Krystol Internal Membrane™ (KIM®)

Instructions for Shotcrete Inspector


Krystol Internal Membrane (KIM) is a chemical admixture in powder form used to create waterproof concrete. KIM is used in place of externally applied surface membranes to protect against moisture transmission, chemical attack, and corrosion of reinforcing steel.

IMPORTANT: Follow the guidelines of ACI 506R Guide to Shotcrete. You are making a waterproof membrane out of the concrete. This is different from traditional construction where the concrete just forms the structure. The KIM concrete you are placing will be the only barrier to water penetration. This means that common defects found in typical concrete cannot be tolerated. Poor consolidation, unplanned cold joints, cracks, penetrations, contaminations, etc. will all result in a leaking structure. To avoid leakage and to achieve success, you must follow the critical instructions outlined in this document.

Preparation for Shotcreting

Shotcrete Supply

Shotcrete Application

Cold Joints and Construction Joints

IMPORTANT: Unintended cold joints may develop long lift breaks during bench gunning if the previous layer of shotcrete hardens before the next layer is placed. This is common during hot weather or when using highly accelerated mixes. Inspect all lift breaks as described in Application Instruction 4.22 — Waterproofing Unintended Cold Joints (Shotcrete), and apply a coating of Krystol Waterstop Treatment before shooting the next layer if the previous layer has already hardened.

Curing and Protection

Inspection of Finished Work