When your concrete floor is damaged, the less costly solution would be to add a fresh concrete on top of the damaged surface or use concrete to fill gaps created by the damage. However, the two layers will not form a strong, serviceable floor as cement within the concrete mix does not contain any bonding adhesive; thus, the need for a bonding agent. But what is the best one to use?
The best concrete bonding agent should be easy to use and apply, provide excellent adhesion, reduce the permeability of concrete, and enhance the concrete’s tensile and bond strength. Furthermore, the bonding agent should provide excellent workability and resistance against frost and cracking.
The rest of this article is an in-depth guide to help provide answers to the topic question. Read on to get the information you need on the best concrete bonding agent to use to achieve your desired results.
Latex Emulsions
In cementitious compositions, latex emulsions are usually used as the oil in water type emulsions. Latex emulsions are categorized into three, with some compositions containing more than 50% water. Some also have greater resistance to water than others.
The composition of latex emulsions is stable in water and cement systems though not all emulsions are compatible with cement. Therefore, to select the appropriate latex emulsion for your project, you need to understand its chemistry.
Using latex without cement content in the mix will result in a failure plane as there is no film formation at the bond interface. However, there are three ways to modify latex emulsions into useful bonding agents:
- Prepare a neat cement slurry with latex forming part of the mixing water.
- Use one-part water to one-part latex diluted material.
- Use re-emulsifiable latex as it can be rewetted and softened when it gets in contact with water.
Acrylic Latex
Acrylic latex is primarily used in the bonding of fresh concrete to the old one. This milky white latex emulsion consists of 45% solid content, Apply it with either a brush, broom, spray, roller, or a trowel.
Styrene Butadiene (SBR) Latex
SBR Latex is a type of latex emulsions that is a co-polymer and compatible with cementitious compounds. This bonding agent is milky white in appearance and consists of 55% solid content. SBR Latex can be used for the following purposes:
If subjected to severe mechanical action, high or freezing temperatures for extended periods, SBR Latex may coagulate.
Polyvinyl Acetate (PVA) Latex
There are two types of PVA Latex:
Polyvinyl Acetate Latex use is limited to areas where there is no possibility of infiltration of moisture to the bond line.
Epoxy Resin
Epoxy Resin is known for being the most versatile of all concrete bonding agents. This bonding agent is ideal for high performance and lightweight parts. Characterized as being strong but brittle, Epoxy Resin can be formulated to become more flexible without losing its tensile strength.
Epoxy Resin is a bonding agent widely used in the construction field because of its high compressive strength, chemical resistance, and strong adhesion. Epoxy Resin has an excellent bonding capability, wets out quickly, and can be used for bonding to a variety of materials as long as the surface is well-prepared.
Some of the properties that give Resin epoxies excellent adhesion characteristics include:
Epoxy Resin is used:
Epoxy Resins are available in different consistencies, from highly filled pastes to water-like liquids and may contain fillers.Epoxy Resins also classified according to type, grade, and class.
Type
Under this classification, the Resin Epoxy bonding system is classified according to physical requirements.
Grade
This classification of epoxy resins is based on flow viscosity.
Class
This classification, based on the test temperatures, the gel times are determined.
Conclusion
Damage on a concrete surface leaves you with two options: to demolish or to re-surface. Removing the old concrete and pouring a fresh one is costly, time-consuming, and wasteful, especially if the concrete was still structurally sound. The better solution would be to resurface the old concrete with a layer of fresh concrete.However, the new layer of concrete will settle on top of the old surface as a separate layer. You should first spread the concrete bonding agent on the damaged surface. The new concrete layer will then adhere appropriately to the old layer, forming a single unit.
Consider the following when applying the concrete bonding agent as they will affect the bonding between the damaged and the new concrete:
