The principle behind the use of a concrete pump truck on a pouring job is quite simple. Concrete is moved from the pumping truck, to the form or area where it is needed. A concrete pump truck is, in its most prevalent form, a large, diesel-powered truck mounting a powerful pump, and an extendable, sectioned hose, or cylinder, and cylinder frame.
The concrete is transported to the truck by a ready-mix concrete truck, commonly known as a cement mixer. The large drums on the cement mixing vehicle must be kept constantly rotating to prevent the concrete from setting-up, or hardening, prematurely. Small amounts of water are added during the mixing process as well for the same reason. Concrete pumping trucks, therefore carry no concrete, only the pumping mechanism, and sectioned hose lengths. Ready-mixed concrete is dumped from a cement mixer into the bay of the truck as the pump is running, thus emptying the pumping bay of the concrete as it’s dumped.
The extendable hose or cylinder booms on concrete pump trucks are usually from 17 meters (55.77 feet) to 61 meters (200.13 feet) in length, when fully extended. Depending on the size of the truck, and, therefore, the boom length, the boom can be folded into three to four sections, including the base section. The length of the boom, of course, determines how far away the truck will be placed from where the concrete is to be pumped.
The concrete to be pumped is in a liquefied state, obviously, and is leveled and worked as it is pumped into the form from the pumping truck. Typically, concrete pumping trucks can pump from 200 to 240 yards of concrete per hour, as long as the specific consistency of the concrete is maintained. When pumping is completed, the cylinder boom is refolded into the emptied bay of the truck.
Most pumps on the larger concrete pump trucks are operated by the truck’s engine in a power-takeoff (PTO) configuration. Some pumps, however, especially on smaller trucks, are powered with their own engine, normally a diesel. Diesel engines are used for this type of heavy-duty work because of their economical, yet powerful mechanical dynamics.
In the industry, concrete pumping is also known as “slabjacking,” “mudjacking,” and grout pumping. The concrete mixing truck, the cement mixer, is sometimes called a “mud buggy.” The concrete itself is often referred to as mud because of its thick, viscous consistency.