Concrete epoxy resin mortars

Another aspect of epoxy resin mortar floorings which needs careful attention is that their coefficients of thermal expansion are approximately three times that of concrete. This, coupled with the relative low thermal conductivity of epoxy mortar, can cause stresses to be induced at the resin mortar/concrete interface under conditions of thermal shock (e.g. thermal cleaning), resulting in break-up of the flooring due to initial failure in the concrete. Two approaches have been tried to overcome this problem ... 

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... 

New Developments in Epoxy Resin Mortars, Concretes and Sealants... 

Another important application of reactive resins is the production of resin-bonded screeds that, by virtue of their high mechanical and chemical stability, are used, for example, for industrial floors. One particular problem is the bonding of old concrete to new concrete, where peeling occurs because of the shrinkage of the new concrete layer. By applying intermediate layers of a suitable epoxy resin mortar, it is possible to establish permanent bonds with strengths greater than that of the concrete. 

C 579 Standard Test Method for Compressive Strength of (Method B) Chemical Resistant Mortars and Monolithic Surfacings C 882-87 Standard Test for Bond Strength of Epoxy-Resin Systems Used with Concrete C 884-87 Standard Test Method for Thermal Compatibility between Concrete and an Epoxy-Resin Overlay... 

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]. 

Resin Mortars This group includes the furans, phenolics, polyesters and the epoxies. Some of these mortars are used as thin membrane beds in lieu of asphaltic. Except for the epoxies and polyesters, most of these are acid catalyzed materials. The alkalinity of the concrete will retard the catalyzing reaction. Therefore, the concrete substrate must be neutralized before such a mortar is installed in direct contact with concrete. 

The recent literature abounds with ideas as to how epoxy resins can be used as binding agents in new and novel applications. A brief review intended to show the development of the epoxy resins in the field of mortars and concretes is presented. 

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. 

Research on polymer-modified mortar and concrete using hardener-free epoxy resins [30]... 

The same basic epoxy resin systems are used as monolithic surfacings and epoxy polymer concrete. In addition to these, epoxy phenol novolac is also used to produce mortars and grouts. This is a higher viscosity resin that requires the inclusion of various types of diluents and resin blends. Table 10.3 lists the atmospheric corrosion resistance of the mortars and grouts. 

In the construction industry, epoxy resins find a variety of applications such as adhesive mortars, composite materials, and coatings. Epoxy polymers show excellent adhesion to the most common metals, glasses, ceramics, concretes, and other materials. 

Epoxy resin grouts which are widely used in filling cracks in concrete members are inappropriate in MHS grouting since the different nature of synthetic materials in terms of water and vapor impermeability makes moisture to be entrapped inside the MHS that is detrimental for old masonry. The ideal grout composition for MHS should present chemical and physical compatibility with the matrix of the MHS mortars like the transfused blood to human body. 

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... 

A red shale brick or quarry tile floor is usually installed over a hot or cold applied mastic membrane. The mastic is applied to the concrete floor then the brick or tile are set with a resin cement. The resin cement can be a furan, a polyester or an epoxy depending on the anticipated exposure conditions. If high temperatures and constant exposure to aggressive chemicals are anticipated, the brick or tile will be bedded in the mortar as well as having mortar joints. 

Epoxy mortars are less frequently used in CRM than other resin bonded systems due to higher cost, lower maximum service temperature, and narrower range of chemical resistance. However, because of their excellent bond strength to concrete, epoxides are frequently used for acid brick floors over concrete. They also have applications in alkali exposure. 

Phenolic resins are not used in monolithic surfacings in grouts or in polymer concretes but are extensively used in mortars. They are two-component systems as are the furan resins using 100% carbon filler, or 100% silica filler, or part carbon and part silica filler. Like the epoxies, the phenolic resins can be allergenic to sensitive skin. Protective clothing should be worn by persons handling the phenolic resins. Phenolic resins have a limited shelf life and must be stored at 45°F (7 C). 

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