IMPROVEMENTS IN THE TREATMENT
Year: 1881

page_text: LETTERS PATENT to Henry Faija, of the Portland Cement Testing Room
and Laboratory, of No. 4, Great Queen Street, in the City of Westminster,
Civil Engineer, for an Invention of IMPROVEMENTS IN THE TREATMENT OF
PROVISIONAL SPECIFICATION left by the said Henry Faija at the Office
of the Commissioners of Patents on the 1st March 1881.
.
HENRY FAIJA, of the Portland Cement Testing Room and Laboratory, No. 4,
Great Queen Street, in the City of Westminster, Civil Engineer. "IMPROVEMENTS
IN THE TREATMENT OF CONCRETE AND CEMENT AS APPLIED IN THE MANU-
FACTURE OF BUILDING BLOCKS AND FOR OTHER PURPOSES."
My Invention relates to improvements in the treatment of concrete and cement
as applied in the manufacture of building blocks and for other purposes, and has
for object to enable concrete and cement (it may be lime) in the shape of blocks or
pipes or in other forms to be speedily hardened ready for use.
The concrete or cement may be mixed or gauged in the required form as usual,
and then is, according to my Invention, subjected to moist heat and thereafter to a
warm bath such as hereinafter referred to. One mode of carrying out my Invention
is as follows:-I place the mixed or gauged concrete or cement in a chamber, into
which I admit free steam or vapour so as to act directly upon the material under
treatment and accelerate its setting; then, to complete or increase the hardening or
induration, I subject the material to the action of a warm bath of sea-water, or of
ordinary water containing or not containing salt or alkali, or a warm silicious bath,
such, for example, as a silicate of soda or potash bath, of the desired strength. The
time during which the material to be hardened is subjected to moist heat and to
the bath will vary according to the nature of the materials, the degree of hardness
required, and other conditions.
According to another part of my Invention, in order to accelerate the induration
of concrete and cement I gauge or mix the concrete or cement with alkali or silica
or salt in solution.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Faija in the Great Seal Patent Office on the 31st August
1881.
HENRY FAIJA, of the Portland Cement Testing Room and Laboratory, No. 4,
Great Queen Street, in the City of Westminster, Civil Engineer. "IMPROVEMENTS
IN THE TREATMENT OF CONCRETE AND CEMENT AS APPLIED IN THE MANU-
FACTURE OF BUILDING BLOCKS AND FOR OTHER PURPOSES."
My Invention relates to improvements in the treatment of concrete and cement
as applied in the manufacture of building blocks and for other purposes, and has
for object to enable concrete and cement (it may be lime) in the shape of blocks or
pipes or in other forms to be speedily hardened ready for use. The concrete or
cement (it may be lime) may be mixed or gauged in the required form as usual,
and then is, according to my Invention; subjected to moist heat and thereafter to
a warm bath, such as hereinafter referred to. One mode of carrying out my
Invention is as follows:-I place the mixed or gauged concrete or cement in a
chamber, into which I admit free steam or vapour, so as to act directly upon the
material under treatment and accelerate its setting; then, to complete or increase
the hardening or induration, subject the material to the action of a warm bath of
sea-water, or of ordinary water containing or not containing salt or alkali, or a
warm silicious bath, such, for example, as a silicate of soda or potassa bath of the
desired strength. The time during which the material to be hardened is subjected
to moist heat and to the bath will vary according to the nature of the material,
the degree of hardness required, and other conditions.
According to another part of my Invention, in order to accelerate the induration
of concrete and cement, I gauge or mix the concrete or cement with alkali or silica,
or salt in solution. Such being the nature of my said Invention, I now proceed
to describe more particularly the manner of carrying the same into practical
effect.
I. Let it be assumed that Portland or other like cement has been mixed in any
suitable proportion with crushed stone, brick, or other material, guaged with water,
so as to form a concrete, placed in a mould of the desired form, and therein formed
into a solid mass, all as well understood. Then, according to my Invention, I
immediately place the mould containing the concrete in a chamber, in which it is
subjected to a moist heat; the temperature may be from 70° Fahrenheit upwards
to about 150°, but I prefer working at a temperature of about 100°, as when the
heat is too great the mass of concrete under treatment may be damaged by blowing
or swelling. The moist heat may be obtained and maintained by any suitable
means, such as by heating the chamber with steam or hot water pipes, and having
pans or reservoirs distributed where necessary, which being filled with water will
gradually evaporate and supply the desired moisture, or by injecting free steam
directly into the chamber, in which case the steam must not be allowed to come
into direct contact with the concrete under treatment until the temperature of the
steam has become sufficiently lowered; or open channels or troughs may be arranged
in the chamber along which hot water may be allowed to flow, the steam or vapour
from which will supply the desired heat and moisture, or the requisite moist heat
may be obtained by any of the methods in use for warming greenhouses up to a
tropical heat. But it is to be carefully noted as an essential feature of this part of
my Invention that the heat must be a moist heat. It is advantageous to provide
the chamber with means of ventilation in order that the temperature may be
regulated as required. When using free steam as the means of producing the
moist heat in the chamber, I have found it necessary to provide very free exit for

page_text: the steam, and that if its escape has been checked to any material extent injury
has resulted to the concrete mass under treatment. Having put the concrete in
the mould into this moist heat, I allow it to remain there until it is sufficiently set
to bear removal from the mould; the time will of necessity vary with the nature
of the cement and the composition of the concrete, as well as with the size and
bulk of the mass, and may be in some cases only about fifteen minutes, whereas in
other cases it may be two, three, or even more hours. It can be readily ascertained
by inspection when the mass is fit to remove from the mould. Having removed
the concrete from the moulds I leave it for a further time in the moist heat until
it is perfectly set and dry, which under ordinary circumstances will be only a few
hours from the time when it was first placed in the chamber. When it is sufficiently
dry and set, I remove it from the moist heat and place it in a warm bath, composed
of the ordinary silicate of soda or silicate of potassa of commerce diluted with
water. I have obtained good results by the use of five or six parts by measure of
water to one part of silicate of soda or of silicate of potassa. As a result of my
experiments I have found that when the bath used is of too great a strength the
mass of concrete under treatment will only be indurated on and near the surface,
and I have noticed this most in dealing with limes or heavily limed cements, and it
is therefore often desirable in order to ensure perfect saturation and induration to
use the bath of a much less strength, say, only one part by measure of the silicate
of soda or potassa to fifteen or twenty parts of water, and to leave the mass in the
bath for a longer period. The temperature of this bath may be from 70° to 150°
Fahrenheit, but I prefer working it at a temperature of from 95° to 120°. A too
great heat in this as in the moist heat is liable to swell and damage the concrete,
more especially if it is not quite dry when it is placed in the bath.
The bath may
be heated and maintained at the desired temperature by means of pipes containing
hot water or steam in circulation and placed around or through the bath or around
and through it, or by means of a circulating boiler or coil of pipes acted upon
directly by a flame, or by any other suitable means. The concrete may remain in
this bath for any desired length of time, but in practice I find that two or three
days is sufficient to render a concrete sufficiently hard for all ordinary purposes.
When taken from the bath the concrete blocks may with advantage be washed
with water. When practicable, a good result may be obtained by removing the
concrete blocks from the bath before sufficient induration has been obtained, and
replacing them in the moist heat for a few hours and then again placing them in
the bath to continue the induration, and this operation may be repeated more
than once if desired, as I find that the induration or hardening of the concrete in
the bath proceeds much more quickly when it is dry.
I am aware that silicates of soda and of potassa have been used before for
hardening concrete, and therefore I do not lay any general claim thereto when
used otherwise than as a warm bath. I would remark that the strength of the
bath may be conveniently maintained by the means described in Highton's Patent
Specification, No. 2048, of 1868, for maintaining the strength of the silicate bath
therein referred to, or by simply supplying the loss due to evaporation and
absorption by the addition of ordinary silicate of soda or of potassa of commerce
diluted with water to the required strength, but I do not claim or confine
myself to either of these modes. In lieu of a warm bath composed of a solution of
silicate of soda or potassa it may be convenient in some cases to use a warm bath
of sea water or of ordinary warm water containing or not containing salt or alkali,
but in practice I find a warm silicious bath as described the most efficient.
II. A concrete differing from No. I. in being made with lime in lieu of cement
may be advantageously treated in a similar manner, but with a weaker bath (say
about fifteen or twenty parts of water to one part of silicate of soda or potassa of
ordinary commercial strength) or the hardening of a neat cement or lime may be
accelerated by the same process.
III. To accelerate the hardening of a mass of cement or cement concrete instead
of gauging with pure or fresh water I sometimes use an alkaline solution, it may

page_text: be of potassa, soda, or other alkali; the strength it is advisable to adopt varies with
different cements and limes, but I find that with ordinary cements a saturated
solution of soda or potassa diluted with five or six times its bulk of water will
cause the concrete to set very quickly. I do not lay any claim to the use of salt or
alkali for accelerating the setting of cement or cement concrete apart from the
above described mode of application in solution.
To accelerate the hardening of lime or lime concrete I gauge or mix the same
with a solution of silicate of soda or of potassa. I have obtained good results by
using four or five parts in bulk of water to one part of the silicate of soda or
potassa.
IV. Cement, or cement concrete mixed with an alkaline solution as described,
also lime or lime concrete treated with a solution of silicate of soda or potassa ás
described, may respectively be afterwards treated with moist heat and a silicate
bath as above described.
Having described the nature of my said Invention and the manner of carrying it
into practical effect, I claim,-
1. Subjecting concrete or cement to a moist heat, substantially as and for the
purpose hereinabove described.
2. The use for accelerating the hardening or induration of cement concrete or
cement of a warm silicious bath, substantially as described.
3. Subjecting cement concrete or cement to a moist heat and thereafter to a
warm bath, substantially as and for the purposes hereinabove described.
4. Gauging or mixing cement concrete or cement with an alkaline solution,
substantially as and for the purpose hereinabove described.
5. Gauging or mixing lime or lime concrete with a solution of silicate of soda or
of potassa, substantially as and for the purpose hereinabove described.
In witness whereof, I, the said Henry Faija, have hereunto set my hand
and seal, this Thirtieth day of August, in the year of our Lord One thousand
eight hundred and eighty one.
TAKYNT TATTA