Frictional Self-draining Structure

Abstract

A frictional, in situ self-draining composite structure for runway and roadway structural docking and pathway surface. The composite structure has a solid base to which is bound a porous superstratum of aggregate and resinous binder. The composite structure is fabricated by applying a first mixture containing about two to about four parts by volume of aggregate particles of crushed rock, river gravel, crushed coral, coarse sand, slag, or crushed refractory material and one part by volume of a settable resinous binder to the base section and allowing it to set, and then by applying a second mixture containing about two to about four parts by volume of scoria and/or slag particles and one part by volume of a settable resinuous binder to the first porous layer.

Description

The field of the present invention includes pavement surfaces, drainage surfaces, and insulating surfaces.

Pavement surfaces consisting of scoria or slag and a settable resinous binder are disclosed in U.S. Pat. No. 2,925,831 to Lloyd G. Welty and John N. Hinkson and No. 3,396,641 to Lloyd G. Welty and Simon J. Sluter. The pavement surfaces disclosed in these patents are solid nonporous structures which have relatively high frictional surfaces. The frictional properties of such pavement surfaces greatly exceed the frictional properties of the surfaces of conventional pavements, such as concrete pavements; however, since these patented pavement surfaces are solid, nonporous and not self-draining, they must be constructed with a sloped top surface to allow water to run off therefrom to prevent pooling of the water on the surface. During rain falls, the surface of the pavement is covered with a layer of water, even when the surface is sloped. A water layer or water pooling creates a dangerous situation on roads and runways because the wheels of most vehicles, including airplanes, hydroplane on wet surfaces when the vehicle is traveling at high speeds, such as a car traveling fifty or sixty miles per hour. (See the technical paper entitled "Phenomena of Pneumatic Tire Hydroplaning" by Walter B. Horne and Robert C. Dreher in NASA Technical Note TN D-2056, November 1963.)

Due to their solid construction, these pavement surfaces are relatively heavy and cannot be used as replacement surfaces on most existing bridges and elevated structures because such bridges and structures were not designed or constructed to support the weight of such pavement surfaces. Furthermore, due to their weight, it is not practical or feasible to employ them in roofing.

Although the aforementioned patented pavement structures are a great improvement over conventional pavements, their use in many areas of the country has been thwarted by economic considerations. In most areas of the country, cement, gravel, and sand are locally available and are the predominant materials used in conventional pavement construction. In contrast, scoria is found only in certain areas of the western states and slag is produced only in steel-making areas. Since scoria and slag are not locally available in most areas of the country, the transportation costs of these materials sharply raises the construction cost of scoria and slag pavement structures.

The present invention is directed to a frictional, in situ self-draining composite structure comprising a solid substrate base to which is bonded a porous superstratum. The porous superstratum has a first porous layer adjacent to the base which consists of aggregate particles of greater size than 1/16-inch mesh and a settable resinous binder which binds the aggregate particles into a cohesive porous mass. The porous superstratum also has a second porous layer which is contiguous with the first porous layer; the second porous layer consists of scoria or slag particles having a size greater than 1/16-inch mesh and a settable resinous binder which binds the particles into a cohesive porous frictional mass. The composite structure of the present invention is suitable for road surfaces, pathway surfaces, runway surfaces, rooftop surfaces, and the like.

An object of this invention is to provide a lightweight, strong, frictional, in situ self-draining surface structure which is suitable for roadways, runways, and the like.

Another object of the present invention is to provide a frictional, in situ self-draining composite structure having a planar, horizontal top surface. More particularly, it is an object of the present invention to provide a frictional, self-draining composite structure surface which will eliminate hydroplaning conditions on high speed roads and on aircraft runways.

A related object is to provide an in situ self-draining composite structure which provides for the rapid drainage therethrough of fuel oil, inflammable liquids, poisonous liquids, caustic liquids and/or obnoxious liquids spilled, either by accident or from spillage during fueling of vehicles or aircraft, on the surface of such structure. More particularly, it is an object to provide a vehicle pavement surface which will permit the rapid in situ self-drainage therethrough of dangerous or inflammable liquids and which will inhibit the burning of drained inflammable liquids.

A further object of the present invention is to provide a partially porous composite structure with insulative qualities. More particularly, it is an object to provide an insulative roadway or runway structure that will inhibit the freezing of water in the porous layer of the structure and of ground water below the base of the pavement.

Another and further object of the present invention is to provide an in situ self-draining composite structure having a highly frictional top surface which is both durable and self-sharpening and has light-reflecting characteristics. More particularly, it is an object to provide a composite structure which has a slag or scoria top surface and which is constructed principally of locally available materials.

Another and further object of the present invention is to provide an in situ self-draining composite structure which is resistant to the action of water, fuel, and oil. More particularly, it is an object of the present invention to provide a self-draining structure which can be back-flushed at periodic intervals with water to remove sand, dirt, rubber particles and the like from the channels of the structure.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross-sectional view of the self-draining composite structure of the present invention;

FIG. 2 is an enlarged cross-sectional view of the self-draining composite structure taken over the encircled area of FIG. 1; and

FIG. 3 is an enlarged cross-sectional view of the self-draining composite structure taken over the encircled area of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the frictional, in situ self-draining composite structure 10 includes a solid substrate base 11 and porous superstratum 12 which is bonded to the base 11. The porous superstratum 12 has a first porous layer 13 which is bonded to the base 11 and a second porous layer 14 which is contiguous with and bonded to the first layer 13. Partially embedded in the base 11 is a drainage conduit 11a having its longitudinal axis at right angles to the plane of the drawing. The upper portion of the conduit 11a is apertured (not shown) with a plurality of slots or holes to permit the flow of water into the conduit 11a from the upper surface of the base 11 and from the porous superstratum 12. The top surface of the base 11 is sloped to assist or promote the run-off of water from the surface into the conduit 11a. The conduit 11a runs the length of the structure 10 and empties into a master drainage system, storm sewer, stream or the like (not shown).

In most instances, the base is impervious to water and is constructed from conventional construction materials such as concrete and asphalt. In the case of bridge roadway construction, the base 11 will generally be made of metal, such as steel or aluminum, structural members, plates or webbed or foraminous members. Foraminous members are particularly advantageous where weight is a critical engineering factor. When the base 11 is a metal web structure, the upper surface of the base 11 usually is not sloped and conduit 11a is omitted because liquids can drain from the porous super-structure through the holes of the foraminous structure. In the case of roofing construction, the base 11 will generally be made of wood board, plywood board, or lightweight metal sheet.

The top surface of the second porous layer 14 is flat and substantially horizontal; however, the top surface can be sloped in the appropriate situation, such as in the construction of banked turns, or roofs.

In FIG. 2 the first porous layer 13 is shown constructed of a plurality of aggregate particles 16 which are bonded together with a settable resinous binder 15 at points of contact 17 (FIG. 3). Between the aggregate particles 16, which are coated with a layer of the settable resinous binder, are lateral and vertical interconnecting drainage canals or channels 18 for the drainage of fluids from the top surface of the first layer 13 down to the base 11. The first layer 13 can be bonded to the top surface of the base 11 with a resinous settable binder; however, other means of securing the first layer 13 to the base 11 can also be employed as described below. The aggregate particles 16 are crushed rock, river gravel, crushed coral, coarse sand, slag, or crushed refractory material, and are at least 1/16-inch mesh, preferably at least 1/8-inch mesh. The first layer 13 contains from about 2 parts to about 4 parts by volume of aggregate particles to give the first layer a porosity of at least 10 percent, that is, at least 10 percent of the total volume of layer 13 are channels or air spaces; preferably the porosity will be at least 20 percent. The porosity is the percentage of free volume in a porous layer that is accessible from the surface of the porous layer by channels and conduits. The porosity is conveniently measured by preparing a cube of known size or volume of the aggregate and binder mixture in a mold. After the binder has set, the cube of material and the mold are weighted. The cube of material in the mold is then filled and saturated with water and the combination is weighted. The difference between the first and second weightings is the weight of water in the free volume of the cube of material, and, assuming water weighs one gram per cubic centimeter, the free volume of the cube is directly found. The porosity is the percentage of the cube's volume that is free volume. With small-sized aggregate particles, i.e., 1/16 -inch mesh, the porosity of the first layer approaches the 10 percent limit; with larger-sized aggregate particles, i.e., 1/4-inch mesh or larger, the porosity approaches 25 percent or more. The first porous layer also contains one part by volume of a resinous settable binder to give the first layer an impact strength of at least 1,000 pounds per square inch, preferably at least 2,000 pounds per square inch. The impact strength increases with increasing proportions of binder.

The preferred settable resinous binders 15 employed in the first porous layer 13 include catalyzed epoxy, phenolic, polystyrene, acrylic esters with resorcinol-formaldehyde, polyurethanes, polyester and silicon resins which set at ordinary room temperature and at accelerated rates with increased temperatures. Epon, or resins (such as 828) supplied by Shell Chemical Company, Araldite resins (such as 502, 6010, 6020, and the like) supplied by Ciba Plastics, Plastics Division, C-8 Devron and other epoxy resins are generally prepared by the condensation of an epichlorohydrin and a bisphenol such as Bisphenol-A (4,4'-isopropylidenediphenol) to various molecular weight polymers. Catalysis by agents and mixtures thereof including organic bases, acid anhydrides, compounds containing active hydrogen, certain resins, and the like, is employed in the multitudinous commercially available formulations. Plasticizers such as Thiokol fluid and others can be employed therein. Phenolformaldehyde liquids can be cured with organic bases, resorcinol-formaldehydes cure at room temperature with additional formaldehyde and urea-melamine- formaldehyde cures at room temperature or copolymerizes with others of the phenolics and epoxies. True polymerizing adhesive bonding agents derived of styrene, allylic compounds, acrylic and methacrylic esters are cured with benzoyl peroxide or other organic peroxide and especially in the presence of a redox catalyst system. Polyurethanes and hybrids with polyurea cure in the presence of water and acid.

Referring to FIG. 2 again, the second porous layer 14 is shown having scoria or slag particles 19 which are bound together with a settable resinous binder, such as one of those binders described above, at points of contact 20 between the particles 19. Between the particles 19, which are coated with a layer of a settable resinous binder, are lateral and vertical interconnecting drainage channels 21 for the drainage of liquids from the top surface of layer 14 down to the top surface of the first layer 13. The second layer 14 is bound to the top surface of the first layer 13 with the resinous settable binder. In general, the channels 21 of the second layer 14 are contiguous with the channels 18 of the first layer 13. The slag or scoria particles 19 are at least 1/16-inch mesh in size, preferably at least 1/8-inch mesh. The second porous layer 14 contains from about 2 to about 4 parts by volume of aggregate particles to give the second layer a porosity of at least 10 percent, that is, at least 10 percent of the total volume of the second layer 14 are canals, channels or air space; preferably the porosity of the second layer will be at least 20 percent. Moreover, the porosity of the second layer is preferably equal to, or greater than, the porosity of the first layer. With smaller-size particles of scoria or slag, such as 1/16-inch mesh, the porosity of the second layer approaches the 10 percent limit; with larger-size particles, such as 1/4-inch mesh or larger, the porosity approaches 25 percent or more. The second porous layer also contains one part by volume of a settable resinous binder, such as one of the binders described above, to give the second porous layer an impact strength of at least 1,000 pounds per square inch, preferably at least 2,000 pounds per square inch.

As employed herein, the slag is defined as the dross which is obtained as a product of smelting a metal from an ore containing silicates and generally a lower specific gravity than the metallic substances extracted. For example, slag may be produced in a smelting operation in which fluxing agents such as limestone and fluorite are intermixed with a siliceous ore, for example, of iron, which mixture is then fused as in a blast furnace. The slag as dross forms a fluid layer overlying matter smelted metal wherefrom it is poured off and cooled. The cool material is then fragmented by conventional grinding, rolling, and screening methods.

The scoria employed in the composite structure is of volcanic origin and is generally cinder-like in character. The scoria may occur in the form of vesicular lapilli, porous volcanic bombs, as scoria or as massive effusive formations of volcanic origin. The material is usually red or black in color and has a cellular structure in which there is a multitude of elongated or spheroidal cavities arranged in contiguity. A large proportion of the cavities is closed, i.e., the structure is largely unicellular, in the natural state. After the scoria is mined, it is reduced to the appropriate size by a fracturing, fragmentation or crushing operation to provide scoria particles having highly irregular forms with large exposed surface areas presenting a myriad of outwardly projecting spicules as well as multitudinous depressions and cavities and the openings thereto exposed but frequently having less area than the area within the cavities.

The use of slag and/or scoria particles in a second porous layer provides that the top surface of the composite structure will be highly frictional and will possess excellent light reflected qualities. The slag or scoria particles have many concave reflective surfaces facing in all directions. This gives a uniform reflective surface for light proportional to the particle size and the number of particles per square foot. In addition, the particle surface creates a backward reflection toward the light source.

The scoria or slag particles maintain their high and uniform coefficient of frictional resistance with wear. When an exposed particle eventually breaks down and disintegrates because of wear, impact, and abrasion, an underlying particle thereby becomes exposed, thus maintaining the high frictional qualities of the top surface. Thus, the composite structure employs a uniformly frictional surface with numerous frictional particles per square foot of surface. For example, one square foot of the second porous layer employing scoria and/or slag particles of 1/8-inch mesh provides a surface with about 12,000 to about 18,000 particles. This type of surface provides a consistent braking action simultaneously to all wheels of a vehicle or aircraft whether the surface is wet or dry.

The 10 percent porosity limit of the first and second porous layers is critical. When the porosity of a layer is below 10 percent, the self-drainage characteristics are adversely affected, that is, drainage of water is effectively inhibited. The reason for this is not understood at this time; however, it is believed that when the porosity is less than 10 percent the channels within a porous layer are quite narrow and have constricted areas with cross-sectional areas approaching the cross-sectional areas of capillary tubes. In such constricted areas, water droplets are effectively trapped by capillary action and block or dam the small channels of the porous layer which inhibits or prevents drainage and allows water to back up and form pools on the surface of the pavement structure. One of the draining characteristics of the present pavement surface that has been observed is that in situ water drains through the pavement surface at an increased rate once the channels of the first and second porous layers have been wetted with water. At the present time there is no explanation for this phenomenon.

As described above, the binder and particles in both porous layers are combined within a certain ratio range to provide that each layer has a porosity of at least 10 percent, preferably at least 20 percent, and an impact strength of at least 1,000 pounds per square inch, preferably at least 2,000 pounds per square inch. The impact strength of a layer can be increased by increasing the proportion of binder within the range; however, the volume of binder used must be controlled to insure that the porous layer has a porosity of at least 10 percent. In normal practice, small pavement samples will be prepared, prior to large-scale fabrications of a pavement structure, to determine the proper volumetric proportions of particles and resin to furnish a pavement structure having the desired porosity and impact strength.

The composite structure 10 of FIG. 1 is fabricated by first preparing a mixture of the aggregate particles of at least 1/16-inch mesh preferably free of fines, and a settable resinous binder in the liquid state; the two ingredients are mixed in a ratio, by volume, of about 2 to about 4 parts aggregate particles to 1 part binder. The aggregate particles and binder are mixed until the particles are uniformly coated or wetted with the binder. The top surface of the base element 11 is precleaned and roughened by sandblasting, wire brushing, acid washing, and the like to remove dirt, loose material, oil, grease and the like. The surface is then coated with a layer of a settable resinous binder in the fluid state. The selection of appropriate settable resin binder will depend upon the nature of the substrate surface and the ambient temperatures under which the surface is to be employed. The mixture of the aggregate particles and binder, is then applied to the base 11 and compacted to insure maximum bonding to the top surface of the base and between the aggregate particles. The mixture can then be allowed to set to form the first porous layer 13 of the superstrata portion 12.

The second porous layer 14 is fabricated by preparing a mixture of scoria and/or slag particles of at least 1/16-inch mesh, preferably free of fines, and the settable resinous binder in the liquid state employing, by volume, about 2 to about 4 parts scoria and/or slag to 1 part binder. The particles of scoria and/or slag and the binder are mixed or tumbled to insure that each particle is uniformly coated or wetted with the binder. The mixture is then applied to the top of the first porous layer 13 and compacted to insure maximum bonding to the top surface of the first layer 13 and between the scoria and/or slag particles 19. This mixture is rolled or tamped before it sets to make the top surface planar and substantially horizontal. The mixture is then allowed to set to form the second porous layer 14. The mixture of scoria and/or slag particles and binder can be applied to the first porous layer before or after it has set; normally after the first layer has set.

The resulting first porous layer 13 and the resulting second porous layer 14 will each have a porosity of at least 10 percent, preferably at least 20 percent, and an impact strength of at least 1,000 pounds per square inch, preferably at least 2,000 pounds per square inch.

Another method of fabricating the composite structure of the present invention includes the step of applying a layer of a fluid adhesive bonding agent to the top surface of the base 11. The selection of an appropriate bonding agent will depend upon the nature of the substrate surface and the ambient conditions under which the surface is to be employed. In some instances the solution of adhesive material will solidify by evaporation of a solvent carrier. Likewise, it is possible to employ bonding agents which can be applied in molten condition and which solidify on cooling; however, it is generally preferred to employ a settable resinous binder with a catalyzed setting tie as described above. Solvent solutions such as asphaltic, coal tar, or other resinous materials exemplify the first-mentioned type of adhesive bonding agents. Aqueous emulsions and dispersions of adhesive bonding agents of a similar character could be employed likewise. Molten asphalts, coal tar, resins and synthetic resins exemplify the second type of bonding adhesive. While the fluid adhesive bonding agent is still in the fluid state, a layer of aggregate particles, free of fines and of uniform size, are preferably applied to the treated surface of the base. Generally the aggregate is applied with rolling action of troweling to assure that lower surfaces of the aggregate particles are thoroughly wetted by the liquid adhesive bonding agent and are embedded partially therein. Surfaces such as pathways and roofs to which only a thin covering is to be applied, mesh sizes of one-sixteenth and one-eighth inch or larger may be employed. In the event that the composite structure is to be used for vehicular or aircraft traffic, such as trucks and airplanes, aggregate of one-eighth, one-fourth, three-eighths, and one-half inch or larger mesh sizes are employed. Ordinarily, the bonding agent is then allowed to set. The mixture of aggregate particles and resin is then applied to the pretreated upper surface of the solid substrate base in the manner described above.

When the composite structures of this invention are being constructed on a new or fresh concrete base 11, aggregate particles, free of fines, and of uniform size, may be partially embedded in the top surface of the concrete base while the concrete is soft and fresh to provide an alternative bonding layer. After the concrete is set, the top surface of the base 11, which is covered with embedded aggregate particles, is covered with a layer of settable resinous binder to which is applied prior to setting the aggregate particles and binder mixture employed in the fabrication of the first porous layer 13.

In a preferred embodiment of the present invention where the top surface of the base 11 is sloped, the first porous layer is laid in such a manner that its top surface is substantially horizontal and the second porous layer is laid in a relatively thin layer such that its top surface is planar and substantially horizontal. In this preferred embodiment the second porous layer has a thickness of at least one-fourth inch and preferably at least one-half inch, whereas the first porous layer has a thickness of at least 2 inches.

In order to insure rapid draining and prevent back-up, the composite structure is constructed with one or more drainage conduits between the phase of the solid substrate base and the first porous layer; the drainage conduits preferably run the length of the base section and perpendicular to the gradient of the base section. The conduits are slotted by a plurality of holes in their upper surfaces, and can be made of metal, brick clay, stone, or plastic material. In an alternative embodiment of the present invention (not shown) the drainage conduit can be a slit trench constructed in the base section, the drainage conduit can be a conduit foraminous about its entire circumference which is merely laid on top of the base 11, and surrounded by the first porous layer.

Although not shown in the drawing, the present composite structure can be constructed with heating elements near the upper surface of the superstratum portion. The use of such heating elements will prevent ice formation in the channels 18 and 21 of the composite structure and will insure adequate drainage during freezing weather. The heating elements can be conduits through which steam or hot water is circulated, or they can be waterproofed electrical heating elements.

The drainage conduit 11a (FIG. 1) not only can be utilized for drainage, but it can also be utilized for back-flushing; i.e., water can be pumped through the drainage conduit under pressure to force water up through the channels 18 and 21 of the porous superstratum and out through the top surface of the composite structure to remove dirt, rubber, and other particles from the channels.

EXAMPLE 1

A concrete runway substrate runway base having a lateral gradient of 2.degree. is coated with a settable resinous binder of the following formula: Component Parts _________________________________________________________________________ _ Epon 828 (Shell Chem. Co.) 100 Triethenediamine or equivalent base 8 Phenyl glycidyl ether 5 Fluid thiokol (plasticizer) 10 _________________________________________________________________________ _

Immediately after application of the binder, a mixture of crushed white rock (50 percent 1/4-inch mesh, 30 percent 1/8-inch mesh, and 20 percent 1/16-inch mesh) and the settable resinous binder of the above formula (221 parts by weight rock to 31 parts by weight binder; i.e., about 3.5 parts by volume rock to 1 part by volume binder) are applied to the base at a thickness no less than 6 inches. The mixture of rock and binder are rolled to form a substantially horizontal upper surface; the mixture is then allowed to set to form the first porous layer having a porosity of 19 percent. After the above mixture has set, a mixture of slag (50 percent 1/4-inch mesh, 30 percent 1/8-inch mesh, and 20 percent 1/16-inch mesh) and the settable resinous binder of the above formula (255 parts by weight slag to 34 parts by weight binder; i.e., about 3.75 parts by volume slag to 1 part by volume binder) is applied to the first porous layer to a depth of 1 inch. The mixture of slag and binder is rolled to form a substantially horizontal surface; the mixture is then allowed to set to form the upper porous layer having an approximate porosity of 23.7 percent.

The finished composite structure has excellent frictional and drainage qualities which are ideal for runway surfaces.

The present frictional self-draining pavement structure is particularly valuable for the prevention of hydroplaning of wheeled vehicles, including airplanes. Hydroplaning can take place when a pavement surface is covered with a thin layer, such as one-sixteenth inch or less, of water and the wheeled vehicle is traveling at speeds greater than 30 miles per hour, depending on vehicle weight. When hydroplaning, the wheels of the vehicle lose contact with the pavement surface which inhibits or prevents effective steering, guidance and stopping of the vehicle. Hydroplaning is a very serious problem on rainy days with respect to high-speed highway driving and airplane landings. The crowning of roads or runways does not circumvent this problem because water runs off across the road or runway presenting a layer of water on the pavement surface. The only practical solution to hydroplaning is to fabricate roads and runways in accordance with the present invention which provides for in situ water drainage through the surface of the pavement structure which in turn prevents liquids from laking on the pavement surface.

A pavement surface substantially equal to the pavement surface described above is prepared by employing the settable resinous binder of the following formula in place of the above-described binder: Component Parts _________________________________________________________________________ _ Liquid resin 1010 (Shell Chem. Co.) 100 Hardener Type U (Shell Chem. Co.) 10 Plasticizer (dimethylcyclohexyl phthalate) 2 _________________________________________________________________________ _

EXAMPLE 2

A used crowned concrete freeway surface having a lateral gradient of 3 percent is sandblasted to remove loose material and acid treated to remove oil, gums and rubber. The surface is then sprayed with an asphalt emulsion. A single layer of 3/8-inch mesh river gravel is rolled on the asphalt treated surface; the surface is sprayed again with the asphalt emulsion. After the asphalt emulsion has solidified, a mixture of river-gravel (1/16-inch to 1/4-inch mesh) and a liquid settable resin of the following formula: Component Amounts _________________________________________________________________________ _ Fluid resin (Applied Plastics Co., #210) 6 parts by weight Hardener (Applied Plastics Co., 1 part by weight #180) Plasticizer (General Mills Corp., #125) 10% by volume of fluid resin and hardener _________________________________________________________________________ _ Binder (175 parts by weight gravel to 36 parts by weight binder; i.e., 24 parts by volume gravel to 1 part by volume binder) is applied to the asphalt treated freeway surface at depth no less than 4 inches to form the first porous layer; the first layer is rolled to form a substantially horizontal surface and allowed to set to form a layer with a porosity of about 20 percent. After the first porous layer has set, a mixture of scoria (50 percent 1/4-inch mesh, 30 percent 1/8-inch mesh, and 20 percent one-sixteenth inch mesh) and liquid binder of the above formula (about 2 parts by weight scoria to 1 part by weight binder, i.e., about 2.6 parts by volume scoria to 1 part binder) is applied over the layer to a depth of about 1 inch to form the second porous layer. The second layer is rolled to form a substantially horizontal layer and allowed to set to form a layer with a porosity of about 24 percent.

The resulting roadway is durable and has excellent frictional and drainage characteristics.

A pavement surface having properties and characteristics similar to the above-described pavement surface is prepared by employing the liquid settable resin of the following formula in place of the above-described resin: Component Parts _________________________________________________________________________ _ Liquid resin: Epotuf 37.130 (Reichold Chem. Co.) 100 Hardener: Epotuf 37-623 (Reichold Chem. Co.) 7.5 Plasticizer: Kesscoflex BCP (Kessler Chem. Co.) 2.5 _________________________________________________________________________ _

EXAMPLE 3

A substrate surface of hot asphalt "plant mix" applied over a standard crushed rock base is covered with 1/2-inch screened crushed quartz aggregate of the character described above. While the substrate is still in a heated condition, the aggregate layer is rolled with sufficient pressure to imbed the aggregate particles about halfway into the soft asphalt layer.

A fluid setting adhesive agent of the following formula is then applied as by spraying over the aggregate studded substrate surface: Component Amount _________________________________________________________________________ _ Fluid resin (Applied Plastics Co., #210) 4 parts by weight Hardener (Applied Plastics Co., #180) 1 part by weight Plasticizer (General Mills Corp., #125) 3% by volume of fluid resin and hardener _________________________________________________________________________ _

EXAMPLE 4

A substrate of freshly poured and rough-finish concrete having a 4 percent sloped surface is covered with a thin layer of slag aggregate of 1/2-inch to 1-inch screen size; the surface is then rolled to imbed the particles about halfway into the concrete. After the concrete has set, a mixture of the fluid epoxy resin of the following formula: Component Parts by Weight _________________________________________________________________________ _ Epon 828 (Shell Chem. Co.) 95 Triethenediamine or an equivalent base 7 Phenyl glycidyl ether 4.5 Fluid thiokol (plasticizer) 5 _________________________________________________________________________ _ is sprayed over the aggregate layer. Before the resin has set, a mixture of slag aggregate (1/2-inch to 1-inch mesh) and the fluid epoxy resin of the above formula (3.5 parts by volume slag to 1 part by volume resin) is applied to the cement base to a depth of 12 inches. The mixture is rolled to form a substantially horizontal surface and then allowed to set to form the first porous layer. A mixture of scoria (1/4-inch to 1/16-inch mesh) and the fluid epoxy resin of the above formula (3.75 parts by volume scoria to 1 part by volume resin) is spread over the first porous layer to a depth of about 1 inch. The material was tamped and rolled to form a substantially horizontal surface which has excellent frictional qualities and drainage qualities.

In the same manner old concrete roadways or runways can be resurfaced; however, the old surface should be pretreated first by sandblasting or abrading mechanically an acid washing the surface to remove dirt, gums, rubbers and other oxidized materials therefrom.

EXAMPLE 5

An upper surface of an aluminum foraminous structural panel is cleaned with detergent and water and allowed to dry. The surface is then cleaned with a petroleum spirit to remove grease, oil and gums. The surface is then sandblasted and wire-brushed to remove all loose material and prepare a clean metal uncovered surface. A catalyzed setting adhesive resin of a phenolic epoxy or silicon-type having a viscosity of about 400 to 5,000 centipoises is applied as a coating to the cleaned surface. Dry scoria aggregate (1/4-inch to 3/8-inch mesh) is applied to the treated surface before the resin has been allowed to set. A dough-like mixture of crushed light quartz (1/4-inch mesh) and a catalyzed setting adhesive resin of the phenolic epoxy or silicon-type (about 3.5 parts by volume rock to 1 part resin) is applied to a depth of 2 inches over the metal substrate. The material is rolled to form a substantially horizontal surface and allowed to set to form the first porous layer. A dough-like mixture of scoria (1/8-inch mesh and a catalyzed setting adhesive resin of the phenolic epoxy or silicion-type (3 parts by volume scoria to 1 part by volume resin) is applied to a depth of one-half inch over the first porous layer. The material is tamped, rolled and troweled to form a substantially horizontal layer and then allowed to set to approximately 24 hours to form a highly frictional lightweight surfacing material. This surfacing is ideally suited for marine decking, traffic decking for bridges, and for a lightweight highly insulative roofing material.

EXAMPLE 6

A substrate of freshly poured and rough-finish concrete having a 5 percent sloped surface is covered with a thin layer of an 80:20 mixture of slag:score aggregate of 1/2-inch to 1-inch screen size; the surface is then rolled to imbed the particles about halfway into the concrete. After the concrete has set, a mixture of the fluid epoxy resin of the following formula: Component Parts _________________________________________________________________________ _ Liquid resin: Epi-rex 510 (Celanese) 100 Hardener: Epicure 872 (Celanese) 5 Plasticizer: dioctylphthalate 5 _________________________________________________________________________ _ is brushed over the aggregate layer. Before the resin has set, a mixture of 50:50 granite:slag aggregate (1/2-inch to 1-inch mesh) and the fluid epoxy resin of the above formula (3.0 parts by volume of the aggregate mixture to 1 part by volume resin) is applied to the cement base to a depth of 12 inches. The mixture is rolled to form a substantially horizontal surface and then allowed to set to form the first porous layer. A 60:40 mixture of slag:scoria (1/4-inch to 1/16-inch mesh) and the fluid epoxy resin of the above formula (3.75 parts by volume of the slag:scoria mixture to 1 part by volume resin) is spread over the first porous layer to a depth of about 2 inches. The material was tamped and rolled to form a substantially horizontal surface which has excellent frictional qualities and drainage qualities.

In the same manner old concrete roadways or runways can be resurfaced; however, the old surface should be pretreated first by sandblasting or abrading mechanically an acid washing to remove dirt, gums, rubbers and other oxidized materials therefrom.

Although the above examples have illustrated the composite structure of the present invention in runway, highway bridge decking, and roofing applications, it is not contemplated that the present invention be limited to such uses.

Claims

I claim:

1. A high strength, frictional, in situ self-draining structure, comprising: a solid imperforate and substantially impervious substrate base having a top surface adapted for the collection and channeling of liquid to a drain; and a superstratum layer porous throughout its depth and bonded to said base for the drainage of fluid from the top surface of said base, consisting of aggregate particles of greater size than 1/16-inch mesh bonded together with a resinous binder which is present in an amount insufficient to fill the voids between aggregate particles and, having about 2 to about 4 parts by volume of said aggregate particles and 1 part by volume of said binder to give said layer a porosity of at least 10 percent and to give said layer an impact strength of at least 1,000 pounds per square inch.

2. The high strength, frictional, in situ self-draining composite structure defined in claim 1 wherein the aggregate particles of the superstratum layer are selected from the group particles of crushed scoria, rock, river gravel, crushed coral, coarse sand, slag, and crushed refractory material.

3. The high strength, frictional, in situ self-draining composite structure defined in claim 1 wherein the drain is at the base of the sloped upper surface of said base.

4. The high strength, frictional, in situ self-draining composite structure defined in claim 3 wherein the drain is a drainage conduit which is partially embedded in the top surface of said base, the top portion of said drain conduit being perforated with a plurality of holes.

5. The high strength, frictional, in situ self-draining composite structure defined in claim 1 including heating means below the top surface of the porous superstratum layer.

6. A high strength, frictional, in situ self-draining composite structure comprising: a solid imperforate and substantially impervious substrate base having a top surface for the collection and channeling of liquid to a drain and a superstratum porous throughout its depth and bonded to said base, said superstratum having a first porous layer bonded to said base and a second porous layer contiguous with and bonded to said first porous layer, said first porous layer consisting of aggregate particles of greater size than 1/16-inch mesh bonded together with a settable resinous binder which is present in an amount insufficient to fill the voids between aggregate particles, said first porous layer having about 2 to about 4 parts by volume of said aggregate particles and 1 part by volume of said settable resinous binder to give said layer a porosity of at least 10 percent and to give said layer an impact strength of at least 1,000 pounds per square inch, said second porous layer consisting of scoria and/or slag particles of greater size than 1/16-inch mesh bonded together with a settable resinous binder which binder serves to bond said first layer to said second layer and which is present in an amount insufficient to fill the voids between aggregate particles, said second porous layer having about 2 to about 4 parts by volume of said scoria and/or slag particles and 1 part by volume of said settable resinous binder to give said layer a porosity of at least 10 percent and to give said layer an impact strength of at least 1,000 pounds per square inch.

7. The high strength, frictional, in situ self-draining composite structure defined in claim 6 wherein said second porous layer is at least one-half inch thick.