pavement placing equipment.

City of Surrey
      Brian Snow of WEB Engineering Ltd. reports that Superpave in B.C. is being implemented on an agency by agency basis and describes the City of Surrey a front runner. According to Snow, implementation is more rapid in urban areas or where there is a competitive market for asphalt pavement producers, while there seems to be reluctance to adopt the changes in smaller markets where there is only one asphalt plant. There is also a lack of design and testing services in remote areas, although mobile equipment is available.
       Marshall mix designs are still used in subdivisions and land development projects with some municipalities not requiring Superpave. The use of Performance Graded binders has been established for five years, as has Superpave volumetric mix design, with two gyratory compactors are in common use. Consultants are doing most of the Superpave QC, with the contractor responsible for QC and the owner responsible for QA.
      Snow note several opportunities for Superpave including improved pavement durability, reduced rutting and pavement performance suited to design traffic and climate, adding that barriers to implementation include equipment availability for design and quality control. That said, Snow reports that there are few if any barriers to implementation in the very competitive Lower Mainland market area. Superpave designed mixes and Marshal designed mixes reportedly cost about the same, although the "more open" appearance of Superpave and easier to compact Marshall mixes have resulted in less Superpave acceptance for subdivision and local roads.
      Snow concludes that the more rigorous design and testing required for Superpave have resulted in better quality oils and aggregate being used locally, compared to the C grade oils and less angular aggregates used previously for most asphalt pavement.

Alberta
Alberta Transportation & Utilities (AT&U) was among the first highway agencies in North America to implement the Superpave system for its primary highways, after two 1km test sections were laid as early as 1995. Chuck McMillan, Pavements Engineering Specialist and Jim Gavin, Construction Standards Specialist for AT&U, report that at this point, the implementation of Superpave designed mixtures is on hold, pending the review of about 1.5 million tonnes of existing Superpave mixtures placed on the provinces highways. The estimated tonnage of Superpave for 2002 was 28 000 tonnes, but with none placed during 2003 and with projections for 2004 and future years unknown at then end of 2003. Up to 2002 approximately 10 per cent of mixes were being placed as Superpave. Alberta Transportation took an early lead in the implementation of Superpave designed mixtures but as it is not constructing additional Superpave projects at this time, Marshall mixtures are being used in all applications. Performance graded binders have been implemented by Alberta Transportation where a modified binder is desired, while non-modified binders are still specified in accordance with Alberta Transportation's conventional asphalt specifications. Modified binders are being specified on new construction as an alternative to conventional asphalts and where the opportunity to construct roads resistant to low temperature cracking can be cost-justified.
      According to McMillan, there are approximately seven gyratory compactors available in Alberta, mainly in the consulting sector. For Alberta Transportation, all QC is the responsibility of the contractor who will do some in-house, although most will employ consultants for Superpave related testing. Consultants do all QA for Alberta Transportation. Improvements in pavement durability, reduced cold weather cracking and reduced rutting are all seen as opportunities of the Superpave system. At this time, Alberta Transportation considers that addressing cold weather cracking using modified asphalts is affective with either Marshall or Superpave designed mixes.
      Overall, issues such as increased permeability, aggregate utilization (the wasting of large quantities of fines), additional costs and little observed benefits have resulted in Alberta Transportation taking a more wait and see approach with respect to further Superpave implementation.

City of Edmonton
      Hugh Donovan of the City of Edmonton reports Superpave has not been implemented within the City of Edmonton with the exception of a number of projects where it has been used. In the City of Edmonton a total of 6000 tonnes of Superpave mix was produced and placed in 2002, representing approximately 2 per cent of all asphalt laid, while for 2003 there were no projects which utilized Superpave. In Donovan's view, Alberta Transportation & Utilities (AT & U) would be the implementation leader in Alberta, and AT&U is on hold with implementation at present. There is currently no timeline for the adoption of Superpave and Donovan does not at this time see the use of Superpave by the City of Edmonton on any project in the near future
       In Edmonton, all the current mixes utilized within the City of Edmonton are Marshall mix designs. The city is slowly getting into the use of Performance Graded binders, with Donovan understanding that the binder suppliers will be specifying their products starting in 2004 with both Canadian General Standards Board (CGSB) and the converted PG grading. Modified binders are being used, including polymer modified binders as well as crumb rubber modified binders on some projects. Volumetric mix design is not yet being done.
      In terms of performance modelling, Edmonton is starting to look at performance modelling of its pavements and currently all overlay design is deflection based. Gyratory compactors have been used in some of the City's more recent work on our SMA mixes as well as our Superpave mixes. The City of Edmonton just recently purchased a gyratory compactor and several of area materials engineering consultants have gyratory compactors. Generally consultants complete Superpave QC and the specifying agencies are moving towards lab certification for asphalt and aggregate materials. Donovan notes that in the Edmonton area reduced rutting is the overall key driver of the majority of studies that the City of Edmonton has been conducting as well as improvement in pavement durability. Some of the barriers seen to implementation of Superpave are the aggregate availability and cost as well as the poor performance of some of the Superpave mixes placed by Alberta Transportation.
       Art Johnston of EBA Engineering also reports that the province of Alberta has pulled back significantly on its use of Superpave mixtures, but has increased the usage of Performance Grade binders, albeit a small portion of their total program. Municipalities generally are increasing their use of Superpave mixtures and PG binders. In Johnston's view, generally speaking, the case in Alberta is opposite to that in Ontario. In Alberta there has been significant usage of mixes designed with Superpave volumetric design methodology, but not much usage of (or specifying) PG binders. Johnston predicts that it will be some time, at least five years, before Alberta sees more Superpave usage than Marshall mixes. Up to the end of 2002, Johnston reports that Alberta Transportation had placed over 1.5 million tonnes of Superpave mix with both conventional (>90 per cent) and PG binder and estimated 2002 tonnage at about 100 000 tonnes. Johnston estimated the provincial tonnage of Superpave for 2003 to be in the 100 000 to 200 000-tonne range for the province and municipalities combined at year end.
      Looking forward, Johnston underscores the position that Alberta Transportation is really in a hold position and wants to continue to monitor the performance of projects in place before making any movement on Superpave. Since 1995 Superpave mixes have been less than 5 per cent of the ministry's program. The high was in 2001, when approximately 13-15 per cent of the program was Superpave designed mixtures while in 2002 it had dropped to less than 5 per cent. Overall, Johnston's guess is that Superpave tonnage as a percentage of all asphalt laid across the province is currently less than 5 per cent.
      For Alberta municipalities however, the use of PG binders and/or Superpave designed mixtures is higher than the province as a percentage of their total program, with the use of Superpave increasing in the order of 10 per cent per year.
      Superpave implementation was initially led by both the ministry and municipalities. Currently it is probably more the municipalities, with consultants playing a significant role in implementation in both jurisdictions. Marshall mix continues to be used for all applications while Superpave, when used, has generally been used on higher traffic applications. Johnston reports that the implementation of PG binders has been slow in Alberta (and generally speaking, West Canada). The primary issue is that the province has been accustomed to high quality binder supply and there is hesitation to implement a new system that may compromise that. That said, Johnston is seeing much more use of PG binder, and specifically modified or engineered binders for special applications such as intersections, but does not think PG binder is established yet. Johnston puts the number of gyratory compactors in the province at 10Æ15 in the province with these in common use. The majority of Superpave QC/QA work is being done by consultants, with at least one contractor having a gyratory compactor.
      Johnston reports a definite difference between the two major Superpave Gyratory Compactor manufacturers, Troxler and Pine, with Pine typically having higher density. Johnston adds that "torture tests", such as Asphalt Pavement Analyser are being used, in some cases, to supplement volumetric designs.
      In terms of the opportunity, Johnston sees the opportunity for PG binders as reduced low temperature cracking and reduced rutting, while for Superpave mixture design the opportunity would be increased durability and reduced rutting. There is one test site in the province to monitor Superpave mixtures, while other test strips constructed by municipalities are less "scientific".
      With respect to barriers to implementation Johnston notes factors for both Performance Grade binders and Superpave mixes. For the binders, Johnston reports concern if a PG binder is specified that the province may not get the quality it has had in the in the past and this has resulted in the splitting of low temperature grades. In terms of cost, modified binders can be very expensive and there is limited evidence at hand to support enhanced performance. Johnston adds that there is currently not much Superpave binder equipment in Alberta (one set known) and this situation would have to change significantly if the province went completely to PG specifications. In terms of Superpave Mixtures, the permeability of Superpave coarse graded mixtures is a concern. In addition there are also aggregate usage and associated cost implications, with additional costs typically in the 0 to 15 per cent range, recognising at the same time that these numbers are somewhat difficult to justify until there is proven performance enhancements in rutting resistance and durability.
      Aggregate quality has not been an issue, as most agencies had aggregate requirements which met or exceeded Superpave criteria. Aggregate cost increases, if any, are the result of securing enough rock to make coarse graded mixtures, recognising that there are no quarry deposits to speak of in Alberta.
      Overall, Johnston thinks that most practitioners agree that Superpave provides a better way of specifying and designing HMA mixtures. Technical developments are needed to supplement the current volumetric design procedures to minimize poor performance, which will impede implementation. Some, including Johnston, feel that Superpave is the most important asphalt technology development in the past 50 years while some believe that Superpave will never be implemented. In Johnston's view, the number one fallacy is that Superpave is a mix type. It is, in fact, a methodology. Not only is Superpave applicable to all pavement applications, but the fact that a mix can be specified and designed to the specific conditions and requirements of a project (low or high traffic, new construction or rehabilitation, climate etc.) is, the primary advantage of the "system".

Saskatchewan
     Bill Pacholka, director of Testing Services for Saskatchewan Highways and Transportation reports that the province has completed test sections on Highway 16 northwest of Battlefield, of which five were Superpave mixes. In addition the province has purchased a gyratory compactor and technicians have been trained in its use and there is some movement towards the use of Performance Grade asphalt binders. However, Pacholka adds that existing mixes are performing well and as a result there is not felt to be a great need to implement Superpave mixes. Overall, the province is maintaining a watching brief on Superpave developments through representation on Canadian Technical Asphalt Association (CTAA) and Canadian User Producer Group for Asphalt (CUPGA) committees and the Western User Producer Exchange (WUPE), whose members include British Columbia, Alberta, Saskatchewan and Manitoba.

Manitoba
      Leonnie Kavanagh, surfacing materials engineer in the Materials Engineering Branch of the Manitoba Department of Transportation and Government Services reports Superpave in Manitoba is at the research and feasibility stage. Implementation would be done as part of the Western User Producer Exchange (WUPE), whose members include British Columbia, Alberta, Saskatchewan and Manitoba. Manitoba's Department of Transportation and Government Services has done Superpave test projects since 1995 and is currently looking at existing binders in terms of their performance grade equivalent, and, as part of WUPE, reaching a consensus on binder requirements.
      The availability of good crude oil is cited as one of the factors translating into not a great sense of urgency and Superpave's slower implementation than elsewhere. The ministry's provincial tonnage for 2002 did not include any Superpave, while in 2003 it consisted of a test strip of 3600 tonnes, completed to full binder specification. Looking forward, the province is looking to full implementation of the Performance Grade binder specification by 2005 as part of WUPE. As a result Marshall mix designs are currently still used in all mix designs, and neither Superpave volumetric mix design nor performance modelling has been implemented. The department has two gyratory compactors, and the full set of Superpave Binder equipment, which are being used to complete the binder comparison with Marshall volumetric, while all QC and QA is completed in house under method specifications.
     The perceived opportunities for Superpave are reduced cold weather cracking and reduced rutting on major routes. While Superpave offers a more scientific approach to binder selection, there are barriers to implementation. These barriers include the incremental cost of binders; based on the information to date from a number of test strips, binders that are currently used are meeting the Æ28ÁC low temperature criteria temperature parameter according to performance grading. In order to meet PG requirements to withstand Æ34ÁC or Æ40ÁC in colder parts of the province, mix costs would be increased by 20-25 per cent. With respect to aggregates, there are increasing costs in some cases associated with improving aggregates from a source to meet Superpave specifications. Finally, transition costs will be incurred, such as the new bank of knowledge with respect to the performance of new binders (such as modified binders) and their appropriate site treatment. Test costs can be higher and be slower, sometimes taking up to 24 hours. That said, Kavanagh does not feel there has been any significant increase in laydown cost due to increased aggregate and testing costs.

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Eastern Region Report

Ontario
     In Ontario, the pace of Superpave implementation has increased rapidly in recent years, and Ontario's Ministry of Transportation (MTO) is seeking to fully implement Superpave by 2005. Anil Virani, Senior Bituminous Engineer with the MTO reports that, as at December 2003, 28 of the ministry's contracts have Superpave mixes, totalling almost 1.5 million tonnes. Of these, fourteen had been completed by December 2003.
      In 2002, 11 contracts were awarded, including a major low temperature trial on Highway 655. The total tonnage in these job was 625 000 tonnes, including one 175 000-tonne contract. Of the total, only 106 000 tonnes was placed in 2002, with two contracts completed, five others underway and four not started. All mix types were placed, including Superpave 9.5 mm through 25.0 mm Nominal Maximum Size (NMS) mixes. In 2003, 16 contracts were awarded plus one negotiated contract for a total of 860 000 tonnes including one 190 000-tonne contract.
      The first MTO Superpave test section was completed on Highway 118 near Bracebridge in 1997 while full Superpave specifications were utilised by the MTO on a 400 Series Highway for the first time in 2001 on Highway 404 near Newmarket.
      In terms of binder implementation, the MTO started using Performance Grade Asphalt Cements in 1996 and made their use mandatory in MTO contracts in 1998. Ontario has three designated primary climatic zones with PG 58-28 used in the South, PG 58-34 used in the North East and PG 52-34 used in the North. PG grades are bumped as required based on criteria such as traffic level and speed in accordance with Asphalt Institute guidelines. Superpave mix implementation started in 2002, with Superpave mix requirements taken directly from the Asphalt Institute. (Traffic categories A, B, C, D, E are used instead of Asphalt Institute traffic count in Equivalent Single Axle Loading or ESAL's). MTO engineers recognise that a performance test is needed to supplement volumetric mix requirements.
      Ontario's first municipal Superpave job was in Frontenac County in 1996, and since then a number of the municipalities in the province have played a leading role in Superpave implementation including the Cities of Toronto, Ottawa, Kingston, Hamilton, Mississauga as well as the Region of Durham. Most of these agencies are enthusiastic about the potential benefits of Superpave, reporting reduced rutting and low temperature cracking. Some recognize that mix costs may be somewhat higher (Toronto indicates about $5/tonne more) while others, such as the City of Ottawa, have found the immediate introduction of Superpave mixes would require adjustments in existing mix designs and limits to the amount of natural sand.
      All MTO contracts require the contractor to provide mix designs and meet End Result Specification (ERS) requirements for hot mix. There is no limitation on aggregate types used, provided the aggregates meet the Source Aggregate Properties and Consensus properties. The MTO ERS system has significant payment reduction potential, with some bonus available for high quality mix, and the risk associated with the ERS system has brought significant focus on the correlation of test results between contractor's QC and the owner's QA testing. Initial contracts saw some significant variation in test results reported for ERS purposes, with referee testing used to resolve these differences. With experience increasing in QA and QC laboratories, test variation is becoming less. Virani reports that about 30 labs are currently participating in the MTO's Superpave Gyratory Compactor (SGC) correlation program. The difference in equipment due to internal angle is still considered to be a significant source of test variability between laboratories. A testing "Best Practices Guide" has been prepared in the hopes of minimizing result variation due to laboratory procedural differences. (See sidebar on gyratory compactor angle for more information).
      For contractors, Superpave challenges include the requirement to complete mix designs to the various categories with minimal experience on aggregate and mix requirements. Innovative solutions developed for the collection of the large samples over 20 kg required for testing include the hopper method, screed auger and other methods. Remaining challenges include learning to monitor and maintain mixes in conformance with all Superpave mix parameters such as N ini, N max, VMA, VFA, DP, in addition to ERS requirements such as Air Voids, AC content, Aggregate Gradation and Compaction.
      For the MTO, the main challenge is that it confirms all mix designs although there has been generally good correlation obtained so far. Other challenges include the administration of Superpave mix parameters, while there are also some concerns with regard to the lower AC contents of Superpave mixes in comparison to traditional Marshall mixes. Current research and development by the MTO includes a parallel study of Marshall and Superpave mix design. Phase one of this study looked at how aggregates and Marshall mix design would be assessed under Superpave, while phase two will look at how some Superpave mixes would test for air voids and stability using Marshall mix design criteria. The MTO is also working with researchers at Queen's University on a project to assess Superpave performance predictability for cold weather cracking.

Quebec
      In 2002, 4.4 million tonnes of hot mix asphalt was produced for MTQ of which some 1.85 million tonnes or 42 per cent of the mixes were designed with a gyratory compactor. Typical HMA production prior to 2002 was 2.5 to 3.5 million tonnes per year. The province's approach is a blend of Superpave design and French design methodology. Mixes here are compacted in a gyratory compactor to Ndes at 80 or 100 gyrations, based on mix type. Mixes are evaluated in a wheel rut tester, with maximum rutting specified. Mix Asphalt Cement (AC) contents are set by specifying a minimum AC content and the gradation of mixes is adjusted to provide AC and mix property requirements. Initial mix designs were completed by the MTQ from 1995 to 1999 with contractors completing mix design since 1999. Mixes have been manufactured with fractionated aggregates since 1999, utilizing fractions sized at zero to 2.5 mm, 2.45 mm to 5 mm, 5 mm to 10 mm, 10 mm to 14 mm and 14 mm to 20 mm. Manufactured aggregates only are specified, with no natural sand content allowed.
      Polymer modified PGAC is specified for use on highways, with PG 58-34 comprising 52.3 per cent of total asphalt, followed by PG 64-34 at 25.9 per cent. PG 70-28 has been used since 2001. Binder implementation was considered to be smooth with minimal problems. In terms of overall implementation, current levels are considered to represent 100 per cent implementation with gyratory design completed on all major highways and where contractors are available that have the equipment to do the design with the specified equipment. In remote locations or areas where contractors do not have equipment, Marshall mixes are specified, or an option is given to use Marshall instead of gyratory design.
       In terms of testing, the province's current QA/QC system requires the contractor to provide test results, with MTQ testing doing limited sampling in one of two MTQ testing labs. If there are differences in test results, the contractor proposes an independent lab as referee and the results obtained from the referee lab are binding. All labs are ISO certified, giving both the owner and contractors the confidence that testing is completed according to requirements.

New Brunswick
      Terry Hughes, Paving Engineer for New Brunswick's Department of Transportation explains that, since the first Superpave project of 1262 tonnes was completed in 1997, a total of 51 projects have been completed to Superpave requirements, giving a total accumulative Superpave tonnage to date of 297 000 tonnes. All of these projects are highway related. The hot mix asphalt tonnage for 2003 for the New Brunswick department of Transportation was 570,000 tonnes of which 114 000 tonnes (20 per cent) has been completed to Superpave requirements. The total tonnage for this year largely depends on a single large job, the twinning of the Trans Canada highway. Nonetheless, Hughes expects the percentage of jobs done to Superpave specification to steadily increase.
      The DOT is leading Superpave implementation, with Hughes reports that Superpave implementation has not required any major changes to existing mix designs and no big changes have being required of aggregate producers. Initial comparison testing of Marshall mixes to Superpave mixes showed similar results between mix design procedures, although some differences in AC content were noted. All primary aggregates used in hot mix asphalt have to be manufactured, with blend sand allowed up to a maximum of 10% in mixes to help obtain acceptable VMA. From 1997 to 2002 inclusive, mix designs were primarily completed by New Brunswick DOT as well as the QC. Contractors had little problem in adapting to Superpave mix due to their similarity with existing Marshall mixes.
      Performance Grade binder (PGAC) was implemented in all projects in 2001, although some municipalities may still be using penetration grades. PG 58-34 is the primary grade of AC for new construction, while PG 58-28 is typically used for resurfacing, and other grades such as PG 64-34 have been utilised in special cases involving unusually heavy truck loading. Hughes reports a noticeable drop in cold temperature cracking due to PGAC implementation, as measured by the required lineal meters of sealer in the yearly crack sealing program.
      New Brunswick DOT tendered their first End Result Specification (ERS) contract in 2003, with contractors now responsible for own mix design and QC testing. The province currently has 6 gyratory compactors including 1 permanent station and 5 portable units, and Hughes predicts the number of compactors in private hands will increase as the province progressively hands off QC responsibility to contractors and consultants. First year correlations between contractors and the DOT were good, with some differences but only minimal problems.
      Overall, Hughes describes implementation as gradual, with the pace of implementation mainly controlled by the availability of funding to purchase the required gyratory compactors. There is also some concern with the variability in results between gyratory compactors and the effect gyration angle has on compacted sample density. Hughes describes this as a major problem when trying to compare QA results done by the DOT with QC results from a contractor. In terms of field performance, Hughes reports that the Superpave mixes have not been down long enough to compare their performance with Marshall mixes.

Nova Scotia
      Tom Gouthro, Manager of Technical Services in Nova Scotia's Department of Transportation and Public Works (TPW), explains that Superpave has not been extensively implemented in the province, with three trials using Superpave mixes completed to date. The Department's total hot mix asphalt tonnage is approximately 500 000 tonnes per year, with Superpave tonnage on DOT projects to date totalling 31 826 tonnes. There are no municipal projects at this time. TPW had no Superpave mixes in 2002 or 2003, and projected 2004 tonnage was unknown at the end of 2003.
      Gouthro feels that the good performance of existing mixes is a factor in the province's pace of implementation, with many of the existing (Marshall design) mixes delivering performance close to Superpave mixes. Asphalt Institute specifications have been used, under which Superpave mixes did not appear to differ significantly from Marshall mixes.
      In terms of binder specifications, the province is in its third year of specifying Performance Grade Asphalt Cement (PGAC), with PG graded asphalt cement 100 per cent implemented in 2000. The DOT and all municipalities now specify Performance Graded Asphalt Binder, typically specifying a 58-28 PG binder. Contractors have adapted well to PGAC specifications with the limited grades utilised, while Marshall mix designs have been used in all applications to date with the exception of the Superpave trial projects. Contracts now include a negative price adjustment to meet the performance grade requirements.
      With respect to the Superpave aspects of volumetric mix design, Gouthro explains that the province has developed aggregate gradations over the past seven years that are similar to those associated with Superpave mixes. Most aggregates used in hot mix asphalt are manufactured, with up to 15% natural sand allowed. TPW has also adopted the Consensus Aggregate Properties as well as moisture sensitivity testing (AASHTO T 283). As a result, no special aggregate production has been was required to meet Superpave mix requirements. There is no firm Superpave mix design implementation schedule.
      Turning to equipment and testing, the province has purchased a gyratory compactor in conjunction with Dalhousie University, although the equipment is not in regular use. For the trial Superpave projects, all QC and QA was contracted out to local consultants. One project has been completed where mix design testing was done with Superpave in combination with Marshall testing. Gouthro adds that there is insufficient data at present to compare the performance of Superpave mixes to Marshal mixes. Non-Superpave mixes appear to be performing reasonably well, and it is therefore difficult to rationalize the cost/benefit for adopting Superpave mixes. There are some concerns over whether durability was adequately addressed in the Superpave research, while compaction was found to be a problem during the paving of Superpave mixes. Overall, TPW is continuing to follow developments in Superpave implementation elsewhere in Canada and the U.S.

Prince Edward Island
      The total reported annual hot mix tonnage in PEI is between 250 000 to 300 000 tonnes, of which 150 000 to 200 000 tonnes is in the construction of larger projects with the remainder in patching. In terms of overall Superpave implementation, the overall message is one of few problems with existing mixes and not strong motivation to change. At present, there is no Superpave mix design implementation schedule although a small job may be possible in 2004.
      Performance grade asphalt cement has been in use in the province since 2000, with PG 58-28 adopted as the standard grade. (The initial grade adopted was PG 58-34 but this was found to be too soft.) To date, no projects have been completed with a Superpave gyratory compactor; plans were in place for the first Superpave project in 2003 but this did not go through.
      Turning to equipment, mix design and testing, PEI's DOT has had a gyratory compactor since 1996 although it is not currently used. The DOT does all mix designs and QC testing. Standard Marshall mixes were tried in the gyratory compactor and it was found that current Marshall mixes meet Superpave requirements. It was also found that gyratory design yielded marginally lower AC contents (0.1 per cent less). For aggregates, 100 per cent quarried (crushed) aggregate is effectively specified for all mixes in the province. Natural sand fine aggregate was allowed up to 1997, but has since been limited as a result of poor results.
      Mixes may still contain 3 to 5 per cent natural blend sand to adjust the Voids in Mineral Aggregate (VMA) content.

Newfoundland
      Newfoundland's Department of Transportation implemented Performance Grade asphalt cement as of 2003, with one grade, PG 58-28 established as the standard grade for the province. It is realized that this grade does not meet all Superpave low temperature requirements, but for Newfoundland, decisions such as these are also based on cost, availability and storage capacities. Complete Superpave design has not yet been completed in the province. No Superpave projects have been completed to date, with one project, planned for completion in 1999/2000, not carried through.
      In terms of mix design, equipment and testing, the Newfoundland DOT has a gyratory compactor but this is little used at present. The DOT does all mix designs for projects and all QC testing, although recent initiatives include the formation of a committee to download and outsource mix design to the private sector. In addition, trials have been completed by compacting existing Marshall mixes in the Superpave gyratory. The results of this work were mixed, indicated that some mixes were found to meet Superpave, while others did not meet Superpave requirements. This particular province places no upper limit on the natural sand content in a Superpave mix.

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Canadian debut for portable sand plant

By Andy Bateman, Engineering Editor

     Making its debut in Canada, a port- able sand recovery unit has in- creased asphalt blend sand output and overall wash plant efficiency for an Ontario aggregate producer.
      The new unit, not only Canada's first but also the first operating in North America, recently went into production at the Norwood sand and gravel pit of Drain Bros Excavating Ltd. This pit supplies significant aggregate volumes to the company's construction, asphalt, and utility divisions as well as the Peterborough market 35 km to the west. Production foreman Craig Oliver explains that the main reason for the new wash plant set up is the increased recovery of asphalt blend sand fine fractions that were previously being lost to the pit's settling ponds. This improved recovery translates into increased output of asphalt blend sand for the company's pit-based hot mix asphalt plant, an overall increase in wash plant capacity and reduced settling pond maintenance costs.
      The Powerscreen FinesMaster 120 sand recovery unit combines twin bucket wheels, twin hydro cyclones, collection tank, dewatering screen and a centrifugal slurry pump on a single chassis. At Norwood, the new unit was teamed with a Powerscreen Commander 1400 rinser plant to produce an integrated portable wash plant up with a reported total throughput rate of 250 tonnes/h. The plant's operation has reportedly been good so far, although its arrival in August 2003 did necessitate some juggling of feed materials. Oliver explains, "For the 2003 construction season, we utilised different feed materials to ensure that the plant's asphalt blend sand output met the gradation required by our existing asphalt mix designs. When producing blend sand, the plant has been fed with pre-screened sand containing a small amount of coarse material. When producing filter media sand we used Granular A, also produced here, as the feed material. However, we will soon be using just the Granular A to produce both asphalt blend sand and filter media sand, using the capability of both the rinsing screen and the sand recovery unit to process two sand sizes at the same time. The resulting small change in asphalt blend sand gradation will be reflected in 2004's asphalt mix designs."
      During blend sand production, a John Deere 744H wheel loader charged the feed hopper of the Powerscreen Commander 1400 rinsing plant with pre-screened sand. From there, the hopper's 1067 mm wide variable speed feed belt regulated material flow onto a 1067 mm inclined conveyor that in turn discharged onto a 5x12 two deck rinsing screen. The urethane upper and lower screen decks had 13 mm and 6.3 mm square openings, respectively, to separate 32 mm x 13 mm and 13 mm x 6.3 mm round roofing stone in the feed from the 6.3 mm minus sand. Oliver estimated the product split off the rinsing screen at 90 per cent blend sand, with the two roofing stone sizes each making up about 5 per cent. A total of 13 spray bars, 6 above each screen deck and another in the screen's wash box, provided sufficient water to both rinse the feed and flush the sand through to the second stage of the process.
      Sand slurry arriving at the FinesMaster 120 plant first discharged into the unit's bucket tank. From there, it was recovered by wheel mounted perforated buckets that provided a steady flow of material to the unit's dewatering screen as well as some initial dewatering. The high frequency 5 x12 dewatering screen was fitted with 500-micron (0.5 mm) polyurethane modular mats and split longitudinally to allow the production of two grades of sand if required. Dewatered product off the screen was conveyed to product stockpiles, while water and fines passed through the screen into a collection tank below. Material settling in the collection tank was pumped up to twin 380 mm cyclones by the unit's onboard Linatex 150 mm x 125 mm pump. The coarse fraction (underflow) from the bottom of the cyclones combined with new incoming material from the bucket wheels and passed once more over the dewatering screen. Meanwhile, the cyclone overflow was piped directly back into the collection tank where, excess water and fines in suspension passed over weirs for return to the pit's settling pond.
      The overall fresh water requirements for the set up were relatively low, with the rinsing screen spray bars the only system fresh water input point. A 150 mm centrifugal pump, also utilised for the previous wash plant, pumped fresh water to the plant. Power was provided by a trailer-mounted Caterpillar generator set that teamed a 3306 engine with a 205kW generator.
      Oliver confirms that the FinesMaster plant has significantly increased the recovery of blend sand fraction between 75 and 300 microns, but is waiting until the plant is running steadily with a single feed before measuring the overall improvement in fines recovery and the corresponding drop in tonnage going to the settling ponds. According to the manufacturers, fine material recovery is 96 Æ 98 per cent for all material larger than 75 microns and 100 per cent recovery of all material larger than 150 microns. The manufacturer adds that FinesMaster users can expect a typical total throughput rate of 120 tonnes/h when producing either one or two grades of sand. The moisture content of the finished product is said to be between 10 per cent and 15 per cent, or low enough for the product to be loaded directly.
      As part of this year's plan to produce two sand sizes from a single feed, Oliver is changing the sizes of the screen cloths on the bottom deck of the Commander 1400 rinsing screen. The first 1.22 m long panel has 3 mm openings while the second and third position panels has 6 mm openings. The lined catch box underneath the bottom deck is split longitudinally so that material passing through the first panel is kept apart from material passing through the second and third panels. Each sand size is then processed separately by the FinesMaster plant and discharged onto separate product stockpiles.
      To facilitate production, the Commander 1400 plant is fitted with a remote tipping reject grizzly on the feed hopper as well as hydraulic angle adjustment on the 1400's rinsing screen. Production boosting features highlighted for the FinesMaster 120 plant include heavy-duty construction, low maintenance, rubber lined wear areas and quick set up facilitated by hydraulic jacks on the bucket tank and bogie. An 11 kW motor drives the bucket wheels with each wheel carrying 14 buckets. Inlet boxes to the bucket wheel tank have been designed to reduce turbulence while the tank's weir discharge system is said to reduce the volume of fines entering the collection tank. To fine tune sand production, the FinesMaster's twin bucket wheels have variable speed control between zero and 3.3 rpm. In addition, the two rubber-lined cyclones (classifying at approximately 75 micron) discharge via an adjustable chute, which can, if required, allocate recovered material to either the coarse or fine product split on the dewatering screen. Mobile and static versions of the Fines Master 120 are available, with the mobile version supplied complete with a fifth wheel for road transport, dual wheel approved braking, single axle leaf spring suspension and air brakes.
      Darrell Drain is president of Drain Bros. Excavating, a fully integrated family run business based in Norwood, Ont. that handles aggregate and hot mix asphalt production, a distribution fleet of some 60 trucks, sewer and water main construction as well as general construction and two road paving crews. The Norwood operation is one of six company sand and gravel pits in regular use in addition to a number of others that are operated on an as needed basis. The company also owns and operates a limestone quarry at 11th line in Dummer Township.

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Focus on Cold Planers

Roadtec RX-500 offers two track assemblies for increased versatility

     The Roadtec RX-500 is a lighter weight, highly manoeuvreble cold planer that allows contractors to tackle a wide range of demanding urban milling jobs. Available with the new four-track assemblies or optional three-track suspension version, the machine features a two-stage covered 813 mm wide front load-out conveyor that features a 60Á swing to either side for ample capacity and greater flexibility when loading trucks in tight places.
      Powered by a Cummins QSX-15 diesel engine rated at 500 hp @2100 rpm, the RX-500 allows contractors to cut up to 3300 mm deep with cutter drum widths of 1.9 m, 2 m, or 2.18 m.
      The drive system comprises a mechanical V-belt drive to the cutter drum planetary and hydrostatic drive for propulsion and conveyor system operation. The hydraulic suspension system can be controlled either manually or automatically.
      The four-track model has B3-HD track drives with 305 mm wide polyurethane grousers, front and back. Travel speeds range from 0-5.1 km/h with a high working speed of 0-46 m/min and 0-31 m/min in low speed operation.
      The three-track machine has two B3-HD track drives with 305 mm wide grousers on the front and one B3-HD drive with 365 mm wide grousers on the back. The travel speeds are the same as on the four-track model however the maximum working speeds are slightly slower at 39 m/min and 30 m/min in high and low mode, respectively.
      Steering is accomplished by a proportional joystick control that offers four modes: coordinated, crab and front only and rear only. The turning radius of the four-track machine is 2 m and 1.7 m with the three-track model.
      The operating weight of the four-track RX-500 with a 1900 mm cutter drum is 26 309 kg while the operating weight for the three-track model with the same width cutter drum is 25 178 kg.
www.roadtec.com

New Wirtgen WR 2500 S boosts performance

     The new WR 2500 S road reclaimer and soil stabilizer from Wirtgen America, Inc. is a next-generation successor to the well-established Model WR 2500. According to the manufacturer, the "S" in the WR 2500 S stands for "Super", because the WR 2500 S is a beefed-up, higher performing version of the existing WR 2500.
      In addition to its high performance as a full-depth base recycler of failed road pavements and as a soil and base stabilizer, like its predecessor, the WR 2500 S can be equipped for foamed or expanded asphalt to make cost-efficient foamed asphalt-stabilized base.
      Among the improvements of the WR 2500 S over the WR 2500 is a new fuel injection system in the 12-cylinder Mercedes engine that boosts engine power from 610 to 670 hp. The engine now meets EPA Tier II regulations.
      Another improvement includes a redesigned, reinforced cutter drum housing that incorporates multiple wear plate inserts to minimize wear. The cutter drum has been redesigned to include bolt-on end rings, which are easier to service.
     The cooling air routing has also been reversed, improving cooling performance, operator comfort, and ambient particulate levels. The engine now rests in a newly enclosed compartment. A new dual-cyclonic air precleaner provides extended service life for the air filtration system.
     Exhaust emissions are now redirected toward the rear of the machine and away from groundsmen. The operator's compartment has been redesigned to feature a larger air conditioning capacity, with increased visibility despite a reduced glass surface area. A second seat has been added. The ergonomic control panel has been redesigned, including a height-adjustable, multifunction computer graphics display which helps the operator visualize and control functions such as steering, drum door position, and emulsion injection system. The area work lighting system has been placed in a bar integrated with the operator's compartment roof for a cleaner and safer performance.
     Its diesel engine powers a 2438 mm wide by 508 mm deep cutting rotor, making it a true, high-horsepower deep-cutting heavyweight. Its two-frame design allows the WR 2500 S to retain Wirtgen's "floating hood" concept, allowing an expanded volume of material to pass freely through the process without creating a "friction brake" effect on the cutter and cutter drive components.
     Material size is controlled by using hydraulically adjustable, manganese-lined breaker bars that can be remotely adjusted by the machine operator to tighten or close down the area between the rotating cutter and the impact bars, a scheme used for decades by the aggregate crushing industry.
     Its Type III holder system allows quick and easy replacement of broken or worn-out cutter bit toolholders without the inconvenience and added cost of a cutting torch and welder. Drum rebuilding can be executed in one day by two workers without removal of the cutter.
www.wirtgenamerica.com

Bomag's new centre-mounted recycler/stabilizer has wider rotor, bigger engine

    Offering contractors and road maintenance agencies the choice of a recycler/stabilizer with a centre-mounted rotor, the new MPH122 from Bomag Canada features a wider rotor, greater cutting depth and a more powerful engine than the previous model.
     The new recycler/stabilizer joins a Bomag product line that currently includes three rear-mounted rotor models: the MPH454R, the MPH362 and MPH364. All four models feature hydrostatic rotor drive with automatic power adjustment that allows them to stabilize or recycle a variety of materials, including oil and chip surfaces and asphalt roadways.
      The new MPH122 offers a 2336 mm wide rotor with 194 cutting teeth and a maximum cutting depth of 500 mm. Cutting teeth are strategically positioned for uniform material pulverizing, sizing and mixing with minimum vibration and shock load to the rotor and drive components. Turning speed of the up-cut style rotor can be varied from 100 to 170 rpm.
      Pulverized material may be mixed with a binding agent or additional granular material for improved road-base performance. Additionally, the manufacturer claims the universal rotor design on the MPH122 makes it equally effective at soil stabilization applications. An optional stabilizer rotor is also available.
      Powered by a 442-hp Deutz BF6M 1015 water-cooled diesel engine, the MPH122 features all-wheel drive for enhanced performance on severe grades or in difficult traction conditions. Manoeuvrability is further enhanced by the combination of a compact design and articulated and rear-wheel steering. Boasting a maximum working speed of 66.7 m/min, the MPH122 features an adjustable rotor hood that allows the mixing chamber to be configured to the type of soil or materials encountered.
      Designed to provide a high degree of comfort and visibility, the MPH122 operator's station includes a laterally adjustable seat with 90-degree swivel, two steering wheels, two driving levers and an ergonomic control layout. For operator safety, a ROPS/FOPS with seat belt is standard equipment. An enclosed cabin with heating and optional air conditioning is also available. Features such as automatic rotor switch-off, automatic brake actuation and emergency stop switch help protect workers in close proximity to the machine.
      Large capacity hydraulic pumps and motors ensure efficient operation of the MPH122, even under extreme conditions. A rigid frame, robust axles and an integrated hydrostatic rotor drive ensure reliability and long life.
      The MPH122 has been designed for ease of maintenance and serviceability. Maintenance points have been minimized and conveniently positioned for quick, easy access. The operator's platform may be lifted to access all components and hydraulic test points are centrally located for simplified fault finding. Bolton rotor segments can be easily replaced, eliminating the need to remove the entire rotor configuration in case of wear. Cutting tooth replacement is simple with an easy tap-in/tap-out design.
www.bomag-americas.com/canada

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January/February 2004 issue

Aggregates and Roadbuilding Magazine
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