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Crystalline waterproofing admixture for concrete

"Crystalline waterproofing powder admixture is an integral crystalline capillary waterproofing admixture for concrete. It is designed for use in above- and below-grade applications".

Technical Definition

Crystalline Technology waterproofs and improves the durability of concrete structures by filling and plugging the pores, capillaries and micro-cracks with a non-soluble, highly resistant crystalline formation.

The waterproofing effect is based on two simple reactions, one chemical and one physical. Concrete is chemical in nature. When a cement particle hydrates, the reaction between water and the cement causes the concrete to become a hard, solid mass. The reaction also generates chemical by-products such as calcium hydroxide, sulfates and carbonates of sodium potassium and calcium as well as un-hydrated or partially hydrated cement particles all of which reside in the capillary tracts of the concrete.

Composition

Consists of Portland cement, very fine treated silica sand and various active, proprietary chemicals. These active chemicals react with the moisture in fresh concrete with the byproducts of cement hydration to cause a reaction, which generates an insoluble crystalline deposit throughout the pores and capillary tracts of the concrete. Thus the concrete with reduces water permeability.

Criteria for Selection of Crystalline Water proofing admixture

1.Dosage: Its proportion of uses with respect to cement and water

2.Dispensing and Mixing: Follow the procedures outlined in ASTM C94 / C94M, Standard Specification for Ready-Mixed Concrete, for general batching and mixing instructions for concrete if adding to a truck mixer.

3.Comapatibility: Admixture can be used with Portland cements approved under ASTM and EN specifications.

4.Corrosivity – Non Chloride , Non Corrosive: Shall confirm neither initiate nor promote corrosion of reinforcing steel embedded in concrete, prestressed concrete or concrete placed on galvanized steel floor and roof systems.

5.Worability: Shall confirm little or no effect on workability of concrete. Prior site trials are advised to assess the effect, and any increase or decrease in the workability can be adjusted by adjusting the admixture dosage or amount of water in use

6.Storage - Must be stored where temperatures do not drop below +5°C

Limitation

Limitations of the crystalline waterproofing technology include the?performance around construction joints, expansion joints, dynamic cracks, failing water stops, areas of poor concrete consolidation, and around penetrations

This also has a self-healing property under presence of moisture and can heal cracks below 0.4 mm depends of product type proposed by admixture company. But it is true that cracks and construction joints are weak points all water pass through it. More care shall be ensuring to follow the concreting after study of full thermal cracks and construction joint proposals.

Reference: Based on Case Study report Project in Dubai UAE 2019-2021