As our company grew, we found it necessary to consider the use of powered vibratory screeds to handle large industrial floor projects efficiently and profitably. We did not immediately choose the air-powered vibratory screed but tried several, considering them from every possible angle. We now have definite ideas about the way a screed should be designed and built and how it should perform. We like a screed to be versatile and durable, easily transported in short sections, easily assembled and disassembled, and to require very little routine maintenance. We have been successful in purchasing screeds to meet these requirements. We keep a screed in reserve on every job, but in more than a year of hard use on thousands of cubic yards of concrete we have not had to fall back on the reserve unit nor had to replace any parts. The floors we construct are usually 6 to 8 inches thick and the slump of the concrete averages 5 inches.
Our company used its present air-powered vibratory screed for the first time in placing a 1.1-million-square-foot industrial floor with a mineral aggregate surface hardener. As the job progressed, the potential of the screed for other than standard flatwork became apparent. For example, it can be used on slopes. It can also be used in situations that require less than normal vibration; for this purpose the vibration can be halved by taping alternate vibrators. Use of a powered screed contributes much toward elimination of human error. The uniformity of vibration makes for good consolidation of the concrete. Consistent vibration also eliminates most or all bull-floating and it can blend concrete of slumps ranging from 4 to 6 inches. Using the vibratory screed not only helps ensure quality floors, but also affords significant savings in finishing costs.
The air-powered vibratory screed is perhaps the most maneuverable piece of equipment in our yard, yet it is unusually simple in construction. Most importantly, it puts the vibration where it's needed into the concrete, not into the machine itself.