Types of Modifiers in Epoxy Resins Used for Concrete Repairs

concrete crackMost property owners disregard the formation of cracks in their concrete structures. They assume that these will not impact their structure’s integrity, much owing to the sheer strength of concrete. In most cases, however, the cracks keep expanding and over time can bring down your entire structure.

Prompt repair of concrete cracks regardless of their location and magnitude is hence essential. There exist different concrete floor repair products you could use to repair concrete cracks. One of the commonly used products is epoxy.

Epoxy has a low risk of shrinking when curing, does not melt and is highly resistant to chemicals and harsh environmental conditions. It is also known for its high adhesive strength and flexibility since some of its chemical and physical properties can be modified to suit your application.

Here are some of the modifiers you can pick for your concrete repair epoxy.

Rubber Additives

These are primarily used to increase the fatigue and crack resistance of your epoxy. Rubber additives will also boost your epoxy’s flexibility and energy absorption. The additives are polymers, which can be particulate, solid or liquid components.


These are used to reduce your epoxy resin’s viscosity and hence improve its handling characteristics. Diluents are further grouped into non-reactive and reactive. Reactive epoxy diluents have glycidyl ethers, which have low molecular weight and viscosity.

They are primarily used to reduce cross-links in your epoxy resin. Non-reactive diluents, including xylene, toluene, and other aromatic hydrocarbons will reduce the thickness of your epoxy more than the reactive ones.

Flame Retardants

concrete crack

Most epoxy resins have a high hydrogen and carbon content, which makes them highly flammable. In applications where fires are a risk, you could add a flame retardant to the epoxy to minimise this risk. The flame retardant could be a filler and introduce halogens in the epoxy, which reduces flammability.

Dyes and Pigments

Concrete repair does not necessarily mean the introduction of ugly marks in your concrete structures. If a high aesthetic appeal is a concern for you, you could add dyes and pigments to the epoxy resin.

Pigments are insoluble particles, which will disperse the resin and form colour. Dyes, on the other hand, are soluble organic molecules. They are unfortunately unsuitable for composite applications since they react differently depending in the temperature.

Non-Reactive Fillers

These include metals, ceramics, minerals, glass, fibres and carbon, among other miscellaneous organic compounds, which confer different properties for your epoxy. Metallic fillers, for instance, enhance the epoxy’s corrosion resistance, while ceramic fillers boost its chemical resistance and enhance its compressive strength. Non-reactive fillers are available as short fibres, whiskers, powders, flakes, micro-balloons, and spheres.

Epoxy is primarily used for concrete crack repair through injection. It will efficiently seal cracks as narrow as 0.05mm in bridges, dams and buildings. The resins are also used for the restoration of concrete structures that have eroded, grouting of cracks and correction of cracked concrete beams and columns. With the modifiers mentioned here, you can choose the epoxy that meets all your application’s needs.