IMPROVEMENTS IN THE TREATMENT OF CONCRETE FOR BUILDING PURPOSES, AND IN APPARATUS USED IN CONSTRUCTING CONCRETE BUILDINGS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Charles Drake at the Office of the
Commissioners of Patents on the 10th March 1880.
$6
CHARLES DRAKE, of the Railway Wharf, Battersea Park, in the County of
Surrey. IMPROVEMENTS IN THE TREATMENT OF CONCRETE FOR BUILDING
PURPOSES, AND IN APPARATUS USED IN CONSTRUCTING CONCRETE BUILDINGS."
This Invention has for its object improvements in the treatment of concrete for
building purposes, and in apparatus used in constructing concrete buildings.
By the most common method of using concrete the exterior surfaces have required
a finish of plaster or cement, and for decoration cement, mouldings, and castings,
both coloured and plain, have been used.
This method of finish has been considered liable to unsoundness and incapable
of satisfactory architectural treatment.
To overcome these objections concrete slabs as facing for concrete walls have
been used, and various methods of giving such slabs coloured and other decorative
finish are described in the Specification of a Patent granted to me, No. 4121, 1876.
Also an improved method of making such slabs to be self fixed to concrete
walls without inner tie bars is described in the Specification of a Patent granted
to me, No. 2641, 1877.
By this Invention I produce a superior and beautiful “concrete stone" suitable
for highly decorative construction, and applicable with advantage to many purposes
of building constrution for which by former methods concrete has not been found
suitable, or if so, only in an inferior degree; and also a superior decorative finish
to the concrete slabs above mentioned.
This Invention also includes improved details in construction of the above
mentioned slabs, whereby they are more perfectly self-fixed to the interior concrete
of the walls-and better-held by each other_in_correct_position, and also includes
improved apparatus for adjusting and.holding them in correct position while being
built.
In the preparation of the concrete for the purpose stated, in addition to the
selection of materials known to produce concrete of great hardness, strength,
durability, and capacity to resist dampness and fire, I select the aggregate to be
mixed with the cement, specially for its colour, as by the treatment in a later
stage of the manufacture the colour or colours, as well as forms and positions of
the particles of the aggregate, are brought into view at the finished surfaces
together with the colour of the cement as a grounding.

page_text: Also for some purposes I select the aggregate specially for its texture, in order
that it may be cut or carved without difficulty.
I find that most of the aggregates commonly used to make concrete are capable
of producing pleasing combinations of colour when treated by the method of this
Invention.
Burnt clay ballast, broken red bricks, tiles, pipes, and other clay ware, and the
burnt red shales, clays, and marles from mines and collieries, all make a bright
and pleasing combination with the grey ground colour of Portland cement, and an
equally pleasing combination is produced by broken yellow or white bricks or
other burnt clay of similar colour
The waste and chippings from stone and marble quarries and works, of granites
and marbles especially, also gravels and beach shingles, all make concrete stone of
great beauty.
Aggregates of dull tints, such as chippings of limestones, whinstones, broken
furnace slag, &c., also make handsome "concrete stone," in combination with
cement coloured to a suitable tint, and I may combine any material whatever, that
may be used as a concrete aggregate, with suitable colours either in the cement or
other aggregate, and produce thereby "concrete stone of excellent appearance, as
well as superior strength, durability, and weather resistance.
"
And I may use one only or more colors in the same piece, or form differently
colored divisions or patterns within the same stone.
Having selected the materials, as described, I mix them together with the proper
proportion of water, as ordinary concrete is mixed, and place the mixture at once
into the moulds to become hard to the form or shape desired.
I sometimes mould them to the precise form, or nearly so, of the finished stone,
and sometimes into blocks to be afterwards cut and worked like ordinary stone
into any desired sizes or forms.
After removal from the moulds, and when or at some time after the "concrete
stone" has become sufficiently hard, I remove the cement colored surface usual to
concrete from those pieces moulded to the finished form by means of rubbing,
scraping, filing, carving, or cutting, or by any means, so that the surface is removed
and the colours of the interior of the concrete are exposed as a new surface.
Such new surface, as also the new surfaces produced by cutting or working the
blocks, as before described, may so remain, or may be polished, varnished, oiled,
or coated with silicate or other transparent stone solution.
•
The concrete stone thus prepared may be used for the entire construction of any
kind of walls or buildings, or may be used as dressings, cornices, string courses,
lintols, sills, or other ornament, or in part with natural stone, brick, or ordinary
concrete.
I also make it into chimney-pieces, doors (being fireproof), door frames, skirtings,
and wall, ceiling, or floor facings, and for all purposes for which ordinary stone is
used.
My concrete stone slabs for building slab faced monolithic concrete walls are
similarly made and finished.
Or in some cases I make the concrete stone and slabs with finished surfaces as
taken from the moulds, but of a sand or grit-like texture, superior to the ordinary
smooth surfaces of cast cement work.
In order to produce this grit faced work the moulds for casting the concrete
stone or concrete stone slabs are first coated with a soap lather, or oil, or some
mixture as ordinarily used to prevent the cement adhering to the moulds, and fine
sand is then dusted into the moulds and adheres to the lather, oil, or mixture. The
concrete is next placed into the moulds, and on hardening and removal from the
moulds the faces of the concrete stone are brushed or dusted to remove the loose
particles of sand, leaving them with the grit like face desired.
"
"
The improved arrangements for fixing my concrete stone or concrete stone
slabs in building, monolithic concrete walls consist of forming the indents at the
inner faces under cut in opposite directions, one half of each slab having under cut

page_text: indents in one direction only, and the other half having under cut indents in
the opposite direction, causing a perfect dovetailing to the wall throughout
the whole length of the slab or stone.
Also in order to cause the slabs to be better held by each other in correct
position I make the projections at their inner faces to project below the bottom
edges, so that the bottom edge of each slab grips the top edge of the adjoining slab
next under it, and the faces are thus kept in true position.
The improved apparatus for better holding the slabs in position while being
built consists of an adjustable clamp, having two arms and two cross bolts with
nuts or two cross bars with graduated pin holes, allowing the arms to be set for
different thicknesses of walls, and to be tightened or adjusted as required to give
the slabs their correct position on the outer surface of the wall.