SAN JOSE, CA - Jerry Blatt thinks running CNG-powered Kenworth mixers makes a lot of sense for his company's new division, Greencrete.
"I like the idea of using these compressed natural gas-powered mixers," said Blatt, owner of Sandman Inc., parent company of Greencrete and Star Concrete in San Jose, Calif. Greencrete produces recycled, ready-mix concrete to local homeowners and contractors.
Greencrete recently put into service three, new Kenworth W900S CNG mixers to help deliver the recycled concrete. That made Greencrete the first fleet to incorporate the Kenworth CNG mixers - which came off the production line with Kenworth factory-installed compressed natural gas powertrains - into its operations.
"I have great hopes for this technology," Blatt said. "When we tried out a demonstration model for one week last year we found that the natural gas-powered Kenworth mixer is very quiet. For delivering concrete, particularly in residential areas, that's a big benefit."
Greencrete's natural gas-fueled Kenworth trucks come equipped with the Cummins Westport ISL G engine and Allison automatic transmission. Rated at 320 hp and 1,000 lb-ft of torque, the ISL G uses a maintenance-free, three-way catalyst and is 2010 EPA- and CARB-compliant without the use of selective catalytic reduction (SCR) technology or a diesel particulate filter (DPF).
Blatt said he wanted to try something that would fit his company's emphasis on environmental stewardship. His local Kenworth dealer, NorCal Kenworth, recommended going with CNG due to its wide commercial availability and number of fueling locations in the San Francisco Bay Area. The company doesn't expect the need for drivers to refuel the mixers while out on deliveries. If such a need does arise, refueling with CNG isn't difficult because it doesn't require special training.
Blatt said Star Concrete's experience in running diesel-powered Kenworth trucks also played a significant role in choosing factory-built CNG-powered Kenworth trucks for Greencrete. "Kenworths have always been our truck of choice because of their reliability and durability," Blatt said. Star Concrete, the company's other division, delivers concrete from its batch plants to contractors for all types of residential and commercial construction sites in the greater San Jose area.
"We have 54 ready-mix concrete mixers, and 44 of them are Kenworth W900s. We also have 15 line-haul trucks, 12 of which are Kenworth W900s. Over the years, we've found that the infrastructure of a Kenworth truck, its suspension and its frame rails for example, are sturdy and well-built," said Blatt. "Our Kenworth trucks require much less maintenance during their lifetime. That's very important for us because we prefer to keep them for a long time. Our oldest Kenworth mixers, which are 1999 year models, have more than 20,000 hours of operation. And some of our oldest line haul Kenworth trucks have more than a million miles on them," he said. |
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The Kenworth CNG-powered mixers are hauling a unique, recycled ready-mix concrete product, also known as Greencrete. The recycled product is made from demolition concrete that is crushed and filtered into rocks and sand, explained Blatt. A customized machine mixes the rock and sand with water and a mix of 50 percent Type II cement and 50 percent recycled cementitious, or supplementary cement material, creating a green concrete that boasts a recycled content of nearly 95 percent. In a five-sack mix, there is 470 pounds of cement - 35 percent slag (leftover material from steel production), 15 percent fly ash (particulate matter from coal-fired power plants), and 50 percent virgin material. The 470 pounds of supplementary cement material is then mixed with 100-percent recycled aggregate and water to create more than 4,000 pounds of Greencrete.
"Recycled concrete is not a new product since nearly everyone in the aggregate industry uses fly ash to make concrete, plus in California, cement made from slag is readily available for most companies," Blatt said. "But what makes Greencrete unique is the combination of slag and fly ash with regular cement and recycled aggregate to create a green concrete that has the same strength as that made from straight cement after 28 days of curing. And after 28 days of curing, Greencrete continues to get stronger."
Greencrete's concrete recycling facility also uses a 406-kilowatt solar panel array that covers the top of the 44,000 square-foot building and generates 500,000 kilowatt hours of energy per year to power the plant's machines.
"With our emphasis on environmental stewardship in the manufacturing of Greencrete, delivering it with these CNG-powered Kenworth W900S mixers just seems to make perfect sense," Blatt said.
