act shape desired and smoothing it. If hand finishing methods are
employed, a plank template is cut to the prescribed cross section and
the concrete is shaped by drawing the template along the side forms.
Sometimes the template is used as a tamper, being moved along very
slowly accompanied by an up and down motion that tends to tamp the
concrete. The template is then drawn along a second time to smooth the
surface finally.

After the surface has been struck off by hand, it is finally smoothed,
first by rolling crosswise with a slight hand roller about 8 inches in
diameter and 30 inches long. The final finish is effected by dragging
a piece of web belting back and forth across the surface.

Machines designed to tamp the concrete and strike it off to the
required cross section are also employed for finishing. The machine is
power operated and is carried on wheels that run on the side forms,
and the machine moves slowly along as the tamping progresses. The
concrete is tamped, struck off to shape and smoothed with the belt at
one operation. This method of finishing produces denser and stronger
concrete than can be produced by hand finishing methods.

=Placing Concrete for Two-course Road.=--The methods employed for the
two-course concrete road are much the same as for the one-course road.
The concrete for the lower course is placed and struck off by means of
hand tools, and after that course has progressed a few feet, the upper
course is placed and finished as has been described for the one-course
road.

=Curing the Concrete.=--The setting action of cement is a chemical
process, not merely a drying out of the water introduced in mixing the
concrete. The chemical action is progressive for a long time, but is
more rapid during the first few hours than during the later periods,
and the concrete reaches about three-fourths of its maximum strength
at the end of seven days. During the setting period and particularly
during the first few days, plenty of water must be available to the
cement.

To prevent too rapid loss of water from the concrete during the
setting period, the surface must be protected from the wind and sun.
This is accomplished by first covering with canvas as soon as the
concrete has hardened sufficiently and by later covering with earth,
to a depth of two inches. The earth covering is kept wet for about ten
days and is left in place for about one month.

In some places the ponding method of curing is adopt