Capping Concrete Cylinders, 3in x 6in Test Cylinder Molds

Capping Concrete Cylinders: 3in x 6in Test Cylinder Molds

Vertical design for capping hardened concrete test cylinders gives smooth, 90 degree end surfaces. Place test cylinder into mold against upright guide after filling recess with capping compound. Capping compound should be of correct thickness and aligned. Fixture can be disassembled for base plate resurfacing if needed to extend life of device.

3” x 6” Concrete Test Cylinders.

Made from high quality steel with 5/8” thick base and ground to 0.002”.

Meets Test Methods: AASHTO T231 ASTM C 617

The 3in x 6in Vertical Cylinder Capper for Concrete Test Cylinder Molds is a high quality and durable fixture to cap hardened concrete test cylinders with smooth, 90 degree end surfaces. Vertical design for precise and accurate capping for consistent results. Various capping materials, sulfur and gypsum cement, can be used.

When using this capper, place test cylinder into mold against upright guide after filling recess with capping compound. Fixture is easy to disassemble for base plate resurfacing if needed. This extends life of device and ensures accuracy and performance. Neoprene pads can also be used as an alternative to traditional capping. Pad caps are reusable Neoprene and will fit various cylinder diameters. Used for unbonded capping during testing.

Made from high quality steel, the 3in x 6in Vertical Cylinder Capper is built to last. Base is 5/8” thick and ground to 0.002”. For maximum precision and stability. For 3” x 6” Concrete Test Cylinders. Meets Test Methods: AASHTO T231 ASTM C 617.

Also see our other related products: Melting Pots, Concrete Capping, Bonded and Unbonded Cylinder Capping, Soil Test Equipment.

For more information check out our blogs: How to cap concrete, Capping compound for cylinder testing, Unbonded caps for concrete cylinders. Tips and information to help you test better.

Buy the 3in x 6in Vertical Cylinder Capper for Concrete Test Cylinder Molds and cap efficiently, precisely and reliably.

Overview

Capping concrete test cylinders is a critical step to get accurate compressive strength test results. Capping involves applying a layer of capping material to the ends of all the cylinders to get a smooth, parallel and uniform bearing surface. This is important to get reliable test results as any irregularities on the surface of the cylinders will affect the compressive strength measurements. In this article we will discuss the equipment and techniques used for capping concrete test cylinders and best practices for good capping.

Equipment and Techniques for Capping Concrete Test Cylinders

Capping concrete test cylinders requires special equipment and techniques to get accurate and reliable results. Most common method of capping is using sulfur based capping compound which is melted and applied to the ends of the cylinders using a melting pot and a cylinder capper. Melting pot should have replaceable heating elements for even heat distribution and an adjustable thermostat to get close temperature control. Avoid overheating. Cylinder capper should have heavy steel fixtures that are precision machined for flatness and perpendicularity.

Heat the capper plate before use to ensure the cap is formed evenly and to prevent pressurization. Even heat from the melting pot prevents pressurization of the partially melted compound.

A thermometer is necessary to monitor the temperature of the capping compound and to ensure it’s within the recommended range. Thermometers must be heat resistant to withstand high temperatures and harsh conditions of concrete capping compound testing.

Sulfur based compounds are the most common capping material because of its high compressive strength and ease of use. Proper temperature control to avoid damaging the properties of the partially melted compound.

Capping Materials and Options

Capping materials is a critical factor to get accurate test results for concrete cylinders. Most common capping materials are sulfur based compounds, neoprene pads and gypsum cement. Each has its own advantages and disadvantages and the choice of material depends on the test requirement.

Sulfur based compounds are the most common capping material because of its high compressive strength and ease of use. They come in flakes or solid ingots and can be melted to form a smooth cap. But they require careful handling and storage to prevent contamination and degradation.

Neoprene pads are a good alternative to sulfur based compounds. They are reusable, easy to install and provides consistent cap thickness. But not suitable for high strength concrete testing and can be damaged if not handled carefully.

Gypsum cement is another option for capping concrete cylinders. It’s a high strength material that can be used for high strength concrete testing. But requires careful mixing and application to get smooth and even cap.

Capping and Best Practices

The capping process involves several steps, preparing the concrete test cylinders, melting the capping compound and applying the compound to the cylinders. Follow the manufacturer’s instruction for the capping compound and make sure the compound is melted to the correct temperature. Correct temperature avoids overheating which can produce excessive fumes and damage to the capping material’s properties. The correct temperature for melting the compound is between 400°F (204°C) and 500°F (260°C). Also make sure the capping material is applied to the correct thickness which is usually 1/8in (3mm). Maximum cap thickness should not exceed 5/16in (8mm) at any point.

Gypsum cement is another option for capping concrete cylinders. Sulfur mortar capping and neoprene compression pads are the two most common end treatments, sulfur capping is the most common end treatment because of its long history of use and predictable strength results.

Best Practices to get Accurate Test Results

To get accurate test results for concrete cylinders follow these best practices:

1. Use a good melting pot: A good melting pot is required to melt sulfur based compounds evenly and to prevent overheating. Look for a pot with replaceable heating elements and adjustable thermostat.

2. Heat the capper plate: Heat the capper plate before use to get even cap and to prevent pressurization.

3. Use the right temperature: Use the right temperature for the capping compound to prevent overheating and to get smooth cap.

4. Thermometer: A thermometer is required to monitor the temperature of the capping compound and to ensure it’s within the recommended range.

5. Metal ladle: A metal ladle is needed to pour the molten capping compound into the capper.

6. Safety equipment: Safety equipment like eye, skin and respiratory protection is required when handling sulfur based compounds.

7. Fume hood vented to outside: A fume hood vented to outside is required to remove fumes and to prevent inhalation of harmful particles.

8. Check the cap: Check the cap to ensure it’s smooth, even and of the right thickness.

9. Heavy steel fixtures: Heavy steel fixtures are required for precision machining and to ensure the cap is aligned with the concrete cylinder.

10. Follow the manufacturer’s instruction: Follow the manufacturer’s instruction for the capping material and equipment to get accurate test results.

By following these best practices and using the right capping material and equipment you will get accurate test results for your concrete cylinders.

Capping Material and Quality Control

The capping material is critical to get accurate compressive strength test results. The capping material should be sulfur based, partially melted compound that meets the requirements of ASTM C617. It should be in flakes for fast melting and even flow or in solid ingots for easy storage and handling. Follow the manufacturer’s instruction for storage and handling of the capping material to ensure its quality and performance.