New or Improved Material for Building Purposes.
Year: 1894

page_text: Date of Application, 26th Oct., 1894-Accepted, 1st Dec., 1894
COMPLETE
SPECIFICATION.
New or Improved Material for Building Purposes.
I, FRANZ WITTMANN, of 26 Kl. Hamburgerstrasse, Berlin, in the Empire-
of Germany, Stone Polisher, 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, reference being had to the
accompanying sheet of drawings, and to the letters and figures marked thereon,.
that is to say:
The object of this invention is to produce a more or less sound-proof building.
material from sifted coal, ashes, and hydraulic binding material.
The drawings hereto annexed show examples of building slabs made from.
material produced in accordance with the invention.
Figures 1 and 2 show a simple slab with a groove in each edge.
Figures 3, 4 and 5 show a similar slab with metallic strengthening parts
inserted.
Figures 6 and 7 are sections through an arch between iron joists.
I have found that the best results are obtained with a mixture composed of-
1 kilogramme of slag or coal ashes
100 grammes of cream of lime
100 grammes of cement
120 grammes of water.
These ingredients are thoroughly mixed together and then moulded or otherwise
shaped to the required form.
This mixture, when set, has a tensile strength, after seven days, of 3.3 kilo-
grammes per square centimètre; and after 28 days, of 3.56 kilogrammes per square
centimètre. The latter result corresponds to a compressive strength of over
30 kilogrammes per square centimetre, so that the material is fully strong enough
for ordinary building purposes, and for arches not too heavily loaded. The
inaterial produced from the above mentioned mixture is very porous and therefore
of very light weight. As the mass is absolutely free from germs and holds the
inoitar well it is specially suited for use in platforms. Slabs made of this material
may be used with or without internal iron stiffening or strengthening stays or ribs
according to the purpose for which they are to be used, or the amount and
character of the strain to which they are to be subjected.
Figures 1 and 2 show a slab a without any internal strengthening means but
having grooves b c d e in its edges which serve chiefly to receive iron rods forming
external strengthening frame-work. To increase the strength of the slabs, iron
stays or ribs may be placed inside them, and for this purpose I prefer to connect
the stays or ribs m.to longitudinal bars k and 1, as shown in Figure 5, and then to
pour the mixed material round the iron ribs in a mould so as to form the slab as
shown in Figure 3 with the bars and laying in the groove gi. Figures 6 and 7
show sections through an arch between two joists n which latter are held together
by bolts p, the material o being rammed in like concrete.
Partition walls made of the above material are bad conductors of sound; they
cost little to construct, and their strength is at least equal to that of walls
constructed of ordinary building materials.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
1 claim is:
The new or improved building material consisting of a mixture of coal ashes,

page_text: cream of lime, cement, and water, moulded or otherwise shaped so as to form more
or less sound-proof building slabs, with or without strengthening iron work,
substantially as described.
Dath Ja
1004
F.
WITTMANN,
Per W. H. Beck,
115, Cannon Street, London, Agent.