ASTM C882 Standard Test Method for Bond Strength of Epoxy-Resin Systems Used with Concrete by Slant Shear

Get Certified ASTM C882 Testing for Reliable Concrete Bond Performance

A bonding system that joins two regions of concrete must carry load across the joint. ASTM specifies the strength developed by the bonding system as its most important property. A weak bond can separate under service load and defeat the purpose of a repair. ASTM C882 provides engineers with a standardized slant shear method for measuring bond strength. The test results enable manufacturers to make informed decisions during product selection, formulation, and quality control of their bonding systems.

The scope of ASTM C882 includes:

• Material type: Bonding systems used with Portland-cement concrete, evaluated on Portland-cement mortar cylinders.
• Purpose: Determination of the bond strength of a bonding system that joins hardened concrete to hardened or freshly mixed concrete. 
• Properties evaluated: Bond strength by slant shear and contact strength, which is bond strength after a specified contact and cure time.
• Testing method: Technicians bond two equal Portland cement mortar sections along a 30° slant, cure the 75 mm × 150 mm composite cylinder, and load it in compression.
• Results: Bond strength in MPa, calculated as the maximum load divided by the area of the bonded surface.
• Test limitations: The minimum mortar strength gives only a qualitative pass or fail result for bond strengths above approximately 13 MPa. SI and inch-pound values are each regarded as standard, and users do not combine the two systems.
• Use conditions: Technicians cure the composite cylinder for the period suited to the bonding system before they load it in compression.
• Applications: Comparative evaluation of bonding systems, selection of systems for concrete repair and concrete-to-concrete joints, and quality control and formulation development.

What are the Uses of ASTM C882 Testing?

ASTM C882 testing helps engineers evaluate how well a bonding system joins concrete under a fixed specimen geometry. Manufacturers then use the results to compare products and support product development.

• Measures the bond strength of bonding systems used with Portland cement concrete.
• Compares different bonding systems on the same specimen geometry.
• Determines contact strength after a specified contact and cure time.
• Supports selection of bonding systems for concrete repair and concrete-to-concrete joints.
• Assists manufacturers in comparing bonding systems for quality control and formulation development.

Which Materials Can Be Tested Under ASTM C882?

ASTM C882 covers bonding systems used to bond Portland-cement concrete, including those that are based on epoxy resins. The test method is suitable for systems that bond hardened concrete to hardened or freshly mixed concrete. Before testing, a technician prepares two equal portions of Portland-cement mortar with 30° bonding faces and joins them together with the bonding system under investigation.

Why is ASTM C882 Important?

ASTM C882 is critical because it gives a manufacturer a standardized test method for evaluating the bond strength of a bonding system. The most crucial characteristic of a bonding system is its ability to withstand the load transferred through the joint between two concrete regions. But when comparing one product to another, the variation in specimen size, bonding angle, and mortar strength may make the evaluation difficult. ASTM C882 standardizes the specimen dimensions, bonding angle (30°), and mortar strength for the evaluation. As a result, the standard enables engineers to compare bonding systems with confidence.

ASTM C882 Testing Process and Data Collection

Technicians prepare two equal mortar sections, each with a 30° bonding face, and join them with the bonding system under evaluation. The composite cylinder is then cured according to the bonding system, and the engineer mounts it in the compression testing machine and loads it until it fails. The technician reads the maximum load from the compression machine. The bonded area is two times the base area of the assembled cylinder. The technician examines the developed bond line, and the bond strength is calculated by subtracting the areas of voids more than 3 mm in size. The results report includes the bond strength, bonded area, and the count of voids, with their total area.

Common Challenges and Troubleshooting

Accurate ASTM C882 results depend on mortar that meets the strength requirement, correct specimen dimensions, and a complete bond line. Mortar sections that fall below the required compressive strength limit the range of bond strengths the test can resolve. Voids in the bond line reduce the effective bonded area. Technicians verify the mortar strength before bonding, follow the specified dimensions and the 30° angle, and inspect each failed specimen for voids before the analyst calculates the result.

• The analyst reports the determined bond strength in MPa.
• The analyst reports the bonding area and the number and total area of voids.
• Higher bond strength indicates that the bonding system carries more load across the joint.
• Engineers compare results between bonding systems that use the same specimen geometry.
• Bond strengths above approximately 13 MPa receive only a qualitative pass or fail result when the mortar sits at the minimum strength.

Link to ASTM C882