Improvements in Pavements or Sidewalks:
Year: 1889

page_text: Date of Application, 19th Feb., 1889
Specification Accepted, 30th Mar., 1889
COMPLETE SPECIFICATION.
Improvements in Pavements or Sidewalks:
I, CHARLES CARROLL GILMAN of Eldora, Iowa, in the United States of America,
Manufacturer of Porous Terra Cotta, 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:-
The object of my invention is to construct a cheap and durable sidewalk having an
indestructible and water-proof foundation which cannot be washed away by the
action of water; and to this end my invention consists in using as a foundation
for a surface layer of asphalt mastic or cement, blocks or slabs of terra-cotta
lumber or porous terra-cotta saturated or impregnated with asphaltum.
The accompanying drawing represents a cross section of a sidewalk constructed
in accordance with my invention.
The foundation of my sidewalk consists of blocks A A¹ of terra-cotta lumber or
porous terra-cotta, preferably three inches in thickness, about twelve, inches wide,
and from sixteen to thirty inches long. Said blocks are saturated or impregnated
with asphaltum. In order to thoroughly impregnate the slabs of said material with
the asphaltum, I place the former in a closed tube, vessel or receiver, from which I
exhaust the air and then admit thereto the hot melted asphaltum, the same being
forced by the atmospheric pressure into the pores or cells (exhausted of air) of the
terra cotta lumber, the latter being heated to about the same or greater temperature
as the said asphaltum, to avoid chilling the latter. ·
The method just described is similar to the well known process employed in
impregnating wood with creosote, and since no claim is laid to said method, a fuller
description thereof is not essential to an understanding of this invention.
The saturated terra-cotta lumber, after it has cooled and the asphaltum hardened
or become solid is in fact a new material, which is much stronger and of greater
weight than the unimpregnated material, is absolutely impervious to moisture,
cannot decay, and is practically indestructible.
The said slabs or blocks, treated as described are arranged in two layers, so as to
break joints with each other in both directions. The lower blocks A¹ rest preferably
on a foundation of sand or gravel B. These two layers of indestructible and water-
proof material make a solid foundation for the surface covering. The upper blocks A

page_text: are covered with a layer of asphalt mastic C composed of ashphalt gravel and
pounded limestone. This mastic is rolled over the same to a thickness of from one
to two inches varying according to circumstances.
I do not wish to limit myself to a formation consisting of two layers of blocks as
one layer of thicker blocks may be used, or the blocks may be formed so as to have
a bearing on each other but the construction illustrated is much to be preferred.
Neither do I desire to limit myself to a wearing surface of asphalt mastic, for a layer
of cement may be used in lieu thereof. It is evident, also, that my invention is
applicable to street pavements as well as to sidewalks; but in the construction of
pavements a stronger foundation and a thicker layer of ashphalt mastic is used.
I am aware that ordinary building bricks have been immersed in a liquid solution
of alum, borax, copperas and water, and after drying boiled in a mixture of caoutchouc
and coal tar, and that it has been proposed to use such bricks, as the surface layer of
a pavement or sidewalk. I am also aware that it has been proposed to lay a surface
layer of terra-cotta blocks upon a foundation of bricks, and also that it is not new to
cure a brick by immersion in a mixture of coal tar bitumen, pine gum, and alum, and
these several things I do not claim.
I am aware that a roller-skating surface has been formed by laying on a foundation
of ordinary brick a composition of asphalt bitumen, and resinous oil; but this I do
not claim as it is entirely different from my invention.
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. A sidewalk or pavement consisting of a surplus layer of ashphalt mastic or its
equivalent and a foundation composed of slabs or blocks of terra cotta lumber saturated
or impregnated with asphaltum, substantially as described.
2. A sidewalk or pavement consisting of a surface layer of asphalt mastic or its
equivalent and a foundation composed of two layers of blocks of terra-cotta lumber
saturated or impregnated with asphaltum and arranged to break joints with each other
in both directions substantially as described.
T
2 IN 1
1000