consolidate concrete by spading, insert the spade
along the inside surface of the forms (figure 7-43),
through the layer just placed, and several inches into
the layer underneath. Continue spading or puddling
until the coarse aggregate disappears into the
LEARNING OBJECTIVE: Upon completing
this section, you should be able to describe
the finishing process for the final concrete
The finishing process provides the final concrete
surface. There are many ways to finish concrete
surfaces, depending on the effect required.
Sometimes you only need to correct surface defects,
fill bolt holes, or clean the surface. Unformed
surfaces may require only screeding to proper contour
and elevation, or a broomed, floated, or trowelled
finish may be specified.
The top surface of a floor slab, sidewalk, or
pavement is rarely placed at the exact specified
Screeding brings the surface to the
required elevation by striking off the excess concrete.
Two types of screeds are used in concrete finishing
the hand screed and the mechanical
Hand screeding requires a tool called a screed.
This is actually a templet (usually a 2-by-4) having a
straight lower edge to produce a flat surface (or a
curved lower edge to produce a curved surface).
Move the screed back and forth across the concrete
using a sawing motion, as shown in figure 7-44. With
each sawing motion, move the screed forward an inch
or so along the forms. This forces the concrete built
up against the screed face into the low spots. If the
screed tends to tear the surface, as it may on
air-entrained concrete due to its sticky nature, either
reduce the rate of forward movement or cover the
lower edge of the screed with metal. This stops the
tearing action in most cases.
You can hand-screed surfaces up to 30-feet wide,
but the efficiency of this method diminishes on
Figure 7-43.-Consotidation by spading and a spading tool.
surfaces more than 10-feet wide. Three workers
(excluding a vibrator operator) can screed
approximately 200 square feet of concrete per hour.
Two of the workers work the screed while the third
pulls excess concrete from the front of the screed,
You must screed the surface a second time to remove
the surge of excess concrete caused by the first
Figure 7-44.-Screeding operation.