Polymer concrete composition for cementitious road repair and overlay on wet and dry surfaces

Abstract: Faults in cementitious roads can be repaired by applying to the fault a novel composition which comprises aggregate and a binder comprising: (1) a vicinal polyepoxide having an average of at least 1.8 reactive 1,2-epoxy groups per molecule; (2) a curing agent; and (3) an accelerator. By using a curing agent comprising (i) triethylene glycol diamine and/or tetraethylene glycol diamine, and (ii) a polyoxypropylene diamine, the composition can be made to bind consistently to wet surfaces.

Description: This invention relates to a composition and a method for repairing or resurfacing cementitious concrete roads. The method comprises the application of an epoxy resin binder-aggregate composition. Epoxy resins constitute a broad class of polymeric materials having a wide range of physical characteristics. The resins comprise epoxide groups and are cured by reaction with catalysts or curing agents to provide cured compositions with certain desirable properties. US-A-4828879 describes a polymer concrete system useful in road overlay and repair using an epoxy resin mixed with triethyleneglycol diamine or tetraethylene glycol diamine. US-A-4487806 describes a decorative epoxy resin aggregate binder composition. The composition comprises a vicinal polyepoxide, a stoichiometric amount of polyoxypropylene glycol diamine curative, nonphenyl and m-xylylene diamine. The composition can be used to bind aggregate to cement surfaces such as patios and driveways of residential houses. The composition is a clear coating intended for outdoor use, which is noted for not yellowing with exposure to sunlight. US-A-4487805 describes a decorative epoxy resin binder-aggregate composition. The composition comprises a vicinal polyepoxide, a stoichiometric amount of polyoxypropylene glycol diamine curative, nonylphenol, N-aminoethylpiperazine and a substituted benzotriazole ultraviolet light absorber. The composition is used to bind aggregate to large cement surfaces such as patios and driveways of residential houses. The composition is noted for not yellowing over time with exposure to sunlight. US-A-3496138 describes curable epoxy resin compositions which include the reaction product of a diepoxide with a diamine, such as the diamines of ethylene glycol, diethylene glycol, poly(ethylene glycol), propylene glycol and butylene glycol. These compositions were used as adhesives and as coatings. US-A-3236895 and -3462393 are pioneer patents describing a series of amine compounds which are solids or liquids and have utility particularly in curing epoxy resins. The amine compounds have the general formula: wherein R's are selectively defined as hydrogen, alkyl radicals and alkylene oxide radicals and x and m are defined numbers. US-A-3875072 describes an accelerator for curing epoxy resins, which comprises piperazine and an alkanolamine in a weight ratio of 1:8 to 1:1. A number of alkanolamines are taught, with triethanolamine being preferred. US-A-4189564 describes an accelerator comprising piperazine, N-aminoethylpiperazine and an alkanolamine. The accelerators are said to be synergistic for accelerating the curing of a polyglycidyl ether of a polyhydric phenol cured with a polyoxyalkylene polyamine at ambient or elevated temperatures. Such amines include polyoxypropylene diamines of the formula: wherein x is 2 to 40. Decorative Aggregate Studies I-IV (Texaco Chemical Company; TSB-1195, -1196, -1198, and -1199) describe the formulation of weatherable epoxy systems for binding decorative aggregate to concrete. Gupta, Kar, and Mani, "Effect of Binder Content and Coupling Agents on Mechanical Properties of Epoxy-Aggregate Composites", Journal of Reinforced Plastics and Composites , Vol. 1 (October 1982), pp. 370-377, discusses the effect of binder:filler ratios, and the use of silane coupling agents in an aggregate-filled epoxy system cured with a polyamide resin. There is a need for an epoxy polymer concrete system which will adhere to both smooth and rough cementitious substances, whether the substrate is wet or dry when the epoxy polymer concrete system is applied. This invention provides a method for repairing a fault in a cementitious road, by applying to the fault a composition which comprises aggregate and a binder comprising: (1) a vicinal polyepoxide having an average of at least 1.8 reactive 1,2-epoxy groups per molecule; (2) a curing agent; and (3) an accelerator; in which the curing agent comprises (i) triethylene glycol diamine and/or tetraethylene glycol diamine, and (ii) a polyoxypropylene diamine. This invention also provides the above-defined composition. Epoxy resin systems have been used to repair or resurface roadways because of their unique ability to bond well with Portland cement concrete. It has been discovered, however, that systems using either polyethylene glycol diamines or polyoxypropylene diamines do not consistently bind well to wet cementitious surfaces. We have invented an epoxy resin-aggregate system which overcomes this deficiency. The binder formulation according to this invention has many of the advantages of the system disclosed in US-A-4828879. As the data in this application will show, the combination of polyethylene glycol diamine and polyoxypropylene diamine as curing agents provides superior adherence to both dry and wet cementitious substrates, where the substrate may be either rough or relatively smooth. The data show that, in a shear test, the bond between the cementitious substrate and the epoxy system according to the invention is stronger than the cementitious surface. Therefore, when a shear force is brought to bear on a cementitious/overlay made according to this invention, the cementitious surface breaks first. This provides a useful advantage, since the overlay will not provide a weak point for further breakage, and the repaired cementitious surface will be stronger than the original. The invention is useful in preparing aggregate-filled systems for road and bridge repair, such as bridge deck overlays. Generally the vicinal polyepoxide-containing compositions which may be cured with the products of the invention are organic materials having an average of at least 1.8 reactive 1,2-epoxy groups per molecule. These polyepoxide materials can be monomeric or polymeric, saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic, and may be substituted if desired with other substituents besides the epoxy groups, e.g. hydroxyl groups, ether radicals, aromatic and halogen atoms. These vicinal polyepoxide-containing compounds typically have an epoxy equivalent weight of 150 to 250. The preferred polyepoxide, which has an epoxide equivalent weight of 175 to 195, is derived from condensing epichlorohydrin with 2,2-bis(p-hydroxyphenyl)propane (bisphenol A) to form 2,2-bis[(p-2,3 epoxy propoxy)phenyl]propane. Preferred polyepoxides are those of glycidyl ethers prepared by epoxidizing the corresponding allyl ethers or reacting, by known procedures, a molar excess of epichlorohydrin and an aromatic polyhydroxy compound, e.g. isopropylidene bisphenol, a novolac or resorcinol. The epoxy derivatives of methylene or isopropylidene bisphenols are especially preferred. A widely used class of polyepoxides which are useful according to the instant invention includes the resinous epoxy polyethers obtained by reacting an epihalohydrin, such as epichlorohydrin, with either a polyhydric phenol or a polyhydric alcohol. Typically the epoxy resins have an average of atg least 1.8 reactive 1,2-epoxy groups per molecule. An illustrative, but by no means exhaustive, list of suitable dihydric phenols includes 4,4-isopropylidene bisphenol, 2,4'-dihydroxydiphenylethylmethane, 3,3'-dihydroxydiphenyldiethylmethane, 3,4'-dihydroxydiphenylmethylpropylmethane, 2,3'-dihydroxydiphenylethylphenylmethane, 4,4'-dihydroxydiphenylpropylphenylmethane, 4,4'-dihydroxydiphenylbutylphenylmethane, 2,2'-dihydroxydiphenylditolylmethane, or 4,4'-dihydroxydiphenyltolylmethylmethane. Other polyhydric phenols which may also be co-reacted with an epihalohydrin to provide these epoxy polyethers are such compounds as resorcinol, hydroquinone, or substituted hydroquinones, e.g. methylhydroquinone. Among polyhydric alcohols which can be co-reacted with an epihalohydrin to provide these resinous epoxy polyethers are such compounds as ethylene glycol, propylene glycols, butylene glycols, pentane diols, bis(4-hydroxycyclohexyl)dimethylmethane, 1,4-dimethylolbenzene, glycerol, 1,2,6-hexanetriol, trimethylolpropane, mannitol, sorbitol, erythritol, pentaerythritol, their dimers, trimers and higher polymers, e.g. polyethylene glycols, polypropylene glycols, triglycerol, or dipentaerythritol, polyallyl alcohol, polyhydric thioethers, such as 2,2'-3,3'-tetrahydroxydipropylsulfide, mercapto alcohols such as monothioglycerol or dithioglycerol, polyhydric alcohol partial esters, such as monostearin, or pentaerythritol monoacetate, and halogenated polyhydric alcohols such as the monochlorohydrins of glycerol, sorbitol, or pentaerythritol. Another class of polymeric polyepoxides which can be cured to form the polymer concrete of the present invention includes the epoxy novolac resins obtained by reacting, preferably in the presence of a basic catalyst, e.g. sodium or potassium hydroxide, an epihalohydrin, such as epichlorohydrin, with the resinous condensate of an aldehyde, e.g. formaldehyde, and either a monohydric phenol, e.g. phenol itself, or a polyhydric phenol. Further details concerning the nature and preparation of these epoxy novolac resins can be obtained in Lee, H. and Neville, K., Handbook of Epoxy Resins, McGraw Hill Book Co., New York, 1967. A combination of two general types of amine curing agents for epoxies is required for this invention. The first type comprises triethylene glycol diamines and tetraethylene glycol diamines. These materials are sold as JEFFAMINE® EDR-148 triethylene glycol diamine and JEFFAMINE® EDR-192 tetraethylene glycol diamine by Texaco Chemical Company. The second type of amine curing agent comprises polyoxypropylene diamines and may be represented by the general formula: wherein x is 2 to 33. Specifically the following commercial products are available from Texaco Chemical Company. Individual multiple products from both types of amine curing agents may be combined for purposes of this invention. Any accelerator known to those skilled in the art may be useful in this invention if it does not detract from the properties of the system. A particularly preferred accelerator is designated Accelerator 399. Accelerator 399 is a mixture of piperazine and 5 to 10% N-aminoethylpiperazine in triethanolamine. It is described in US-A-4189564. Because of the relative cost, it is desirable to minimize the amount of binder in any composition. To achieve this end, while maintaining a product of acceptable quality, the aggregate combination must be chosen to yield the smallest void volume. The aggregate formulation used in the Example is based on the results of the publication Optimization of Polymer Concrete for Flame Spread Specimens , by Troy Madeley, Technical Memorandum No. 2, University of Texas, Austin, Texas, July 1984. This publication reports that a combination of 60 wt% of 3/8 inch (9.5 mm) gravel, 30 wt% of sand and 10 wt% of fine material produced a low void volume. As a result, the aggregate used in the present work was 60 wt% of 3/8 inch (9.5 mm) gravel, 30 wt% of sand and 10 wt% of fly ash. The aggregate-binder ratio was adjusted to yield the most workable system. Ratios of 7:1 to 12:1 were tried. It was found that for an aggregate based on 3/8 inch (9.5 mm) gravel, the optimal weight ratio of aggregate-binder was 11:1. For an aggregate comprising pea gravel, a ratio of 8.5:1 was determined to be most workable. Compositions comprising more aggregate, i.e. more than 12:1, were judged to be unworkable. Compositions comprising less aggregate than 7:1 ratio were judged not to be cost effective. This invention is shown by way of Example. EXAMPLE 1 Properties of Unfilled Binder System. EXAMPLE 2 Mechanical Properties of Polymer Concrete (PC) Formulations EXAMPLE 3 Shear Bond Strength Between Polymer Concrete and Portland Cement Concrete Thin overlays of polymer concrete were applied to blocks of cured Portland cement concrete. The Portland cement concrete blocks had either smooth surfaces or rough surfaces and were either dry or saturated with water. Shear force was applied until either the bond between the polymer concrete failed or the Portland concrete substrate failed. The above results show that with PC-3, the bond between the Portland cement concrete and the epoxy concrete overlay was stronger than the Portland cement concrete under all conditions.

Claims: A method for repairing a fault in a cementitious road, by applying to the fault a composition which comprises aggregate and a binder comprising: (1) a vicinal polyepoxide having an average of at least 1.8 reactive 1,2-epoxy groups per molecule; (2) a curing agent; and (3) an accelerator; characterized in that the curing agent comprises (i) triethylene glycol diamine and/or tetraethylene glycol diamine, and (ii) a polyoxypropylene diamine. A method according to Claim 1 characterized in that the aggregate comprises gravel, sand and fly ash. A method according to Claim 1 or 2 characterized in that the aggregate:binder weight ratio is 7:1 to 12:1. A method according to any one of Claims 1 to 3 characterized in that the polyoxypropylene diamine has the formula: wherein x is 2 to 33. A method according to any one of Claims 1 to 4 characterized in that the accelerator comprises a combination of piperazine and N-aminoethylpiperazine. A composition which comprises aggregate and a binder comprising: (1) a vicinal polyepoxide having an average of at least 1.8 reactive 1,2-epoxy groups per molecule; (2) a curing agent; and (3) an accelerator; characterized in that the curing agent comprises (i) triethylene glycol diamine and/or tetraethylene glycol diamine, and (ii) a polyoxypropylene diamine. A composition method according to Claim 6 characterized in that the aggregate comprises gravel, sand and fly ash. A composition method according to Claim 6 or 7 characterized in that the aggregate:binder weight ratio is 7:1 to 12:1. A composition method according to any one of Claims 6 to 8 characterized in that the polyoxypropylene diamine has the formula: wherein x is 2 to 33. A composition according to any one of Claims 6 to 9 characterized in that the accelerator comprises a combination of piperazine and N-aminoethylpiperazine.

Inventors: SELLSTROM KATHY BETH, WADDILL HAROLD GEORGE, SELLSTROM, KATHY BETH, WADDILL, HAROLD GEORGE
Applicants: HUNTSMAN CORP, HUNTSMAN CORPORATION
Application year: 1990
Main classification: C08G59
IPC codes: C08G59, C08L63, C04B26, C08K3, E01C7