Capping Concrete Cylinders, Humboldt Kit for 6 x 12in Cylinder

Capping Concrete Cylinders – Humboldt Kit for 6 × 12in Cylinders

Concrete Test Cylinders Overview

Concrete test cylinders are the standard specimens used to determine the compressive strength of concrete. Proper preparation of these cylinders is essential to ensure accurate and repeatable test results.

One of the most critical preparation steps is capping concrete cylinders. Capping creates smooth, flat, and parallel bearing surfaces so the applied load during compression testing is evenly distributed. Without proper capping, test results can be inaccurate and unreliable.

Explore related tools in
Concrete Compression Testing Equipment.

Cylinder Topping with the Humboldt H-2951 Kit (6 × 12in)

Cylinder topping prepares the ends of concrete cylinders to be perpendicular to the applied axial load. This ensures uniform load transfer during compressive strength testing.

The Humboldt H-2951 Capping Kit is designed specifically for 6 × 12in concrete cylinders and provides consistent, standard-compliant results for laboratory testing.

Common Cylinder Topping Methods

Several topping methods are used in concrete testing labs:

• Sulfur mortar capping
  Produces a hard, smooth surface by applying partially melted sulfur-based compound.
• Neoprene pads with steel retaining rings
  Elastomeric pads distribute load evenly and are reusable.
• End grinding
  Produces plane surfaces, often used for high-strength concrete.

Each method ensures the cylinder ends are flat, smooth, and aligned for accurate compressive strength testing.

Why Proper Topping Matters

Proper topping is essential because it:

• Ensures even load distribution
• Reduces testing errors caused by surface irregularities
• Improves accuracy and repeatability
• Ensures compliance with ASTM and AASHTO standards

Improper topping can result in uneven stress, premature failure, and misleading compressive strength values.

Learn more about specimen preparation in
Concrete Cylinder Testing Equipment.

Humboldt H-2951 Kit – Features & Benefits

• Designed for 6 × 12in concrete cylinders
• Reusable neoprene pads in steel retaining rings
• Produces smooth, parallel bearing surfaces
• Pads available in multiple durometers for different concrete strengths
• Cost-effective and lab-friendly design
• Ideal for routine quality control and compliance testing

Standards Compliance

The Humboldt H-2951 Kit meets or exceeds the following standards:

• ASTM C39 – Compressive strength of cylindrical concrete specimens
• ASTM C617 – Capping cylindrical concrete specimens
• ASTM C1231 – Unbonded caps for compression testing
• ASTM C31, ASTM C192, ASTM C430, ASTM C114
• AASHTO T22, T23, T126, T231

Compliance with these standards ensures reliable, consistent, and comparable test results.

Kit Includes

• H-2945 cylinder carrier
• H-2952 vertical cylinder capper
• H-2953 melting pot for capping compound
• H-2959 capping compound
• H-2958 ladle

Each component is designed to streamline cylinder capping and improve lab efficiency.

View additional accessories under Concrete Testing Accessories