written by W.B.King;
It takes approximately 188 shovels full of pre-mixed sand and gravel to create a yard of concrete, a thought heavy enough to cause back pain—which is why technological advancements are welcome innovations within the industry.
When it comes to mixing concrete, every step from mix to pour to form has a dollar value attached. Employing the appropriate technologies and processes is essential for avoiding a beguiling contracting phrase: money drain.
INNOVATION: A NEW TAKE ON THE CUBE
Since every project is different, manufacturers have developed products for virtually every application. Take, for example, the Oregon-based Cart-Away Concrete Systems, Inc. that recently took home the Attendees Choice Award from the 2006 World of Concrete Convention [WOCC] held in Las Vegas for it newest product:
Cart-Away Universal Batching Equipment or C.U.B.E. With over 70,000 in attendance, the award, in the concrete mixing category, is highly coveted.
“It takes approximately 188 shovels full of pre-mixed sand and gravel to create a yard of concrete”
“About a year ago, we decided to take the technology of conveyors and mixing drums and put them together in one box,” says General Manager, Bruce Christensen. “The response from the field has been great,” he adds.
With a full one-and-a-half yard mixing capacity the C.U.B.E. can produce six to eight yards of concrete per hour in a specific mix design, explains Christensen. The loading, mixing and dispensing of the concrete materials are all completed inside of the box, which reduces the amount of equipment needed at the job-site. A unique feature of the C.U.B.E. is that operators can control their batch size, mix design, labor costs and overall ready-mix expenses on every project.
On-site batching eliminates short-load fees, reduces labor costs waiting on ready-mix trucks and gives the profits from readymix to the C.U.B.E. owner. “There is nothing quite like it on the market right now,” says Christensen.
With dimensions of four feet wide, six-and-one-half feet tall and 11-feet long, the C.U.B.E. was specifically designed to be hauled by one-ton pick up trucks, says Christensen. The reason for this design concept is for reaching remote locations otherwise impossible to traverse with a conventional mixing truck.
For instance, a C.U.B.E. was recently airlifted by helicopter to a job site in California where repairs were being made to remote location on a dam. Another customer, Rick Kubesh, owner of the Colville, Washington-based Kubesh’s Site Mixed Concrete recently employed a C.U.B.E. for a remote project in the dark recesses of the Pend Oreille Mine.
“This job required approximately 100 yards of five sack concrete. Placement would be seven-and-a-half miles down in a hard rock mine,” Kubesh continues. “Limited access prompted us to look at alternative ways of providing our services.
In the past, Kubesh explains that its partnering agent on the project, Knight Construction, resorted to premixed 80 pound sack concrete and a three foot cubic mixer but resulted in “too many hours to complete and left most of the crew totally exhausted the following day.” For example, mixing six yards of concrete in these extreme conditions took over seven hours to pour. After attending the WOOC this year, Kubesh says he saw the light, literally. “Once we saw the C.U.B.E. at the WOOC we contacted Bruce Christensen at Cart-Away,” remembers Kubesh.
“Looking closely at the measurements it was decided that the ‘Cube’ could fit on a pickup and be transported to the bottom of the mine,” he adds.
But getting to the required destination was a challenge. “The trip started at 2,300 feet above sea-level and ended seven miles later at minus 50 feet below sea-level. With limited clearance the ‘Cube’ made the trip with only inches to spare,” says Kubesh.
ATTAINING THE RIGHT MIX UNDER SEA LEVEL
Supplying the premix for this project was equally challenging. “We purchased super sacks with spouts on the bottom. With volumetric mixers we were able to mix the five sack concrete less the water in increments of half-per sack,” says Kubesh.
Knight Construction then transported the sacks down to the job site via pick-up trucks.
“The super sacks were loaded two at a time into the C.U.B.E. and water was metered in from the mounted water meter and within six minutes one yard of concrete was mixed,” explains Nelson Wells of Knight
Construction. The C.U.B.E. was then extended out over the forms via a Gradall and the concrete was placed. This process allowed the placement of up to 13 yards in a single shift and left the crew able to set up for the next days pour by placing rebar and forms ahead of schedule.
“It saved us a lot of hours over our previous method of mixing down in the mine. And anything is better then mixing with those small bags,” says Wells, adding “it saved us so many hours of manpower.
Dave Konsbruck, Mechanical Engineer for Pend Oreille Mine offered: “It is a good size for working underground, and was able to get into places larger units would not. We mixed about 70 yards with it and had no breakdowns.” Like all new products, however, the C.U.B.E. is a not safe from critique. “The feed chute for dumping the sacks could have been bigger, there was a fair amount of spillage and we had to use plywood to contain it,” says Konsbruck, adding “the fork pockets for transporting the unit were too small.”
Regardless of design tweaks, this new mixing device answered the call for a concrete job that fell between a project size of a wheelbarrow and a mixing truck. “By utilizing Cart-away’s ‘Cube’ we were able to not only successfully bid on a different type of job, but also enabled us to complete the job,” says Kubesh. “The guys at Cart-Away were great to work with and very attentive to our needs.”
ALTERNATIVES AND ADVANCEMENTS
Whereas the C.U.B.E. handles jobs that require concrete output for large remote locations, another fairly new product was placed on the market is Mixing Innovations, TMS2000, a compact, stationary, upright drum mixer for ready-mixed materials in sacks including mortar, grout, cement, plaster, flooring compounds, terrazzo and rough casting.
Tom Blocher of the Louisville, Kentucky-based Mixing Innovations, LLC explains that the TMS2000 mixer combines speed, mobility and reliability to help the contractor mix even the most viscous materials consistently. It is small enough to fit in a truck, has large wheels for easy mobility through narrow spaces and a slide valve to empty the material quickly into a wheelbarrow, or other delivery device.
“It is a portable concrete mixer that handles mortar as well and has better mixing action than the rotary drum style. It fits in the back of a truck and has real innovative features and it is narrow enough to fit through 30 inch doors—the large wheels allow it to go up and down stairs,” says Blocher, adding “it has rollers to easily load on and off a truck, too.”
Two years ago at the WOCC, attendees and a group of industry experts voted the Collomix TMS 2000 as the Experts Choice as the Most Innovative Product in the Concrete Construction Equipment category.
For more information about the C.U.B.E call: 1-800-909-9809.