To understand why Lythic products work, one must first understand the effect Colloidal Silica has on concrete chemistry. As cement reacts with water and begins curing, Calcium Silicate Hydrate (CSH, or cement paste) forms with Calcium Hydroxide (lime) as a by-product in the. Lime can compose up to 25% of the cement paste, yet it has no benefit and can even contribute to efflorescence. This by-product material can be problematic in concrete.
Pozzolans, such as fly ash and silica fume, can be added to the mix to reduce formation of lime and create more cement paste. Densifiers are topically applied pozzolans that can be added after placement, hardening the upper layers of the concrete through this cement past formation. Colloidal Silica is a densifier, unique because it does not contain reactive metals such as lithium, sodium, and potassium.
These reactive metals, combined with silica are classified as silicates. The mineral salts present in these silicates can make them dangerous to handle and classify them as hazardous material. Mineral salts can also contribute to the formation of residue and whiting that necessitates scrubbing and film removal. Colloidal Silica, on the other hand, is a nearly pure silica suspended in liquid. The lack of contaminating materials means Colloidal Silica can react faster, and more efficiently with no residue formation. Colloidal Silica not only reacts with Calcium Hydroxide, but bonds to itself for faster build-up of hardened material. Furthermore, Colloidal Silica is not as caustic as other densifiers, making it safer to handle.