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Chemical Fixations

Chemical Resin Anchors

  • May 15, 2021

Chemical bushing or chemical anchoring is a chemical fastening technology based on the cohesion between a metal part (such as a threaded bar) and a rigid support (such as concrete, stone) using strong adhesive with fast setting time. In some cases this form of fixation offers advantages over mechanical fixation.

Main features:
I. Greater load capacity: loads are distributed along the entire length of the inlay, developing maximum tensile strength;
II. There are no expansion forces: there is no radial pressure on the base material, which eliminates the possibility of fatigue failure (“cracks”);
III. Resistance to vibrations: specific products support both static and dynamic loads, without presenting any failure of the anchorage;
IV. Precision in Installation: Even in the most difficult cases (“ceiling and underwater fixings”), the installation is precise, reducing labor costs and subsequent maintenance.

The bonding capacity of resins depends on the material they are made from (vinyl ester, polyester, methacrylate, epoxy, etc.). It also depends on the robustness of the system (bolt diameter, drill depth, etc.) and the type of substrate material. To scale the system, some manufacturers provide calculation software.

Polyester resins (Cmix)
This is the classic reactive resin easy and quick to use and characterized by limited chemical resistance (in alkaline and other media), it has a shrinkage of about 1%, the internal stress bulb in the base element is superior to other resins. the values ​​of minimum anchorage distances are high.

Vinylester resins (epoxy acrylate) (Epomax)
These Vinylester resins and injection mortar combine the good thermal and mechanical properties of epoxy resins with the easy and fast processing capability of unsaturated polyester resins. New generation Vinylester resins are styrene-free, in which dimethacrylates are used as reactive solvents. Vinyl ester resins and the reactive resin mortar made from them are characterized by, among others, a very high level of chemical resistance, especially in alkaline media. It has a contraction of 0.5%.

Epoxy resins (Epcon)
Epoxy resins are characterized by very good thermal and mechanical properties and excellent chemical resistance. The amount of shrinkage due to hardening is very low (0.05%). Waterproofs and electrically insulates the connection reinforcement.

Methacrylate Resins (Multimax, Maximum)
It has a mechanical behavior slightly inferior to Vinylester resins, but much superior to polyester resins.

Hybrid Resins
They are usually formed by the Epoxies and Vinylester families, with other components, such as cement and water. It has a contraction of 0.5%
The analysis of the resin's resistance must be carried out from a mechanical point of view and taking into account the environment, namely chemical factors, such as the presence of water or elements with an alkaline base.

Author: Eng.º Joselito Pereira