When you run a concrete company, green is a relative term. But for one California company, it is turning concrete, and the compressed natural gas trucks that deliver it, into a valuable tool to promote the business.
“I like the idea of using these compressed natural gas-powered mixers,” says Jerry Blatt, owner of Sandman Inc., parent company to Greencrete and Star Concrete in San Jose.
Greencrete produces a recycled, ready-mix concrete product for homeowners and contractors. While the product is green, though, the trucks that poured it were not until Greencrete, a relatively new division of Sandman, purchased three Kenworth W900S compressed natural gas mixers. The company was the first at the time to put into service Kenworth CNG mixers.
“I have great hopes for this technology,” Blatt says. “When we tried out a demonstration model for one week last year, we found that the mixer is very quiet. For delivering concrete, particularly in residential areas, that's a big benefit.”
The trucks are equipped with Cummins Westport ISL G engines rated at 320 hp. and 1,000 lbs.-ft. of torque. Allison automatic transmissions ensure smooth shifting and the ISL G uses a maintenance-free, three-way catalyst to meet 2010 EPA and CARB emissions regulations without the use of selective catalytic reduction (SCR) technology or a diesel particulate filter. The catalyst takes the hydrocarbons, carbon monoxide and nitrogen oxide produced by the engine and with the use of Cummins' Cooled EGR (exhaust gas recirculation) process, converts them to water, carbon dioxide and nitrogen as by-products, creating a cleaner product.
HISTORY PREVAILS
The choice to go with Kenworth's W900S was an easy one for Blatt. Working with local dealer NorCal Kenworth, Blatt chose the CNG trucks based on the availability of natural gas fueling stations in the San Francisco Bay area. The trucks also fit well with Greencrete's environmental platform, and the experience sister company Star Concrete had running Kenworths factored into the decision as well.
“We have 54 ready-mix concrete mixers, and 44 of them are Kenworth W900S [models],” Blatt says. “We also have 15 linehaul 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. 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.”
The older mixers in the fleet are 1999 models with as many as 20,000 hours of operation on them. Blatt says some of the oldest linehaul trucks in the fleet have been driven more than one million miles.
The new Greencrete CNG mixers are delivering a unique product that is helping to change the concrete industry — and it is being done in an environmentally friendly way. Greencrete's concrete recycling facility also uses a 406-kW solar panel array atop a 44,000-sq.-ft. building. It generates 500,000 kWh of energy per year to power the plant's machines.
The concrete itself is made from demolition concrete that is crushed and filtered into rocks and sand. A customized machine then mixes both with water and a mix of 50% Type II cement and 50% recycled cementitious, or supplementary cement material, creating a concrete that is nearly 95% recycled material.
“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 says.
