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ICCX SPECIAL Only a few weeks to go until the ICCX Russia 2016 NEWS Ongoing Recovery inEuropean Construction CONCRETE TECHNOLOGY PennStress builds strong foundation for growthwith state-of-art batch plant CONCRETE PRODUCTS New wet-cast system for Bachl CONCRETE PIPESAND MAN HOLES Public agencies are influencing products for resilient pipelines and culverts PRECASTCONCRETE ELEMENTS Shanghai Baoye relies on state-of-the-art precast construction technology

OCTOBER

2016 5Concrete Plant InternationalNorth America Edition

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PennStress senior vice president and chiefoperating officer, Greg Gorman, who helda similar position in the Newcrete organiza-tion, developed a strategy to enable thefirm to transition to an in-house batch plant.According to Gorman, the firm had experi-enced challenges over the years producingprestressed concrete structural productsusing solely ready-mix concrete.

Choosing the right tool for the job

The nature of the high performance con-crete (HPC) products manufactured atPennStress demand advanced mix designs.Large PennStress “I” beams, for instance,may be prestressed with steel cable ten-dons to forces totaling more than three mil-lion pounds of pre-tensioning. The beamforms are filled with HPC and allowed to

steam-cure for approximately 26 hoursbefore the forms are released and tensionstrand ends cut. Inconsistencies in concretecompressive strengths can result in differen-tial camber from beam to beam. “Our mix designs require in excess of10,000 psi in specialty mixes,” Gormannotes. “It’s very difficult to get consistenthigh-strength concrete from a high volumeready-mix plant. So consistency in concretequality was an ongoing concern and costwas another important factor. We sacri-ficed economy in mix constituents to com-pensate for the lower mixing energy typicalin conventional ready mix.” Gorman adds, “Ultimately, we needed theright batching tool for our specific require-ments. One that would enable us to deliverquality products and provide greater pro-duction efficiencies.” Once PennStressbegan operations, the decision to transitionto an in-house batch plant came swiftly.Gorman and his production managementteam had been researching their options inmixing and batching technology for almosta year by the time the company sale tookplace. The batch plant acquisition teamadded an experienced plant operator, EdFlaugh, to help strengthen the decisionprocess. The team used research from theNational Institute of Standards andTechnology, industry sources, referencecalls, sites visits, and other resources tochoose the right mixer – a planetary coun-tercurrent pan mixer. It came down to fourvendors. “We did our due diligence, that’sfor sure,” Gorman notes. “We saw the ven-dors at the PCI annual show, met with themindividually, called their customers, and wereceived their proposals and drawings. Wenarrowed it down to three, then one:Advanced Concrete Technologies.”

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CONCRETE TECHNOLOGY

PennStress builds strong foundation for growth with state-of-art batch plant

Advanced Concrete Technologies, Inc., Greenland, New Hampshire, 03840, USA

In December 2014, the Newcrete precast division of New Enterprise Stone and Lime Co., Inc., of Roaring Spring, Pennsylvania, USA, wasacquired by the MacInnis Group, LLC, and relaunched as PennStress. The precaster is a leading regional supplier of structural prestessedconcrete elements for DOT and commercial projects, including highways, parking garages, stadiums, bridges, and modular correctional facil-ities. Since its founding in the 1950s, Newcrete relied on concrete from the parent company’s high volume ready-mix operation. Under newownership, PennStress evaluated new production options, including the choice to continue using ready-mix or invest in its own concretebatching system.

The PennStress precast facility (background), in Roaring Spring, Pennsylvania, USA, features250,000 square feet of production space under roof. The company is a leading regional producer of high performance precast prestressed concrete products such as the “I” beamsshown in the foreground.

www.concretebiz.com 603.431.5661American Division of Wiggert & Co. GmbH and Würschum GmbH

North American Supplier of

Customized Concrete Plant

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CONCRETE TECHNOLOGY

Gorman says his team liked ACT for sever-al important reasons. “We especially likedthe fact that ACT provides a complete,turnkey system that included everything weneeded. We felt that the overall integratedand tested design of the ACT solution setthem apart from other options.”

Laboratory mixer saves months of testing

The PennStress selection team also liked thefact that ACT could provide a laboratory-scale batch plant that featured a planetarycountercurrent mixer, which allowed thecompany to test and perfect mix designsprior to receiving the production system.“We knew that whichever batch system wechose, it was going to take some time tomanufacture, ship and install the system,”Gorman explains. “So we included in ourspecification that we wanted the vendor toprovide a temporary small mixer in themeantime so that we could begin testingmix designs.”ACT had a laboratory-scale mixer avail-able for immediate delivery. Within a fewweeks of signing the deal in the spring of2015, PennStress had the small countercur-rent planetary mixer plant from ACT in itsshop. “That was a huge time savings forus,” Gorman notes. “The ACT lab mixerhelped us adjust our mix designs to match

Batch plant acquisition analysis team forPennStress included, from left to right, batchplant operations supervisor Ed Flaugh; vicepresident of engineering and productionRussell Dickson, PE; senior vice presidentand chief operating officer Greg Gorman,PE; plant supervisor Frank Musselman; andchief estimator Anthony Gayle.

A rail-mounted ACT/Wiggert concrete transporter can carry up to two concrete crane buck-ets – one full, one empty – and supplies two of three production bays at the PennStress plantin Roaring Spring, Pennsylvania, USA. A crane bucket on the transporter is shown here beingloaded from one of two mixer discharge gates. The third production bay is served by either aforklift-mounted bucket or a Tucker concrete transporter. The ACT/Wiggert HPGM 3450 plan-etary countercurrent mixer still looks brand new, even after nearly a year of operation thanksto the diligence of the PennStress operations crew aided by the ACT automatic high pressuremixer cleaning system that makes clean-up a 10-minute job at shift end or during breaks.

PennStress chose an ACT/Wiggert MobilMat Mo3450 batch plant, equipped with an HPGM3450 planetary countercurrent mixer, to supply high performance concrete for its three pro-duction bays. This flexible system features two discharge gates that allow the use of multipleconcrete delivery systems simultaneously, including a rail-mounted crane bucket transport cart(at left in photo), a Tucker concrete transport vehicle (under mixer platform), and a forklift-mounted bucket (not shown). The entire batch plant, including four silos (in foreground) andaggregate storage, is located inside the facility allowing all-weather operations and consistentaggregate conditioning.

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CONCRETE TECHNOLOGY

the intensive mixing energy of the countercurrent planetary mixer.We were able to test mix designs and go through the curing andstrength testing process so we could hit the ground running whenthe production plant was ready. We saved at least three monthsand saved a lot of material that we would have wasted if we hadto wait and test after plant installation.”ACT engineering staff assisted PennStress at every stage to designthe plant solution, produce engineering drawings, prepare theinstallation site, batch plant installation, start-up and operator train-ing. A centrally located area of the PennStress plant offered 21,000square feet of space between its key production bays. The area wasthe ideal location for the new batch plant; however, a relatively lowroof line made it a tight fit. “It was a real positive to be able to geteverything inside, including our aggregate storage and silos,”Gorman says. “Fitting the silos was a game of inches. The tops ofthe tallest silo is nestled between a couple of beams with aboutseven inches of clearance! We used a very experienced local erec-tor and ACT was there to supervise everything.” The ACTMobilMatMo3450-4-PCS batch plant installed in the PennStressfacility includes the following components and systems: • ACT/Wiggert HPGM 3450 planetary countercurrent high-

shear mixer capable of producing approximately 60 cubicyards per hour of high specification concrete. The three (3)cubic-yard mixer is equipped with two discharge gates for effi-cient filling of crane buckets or a Tucker concrete transporter.Concrete holding hoppers below each discharge gate provideenhanced efficiency during peak production.

• Rail-mounted ACT/Wiggert crane bucket transporter automati-cally shuttles crane buckets back and forth across two produc-tion bays from the mixer platform. The transporter can carryup to two buckets—one full, one empty—for optimal workflowefficiency.

• Four-compartment aggregate bin with up to 200 tons of capac-ity. The bins are currently charged via front end loader, butPennStress has future plans to implement an automated charg-ing system that would allow the system to be charged by dumptruck from a drive-over hopper feeding a conveyor system.

• Hydrotester moisture sensors are installed in two of the aggre-gate compartments to monitor and auto correct for the sandmoisture content.

• WCS Control System is PC based and provides intuitive color-coded real-time display of critical elements of the batchingprocess, as well as tracking of production statistics and report-ing for material consumption, inventory, and maintenancescheduling. The WCS includes statistic, batching history andreporting that satisfies stringent DOT requirements.

• Hydromat moisture measuring and control system providesautomatic batch water correction, which is critical for precisionmix designs such as SCC.

• Four silos, installed near the mixer platform, provide up to 280tons of total storage for cement, fly ash, and other compo-nents. The silos are fitted with anti-over-fill protection systemsfurther protecting the environment.

• Ground-mounted dust collector uses cartridge style filters andfeatures automatic air-shock cleaning to capture dust from silocharging and batching operations.

• High-pressure automatic mixer cleaning system reduces thecleaning cycle to about 10 minutes at the end of shifts or dur-ing breaks. Hand-operated lances allow spot cleaning andcleaning outside of mixer, chutes and crane buckets at the endof the day. Good housekeeping equals a happier work environment and longer life for equipment.

• Waste water reclamation system.

ACT/Wiggert MobilMat batch plant features PC-based WCS ControlSystem with intuitive color-coded screen representation of all batch-ing system components. The WCS system features integratedHydromat moisture measuring with automatic batch water adjustmentplus Hydrotester moisture sensors in sand bins to automatically main-tain target batch yield. The WCS communicates with PLC controllersfor execution of all commands. The controls feature password protec-tion, recallable mix recipes, batching history, inventory control, andreporting for DOT compliance.

A four-compartment aggregate storage bin is housed inside the plantand can hold up to 200 tons. A weigh belt under the bins emptiesonto a conveyor that feeds a skip hoist for the final lift up to theACT/Wiggert HPGM 3450 planetary countercurrent mixer. Indoorstorage allows aggregates to be conditioned for temperature andmoisture to help ensure consistent batching.

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CONCRETE TECHNOLOGY

Hitting the mark on the first try

“From left to right and front to back, welocated our batch plant in the absolutesweet spot in terms of servicing our threemain production areas,” Gorman com-ments. The ACT/Wiggert MobilMat batchplant was installed and operational byearly November 2015. “Pretty much all ofthe goals we set forth in our proposal havecome true for us. By locating our batchplant completely indoors we can conditionour aggregates in terms of moisture andtemperature for optimal mix results.” He continues, “The central location of theplant and the multiple systems we have formoving concrete to the casting areasmeans we can pour in multiple locationssimultaneously and achieve better efficien-cy results. We’re using the bucket trans-porter for two bays, a forklift mounted buck-et for a third bay and a Tucker transporterfor pouring large volume products such asdouble tees for parking structures.” Gorman emphasized that they have per-fected key mix designs to take advantageof the higher energy provided by theHPGM planetary countercurrent mixer. Thestandard deviation in compressive strengthand the time required to achieve earlystrength has drastically improved with thenew batching system. Today, standard devi-ation is in the range of a few hundred p.s.i.

and the firm is seeing savings in the amountof constituent materials required to hitrequired strengths. The consistent workability and quality ofconcrete produced in the new batch plant isfar superior to the ready mix it relied on fordecades. “Bugholes are virtually eliminatedand finish consistency is always excellent,”Gorman says. The availability of HPC on acontinuous basis has led to the implementa-tion of key lean process improvements.

ROI is real

Bottom-line savings have emerged sinceinstalling the ACT MobilMat batching sys-tem. PennStress is able to change or adjustits mix design on-the-fly enabling the com-pany to easily pour different products simul-taneously. The firm is able to use its labormore effectively thanks to more predictablecuring times and form releases. There’s alsoless wasted material since the companycontrols its own mixing and batching. “Conservatively, I’d estimate our concrete-related savings across the board to be onthe order of 20 percent,” says Gorman witha smile. “There’s no limit to what we canaccomplish now. We have the flexibilityand control to produce the highest qualityconcrete and therefore the highest qualityproducts on the market. While we’re prima-rily a structural precaster, we are also certi-

fied as an architectural plant as well. Ournew initiatives and new batching capabili-ties have opened the door for us to growinto new markets.” �

PennStress plant operations staff include:batch plant operations supervisor EdFlaugh; batch plant assistant Josh Andrews;batch plant operator Matt Mock; and batchplant assistant Andrew Gorman.

A crane bucket is used to place high performance concrete in a form on the production floor at PennStress in Roaring Spring, Pennsylvania, USA. The company transitioned in thesummer of 2015 from an all ready-mix operation to an ACT/Wiggert in-house concretebatching system. Since that time, the company has seen improvements in concrete consistency,far less deviation in compressive strength, better product quality, and a significant reduction in production costs.

FURTHER INFORMATION

Advanced Concrete Technologies, Inc.300 Portsmouth AvenueGreenland, New Hampshire, 03840, USAT +1 603 4315661F +1 603 4315547info@concretebiz.comwww.concretebiz.com

Wiggert & Co. GmbHWachhausstr. 3b

76227 Karlsruhe, GermanyT +49 721 943460F +49 721 402208info@wiggert.comwww.wiggert.com

PennStress 8180 Woodbury Pike Roaring Spring, PA 16673, USAT +1 814 6952016www.pennstress.com