Year: 1888

page_text: Date of Application, 30th May, 1888
Complete Specification Left, 28th Feb., 1889
Complete Specification Accepted, 30th Mar., 1889
I, LOUIS CHRISTOPHE, of Royan (Charente Inférieure) France, Constructor of
Gas Works, do hereby declare the nature of this invention to be as follows:-
This invention relates to a method of making roads by the application of coal
tar in the manner hereinafter more particularly referred to. It is applicable to the
maintenance and repair of existing roads, and also to the construction of new ones.
Roads constructed in accordance with this invention possess great advantages over
roads as usually made which are open to objection for various reasons.
Thus it is found that the more or less rapid deterioration of roads as usually made
even if well constructed, is due not only to the wear and tear of the traffic, but also to
atmospheric influences. Furthermore rain softens the clayey particles which bind
together the silicious or other constituents of the roadway, which is thus rendered
incapable of offering the necessary resistance and incompressibility to the passage of
vehicles. In consequence of these draw backs it has been necessary to periodically
repair roadways with fresh layers of materials, which is an expensive proceeding and
is objectionable by reason of the impediment to traffic caused by the rough surface that
obtains for some time after the roadway is completed.
My invention has for object to obviate these drawbacks, and to enable solid and
durable roads to be constructed quickly and at small cost.
In the usual methods of road making based upon the employment of asphalte or
bitumen, the latter, not adhering to the soil, does not enter into intimate union with
the body of the roadway; it thus forms merely a kind of coating or crust, influenced
by the variations in temperature, becoming soft during hot weather and contracting
in cold weather thereby forming fissures which allow the crust to become detached in
sheets and making the road defective and impassable. By my invention-this defect of
asphalte and bitumen is obviated and the roadway is rendered impermeable and incom-
pressible and capable of resisting the heaviest vehicular traffic.
Moreover, coal tar, can, by my invention, be applied without macadamming or
metalling, for the construction of roadways upon sandy soil and norasses where
ordinary metalling could not resist the weight of heavy vehicles.

page_text: In such cases the soil must be well rammed and reduced to the desired form in
cross sections.
Heretofore in places of the kind referred to recourse has had to be had to the costly
process of paving.
The solidity and impermeability of roadways made in accordance with this invention
is owing to the thorough penetration of the tar into the soil whereby perfect agglome-
ration of the particles composing the roadway is effected. It is therefore preferable to
carry out the application of this system during the hot-season of the year. According
to one method I proceed as follows:-After the lapse of about a week of hot weather,
the road is carefully levelled and has given to it a suitable profile in cross-section; it
may have been previously metalled, or may be new and be not metalled. .
The road is then abundantly sprinkled several times with coal tar which has been
slightly heated in a boiler of the kind usually-employed in the preparation of asphalte
for example.
Tar thus heated is in an extremely liquid state and penetrates easily to a depth of
five to ten centimetres, its penetration being facilitated by the heated condition of
the soil.
As soon as the liquid is completely absorbed a second sprinkling process is
performed in a manner similar to the precceding. Immediately afterwards the road-
way is covered by coarse silicious sand or gravel applied by means of a spade for
example, and extending to a depth or thickness of about two centimetres.
After the lapse of five or six days, during which time the workmen can have
continued working on another part of the roadway, any sand or gravel which has not
entered into union with the body of the road is removed with suitable appliances such
as-scrapers commonly used by road labourers. This sand or gravel can be afterwards.
used again. The road may now be opened to traffic, and presents the appearance of
an ordinary asphalted road, but is much less slippery, because the coal tar having been
absorbed by the soil, does not forin as in the case of asphalte, a coating superposed on
the roadway. A roadway so made is of-dark-color and does not reflect the sun's rays
to such an extent as with roads of usual construction.
In the application of this invention to the construction of side walks roads or paths
used by foot passengers only, the coal tar is applied in the same manner as for roads
for vehicular traffic with the exception that in the case of second sprinkling the tar
instead of being only slightly heated so as to obtain complete liquefaction, must be
boiled tar that is tar which has been subjected to an hours ebullition in the boiler.
This second layer of tar adheres firmly to the soil which is already impregnated,
and quickly hardens on the surface, uniting with the layer of gravel and forming
a very hard, impermeable road which affords very soft ways for foot passengers.
For economically making very hard roads for vehicular traffic without the use of
metal upon shifting clayey or sandy soils the soil must be rammed down firmly
before the tar is applied.
Dated this 20th M.. 1000

page_text: COMPLETE SPECIFICATION.
Improvements in the Making of Roads, Paths, or Ways.
I, LOUIS CHRISTOPHE of Royan (Charente Inférieure), France, Constructor of
Gas Works, do hereby declare the nature of this invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to a method of making roads by the application of coal
tar in the manner hereinafter described. It is applicable to the maintenance and
repair of existing roads, and also to the construction of new ones. Roads constructed
in accordance with this invention possess great advantages over roads as usually
made which are open to objection for various reasons. Thus it is found that tho
more or less rapid deterioration of roads as usually made, even if well constructed,
is due not only to the wear and tear of the traffic, but also to atmospheric influences.
Furthermore rain softens the clayey particles which binds the silicious or other
constituents of the road together, which is thus rendered incapable of offering the
necessary resistance and incompressibility to the passage of vehicles, especially if
such vehicles are heavily loaded."
In consequence of these drawbacks it has been necessary to periodically repair
roadways with fresh layers of materials, which is an expensive proceeding and is
objectionable by reason of the impediment to traffic caused by the rough surface
that obtains for some time after the roadway is completed.
My invention has for its object to obviate these drawbacks and to enable solid
and durable roads to be constructed quickly and at small cost.
In the usual methods of road making based upon the employment of asphalte or
bitumen, the latter, not adhering to the soil, does not enter into intimate union
with the body of the roadway; it thus forms merely a kind of coating or crust,
influenced by the variations in temperature, becoming soft during hot weather and
contracting in cold weather, thereby forming fissures which allow the crust to become
detached in sheets and making the road defective and impassable.
By my invention this defect is avoided and the roadway is rendered impermeable
and incompressible and capable of resisting the heaviest vehicular traffic. Moreover,
coal tar, can, by my invention, be applied without macadamizing or metalling for the
construction of roadways upon sandy soil and morasses where ordinary metalling could
not resist the weight of heavy vehicles. In such cases the soil must be well rammed
and reduced to the desired form in cross section. Heretofore in places of the kind
referred to recourse has had to be had to the costly process of paving.
The solidity and impermeability of roadways made in accordance with this invention
is owing to the thorough penetration of the tar into the soil, whereby perfect agglome-
ration of the particles comprising the roadway is effected. It is therefore preferable
to carry out the application of this system during the hot season of the year.
In carrying out my invention I proceed as follows:-After about a week of hot
weather, the road is carefully levelled and has given to it a suitable profile in

page_text: cross section; it may have been previously metalled or may be new and be not
metalled. The road is then abundantly sprinkled several times with coal tar which
has been slightly heated in a boiler of the kind usually employed in the preparation
of asphalte.
Tar thus heated is in an extremely liquid state and penetrates easily to a depth
of five to ten centimetres, its penetration being facilitated by the heated condition
of the soil.
After
As soon as the liquid is completely absorbed a second sprinkling process is
performed in a manner similar to the preceding. Immediately afterwards the road-
way is covered by coarse silicious sand or gravel applied by means of a spade for
example and extending to a depth or thickness of about two centimetres.
the lapse of five or six days, during which time the workmen can have continued
working on another part of the roadway, any sand or gravel which has not entered
into union with the body of the road is removed with suitable appliances, such as
scrapers, commonly used by road labourers.
The road can now be opened for traffic and presents the appearance of an ordinary
asphalted road but is much less slippery, because the coal tar having been absorbed
by the soil, does not form, as in the case of asphalte, a coating superposed on the
roadway. A roadway so made is of dark colour and does not reflect the sun's rays
to such an extent as with roads of usual construction.
In the application of this invention to the construction of side walks, roads or
paths used by foot passengers only, the coal tar is applied in the same manner as
for roads for vehicular traffic with the exception that in the case of the second
sprinkling the tar instead of being only slightly heated so as to obtain completo
liquefaction must be boiled tar, that is, tar which has been subjected to an hour's
ebullition in a boiler. This second layer of tar adhores firmly to the soil which is
already impregnated, and quickly hardens on the surface uniting with the layer of
gravel and forming-a-very hard, impermeable road which affords an agreeable way
for foot passengers.
For economically making very hard roads for vehicular traffic, without the use of
metal, upon shifting, clayey or sandy soils, the soil must be rammed down firmly before
the tar is applied.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The employment of coal tar in the liquid state or otherwise applied substantially
in the manner set forth for the maintenance, repair or construction of roads, roadways,
⚫ footpaths and the like.
2. The hereinabove described method of macadamizing or consolidating roads by
means of coal tar.
Dated this 30th d
1000
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.