What is the primary test for bond strength?

The slant shear bond strength test (Appendix A). The requirement is that failure must occur in the concrete, not at the bond interface.

What is the required gel time for the epoxy system?

The gel time for the mixed system must be between 30 and 90 minutes when tested at 27 ± 2 °C (Table 1).

How should the epoxy system be supplied?

It should be supplied as a two-pack system, with the base resin and the hardener in separate, sealed containers to be mixed on-site just before use (Clause 5.1).

What is the minimum compressive strength for the cured epoxy resin itself?

The cured epoxy resin must have a minimum compressive strength of 70 N/mm² after 7 days of curing (Table 1).

IS 9989

: 1981

Epoxy based resin systems for bonding fresh concrete to hardened concrete - Specification

CurrentSpecializedSpecificationMaterials Science · Admixtures and Chemical Products for Concrete

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This standard specifies the requirements and test methods for two-component epoxy resin based systems used for bonding fresh plastic concrete to hardened concrete surfaces. It covers essential physical properties like viscosity and gel time, and performance criteria such as bond strength and compressive strength of the cured resin system.

Specifies requirements for epoxy resin systems used as bonding agents between fresh and hardened concrete.

Quick Reference Values

Gel Time at 27 ± 2 °C30 to 90 minutes

Viscosity of Mixed System at 27 ± 2 °C100 to 200 Poise

Compressive Strength of Cured Resin (7 days)Minimum 70 N/mm²

Tensile Bond Strength (Optional Test)Minimum 2 N/mm²

Slant Shear Bond Strength (7 days)No failure in bond

Practical Notes

Surface preparation of the hardened concrete is critical for achieving the specified bond strength; it must be clean, sound, and free from any laitance, dust, oil, or grease.

Always mix the base and hardener components in the exact ratio specified by the manufacturer, as deviations can significantly affect performance, gel time, and final strength.

Pay close attention to the pot life (related to gel time) of the mixed system, especially in hot weather, as it dictates the workable time available for application before the resin starts to harden.