The use of aggregate material continues to grow throughout the US and aggregate equipment manufacturers are improving their products to meet the demands for higher efficiency and uptime. According to the US Geological Survey (USGS), third-quarter consumption of crushed stone in 2013 was up 8% from the same period in 2012, but don’t forget recycled materials such as concrete, glass and RAP (recycled asphalt products). All told, contractors are handling higher volumes of aggregates, and that requires tougher equipment to stand up to the task. Not surprisingly, manufacturers are answering the demand with new designs that deliver more power and better fuel economy. So, let’s take a look at some great examples of these hard working products, and we’ll wrap it up with some amazing compacting technology for insuring a perfect pavement density.
If there’s one common denominator to aggregate handling, it’s simply that these products have to be strong. Especially if you’re transporting a load of recycled concrete in the range of 26.5 to 43 tons, a task that’s well suited to Volvo’s new line of G-Series articulated haulers. There are five models in the line, and to keep things moving, these brutes can haul a load around at 33–35 mph. Moreover, the articulated design offers additional safety, according to Eric Hillman, Volvo product manager for articulated haulers and wheel loaders.
“The big difference between the articulated and solid frame is that all of stress goes into a solid frame when driving over potholes or obstacles in the road,” says Hillman. “But the articulated design allows the front and rear to rotate in our trucks as two separate components. They are designed so that if for some reason the back end of the truck flips over on its side it can be lifted up and flipped back over again. Without that the whole truck could flip over, and it’s very dangerous to the operator.”
Those rough roads are stressful for drivers, but the ride will remain smooth, even on the ugliest terrain, if you choose the full suspension option. “The full suspension is a real advantage for high productivity because you can travel much faster,” says Hillman. “Typically if you’re driving a rigid frame truck, or even in articulated one, you have to maintain the quality of the entire road to keep the hauler safe from those bumps and potholes. But with this suspension, you don’t need to, so you’re also reducing the amount of the equipment and labor required to get the job done.”
The engineering behind the full suspension is another example of how technology is progressing. The system supports every axle on the vehicle and uses sensors to monitor the payload where the axle is located. Thus, if one axle drops down, the oil can travel between cylinders at the middle axle and the rear, and if the wheel on the opposite side drops, it can transfer oil diagonally and longitudinally as well.
“These are very sophisticated electronics,” says Hillman. “Also, it’s different than the typical nitrogen-over-oil suspension where the fluid is trapped in the cylinders, and if anything should happen such as contamination, it could destroy the seals. In the Volvo’s system, the oil is moving in and out all the time, and we’re taking it back and cooling it and running it through the filter. So we send fresh oil out as well.” For public highway transportation to sites, the operator can activate a switch in the cab and lower the suspension by draining the oil out of the cylinders, dropping the height significantly.
Another tough competitor in the articulated category comes from Komatsu America Corp. in Rolling Meadows, IL. The company recently introduced the HM300 Tier 4 Final articulated dump truck. It can haul a 30.9-US-ton (28-metric-ton) payload and features the Komatsu Traction Control System to automatically optimize traction when operating in soft ground conditions. If tire slippage is detected by the speed sensors located on four wheels, automatic application of the inter-axle differential lock occurs. Should the slippage continue, four independent brakes can be applied to slipping wheels to regain traction.
If you’re filling large trenches with aggregate, take note, Komatsu has launched its third generation Hybrid HB215LC-2 Hydraulic Excavator. The Komatsu Hybrid System includes Komatsu’s electric swing motor, power generator motor, ultra-capacitor, and a 139 HP diesel engine. The design works on the principle of swing energy regeneration and energy storage to capture kinetic energy generated during the swing-braking phase. The reserve power stored by the hybrid technology equates to approximately 60 additional horsepower and saves an average of 20% in fuel usage.
Caterpillar has also developed a hydraulic hybrid excavator. The Peoria, IL, company debuted its 336E H model last year and, according to Kent Pellegrini, product application specialist for Cat Excavators North America, customers appreciate fuel savings that don’t compromise performance. “In general, it’s a step up, and it’s not a price killer for a contractor to purchase,” says Pellegrini. “It’s a simple system to understand, and economical. Customers with a traditional 336E have been running at about 11.5 gallons an hour on a high load factor, but this machine on average is about 8 to 8 1/2 gallons an hour, and that makes a big difference.”
The Cat hydraulic hybrid system doesn’t convert kinetic energy to electricity—instead it uses an electronic standardized programmable (ESP) pump that provides power when needed and reduces power when not needed. Moreover, the fuel savings aren’t limited to swing-intensive jobs. Cat performance tests have shown that in multiple applications customers see significant reductions in fuel consumption—up to 25% less than the 336E, because engine rpm is significantly lower than the standard 336E model, and the larger displacement, electronically controlled pump is used to compensate.
“In utility applications where you’re working primarily right out in front of the machine and you’re not demanding as much power, such as putting in bedding material, the pump won’t work as hard,” explains Pellegrini. “But when you’re loading a truck at 90 degrees and using the full extension from the bucket stick and boom, it’s putting a higher demand on the pump, so it strokes up. Then, the adaptive control system, which is the main valve, provides power precisely when it’s needed, as well as regenerating oil flow within the main valve. One of the biggest things to overcome for customers is just understanding how a machine can run at 1550 rpm maintain power, because it makes a huge difference in noise as well. It’s amazing to see it running and digging right in front of you, and yet you can barely hear it.”
A wheeled excavator can speed up travel time at the jobsite, and Hyundai’s R180W-9A offers a good benchmark for features on a machine with an operating weight of 38,100 pounds. As with so many other manufacturers of construction equipment, the Norcross, GA-based company has focused on improvements to hydraulic system technology as a priority. For the R180W-9A, hydraulic design upgrades provide the operator with fine touch and controllability. Improved pump flow minimizes fuel consumption and improved spool valves are engineered to provide more precise flow to each function with less effort. Enhanced hydraulic valves, precision-designed variable volume piston pumps, fine-touch pilot controls and enhanced travel functions make for smooth and easy operation. Arm-in and boom-down flow regeneration and control valve technology have improved, and an innovative auto boom-swing priority function optimizes performance across multiple applications.
Hyundai also offers a wide choice of recently upgraded wheel loaders in its 9A series product line. The HL780-9A wheel loader is designed for contractors working in recycling, quarrying, aggregates, and timber yard applications. With its bucket capacity of 7.1 cubic yards (5.4 cubic meters) and a 352-hp engine, this is a machine built for big jobs. For projects that require loading high-sided trucks or hoppers where a higher dump height is needed, there’s an extended reach (XTD) model. But maybe your projects just don’t need such a large machine. In that case, take a look at the HL730-9A, advises, Lee Shirey, Hyundai construction equipment trainer.
“The HL730 is versatile and a good size that can move aggregate around,” says Shirey. “The 128-hp engine is fuel-efficient, and this machine has features that are shared across the range of 9A wheel loaders, such as the clutch control and engine power.”
The HL730-9A loader has a fully automatic transmission for improved travel speed and low noise. The improved clutch control and minimizes shifting shock and the operator can customize the machine’s engine power, automatic transmission, shift time, and clutch cut-off activation based on the job condition and personal preference. Engine power modes include: power, standard, and economy, plus, four transmission power shift modes; manual, light, normal, and heavy. It’s also available in a tool carrier model which offers parallel lift for tasks such as pallet handling and pipe laying.
“Wheel loaders are the workhorses of the jobsite, especially if they’re equipped with a tool master option where you can change attachments and use forks or other attachments,” notes Shirey. “Contractors use them to carry pipe, gravel, various materials, and they put them through their paces every day. Depending on the jobsite and application, you might see them traveling at high speeds up and down roads moving materials.”
So far, we’ve spoken about products from Volvo, Komatsu, Caterpillar, and Hyundai, all manufacturers of broad product lines for the excavation and construction industry, and, all offer remote monitoring maintenance programs, which are gaining in sophistication and depth as the industry continues to evolve. In fact, service and remote diagnostics are becoming key points of competition for manufacturers, including a company that we haven’t spoken about yet, John Deere Construction Equipment, Moline, IL. At CONEXPO 2014, the company introduced Ultimate Uptime, a customer support solution designed to improve customers’ profitability by maximizing productivity and uptime while lowering operating costs.
“Customers want power and features,” says Robert Burnett, product manager for marketing services at John Deere, “but the number one concern is machine availability or uptime. Ultimate Uptime pulls together our old-fashioned product support, programs, and warranties, and puts it together with new technology in one comprehensive support package that’s highly customizable. We have a base package and premium package, and a premium plus package, but the base package is a suite of technologies that includes John Deere Worksite. It features three years of JDLink telematics, plus three years of our remote programming and diagnostics, and three years of our machine health prognostics, all under our John Deere Worksite umbrella, then with machine inspections, we make sure there’s a flawless delivery.”
The remote programming functionality enables dealers to dial in and see diagnostic codes and if appropriate, clear and reset them. They can set up and do a recording as if they were plugged into the machine to check parameters, and even run remote programs. If an electronic control unit needs to be programmed a service technician can remotely send that as a payload to the machine, and when the operator gets in the machine the monitor confirms the update.
According to Liz Quinn, the product marketing manager for Worksite, remote diagnostics and reprogramming is a key to delivering higher uptime for customers. “It’s an application that actually sits on board the machine in the JDLink box and it allows the dealers to dial in and run a recording of events while the machine is operating. So, it really boosts the ability to diagnose the machine and even predict what may happen. Dealers are starting to perform remote diagnostic sessions on every service call they get, and that allows them to diagnose the problem before the get out there, and in some cases a trip isn’t needed.”
Another benefit of the diagnostics is the ability to store a database of cases and solutions that all dealers in the network can leverage. Additionally, machine health prognostics can analyze data from JDLink, fluid analysis, and machine inspections, and e-mail the dealer and customer with recommended solutions.
Earlier, in our discussion of wheel loaders, Shirey of Hyundai described them as the workhorses of the jobsite, especially when running attachments. One category of attachments for wheel loaders and other equipment, is the crusher bucket. For example, ALLU, based in Teterboro, NJ, offers its Screener Crusher bucket, as a versatile accessory for a wheel loader, excavator, or skid steer. This product can screen, crush, pulverize, aerate, blend, mix, separate, feed, and load materials—all in one stage. Appropriate materials include: demolition waste, construction waste, milled asphalt, glass, coal, oil shale, limestone, and several other materials, sized from 5/8-inch to 5-inch fragment sizes.
Bucket crushers can reduce travel and transportation costs and they’re an economical way to recycle materials created during demolitions. The MB Crusher Bucket, from MB, Reno, NV, is uniquely adept at separating rebar from concrete during the crushing process.
Moving up the ladder to larger crushers that are still classified as compact, Rubble Master, Valparaiso IN, has a line of track driven crushers designed as cost-effective solutions for mobile processing of mineral starting material into high-quality, cubic and homogeneous aggregate directly onsite and in a single step. The RM 70GO! produces up to 120 t/h of aggregate, the 80GO! handles up to 160 t/h, and the 100GO! can crush up to 250 t/h of material.
For larger jobs, Terex Finlay, Louisville, KY, has a variety of tracked mobile jaw crushers that can handle the reduction and sizing of aggregates for construction materials, and also recycling construction waste. The company also makes tracked mobile impact crushers for the reduction and sizing of soft to medium natural granite and limestone and non-abrasive materials, as well as recycling construction demolition waste. Impact crushers are ideal for producing a quality end product where grain shape, distribution, and consistency are paramount.
Impact crushers are convenient for medium-hard stone such as limestone, and rock-based materials including bricks, concrete and asphalt. AIS Construction Equipment, Grand Rapids, MI, manufactures the Lokotrack LT1110 mobile impactor plant, a mobile unit that features a modular design for lower-operating noise levels. If a uniform cubical product is needed for a project, IROCK, Valley View, OH, recently introduced their RDS-20 Primary Crushing Plant. The RDS-20 combines a closed circuit design for producing uniform cubical product from quarry rock, demolition debris, plus recycled concrete or asphalt. The closed circuit design makes it convenient for both decks of oversized material to pass through the crusher after the initial round of screening.
Often, a project can require a variety of aggregate processing equipment. KPI-JCI, Yankton, SD, can supply a contractor with products such as, sand classifying-washing, conveyors, screening plants, and portable/stationary/track mounted plants. The firm of Lippmann Milwaukee, Cudahy, WI, also supplies a full line of aggregate handling equipment. The company’s model 4248 Portable Primary Jaw Plant is designed for high capacity jobs requiring extra large feed openings for accepting aggregate of different sizes and compositions.
For those that need an efficient system for dewatering sand, Superior Industries, Columbus, NE, offers it’s Portable Aggre-Dry Dewatering Screen. The system is designed to maximize water recycling while producing sand and gravel products with a moisture content as low as 7 to 12%.
You know you’re in high power territory when a crusher packs a 475-hp Caterpillar diesel engine under the hood. In the case of the 5256T Impact Crusher from Screen Machine Industries, Etna, OH, those 475 horses drive a track-mounted crusher with a 56-inch hopper/feeder. That’s a lot of capacity, and the 5256T features a wireless remote control lifting lid so oversized material such as recycled concrete and asphalt, can pass through the crusher without stoppage.
Thanks to a variety of products, recycled asphalt product (RAP) has earned a reputation as a an efficient and economical paving material. Gathering the RAP from old roads requires a tough machine, such as the SX-4e reclaimer-stabilizer, from Roadtec, Chattanooga, TN. This mid-sized workhorse offers cut depths of up to 20 inches, and cut widths up to 100 inches. Roadtec also makes pavers. The company recently introduced the RP2505, a steel-tracked paver designed to operate with high density tamper bar screeds that can achieve high densities in stiffer mixes, such as, hot mix, cold mix, base materials, and roller compacted concrete.
Transferring RAP to a paver also requires a tough machine, such as the recycle systems manufactured by Asphalt Drum Mixers, Huntertown, IN. The company’s system includes a 2-foot-wide, heavy-duty conveyor that weighs the material and introduces it to the dried aggregate mix after the heating process. An optional lump breaker can insure that the RAP arrives in the proper size.
Looking for a paver that can handle a wide road with the least amount of passes? The F800T from Dynapac USA, a division of Atlas Copco North America, Parsippany, NJ, offers a range of 8 to 19 feet wide. A 6-cylinder 173-hp Cummins diesel engine provides travel speeds up to 8.5 mph. For jobs that justify an even wider paving capacity, the SD2500CS has a range of 8 to 32 feet.
Feeding a large paver isn’t a trivial operation, especially on long roads and projects where interruptions mean costly downtime. The E650B windrow elevator from Weiler, Knoxville, IA, is one example of the many choices available to contractors in high production paving.
The machine’s material-feed system employs two auger segments and slat conveyors. The augers remix the material and move it to the slat conveyors for distribution into the hopper. Another company, Carlson Paving Products, Tacoma, WA, makes the WP 810 Windrow Pickup Machine, designed to couple to the front of an asphalt paver and transfer mix asphalt. It can re-blend the hot mix as it is picked up and transferred into the paver hopper at rates up to 800 tons per hour.
No matter the choice of paving equipment, the final step is the compaction process, and this is another category where technology has made great progress. For example, BOMAG, Kewanee, IL, recently introduced its 4.5 ton BW138AC-5 roller. The 54-inch-wide model has a traditional vibratory steel drum up front and four smooth pneumatic tires at the rear. The design is well suited to compaction of commercial parking lots, driveways, highway shoulder construction, and secondary roadway maintenance. The optional BOMAG Economizer offers real time compaction level data to the operator.
CASE Construction Equipment, Racine, WI, recently introduced two Tier 4 Interim high frequency asphalt compactor models. The DV209 and DV210 have operating weights of 21,030 pounds and 22,730 pounds, respectively, and a standard drum width of just more than 66 inches on both machines. Both machines feature a frequency range of 42- to 55-hertz standard and 46- to 67-hertz high frequency. Also, both are compatible with optional ACEforce asphalt compaction technology, a compaction management and documentation system that provides precise measurement and evaluation of material stiffness.
“The science behind this technology is amazing,” says Katie Pullen, brand marketing manager, CASE Construction Equipment. “A compaction meter will measure how much rebound is on the drum and as it gets more compacted the drum will jump more because the ground can’t absorb it. The operator sets the meter to show the desired compaction level that they’re looking for when they make a test pass. After the pass, the system specifies the optimum frequency and travel speed to complete the compaction. There’s also a mapping technology that identifies your jobsite map how many passes were made and the compaction status on a particular pass.”
By choosing variable amplitude settings, the operator can fine-tune their machine to efficiently handle thinner lifts (low amplitude/high frequency) and thicker lifts (high amplitude/low frequency). Centrifugal force can also be dialed in to best match the thickness of the lift and the desired depth of compaction.
“With asphalt you need different levels of frequency and amplitude depending on how thick the layer is and the type of polymers,” explains Pullen. “So we have a high frequency machine that will work on thinner layers. Asphalt is a temperamental material and it has to be worked with at a certain temperature. If you let it get cold, you might not be able to get the right compaction. So with the thinner layers, which is typical in repair work, you run at your high frequency, so you can travel quicker and get the pressure into the thin layer of asphalt without it cooling.”
Beyond controlling the compaction options, steering controls include a new operator station that can turn and slide through the entire width of the cab. A color monitor in the center of the steering wheel stays in the same position, even when the steering wheel is turning. Upon job completion, ADS documentation software can analyze historical results/performance, and is compatible with mapping and GPS operator guidance technologies from Topcon, Trimble, and Leica.
Today’s machines offer efficiency and economy at all levels of project size, and contractors can benefit from higher productivity, thanks to features such as remote maintenance, advanced electronics, data analysis, and GPS guidance systems.
Ed Ritchie specializes in energy, transportation, and communication technologies.
