What are the main conditions related to the bonding properties of epoxy resin and concrete?
Thousands Chemical is a professional one-stop supplier of composite materials, for many years has been insisting on providing the most high-quality composite material solutions for the majority of users, in the study of epoxy resin and concrete bonding properties found: Relatively rough, dry concrete surfaces, matching epoxy resin materials and the optimal ratio and subsequent high-quality construction technology can greatly improve the bonding effect of the interface.
First of all, let's talk about the advantages of epoxy resin. Compared with other resins, epoxy resin material has the advantages of wear resistance, high strength, impermeability, frost resistance and impact resistance. It is because of these characteristics that its engineering application in the fields of water conservancy and hydropower, civil and industrial construction is more and more extensive. Therefore, more and more attention has been paid to epoxy resin materials, and improving the interface bond between epoxy resin materials and concrete has always been an important subject of engineering application research.
The reaction heat of EM is the factor that affects its bond degree. The heat released by EM in the curing reaction and high exothermic temperature greatly affect the performance of the curing system. The higher the peak temperature, the more intense the curing reaction, the shorter the molecular chain of the curing system, the greater the brittleness of the structure, the greater the shrinkage rate. The main factor that affects the curing temperature is the curing agent. In the expert test study, four curing agents with different peak exothermic temperatures of curing reaction were compared to test their curing system shrinkage respectively, which proves that the selection of curing agent is very important in EM application.
The actual operation process also found that the bond strength of the influence factors and concrete surface humidity factor. As a porous material, concrete has high interface energy, and the internal capillary and surface are easy to absorb a large number of water molecules, and form a water film on the surface of concrete, which reduces the interface energy of the bonding surface, is not conducive to the infiltration of EM on concrete, and reduces the bonding force. In addition, the water adsorbed on the concrete surface contains a large amount of Ca(OH)2, which makes the water liquid alkaline. In the alkaline environment, the effective groups of the epoxy resin will be damaged, and cause the break of the molecular chain, and reduce the adhesion of EM. It can be seen from the test results that the lower the water content of the concrete surface, the higher the bond strength of the interface. The influence of the concrete surface humidity on the bond strength is as follows: 1.3 bond strength /MPa in water, 2.1 bond strength /MPa in saturated surface, 3.9 relative humidity (60%), 5.8 dry.
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