IMPROVEMENTS IN THE COMPOSITION AND MANUFACTURE OF BITUMINOUS AND OTHER COMPOUNDS, AND IN THE APPLICATION OF SUCH COMPOUNDS TO PAVING AND OTHER PURPOSES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by George Clark at the Office of the
Commissioners of Patents, with his Petition, on the 5th April
1875.
I, GEORGE CLARK, of No. 10, Craven Buildings, Drury Lane, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE COMPOSITION AND MANUFACTURE OF BITUMINOUS AND
OTHER COMPOUNDS, AND IN THE APPLICATION OF SUCH COMPOUNDS TO PAVING AND
OTHER PURPOSES," to be as follows.-
--
This Invention relates to the production and manufacture of
compounds composed of bituminous or plastic substances combined
with other materials, and to the application of such compounds for
paving and other purposes, comprising certain improvements of which
respectively the following is a description.-
No. 1. This improvement has for its object the production and manu-
facture of a bituminous compound in blocks similar in character to
native rock asphalte, and which I designate as asphaltum mastic, having
for its base asphaltum in combination with other substances by mixing
with such asphaltum when by the action of heat it is in a melted and semi-

page_text: fluid or plastic state other materials such as carbonate of lime or lime
silica, alumina, and broken stone, in proportions of all or any of them
adapted to the paving or other work to be exccuted and in such a con-
dition that the aforesaid blocks shall be what I term complete mastic,
easily melted in a copper, and when so melted shall be ready to be laid
down or otherwise used in a properly heated state. The uses to which the
said bituminous compound are to be applied are so various requiring
different degrees of hardness, toughness, or plasticity, into the mastic
depending on the proportionate combination of the aforesaid materials,
that for the production of the aforesaid mastic it is impossible to give
precise directions as to the quantities of such materials to suit all cases,
but the following example will serve to illustrate the proportions and
the method of preparation I prefer to employ :-Asphaltum forming the
basis of the said compound varies in composition, usually containing
from 40 to 90 per cent. of bitumen, therefore the quantity of bitumen it
contains must be previously ascertained and taken into account. With
asphaltum containing an average quantity of 75 per cent of pure
bitumen which can be obtained in large quantities, the proportions of
the aforesaid materials for the production of a good medium quality of
complete mastic should be, say, 20 per cent of such asphaltum, 20 per
cent of chalk or lime, 20 per cent of fine sand or pulverized stone, 10
per cent. of dried clay, and 30 per cent of coarse sand or broken stone.
The said materials properly proportioned as above indicated are formed
into a compound mass by first melting in a copper till it is brought to a
liquid state, with the aid of any suitable solvent the whole quantity of
asphaltum mentioned, and then by degrees and cach kind separately
adding and stirring into such melted asphaltum the other materials, one
after the other in the order they are named, until the whole is perfectly
combined and brought into a rather fluid plastic state The most
suitable solvents are petroleum or residuum oil from the distillation of
petroleum, coal or wood tar, or so called dead or green oil or pitch,
obtained from the distillation of such tars The complete mastic
produced by the process above described is whilst in a hot and sufficiently
fluid state poured into moulds, and the blocks of such mastic when
cooled and hardened are ready for use by being iemelted in a pot.
No. 2. This improvement consists in the formation and manufacture
of paving blocks or slabs to be used for any kind of pavement, by con-
structing boxes or frames of wood of any required dimensions, and filling

page_text: such wood boxes or frames with asphaltum mastic prepared as described
under improvement No. 1, or any other suitable bituminous compound
in a hot and plastic state, whereby when the said asphaltum mastic
or other bituminous compound has cooled and hardened it adheres
tonaciously to the inner surfaces of the said wooden box or frame, and
a solid compound block composed of the bituminous material inside and
the wooden casing outside is produced, or these compound blocks may
be made in the way above described with a wooden casing on only one,
two, or three sides This paving block laid on a hard and level
foundation, for which concrete is well adapted, offers a firm resistanco
to superficial pressure on its upper surface To render this resistance
more complete the fibre of the wood forming the casing should bo
vertical, offering the same resistance to vertical pressure as that which
(as well known from practice) is afforded by wooden paving blocks. I
consider that the suitable dimensions of blocks made as above described
for paving carriage ways, stables, and courtyards, are 9 or 10 inches in
length, 3 to 5 inches in width, and 3 to 4 inches in depth. But they
may be of any dimensions better appropriated for any kind of pavement
to be laid down. The concrete forming the foundation on which the
aforesaid compound blocks or laid should be level and smooth, and it
will be improved by imbedding in the surface of the concrete battens of
wood placed longitudinally in the direction of a roadway, breaking joint
at their extremities, and at such distances from cach other, laterally, that
a part of every block laid transversely thereon shall rest on one or more
of the battens, or the said battens may be laid on the surface of the
concrete close to or a little apart from each other with bituminous
compound between the said battens By this support and arrangement
of the aforesaid blocks none of them will be liable to sink below the
level of the others should there be any irregularity or sinking in parts of
the surface of the concrete. These compound blocks, which I designate
as ligno-asphaltum paving blocks are laid in rows transversely to the line
of the roadway like paving stones or wood paving blocks, in close
contact with each other, breaking joint in the several rows, and in order
to make perfect joints and prevent the percolation of water between the
blocks I coat the outside of the wood casing with melted bitumen or
varnish paint, whereby each block will be cemented to and will securely
adhere to the other blocks with which it is in contact; or to effect the
same objects of perfect adhesion of the aforesaid blocks to each other,
and the prevention of water or other fluid percolating between them I

page_text: propose coating the outside surfaces of the sides and ends of such blocks
with asphalted felt, and when the rows of paving blocks are laid on the
concrete foundation as above described I complete the consolidation of
the pavement by wedging up four or five courses or rows of blocks
successively with a rammer. In some cases wooden boxes or frames
may be filled with concrete, cement, or any other suitable plastic material
applied in the manner above described for paving and also for con-
structive purposes.
No. 3. This improvement consists in comprising in the asphaltum
mastic made as above described or in any other bituminous compounds a
suitable per centage say from 5 to 15 per cent. more or less, by weight of
sawdust. The admixture of this material with any of the other materials
herein-before- mentioned being- especially adapted for paving or con-
structive work wherein clasticity combined with toughness is desirable
to prevent the material when laid down from cracking through vibration.
In order to produce asphaltum paving blocks under the conditions of
elasticity and toughness just mentioned, any other fibrous material in
small particles, such as hair or wool, or any kind of vegetablo fibre in
combination with sawdust, or any of them separately or combined with
any one or more of the others may be mixed with any bituminous
compound whilst in a hot and plastic staic.