IMPROVEMENTS IN CONCRETE MATERIALS MANUFACTURED INTO BLOCKS FOR PAVING AND BUILDING PURPOSES."
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Ernest de Pass at the Office
of the Commissioners of Patents on the 20th September 1881. A communi-
cation from abroad by William Hunt, of New-York, in the United States of
America.
ERNEST DE PASS, of the Office for British and Foreign Patents, 68, Fleet Street,
in the City of London, Patent Agent. IMPROVEMENTS IN CONCRETE MATERIALS
MANUFACTURED INTO BLOCKS FOR PAVING AND BUILDING PURPOSES." A com-
munication from abroad by William Hunt, of New-York, in the United States of
America.
This Invention relates to the combining of new ingredients which, when treated
by heat and mechanically compressed into the form of blocks, are suitable for
paving and building purposes.
I am aware that concrete materials have been similarly treated by heat and
compression to that used by me in the method employed and herein described, but
the difference between this Invention and former ones is, that others have combined
a calcareous substance with asphalte, whereas I use granite, rock, or other non-
calcareous matter, in combination with asphaltum which has been tempered with
oil, and by preference the residuum of petroleum, although other distillations of
mineral oil may be used.
This Invention therefore consists of a concrete material composed of granite,
stone, or other non-calcareous matter, with asphaltum and mineral oil compressed
into blocks.
In order that this Invention may be understood, I proceed to explain the mode
by which the blocks may be manufactured.
I take stone and crush and pulverize it into granulated pieces and dust. I take
asphalte and mix it with the required amount of mineral oil, which acts to flux it
and temper it into a solvent for use.
Before mixing the stone with the prepared asphalte both are separately treated
by heat, the stone so that all moisture is expelled therefrom, and the asphalte so
that all moisture is evaporated and it reduced to a fluid condition.
When all the ingredients are thoroughly treated and the moisture thoroughly
expelled, they are brought together in proper proportion and mixed well together,

page_text: and while thus mixed are subjected to high compression in moulds into the form of
blocks, which are emerged from the compression into water, which serves to cool
them, and thereby preserve them in their compressed form.
The quantities of material vary somewhat, according to the different kinds of
material employed, but the usual average would be about 88% of stone to 12% of
the asphalte prepared with oil. The quantity of oil required depends upon the
quantity of asphalte used; but to seven tons of Trinidad asphalte about 150 gallons
of crude petroleum would be used. Experience alone demonstrates the requisite
proportions, because all depends upon the richness of the asphaltic material.
Again, just at compression of the material, much depends on having the mixture
in proper heat and condition. To illustrate this, it may be said that the material,
when in condition to be compressed, should somewhat resemble the steaming mash
from a still. The temperature of the mixture at this point should be about 150
degrees. The beat applied to the pulverized stone during its drying should be
about 300 degrees, or sufficient to free the stone from all moisture. The heat
applied to the asphalte and oil should be a slow fire, the object being to evaporate
all moisture and reduce, as also temper the asphalte, with oil to a fluid condition, so
that when mixed with the particles of stone and dust they will become coated
therewith; and thus when compressed the mass will be compacted into a dense body
and capable of resisting abrasion to a high degree.
Experience has shewn that these coated particles will adhere, when compressed,
quite as firmly as limestone or other calcareous substance; hence it is evident that
these blocks will stand greater wear than those made of calcareous matter. Again,
the advantage of manufacture will be greatly enhanced, inasmuch as non-calcareous
substances are more generally obtainable than limestone or its calcareous equivalent.
This also effects an economy of production, because if calcareous matter alone
were used it could not always be had at places, except at great expense for
transport.
By this Invention I therefore gain the following advantages over a calcareous
made block, viz. :-
Durability, because of its greater hardness, and consequently better wear.
Economy, because of its general existence in comparison with a calcareous
matter, thereby saving expense of freight in districts where calcareous matter
does not exist.