There are numerous advantages to the use of bonded anchors, but in order to make the most of them, it is important to keep some basic rules in mind. Learn for how long a bonded anchor should be left to dry, what the resin setting time depends on, and how setting time differs from installation time.
Fixing with a bonded anchor: most important information
Chemical anchors (also known as bonded anchors) provide strong and durable fixing under a variety of conditions – often quite complex. However, in order to attain maximum load bearing capacity of resin and make sure that the connection thus developed meets all the requirements, one should see to appropriate application of the bonded anchor.
Bonded anchor for concrete. Step-by-step installation instructions
- Drilling holes for bonded anchors: unlike with mechanical anchors, the holes for resin application must always be larger than the rod to be installed.
Find out more about dustless hole drilling for the application of bonded anchors and how much time it can save:
Table of contents
- Fixing with a bonded anchor: most important information
- Bonded anchor for concrete. Step-by-step installation instructions
- Which bonded anchor for home use, and which one for construction site applications? Types of anchors for concrete
- How a bonded anchor works: factors which affect setting time
- Bonded anchor handling. Setting time of an anchor for concrete vs temperature
- Properties of bonded anchors. Why is the setting time of bonded anchors so important?
- How bonded anchors work. Difference between installation time and setting time
- Anchoring in concrete. Safety first!
- Hole cleaning: depending on what the relevant technical approval indicates, you can use a hand pump or compressed air and a brush for this purpose.
- Hole filling with the compound: when fixing in solid substrates, fill the hole to 70 per cent of its space, while for hollow base materials, use a mesh sleeve and fill the hole completely.
- Installing anchor rods: introduce the rod into the hole in a rotating motion and wait until the resin has set completely.
- Full loading of bonded anchors: once you make sure the resin is completely dry, you can proceed to applying the full load.
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Which bonded anchor for home use, and which one for construction site applications? Types of anchors for concrete
Before analysing what the setting time of a bonded anchor depends on, one should understand what this product actually is. A bonded anchor is a kind of fixing solution used in construction, and it consists of two components: a chemical compound (i.e. resin) and a connecting piece (metric rod or internally threaded socket). Once the hole has been filled with resin and the rod introduced, the compound hardens to form an extremely strong and stable connection. It is the resin type that determines the parameters of the bonded anchor. There are four anchor types to choose from when working in concrete:
- epoxy resin anchors – they guarantee the best performance; epoxy resin anchors are designed for the most demanding professional applications in structural elements and for deep anchoring;
- hybrid anchors – another anchor type for professional use; resins of this kind are characterised by high load bearing capacity, and they are suitable for deep anchoring;
- vinyl-ester anchors – intended for medium and high loads;
- polyester anchors – the most popular type of bonded anchors, typically intended for home use; they are designed for medium loads and as many as fifteen different substrates (including concrete and stone).
Not sure which anchor to choose for concrete? Have a look at our video guide:
How a bonded anchor works: factors which affect setting time
The setting time of a bonded anchor depends on several factors. The most important ones are resin type and temperature. It takes from a few minutes to an hour for standard bonded anchors to set.
Choosing a bonded anchor. Which resin dries fastest?
The setting time of a bonded anchor depends predominantly on the resin type. Polyester anchors are the quickest to set. They reach their full load bearing capacity in as little as a dozen minutes. Much more time is needed for vinyl-ester anchors to set (up to an hour), while epoxy resin anchors are characterised by the longest curing time, which may reach up to several hours.
Bonded anchor handling. Setting time of an anchor for concrete vs temperature
There are two temperatures which affect the setting time of a bonded anchor:
- Bonded anchor temperature (depending on the packaging type: cartridge, film, or capsule). It depends on a number of factors, including the resin storage conditions. The lower the temperature of the resin itself, the longer its setting time.
- Substrate temperature at the application point.
Inappropriate resin choice considering the substrate temperature makes chemical bonding weaker. Too low a temperature for the compound makes installation time longer, while too high a temperature reduces resin setting time, making it difficult to install the rod properly.
Properties of bonded anchors. Why is the setting time of bonded anchors so important?
The setting time of a bonded anchor is decisive of its performance. If an anchor is not given enough time to dry before being loaded, the connection may be not strong enough, which can lead to structural damage or – in the worst case scenario – to accidents.
Additionally, if a bonded anchor has not set properly, its mechanical strength and durability can be affected. Even if the anchorage appears strong at first, inadequate curing process can lead to cracks and weaken the connection over time.
How bonded anchors work. Difference between installation time and setting time
Since the chemical anchoring process proceeds in several stages, there are two types of resin setting time to consider:
- installation time (also referred to as gel time or working time), i.e. the time after resin mixing and application within which the rod should be embedded;
- curing (or setting) time, running from the end of resin mixing until its complete setting, after which load is applied.
Setting time is typically longer than installation time, and it may range from a few hours to even a few days. Both times depend on a number of factors, including temperature, humidity, substrate type, and a specific resin formula.
Anchoring in concrete. Safety first!
Before working with a bonded anchor, always read the product label first. This is where you will find the resin expiration date as well as a table specifying the correlation between the resin and substrate temperature and the time for the rod embedment (installation time) as well as the time needed for the resin to set (i.e. resin curing or setting time). Also, never forget to take care of your own safety. When improperly handled and applied, resin can scald or even burn. Wear safety goggles and gloves when fixing with bonded anchors.
Find out how to apply bonded anchors correctly:
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