BOTTOMS UP: PUMPER IMPROVES QUALITY BY DEFYING CONVENTION 2006
ACPA member Central Concrete Pumping (CCP), Fort Worth, TX has been serving the Dallas/Fort Worth area for over 31 years. The contractor’s dedication to safety and operator training and ACPA certification is only one way the contractor assures quality control on every job. According to General Manager Carl Walker, the company has further improved the aesthetic and homogeneous characteristics of pumped concrete by utilizing an increasingly popular placing method.
“We pump just about anything from the bottom up,” says Walker. “The potential for voids is minimized, which not only creates a better look, it also maximizes the soundness and quality of the finished product.”
CCP Owner Mel Grantham says their clients are excited. “More and more our customers are calling in employees from other job sites to get a look at how we do things. There’s increasing recognition that there are real applications for this placement method.”
For instance, the pumper recently took the time during construction of the new AUI Contractors headquarters in Forth Worth, TX to educate AUI employees on the types of forms and supplemental parts that are needed to make the bottom-up pouring method successful. “They are a very loyal customer of ours,” says Walker. “We wanted to make sure they are as knowledgeable as we are when it comes to the fittings necessary to make this method work.”
In order to assure site safety and achieve a quality end product through this placing method, Walker says the customer is responsible for providing good forms. “There’s no trick to the pumping – our fleet can handle just about anything,” says Walker, referring to an extensive Schwing fleet ranging from line pumps to 47 meter boom pumps. “But the forming system needs to accommodate a four to five inch pipe at the base for proper concrete supply.”
To complete poured-in-place panels that now serve as the exterior walls of AUI headquarters, the forms were customized with a welded fitting to accommodate a five-inch line. Local ready-mix supplier Beall Concrete, also out of Fort Worth, flew in experts from around the country to design a special cast-in-place concrete mix that would create a defect-free surface.
According to Beall Concrete Quality Control representative Ron Terrelonge, a 4,000 psi self-compacting concrete mix further improved the walls’ aesthetic appeal. Before dumping into the hopper of CCP’s BPL 4000, each batch was sampled individually and monitored for quality. “The combination of the special mix design and the placing method resulted in a better quality finish, and something that could serve as a showpiece,” said Terrelonge.
“The 4000 was certainly overqualified for that particular project,” says Walker. Equipped with the Schwing-patented Rock Valveä and the ability to handle up to 1-1/2-inch aggregate, the truck-mounted unit combines compact maneuverability with the ability to provide continuous high volume output on big pours.
CCP also recently completed column repair on a bridge in the Fort Worth area, where their experience with the bottom-up method was absolutely necessary.
“An 18-wheeler came through and did a lot of damage to one of the columns,” recalls Walker. “On a completed bridge, there’s absolutely no way to pour concrete from the top down into a column.”
General contractor Austin Bridge & Road, Inc., Austin, was able to weld a fitting directly on to the base of the forming system to allow for a four-inch line. The pipe was also equipped with a slide valve to minimize concrete waste.
“We brought in our BPL 4000 to pour a whopping eight yards,” says Walker. “The customer called in supers from other sites to take a look at the method, but we completed the job in about eight minutes. By the time everyone got there for a pe