Chemical bolts rely on the combined effect of the grip force between the bolt and the concrete and the mechanical interlocking force to resist uplift and the bolt itself to resist shear. They are mainly used in the connection of new and old structures.
You can find the mechanical indicators in the product introduction provided by the manufacturer.
I. Features
1. The construction temperature range is wide, and it can be constructed within the temperature range of -5℃ to 40℃.
2. It is an anchor without expansion force, which does not exert squeezing force on the base material and is suitable for various base materials.
3. The bolt spacing and edge distance are small, making it suitable for narrow spaces.
4. It is convenient to install and operate, and it can solidify quickly after installation. It has a high load-bearing capacity.
5. The anchoring thickness is relatively large.
II. Application Scope
1. It is suitable for ordinary concrete with a strength grade of C15 or higher (un-cracked concrete) and dense natural stone.
2. It can be used to fix various components.
3. It is suitable for heavy loads and various vibration loads.
4. In reinforcement and renovation projects, it can be used in combination with large-area steel bonding, achieving good reinforcement effects.
It not only enhances the shear resistance of the steel plate but also fills the internal voids of the old building’s concrete beams and slabs, thereby improving the overall load-bearing capacity of the components.
III. Working Principle
The anchor bolt and the hole wall are bonded through synthetic resin mortar, forming an integrated structure of the anchor bolt, base material, and the object to be anchored, thereby achieving the effect of fixing the component and enhancing its load-bearing capacity.
IV. Process Flow and Key Points of Operation
Process Flow: Drilling → Hole Cleaning → Inserting the Agent Tube → Drilling in the Bolt → Gelation Process → Hardening Process → Fixing the Object.
Table 25 Installation Parameters of Chemical Bolts
| Screw Size | Drill Bit Diameter (mm) | Anchor Depth (mm) | Maximum Anchor Thickness (mm) | Drilling Diameter in Fastener (mm) |
| M8 | 10 | 80 | Determined by product | ≤9 |
| M10 | 12 | 90 | ~20, determined by product | ≤12 |
| M12 | 14 | 110 | ~25 | ≤14 |
| M16 | 18 | 125 | ~35 | ≤18 |
| M20 | 25 | 170 | ~65 | ≤22 |
| M24 | 28 | 210 | ~65 | ≤26 |
| M30 | 35 | 280 | Determined by product | ≤33 |
Note: Parameters provided by different manufacturers may vary slightly.
1. Drilling and cleaning the hole
2. Insert the chemical agent tube
3. Insert the chemical agent tube into the clean hole
4. Drill in the bolt
5. Use an electric drill to screw in the screw until the chemical agent flows out.
6. As the bolt is screwed in, the chemical agent tube breaks, and the resin, curing agent, and quartz particles mix and fill the gap between the anchor bolt and the hole wall.
7. Gelation process
Keep the installation tool in place. The chemical reaction time should not be less than the time specified in Table 26.
Table 26 Chemical Reaction Time
| Temperature（℃） | Gelation Time（min） | Hardening Time（min） | ||
| -5-0 | 60 | 300 | ||
| 0-10 | 30 | 60 | ||
| 10~20 | 20 | 30 | ||
| 20~40 | 8 | 20 | ||
8. Hardening Process
Remove the installation tool and wait for the agent to harden. (The hardening time should not be less than the relevant time requirements in Table 12.)
9. Fixing the Object
After the agent has completely hardened, add a washer and a hexagonal nut to fix the object.
Chemical Bolt Construction Method
When calculating, you should refer to the data provided by the manufacturer because the chemical adhesives produced by different manufacturers are different, and thus their bonding capabilities also vary. Chemical bolts are a type of post-installed anchor and are used in cases where pre-installed anchors are missing or in post-construction projects.
The chemical bolt anchoring technology belongs to the post-reinforcement technology. In recent years, as a new, simple and effective post-fixing method, it has been widely used in building renovations, changes in building usage, or the expansion and renovation of existing buildings.
I. Components of Chemical Bolts
Chemical bolts consist of a chemical tube, a screw, a washer, and a nut. The screw, washer, and nut (hexagonal) are generally made of galvanized steel or stainless steel (can also be hot-dip galvanized upon request). The chemical tube (or the plastic-packaged agent tube) contains reactive resin, curing agent, and quartz particles.
II. Relevant Parameters of Chemical Bolts
• Hole depth: The required hole depth is determined by the type and size of the anchor bolt. Except for a few exceptional cases, it is generally greater than the anchoring depth. During drilling, controlling the hole depth is particularly important.
• Anchoring depth: The distance from the surface of the anchoring base structure to the bottom of the screw, which is an important parameter affecting its bearing capacity.
• Anchoring thickness: The anchoring thickness is equal to the thickness of the object being anchored. If the anchoring base has at least a plaster or tile, insulation layer covering, the anchoring thickness should be at least equal to the thickness of the plaster or tile, insulation layer plus the thickness of the object being anchored.
• Edge distance: It refers to the distance from the bolt axis to the free edge of the component.
• Spacing: It refers to the distance between the axes of adjacent bolts.
• Component thickness: It refers to the thickness of the anchoring base. To ensure the maximum bearing capacity of a bolt, certain spacing, edge distance, and component thickness must be guaranteed. The data is generally based on the technical parameters provided by the manufacturer.
1. It is suitable for common concrete with strength grade greater than or equal to C15 (un-cracked concrete) and dense natural stone.
2. It is used for fixing common steel structures, bases, guide rails, column caps, column feet, corbels, fences, stairs, curtain walls, flat steel and shaped steel, embedded reinforcing bars, embedded formworks, etc.
III. Features:
1. The construction temperature range is wide, from 15℃ to 40℃.
2. It is an anchor without expansion force, which does not generate compressive stress on concrete and is suitable for various base materials, and performs better on concrete with poor strength.
3. Safe and convenient (such as the special upside-down shape of Hilti bolt cartridge, which ensures that the hanging construction on vertical surfaces will not fall).
4. Small spacing and edge distance, suitable for narrow spaces.
5. Easy to install and operate, and can be quickly consolidated after installation, with high bearing capacity.
6. Suitable for heavy loads and various vibration loads.
7. Large anchoring thickness.
IV. Process Principle
Through the synthetic resin mortar to bond the anchor bolt and the hole wall, the anchor bolt, the anchoring base and the object to be anchored form an integral whole, thereby achieving the effect of fixing components or improving the bearing capacity of components.
V. Process Flow
Installation Procedure: Drilling – Hole Cleaning – Inserting Cartridge – Drilling in Bolt – Gelation Process – Hardening Process – Fixing Object
1. Drilling: First, according to the design requirements, determine the position according to the spacing and edge distance on the drawing, and drill holes on the base layer. The hole diameter and depth must meet the design requirements.
2. Hole Cleaning: Use air pressure blow tubes and other tools to remove the floating dust and dirt in the hole to keep the hole clean.
3. Inserting Cartridge: Insert the cartridge into the clean hole. When the resin can flow like honey at hand temperature, the cartridge can be used.
4. Drilling in Bolt: Use an electric drill to screw in the bolt until the agent flows out. Generally, an impact drill or hand drill is used, with a drilling speed of 750 revolutions per minute. At this time, the bolt is screwed in, the cartridge will break, and the resin, curing agent and quartz particles will mix and fill the gap between the anchor bolt and the hole wall. At the same time, the anchor bolt can also be inserted into a wet hole, but the water must be drained from the hole. The waiting time for the gelation process and the hardening process must be doubled.
5. Gelation Process: Keep the installation tool still. The chemical reaction time is as shown in Table 1.
6. Hardening Process: Remove the installation tool and wait for the agent to harden. The chemical reaction time is as shown in Table 1.
7. Fixing Object: After the agent is completely hardened, add a washer and a hexagonal nut to fix the object.
VI. Quality Requirements and Control
1. It is best to use a drill bit matching the anchor bolt when drilling, and the reinforcing bars must not be damaged.
2. Before construction, the material mechanical performance test of the anchor bolt must be carried out. Only after passing the test can it be used on site.
3. On-site application condition determination tests of anchor bolts should be conducted on site to fully test the bearing capacity. The tests should be conducted not only in low-strength concrete but also in high-strength concrete.
In the test, the allowable load, corresponding spacing, edge distance and component thickness should be determined according to the manufacturer’s instructions for embedding anchor bolts.
The tests should be conducted under axial tension, shear force and combined tension-shear force to determine the influence of the load direction on the bearing capacity.
4. The dust and floating dust in the hole must be cleaned thoroughly during hole cleaning.
5. In winter construction, the cartridges should be insulated in advance to ensure that they have sufficient fluidity when inserted into the drill hole (at hand temperature, the resin flows like honey).
6. The bolt must be screwed in with an electric drill and must not be hammered in directly.
7. There must be no water in the hole.
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