Delivery Differentiation

West Oahu Aggregate brings front discharge trucks to a crowded Aloha State market

Since Hawaii follows the Federal Bridge Formula for axle configuration, WOA went with the six-axle Terex truck that offers an extended 391-in. front to rear axle span with the tag axle lowered.

Terex FDB6000 trucks maximize payload by allowing WOA to transport 10 yd. of concrete the short route over the mountain versus the rear discharge payload of only 6 to 7 yards.

For West Oahu Aggregate Co. (WOA), Honolulu, Hawaii, the transition to producing and delivering its own concrete product was a simple decision. Starting in 1993 as an aggregate producer, the company has diversified into several related businesses, including recycled rock, concrete and asphalt; disposal and recycling of municipal, construction and demolition waste; and, supplying on-road and off-road diesel. “Moving from crushing and recycling to waste removal and demolition to concrete production and delivery just felt natural to us,” says WOA owner Georgette Silva.

A Honolulu affiliate company, Pineridge Farms, Inc., complements WOA’s business through construction trucking and heavy hauling. It offers aggregate hauling, trucking of asphalt paving materials and lowboy trailers for heavy equipment transport. When a strong commercial market put concrete in short supply for WOA projects, the vertically integrated company did what came natural: Diversify into ready mixed production. “We purchased a 200-yard-per-hour portable concrete batch plant a couple of years ago to produce concrete for our own projects,” notes Silva. “It also gave us the potential to sell concrete to other contractors.”

While the plant offered internal sourcing capability, WOA needed a way to differentiate itself from the island’s saturated ready mixed concrete market in order to successfully sell material to other companies. Despite the island state’s relatively small geographical area, notes Terex Advance District Sales Manager Scott Kutz, “There are 13 ready mix companies operating in Hawaii.”


For WOA, the primary market for its concrete product was the private sector, specifically housing. The plant purchased to produce concrete wouldn’t necessarily give the company a significant advantage over other operators. However, how the concrete made it to the jobsite, navigated the island’s rugged terrain and discharged its loads would.

Prior to WOA entering the ready mixed concrete business, Hawaii was entirely a rear discharge mixer truck market. Therefore, all of the producers operating in Oahu relied solely on this truck design to deliver concrete to every corner of the island for both commercial and private customers. Yet island terrain, as Silva discovered, was not necessarily conducive for rear discharge trucks to efficiently deliver concrete to all customers.

The Oahu Island was formed by two former shield volcano mountain ranges. The Wai’anae range on the west and Ko’olau range to the east run parallel to each other and flank a broad valley, where the majority of the island cities are located. The rugged Wia’anae mountain range rises more than 4,000 feet above sea level, while the highest peak of the Ko’olau is 3,150 ft.

With the plant’s Honolulu location positioned to the west of the Ko’olau range, trucks carrying WOA’s concrete product to cities like Kaneohe and Kailua on the east side of the mountain had two choices. “They could drive on highways built over the steep mountain incline or go around the flat land route, which adds approximately an hour to the trip,” explains Kutz.

While crossing the mountain would initially appear as the obvious choice for shortening delivery times and improving truck efficiency, there was a significant drawback to climbing steep grades with rear discharge mixer trucks. Their low, gravity-fed discharge point limited the capacity the trucks could carry up steep grades. “If you fill the mixer drum with too much concrete, it can spill out the discharge outlet,” says Silva. “The payload when driving over hilly terrain is only 6 to 7 yards.”

Taking the flat route allowed more payload capacity, approximately 10 yd. of concrete, but it meant taking a longer route, resulting in fewer loads per truck each day. “Rear discharge truck owners would have to calculate the difference between driving a longer distance with higher payload or more trips carrying less concrete for driving over the mountain,” adds Kutz.

On a trip to Oahu, he visited with WOA officials to show them an alternate truck design for transporting concrete to the jobsite. The front discharge mixer truck positions the discharge chute above the driver’s cab, at a much higher point than on a rear discharge mixer. “As a result, ready mix producers working in markets with steep terrain like WOA do not have to sacrifice payload to navigate the hills,” Kutz affirms.

He further notes that the front discharge design offers significant advantages for operations that focus on residential construction. “The trucks drive into the jobsite, quickly discharge their load and quickly drive out,” he says. “The driver can discharge the load from inside the cab, so producers do not need an extra chute operator for discharging the load.”

Silva saw the potential for labor savings by eliminating one worker. “The labor rate for contractors is $75-90 per hour,” she says. “Over time, this adds up to significant cost savings.”


For two years, WOA has been delivering concrete to its own workers and residential builders. It was the first to bring the front discharge design to Hawaii, and is very happy with the competitive advantages accompanying the trucks.


After purchasing a portable concrete batch plant, West Oahu Aggregate differentiated itself from other producers by purchasing Terex front discharge mixer trucks for concrete delivery.

The driver can discharge the load from inside the cab to eliminate the need for an extra chute operator, which adds up to significant cost savings over time on the island.

The design of choice for WOA is a six-axle bridge-formula model, which allows the company to maximize payload. “Hawaii does follow the Federal Bridge Formula for axle configuration, but as long as gross vehicle weight is not exceeded, producers can transport as much material as possible,” notes Kutz.

“We can transport 10 yards of concrete in our front discharge mixers, regardless of whether the trucks are navigating the hilly roads or the flat valley areas,” adds Silva, citing the potential to significantly increase the amount of material delivered per truck each day.

With the market success of the front discharge mixer trucks in Hawaii, WOA representatives attended World of Concrete 2016 in Las Vegas, looking to purchase two new trucks. They visited with Kutz in the Terex exhibit, which included two different show truck models offering features new to the market. “We were showing concepts like front and rear tandem axles with disc brakes and a new drum drive installation that reduces truck tare weight to improve payload capacity,” recalls Kutz, “and we had a new barrel paddle design inside the rear section of the drum to improve concrete consistency.”

WOA officials purchased two new Terex Advance FDB6000 front discharge mixers. The trucks have a long, 206-in. wheel base to offer a smooth ride when navigating hills and rough terrain. The MTU Series 1300 (DD13) diesel engine offers 450 hp and 1,550 ft.-lb. torque to deliver the power necessary to climb Hawaii’s steep mountainous terrain when carrying a full payload.

Another truck amenity offered by the front discharge design is the Allison 6-speed automatic transmission that features Smart-Control technology for improved shifting performance and enhanced fuel economy. “Driving the front discharge trucks with automatic transmission is much more comfortable for our drivers than the standard transmission commonly found on rear discharge trucks, especially when going up and down the hills,” says Silva.

With features built into the trucks to reduce tare weight, WOA can take full advantage of the 11-yd. mixer drum capacity to improve trucking efficiency. “The drum capacity and design really helps us reduce the number of trips up the hill, which also saves wear on the truck,” adds Silva.

Once on site, the operator controls all FDB6000 truck functions from inside the cab, which helps to expedite concrete discharge. “With single joystick operation, our Terex Total Control System inside the cab controls drum charge/discharge, engine throttle high/low, emergency drum stop and precise chute positioning,” notes Kutz. “Additionally, the high discharge point of our front discharge truck allows for concrete discharge into some wall projects that rear discharge mixer trucks cannot due to their low discharge point.”

Finally, Silva reports visibility as being one significant trucking and safety advantage that WOA’s drivers like about operating the front discharge mixer. “The drivers have a direct view of and can operate the chute while they are inside the cab of the truck,” she says.

The combination of mixer capacity, power and visibility has sold WOA on the front discharge mixer design. The ability to carry more material up the steep hills of the Wai’anae and Ko’olau mountain ranges and eliminate one extra laborer to discharge the load offer this producer significant savings and the distinct competitive advantages it needed to stand out in a crowded Oahu concrete producer market.

Prepared by Rick Zettler for Terex Advance Mixer, Ft. Wayne, Ind.;