Cementitious Composition With High Bond Strength To Both Asphalt And Cement Based Materials

Abstract

A hydratable cement composition which will bond to both asphalt and cementitious substrates is supplied for the repair of various surfaces. The composition comprises of a combination of Portland cement, calcium sulfoaluminate cement or calcium aluminosilicate, and an alkali metal salt activated pozzolonic powder, wherein the Portland cement content of the hydratable portion of the composition is greater than 20%. The composition is free from latex bonding agents and calcium aluminate. The composition is mixed with water to form a typical cement, mortar, or concrete consistency, placed and allowed to cure. The result is a self-adhering patch to damaged surfaces. The hydratable cement composition may also be used to fabricate items of original construction by casting into molds or forms.

Claims

1-10. (canceled)

11. A cementitious composition comprising: a Portland cement; calcium aluminosilicate; a non-Portland hydratable cement powder, which includes a pozzolanic powder and has a calcium content expressed as oxides of at least 15 weight percent based on the total weight of the non-Portland hydratable cement powder; and an alkali salt; wherein the Portland cement has a content of at least 20 percent based on the total weight of the non-Portland hydratable cement powder.

12. The cementitious composition of claim 11, wherein the composition is free of latex bonding agents and calcium aluminate cement.

13. The cementitious composition of claim 11, wherein the calcium aluminosilicate content is between 0.5 and 70 percent of the composition.

14. The cementitious composition of claim 11, wherein the alkali salt content is between 0.1 and 10 percent of the composition.

15. The cementitious composition of claim 14, wherein an alkali ion of the alkali salt is selected from a group comprising lithium, sodium, potassium, magnesium, and calcium.

16. The cementitious composition of claim 15, wherein the alkali ion is in stoichiometric proportion with a hydrocarboxylic acid to form a pH neutral salt.

17. The cementitious composition of claim 16, wherein the hydrocarboxylic acid is selected from a group comprising citric, lactic, and propionic.

18. The cementitious composition of claim 11, wherein the pozzolanic powder is selected from a group comprising Class C Fly Ash, Class F Fly Ash, volcanic ash, diatomaceous earth, rice hull ash, opal, and a high free lime content powder.

19. The cementitious composition of claim 18, wherein the high free lime content powder is selected from a group comprising lime kiln dust, cement kiln dust, slag, granulated blast furnace slag cement, and calcium oxide.

20. The cementitious composition of claim 11, further comprising an additive selected from a group comprising retarders, shrinkage reducing agents, air entraining agents, aggregates, fillers, extruders, pigments, water reducers, fiber reinforcements, rheology modifiers, and set accelerators.

21. The cementitious composition of claim 20, wherein the retarders are selected from a group comprising boric acid, sodium tetraborate, potassium tetraborate, boric oxide, sodium borate, potassium borate, borax pentahydrate, borax decahydrate, sulfate salts, sugars, sugar acids, and lignins; and wherein a total of the retarders is between 0.1 and 2.5 percent of the composition.

22. The cementitious composition of claim 20, wherein the shrinkage reducing agents are configured to inhibit moisture egress during hydration.

23. The cementitious composition of claim 20, wherein the shrinkage reducing agents are selected from a group comprising silica fume, liquid glycol, neopentyl glycol, a liquid glycol adsorbed on a surface of a solid carrier, calcium stearate, and magnesium stearate.

24. The cementitious composition of claim 20, wherein the shrinkage reducing agents comprise a fine particulate metal powder selected from a group comprising alkali metals, alkali earth metals, aluminum, titanium, zinc, iron, magnesium, manganese, nickel, zirconium, and vanadium; wherein the fine particulate metal powder is configured to react with water to generate hydrogen or oxygen gas.

25. The cementitious composition of claim 20, wherein the aggregates are selected from a group comprising pea gravel, river rock, sand, and crushed rock.

26. The cementitious composition of claim 20, wherein the fillers are selected from a group comprising ground glass, cenospheres, aluminum oxide, ground nutshells, ground rubber, fine ground hardened Portland cement, fine ground Portland concrete, find ground ceramic, fine ground clay brick, calcium carbonate, nephylene syenite, aluminum trihydrate, pumice, wollastonite, Class F fly ash, kaolin, meta-kaolin, silicon dioxide, dolomite, perlite, slate, and other fine ground types of stone.

27. The cementitious composition of claim 20, wherein the pigments include iron oxide, titanium dioxide, or a combination thereof.

28. The cementitious composition of claim 20, wherein the water reducers are selected from a group comprising lignin, melamine, naphthalene, polycarboxylate, and acrylic latex.

29. The cementitious composition of claim 20, wherein the fiber reinforcements are selected from a group of fibers comprising nylon, polypropylene, Kevlar, steel, polyester, polyamide, acrylamide, basalt, e-glass, and s-glass; and wherein the fibers are between 0.125 and 2 inches in length.

30. The cementitious composition of claim 20, wherein the rheology modifiers are selected from a group comprising lignin, melamine, naphthalene, polycarboxylate, acrylic latex, silica fume, fumed silica, precipitated silica, and polyethylene oxide; or wherein the set accelerators are selected from a group comprising lithium carbonate, lithium hydroxide monohydrate, lithium nitrate, lithium fluoride, lithium chloride, lithium borate, lithium acetate, lithium citrate, lithium lactate, and lithium gluconate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 shows a poor bond between a Portland concrete and an asphalt pavement.

[0044] FIG. 2 shows a separation of a concrete slab from a Portland concrete substrate.

[0045] FIG. 3 shows a bond between the present teaching and asphalt pavement.

[0046] FIG. 4 shows an enlarged image of FIG. 3.

[0047] FIG. 5 shows a bond between the present teaching and a Portland cement mortar.

DETAILED DESCRIPTION OF THE INVENTION

[0048] This application discloses several numerical ranges in the text. The numerical ranges disclosed inherently support any range or value within the disclosed numerical ranges even though a precise range limitation is not stated verbatim in the specification because this present teaching can be practiced throughout the disclosed numerical ranges.

[0049] For the purpose of this teaching, the phrase “substantially free” shall mean present in an amount of less than 1 weight percent based on the total weight of the referenced composition.

[0050] In compliance with the statute, the present teachings have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the present teachings are not limited to the specific features shown and described, since the systems and methods herein disclosed comprise preferred forms of putting the present teachings into effect.

[0051] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to a/an/the element, composition, apparatus, component, means, step, etc., are to be interpreted openly as referring to at least one instance of the element, composition, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. The use of “first,” “second,” etc. for different features/components of the present disclosure are only intended to distinguish the features/components from other similar features/components and not to impart any order or hierarchy to the features/components.

[0052] To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, Applicant does not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.

[0053] The composition of one embodiment, according to the present teaching, includes, but is not limited to, a Portland cement, a calcium sulfoaluminate cement, calcium aluminosilicate, and a non-Portland hydratable cement powder, a metal alkali salt, or alkali earth metal salt, and wherein the non-Portland hydratable cement is a pozzolanic powder that has a calcium content expressed as oxides of 15 weight percent or more based on the total weight of the non-Portland hydrolysable cement, and wherein the Portland cement content is greater than twenty percent based on the total weight of the non-Portland hydratable cement, and wherein the cementitious composition is essentially free of latex bonding agents, and wherein the cementitious portion of the composition is essentially free from calcium aluminate cement, and wherein the calcium sulfoaluminate cement, or calcium aluminosilicate content is between 0.5 and 70 percent of the compositions, and wherein the metal alkali salt comprises between 0.1 and 10 percent of the composition, and wherein the metal alkali ion of said salt may be lithium, sodium, or potassium and the alkali earth metal ion may be magnesium or calcium, or in combinations thereof, in stoichiometric proportion with a hydrocarboxilic acid to form a pH neutral salt.

[0054] The composition of one embodiment, according to the present teaching, includes, but is not limited to, a Portland cement, which has a content greater than 20% based on the total weight of non-Portland hydratable cement, a calcium sulfoaluminate cement, a non-Portland cement, which includes a pozzolanic powder and has a calcium content expressed as oxides of 15 weight percent or more based on the total weight of the non-Portland hydratable cement, and an alkali salt.

[0055] According to one embodiment the cementitious composition is substantially free of latex bonding agents and calcium aluminate cement.

[0056] According to one embodiment the calcium sulfoaluminate cement, or calcium aluminosilicate content is between 0.5 and 70 percent of the cementitious composition.

[0057] According to one embodiment the pozzolanic powder is selected from a group consisting of Class C Fly Ash which was produced from the combustion of sub-bituminous or lignite coal, Class C Fly Ash which was produced by co-combustion of coal with clay and slag, Class F Fly Ash which was produced via co-combustion of coal with clay and slag, volcanic ash, diatomaceous earth, rice hull ash, opal, combinations thereof, or a blend of a high free lime content powder, and wherein the pozzolanic powder contains less than 15 percent calcium oxide and the overall calcium content of the calcium oxides is greater than 15 percent.

[0058] According to one embodiment the high free lime content powder is selected from a group consisting of lime kiln dust, cement kiln dust, slag, granulated blast furnace slag cement, calcium oxide, or combinations thereof.

[0059] According to one embodiment the alkali salt comprises either an alkali metal ion or an alkaline earth metal ion and comprises between 0.1 and 10 percent of said cementitious composition.

[0060] According to one embodiment the alkali metal ion is selected from a group consisting of lithium, sodium, or potassium and said alkaline earth metal ion is selected from a group consisting of magnesium or calcium, or in combinations thereof, in stoichiometric proportion with a hydrocarboxilic acid to form a pH neutral salt.

[0061] According to one embodiment the hydrocarboxilic acid is selected from a group consisting of citric, lactic, propioinic based, or combinations thereof.

[0062] According to one embodiment the cementitious composition further comprises an additive selected from a group consisting of retarders, shrinkage reducing agents (SRA), air entraining agents (AEA), aggregates, fillers or extenders, pigments, water reducers, fiber reinforcements, rheology modifiers, set accelerators, or combinations thereof.

[0063] According to one embodiment the retarder is selected from a group consisting of boric acid, sodium tetraborate, potassium tetraborate, boric oxide, sodium borate, potassium borate, borax pentahydrate, borax decahydrate, sulfate salts, sugars, sugar acids, lignins, or combinations thereof in total consisting of between 0.1 and 2.5 percent of said cementitious composition.

[0064] According to one embodiment the shrinkage reducing agents functions by expanding to offset the autogenous shrinkage of the Portland and pozzolanic materials, including certain compounds which can form ettringite in-situ, and/or metal oxides whose hydrates have a lower specific gravity than their oxides.

[0065] According to one embodiment the ettringite formation during hydration is the product of various combinations of calcium sulfate cement (CS), calcium sulfoaluminate cement (CSA), calcium sulfate hemihydrate, calcium sulfate, and/or aluminum sulfate.

[0066] According to one embodiment the shrinkage reducing agent functions as an inhibitor to moisture egress during hydration and is selected from a group consisting of silica fume, liquid glycol, neopentyl glycol, a liquid glycol adsorbed on a surface of a solid carrier, calcium stearate, magnesium stearate, or a combination thereof.

[0067] According to one embodiment the shrinkage reducing agent further comprises a fine particulate metal powder selected from a group of alkali metals, alkali earth metals, aluminum, titanium, zinc, iron, magnesium, manganese, nickel, zirconium, vanadium, or combinations thereof which will react with water to generate hydrogen or oxygen gas.

[0068] According to one embodiment the aggregate is selected from a group consisting of pea gravel, river rock, sand, crushed rock, or combinations thereof.

[0069] According to one embodiment the filler or extender is selected from a group consisting of ground glass, cenospheres, aluminum oxide, ground nutshells, ground rubber, fine ground hardened Portland cement, fine ground Portland concrete, find ground ceramic, fine ground clay brick, calcium carbonate, nephylene syenite, aluminum trihydrate, pumice, wollastonite, Class F fly ash, kaolin, meta-kaolin, silicon dioxide, dolomite, perlite, slate, other fine ground types of stone, or combinations thereof.

[0070] According to one embodiment the pigment is selected from a group consisting of metal oxides including iron oxides, titanium dioxide, or combinations thereof.

[0071] According to one embodiment the water reducer is selected from a group consisting of lignin, melamine, naphthalene, polycarboxylate, acrylic latex, or combinations thereof.

[0072] According to one embodiment the fiber reinforcement is selected from a group of fibers consisting of nylon, polypropylene, Kevlar, steel, polyester, polyamide, acrylamide, basalt, e-glass, s-glass, or combinations thereof, in various lengths between 0.125 and 2 inches in length.

[0073] According to one embodiment the rheology modifier is selected from a group consisting of lignin, melamine, naphthalene, polycarboxylate, acrylic latex, silica fume, fumed silica, precipitated silica, polyethylene oxide, or combinations thereof.

[0074] According to one embodiment the set accelerator is selected from a group consisting of lithium carbonate, lithium hydroxide monohydrate, lithium nitrate, lithium fluoride, lithium chloride, lithium borate, lithium acetate, lithium citrate, lithium lactate, lithium gluconate, or combinations thereof.

[0075] According to one embodiment the Portland cement, non-Portland cement, and calcium sulfoaluminate cement elements of the cementitious composition are free of the following materials: citric acid; lactic acid; alkali metal; metal carbonate; amine based activators; caustic compounds, such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; geopolymers; non-aqueous thermoset organic polymers, such as polyurethane, epoxy, polyurea, and polyacrylates; bitumen; asphalt; asphalt polymer blends; chloride, iodide, bromide, and fluoride ions and salts; and combinations thereof.

[0076] According to one embodiment the cementitious composition can be used to repair roadways, sidewalks, foot paths, driveways, foundations, masonry work, joints for drains and pipes, water tightness of a structure, floors, roofs, beans, stairs, pillar, fencing posts, bridges, culverts, dams, tunnels, wells, water tanks, lighthouses, tennis courts, lamp posts, although not limited thereto.

[0077] Referring now to FIG. 1, the figure shows the lack of a good bond between a Portland concrete over asphalt pavement. FIG. 1 shows the current problem in cementitious compositions.

[0078] Referring now to FIG. 2, the figure shows the bond separation at the bottom of a concrete slab from a Portland concrete substrate.

[0079] Referring now to FIG. 3, the figure shows the cementitious composition according to the present teaching bonding to asphalt pavement in the upper left corner after outdoor exposure. The surface area was struck with repeated hammer blows in an unsuccessful attempt to delaminate the two dissimilar materials. There is a diagonal crack in the present teaching layer originating in the left center edge of the photograph. The crack was created by the sharp impact which caused the ejection of some aggregate in the asphalt layer. The interface bond remained intact demonstrating that the bond is stronger than either of the two dissimilar materials as evidence by failure within each material but not at the bond.

[0080] Referring now to FIG. 4, the figure shows an enlargement of the interface fracture surface section from FIG. 3. The figure shows the full contact between the two dissimilar materials even after the adjacent areas receiving fracture inducing forces.

[0081] Referring now to FIG. 5, the figure shows the cementitious composition according to the present teaching bonded to a Portland cement mortar after outdoor exposure. The area was struck with repeated hammer blows in an unsuccessful attempt to delaminate the two dissimilar materials. The present teaching is depicted in the upper portion of the photograph and the Portland mortar is in the lower portion of the photograph.

[0082] FIGS. 3, 4, and 5 show that the bond between the present teaching and the substrates remained intact through several thermal and freeze and thaw cycles.

[0083] Upon varying the ratios of the three different cement types, it was found that a strong bond to both Portland concrete and asphalt was obtained when the Portland cement comprised between 20% and 90% of the cementitious portion of the mortar and when the calcium sulfoaluminate cement comprised between 0.5% and 70% of the cementitious portion of the binder.

[0084] Upon varying the ratios of the three different cement types, it was found that a strong bond to both Portland concrete and asphalt was obtained when the Portland cement comprised between 20% and 50% of the cementitious portion of the mortar and when the calcium sulfoaluminate cement comprised between 0.5% and 5% of the cementitious portion of the binder.

[0085] Upon varying the ratios of the three different cement types, it was found that a strong bond to both Portland concrete and asphalt was obtained when the Portland cement comprised between 50% and 70% of the cementitious portion of the mortar and when the calcium sulfoaluminate cement comprised between 5% and 35% of the cementitious portion of the binder.

[0086] Upon varying the ratios of the three different cement types, it was found that a strong bond to both Portland concrete and asphalt was obtained when the Portland cement comprised between 70% and 90% of the cementitious portion of the mortar and when the calcium sulfoaluminate cement comprised between 35% and 70% of the cementitious portion of the binder.

TABLE-US-00001 TABLE 1 Ranges: Portland Cement: 20 to 90% CSA Cement/Calcium Aluminosilicate: 5 to 70% Class C Fly Ash: 10 to 75% Example Formulations #1 #2 #3 #4 #5 #6 Portland Cement 20% 20% 20% 50% 70% 20% CSA Cement/  5% 25% 35% 20% 20% 70% Calcium Aluminosilicate Class C Fly Ash 75% 55% 45% 30% 10% 10% Ultimate  1.19  5.35  5.15  1.34  1.16  8.32 Compression 5  0  0  5  5  2  Strength, psi

[0087] The above description is presented to enable a person skilled in the art to make and use the present teaching, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present teaching. Thus, this present teaching is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.