Epoxy-Modified Concrete

Table 7,1 Typical Mix Proportions of Epoxy-Modified Concrete. ( 1987, American Concrete Institute, reprinted with permission.)...

Figure 7.3 Compressive strength of epoxy-modified concretes.

Property Epoxy-Modified Concrete 28-Oay Water-Cured Unmodified Concrete... 

Table 7.5 Properties ofa Typical Epoxy-Modified Concrete in Comparison with Those of an Unmodified Mortar.

In recent years, there have been some interesting developments in epoxy-modified mortar and concrete in Germany. The developments include a one-component epoxy resin system for the cement modifier and a dry mortar using epoxy resin. The former does not need any hardeners added at the construction site. The latter is produced as a dry mixture of an epoxy resin with a hardener, cement, and aggregates, and can be applied by adding only water in the field. 

Repair of damaged SBR concrete specimens using of epoxy resin and of the hard flexible polymer PT. According to the first approach, three pairs of specimens from each group of modified concrete (C5% le and C5% lpt, C10% 2e and C10% 2pt, C20% 3e and C20% 3pt) were tested up to damage with measurements of force and vertical displacement (deflection). Obtained results are presented in form of force-displacement diagrams in Fig. 12a,b,c. Specimens repaired in each pair with the epoxy resin (e5 l, e5 2, e5 3) and the polymer PT (pt5 l, pt5 2, pt5 3) were tested also up to damage. Obtained results are presented as comparison in Fig. 12a,b,c. Every specimen was broken in concrete in a certain distance from the repair joint (Fig. 13a,b). 

Uses Epoxy modifier for adhesives, potting and encapsulating compds., concrete adhesives and coatings... 

Uses Epoxy modifier esp. suited for use in wh. and pastel coatings, and in hot-melt, hot-melt pressure-sensitive, and pressure-sensitive adhesives diluent for low-vise, epoxy systems pigment wetting agent plasticizer for epoxy system injections provides impermeable membrane between asphaltic surfs, and concrete bridge decks Properties Gardner 1 resin sol. in alcohols, chlorinated hydrocarbons, esters, ethers, ketones (except acetone), aromatic, naphthenic, and terpene hydrocarbons partially sol. in paraffinic hydrocarbons m.w. 225 vise. 1.75 poises hyd. no. 50 Toxicology TSCA listed Nevoxy EPX-L5 [Neville]... 

Epoxy resin has superior properties such as high adhesion and anticorrosion, and has widely been used as adhesives and anticorrosives in the construction industry in the world. Provided the incorporation of the epoxy resin into cement mortar can give its superior properties to the mortar, it is possible to produce a highly polymer-modified cement mortar. The first patent of an epoxy-modified cement system was taken by Donnelly in 1965 [1]. Since the patent, 30 or more papers on the epoxy resin modification of the cement mortar and concrete have already been published [2]. Most epoxy resin-based cement modifiers dealt with in the papers are specially compounded by the manufacturers, and the procedures for mixing them to fresh mortar and... 

Uses Epoxy modifier esp. suited for use in wh. and pastel coatings, and in hot-melt, hot-melt pressure-sensitive, and pressure-sensitive adhesives diluent for low-vise, epoxy systems pigment wetting agent plasticizer for epoxy system injections provides impermeable membrane between asphaltic surfs, and concrete bridge decks... 

Of the several types of the polymer-modified mortars and concretes used for various construction applications, latex-modified mortar and concrete are by far the most widely used materials. Latex-modified mortar and concrete are prepared by mixing a latex, either in a dispersed liquid or as a redispersible powder form with fresh cement mortar and concrete mixtures. The polymers are usually added to the mixing water just as other chemical admixtures, at a dosage of 5-20% by weight of cement. Polymer latexes are stable dispersions of very small (0.05-5 pm in diameter) polymer particles in water and are produced by emulsion polymerization. Natural rubber latex and epoxy latex are exceptions in that the former is tapped from rubber trees and the latter is produced by emulsifying an epoxy resin in water by the use of surfactants [87]. 

Oligophenylethoxysiloxanes are used as modifiers for various polymers to improve their weather resistance and other technical characteristics, as well as to increase the heat resistance of coatings. E.g., PES-50 is used to modify polyethers, aciylic and epoxy polymers PES-80 is used to modify alkyd and urea-formaldehyde resins. Besides, PES-80 is used as an additive in paints and enamels (to improve their flow properties, gloss and colour), as well as in concrete mixes (to improve the water resistance and durability of concrete works). 

Epoxy resin mortars have been used in repairing or conserving massive concrete structures. It has been found that the adhesive properties of epoxy resins modified with polysulfides is... 

A sand filled epoxy compound will have lower stresses because the coefficient of thermal expansion will have been reduced and will have been brought closer to the coefficient of thermal expansion of Portland cement concrete. Some of the requirements for an epoxy system, based on a polysulfide-modified epoxy binder, are typically as follows ... 

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