AN IMPROVED CONSTRUCTION OF ROADWAYS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Andrew Dunn at the Office of
'
the Commissioners of Patents, with his Petition, on the 23rd June
1874.
I, ANDREW DUNN, of No. 38, Southwark Street, in the Borough of
Southwark, and County of Surrey, Iron Merchant, do hereby declare
the nature of the said Invention for "AN IMPROVED CONSTRUCTION OF
ROADWAYS," to be as follows:-
The object of this Invention is improved construction of roadways, by
which a level surface can be maintained without reference to the kind
of traffic that may have to pass over it, and whereby the formation of
ruts, hollows, and other sunken portions can be obviated; also by which
repairs of pipes, etc., are facilitated when such are necessary.
In the usual method of constructing or forming a roadway a sub-
stratum of concrete is laid, upon which the cubes or pitch stones are
placed direct, the interstices of the cubes being afterwards filled in
with "wet stuff" and then rammed home, the ramming being often.
irregularly effected, and left in that condition so long as the surface
appears regular and pleasing to the eye.
According to another method a double substratum of planks are laid

page_text: "end on," are placed, and in some cases nailed thereto in combination
with strips of wood at the lower part to form spaces above, into which
coarse gravel or the like is rammed.
Both of the above methods are open to certain objections. In the
first place the concrete substratum to receive the cubes or pitch stones is
not placed upon a solid and good foundation, the ground below being
often of a spongy character, that when the ordinary traffic passes over
the cubes the weight of it causes the substratum of concrete to give and
sink into the ground beneath the cubes immediately above sinking;
also, and forming ruts or hollows, in which water and mud accumulate,
and cause inconvenience and damage to horses, carriages, and persons.
In the second case the area covered by the substratum of long planks,
which cross each other at right angles, is so large that in order to repair
pipes or drains below, such a large opening has to be made that the
roadway for some feet round the opening is so disturbed as to practically
destroy the solidity of the superstructure on or over which the traffic has
to pass in the future.
Now according to my Invention the above inconveniences are obviated,
and a sound solid roadway is formed, which can be taken up for repairs
when and where desired, and the surface be remade and maintained in
a level condition, notwithstanding besides which old material of a
valuable kind can be utilized, and yet be kept fit for it usual purposes.
My Invention consists in flagging the ground with York or other flag
paving stones, or with flag stones that have been worn thin and removed
from paths. These flag stones are laid in the ordinary manner, with
mortar or cement joints upon the ground, direct, or upon a floating of
wet stuff to bind them temporarily in position. Upon these so laid flag
stones I place cubes or pitch stones, which I bind in position in the
usual manner of paving by running into the interstices a wash of
hydraulic cement, the whole acting in unison to solidify the roadway
over which the heaviest traffic may pass, and yet be of such a character
that portions can be taken up for repairs of pipes, etc., and be relaid
without disturbing any surrounding or adjoining portion.