Enhanced Concrete Durability

Reduction or elimination of Alkali-Silica Reaction (ASR)
Silica is present in concrete due to the cement hydration process, and will react with the different aggregates found in concrete. As a result, this silica can dissolve and produce a gel. When moisture is present, the gel expands and results in stresses on the structure which can lead to cracks in the concrete. KAOROCK, with its structure and reactivity, greatly reduces ASR.

Since it reacts with lime, KAOROCK lowers the alkalinity of concrete, decreasing the reactivity of the silica. The graph shows expansion due to alkali-silica reaction at a water to cementitious materials ratio of 0.47 (ASTM C 1260, accelerated mortar bar test). This method has proven reliable for evaluating the effectiveness of SCM’s in suppressing ASR. KAOROCK passed while the control and silica fume failed.
Reduction of elimination of efflorescence
Water enters the masonry structure through absorption and through cracks and joints. This water dissolves the available calcium hydroxide (lime) that is produced during cement hydration. This water migrates to the surface and evaporates leaving behind the lime, which can show up as a crystalline or powdery, unattractive deposit.

KAOROCK helps to eliminate this effect by reacting with the free lime to form additional cement and by lowering the permeability of the structure; thereby, making it more difficult for water to move to the surface.

This is an example of a concrete slab with efflorescence.

KAOROCK helps to eliminate this in concrete structures.

Reduced permeability
Due to its particle shape and size, KAOROCK can greatly reduce the permeability of a concrete mix. It is very effective in reducing chloride ion ingress, with values in the low or very low (below 2000 Coulombs) range.

The graph shows experimental test data on rapid chloride permeability showing KAOROCK with a remarkably lower permeability than the control and silica fume.
For a complete report on the laboratory tests completed at Georgia Tech submitted to ACI, please click this link Georgia Tech Comparison Study.

® Thiele Kaolin Company 2005 P. O. Box 1056, 520 Kaolin Road, Sandersville, GA 31082 USA

Phone: (478) 552-3951 Fax: (478) 552-4131