IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL STONE OR CONCRETE
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by George Hodson at the Office of the
Commissioners of Patents on the 3rd July 1882.
GEORGE HODSON of Loughborough in the County of Leicester Civil Engineer.
"IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL STONE OR CONCRETE."
In carrying out my improvements I mix with the Portland cement to be
employed in the manufacture of the artificial stone or concrete, native oxide of iron
which is free from cláy or matter deleterious to the strength of the manufactured
article, and on account of its natural purity I have found the best results to be
obtained by the use of oxide of iron, or ochre, obtained in the Malago Vale in the
neighborhood of the City of Bristol.
.
In employing this coloring matter in the manufacture of artificial stone, or
concrete, from Portland cement, I have found by experiment that the proportion of
Portland cement combined with the oxide of iron, or ochre, can vary very con-
siderably, dependent upon the tint, or shade, or depth of color required whilst
various modifications of tint, or shade may be attained by mixtures in various
proportions of the yellower and redder colored of those oxides, or ochres, and I do
not confine myself to the proportions herein stated.
As an instance of the proportions employed giving a good result when imitating
in artificial stone, or concrete, a natural deep buff stone I use (by weight) 8 parts
of the yellow oxide of iron or ochre of the Malago Vale. 1 part of the red oxide,
or ochre, and 36 parts of the Portland cement.
Or when imitating the color of Bath stone I employ 4 parts of the yellow oxide
of the previous instance, part of the red oxide or ochre and 36 parts of the
Portland cement.
Or when imitating the tint of Caen Stone I mix 4 parts of the yellow oxide
referred to in the last example with 36 parts of the Portland cement (omitting
altogether the red coloring matter) or for a red stone I mix 9 parts of red oxide
or ochre with 36 parts of the Portland cement.
The ingredients in each example when combined being mixed together by dry
mixing and when intimate admixture has been obtained the material thus colored
may, for, use in the manufacture of artificial stone, or concrete, be combined with
the requisite quantity of water and then cast to the desired forms in suitable
moulds.

page_text: For the manufacture of concrete in imitation of various colored stones. I, by dry
mixing, the prepared colored powder composed as above described with suitable
aggregates such as granite, Ragstone, gravel, broken pottery, blast furnace slag,
Red Haematite, Iron ore or other aggregate suitable for concrete making, reduced
to fine fragments and thoroughly freed by washing, from impurities, in proportions,
varying from equal parts by weight of the colored powder and aggregate, to 5 parts
of aggregate to one of powder according to the class of the goods to be manufactured
and their required strength, and admixtures in different proportions may be
employed in the execution of the different portions of the goods made.
If it is desired only to color the external face of the concrete leaving the interior
portion of the blocks the natural.cement color. I..mix..the..concrete aggregate into
Portland cement, I then make a "slip" of the colored powder which I pour into
the moulds and afterwards add the concrete mixture in the centre of the mould,
manipulating the mass during the process of filling so as to keep the colored
matter to the sides and corners of the mould, If I require to hasten the process of
manufacturing I place the moulds in a chamber kept at about 100 degrees of heat
until the mass is set, I the take it from the moulds and leave it in the hot
chamber for two or three hours and afterwards submerge it in a bath of silicate of
soda until it is sufficiently hardened for sale. .