US863096A - Pavement. - Google Patents

Description

HERMAN J. RUFLI, OF MOBILE, ALABAMA.

PAVEMENT.

Specification of Letters Patent.

Patented Aug 1a, 1907.

Application filed February 12, 1907. Serial No. 857,029.

' To all whom it may concern:

wearing surface, practically unaffected by heat, cold,

dampness or changing weather conditions.

. It is a purpose of this invention to provide means for maintaining theelasticity and wearing quality of the surface of the pavement and to that end, means are provided'for renewing the oil which evaporates,

from the surface of roadways.

It is well known that the surface of a bitumen pavement or any pavement with wearing surface composed of bitumen oroil for binding agent becomes hard and brittle, owing to the evaporation of the oils contained therein, and that such hardening of the surface results in the loss of elasticity and in the disintegration of the particles thereof.

It is furthermore, a purpose of this invention to provide a basic layer of material containing an increased per cent of oil as compared with that usually employed as a binding agent, such as maltha, or other similar oil.

Itis furthermore, the purpose of this invention to provide a top wearing surface consisting of a mineral base in which a binder is utilized to retain it in a compact mass, to withstand wear and the action of the elements, the said surface layer being renewed, so far as the oil is concerned, by the absorption of the excess oil in the basic layer.

In the production of a pavement in accordance with this invention, the material forming an ordinary country road or city street is excavated a suitable depth and the material thus reclaimed, may be heated to a temperature of 120 to 140 F. for the purpose of drying the same and for the further purpose of preventing chilling of the binding agent when applied. As stated,

for the lower layer I prefer to add to the material thus reclaimed, a binding agent consisting of oil of maltha or any other suitable oil in the proportion of 20 parts of oil to 80 pzgts reclaimed material. By the term reclaimed material I mean the material that has and thereafter the top layer forming the wearing surface of the roadway is placed in position. The said upper layer is preferably composed ofa portion of the reclaimed material containing the binding agent, consisting of the pitch of coal tar or any other suitable binding agent, and itmay be in the proportion of 85 parts of reclaimed material to 15 parts of the pitch of coal tar or any other suitable binding agent, although the proportion may be varied to 'suit particular requirements. The composition thus produced is placed in the excavation on the basic layer and suitably rolled to compress it into a dense mass as is now ordinarily done in the laying of bitumen or asphaltic pavement. The upper layer will quickly harden to a suflicient degree to withstand the usual travel, and as evaporation takes place from .the surface of the roadway, by reason of the action of the elements, a suitable proportion of oil will be drawn from the basic layer (which will act as a reservoir) for renewing the life of the wearing surface of the roadway.

In carrying out the invention above set forth, it may be desirable to screen the reclaimed material and utilize the larger pieces or fragments for the base of the pavement, or as a basic layer and employ the finer material for the top or the wearing surface, If this method is employed, the larger pieces may be treated with the oil laid, the larger pieces of the reclaimed materisl'will I gravitate to the bottom of the mass and form a roadway in which the material is automatically graduated in size from base to surface in much the manner as it would be if put down'in sheets or layers of material that is graduated by screening. In accomplishing this result, it is necessary to have the material quite plastic, and to that end a binding agent of less density must be employed. That is to say, the binding agent must have a greater proportion of oil than it would have ordinarily and the surface must be rolled and re-rolled to cause sufficient agitation of the material to bring about the change in position of the pieces of reclaimed material. Of course, a greater time is required for proper hardening of the surface, but when the surface becomes solid, the lower portions of the pavement retain its excess of oil and the surface is renewed for a prolonged period. The pavement, therefore, retains its elasticity and wearing quality to anunu sual extent. In mixing the materials 'for producing this more plastic compound, it is necessary to employ approximately 10% of any suitable oil and 7M1; of coal tar to 83% of the reclaimed material.

I have also found in practice that the principle of this invention may be employed in connectionwith what is known as wooden pavements made up of blocks,which form the surface of the road-way. Ernploying the invention in this connection, the. lower layer is formed in practically the same manner as that heretofore described containing an excess supply of oil to the wooden vblocks properly creosoted or otherwise treated are then placed on the basic layer and the excess oil in the basic layer is absorbed by the wooden blocks to such an extent that the wooden blocks are preserved for an indefinite period. If desired, a coast of pitch could be used on the surface of the base and the wooden blocks laid directly on the pitch and they would'thereby be held firmly in their places and with the excess of oil used in the base which would overcome all possibility of the block swelling with the advent of a heavy'rain after'a protracted dry season. It is well known that the swelling of wooden blocks after they have been used for several years and the oil has evaporated, the moisture is allowed to enter with the results stated, but by having the excess oil in the basic layer, the oil evaporating from the surface is renewed from the base. The same basic formation will also preserve the life of an asphalt surface or any pavement with a top surface having a binding agent containing oil for regardless of the quality of the oil, a certain percentage will evaporate.

excess supply of oil adapted to feed and replenish the oil evaporated from the upper layer.

2. The herein described method of producing pavement consisting of excavating an ordinary roadway to reclaim the material forming said roadway, drying and heating the said reclaimed material and in replacing the said material in layers in the excavation with a suitable binder, the lower layer having an excess of oil adapted to replenish the oil evaporated from the upper layer. v

3. The herein described method of producing pavement consisting of excavating a roadway to reclaim the material forming said roadway, and drying the said reclaimed ma terial and adding thereto, a binder having an excess of oil, the said reclaimed material being replaced in the excavation and agitated to cause the.heavicr parts to descend and automatically graduate the size-of the particles from base to top.

4. The herein described method of producing pairenicnt consisting of excavating a roadway to reclaim the material forming said roadway, and drying the said reclaimed mate rial and adding thereto a binder, the said reclaimed'material being replaced in the excavation and agitated to cause the heavier parts to descend and automatically graduate the size of the particles from base to top.

A pavement consisting of a basic layer having an err cess of oil, and wooden blocks applied to the said basic layer and adapted to have the oil thereof renewed from the basic layer.

In testimony whereof I affix my signature in the pres once of two witucsses this 8th day of January, 1907.

HERMAN .i. RUFLI.

Witnesses JAMES PETERS, JOHN N. Jones.