Krystol Internal Membrane™ (KIM®) is a hydrophilic crystalline admixture used to create permanently waterproof concrete. When added to concrete, KIM chemically reacts with water and un-hydrated cement particles to form insoluble needle-shaped crystals that fill capillary pores and micro-cracks in the concrete and block the pathways for water and waterborne contaminants. Any moisture introduced over the lifespan of the concrete will initiate crystallization, ensuring self-sealing, permanent waterproofing protection.