Keywords
Metakaolin, Amorphous Aluminum Silicate, High Reactivity, Mineral Admixture, Pozzolan Material, Alkali Aggregate Reaction Inhibition, Metakaolin Cement, Amorphous Al2O3 · 2SiO2, AS2
Introduction
Highly reactive metakaolin is composed of highly reactive metakaolin, an amorphous aluminosilicate produced from calcined kaolinite.
Metakaolin (metakaolin, referred to as MK) is anhydrous aluminum silicate (Al2O3.2SiO2, referred to as AS2) formed by dehydrating kaolin (Al2O3.2SiO2).
Production Process
Kaolin belongs to layered silicate structure. When kaolin is heated in the air, it will undergo several structural changes. When heated to about 600 C, the layered structure of kaolin will be destroyed due to dehydration, forming a transition phase with poor crystallinity-partial phase. Kaolin. Since the molecular arrangement of metakaolin is irregular, it presents a thermodynamic metastable state and has gelation property under proper excitation.
Features
Metakaolin is a highly active artificial pozzolanic material, which can react with Ca(OH)2(CH) and water to generate hydration products similar to cement. Utilizing this feature, when used as an admixture of cement, it reacts with CH generated during cement hydration to improve certain properties of cement.
Adding metakaolin does not affect the workability and fluidity of concrete. Under the condition of the same dosage and maintaining the same slump, the viscosity of concrete mixed with metakaolin is smaller than that of silica fume, and the surface is easy to smooth. Save 25% of high-efficiency water reducer. The fluidity of concrete mixed with metakaolin and fly ash is obviously increased than that of single mixed. When the content of metakaolin reaches 20% of the cement content, it can effectively inhibit the alkali-aggregate reaction.
Uses
Metakaolin is a highly active mineral admixture. It is an amorphous aluminum silicate formed by calcining ultrafine kaolin at low temperature. It has high pozzolanic activity and is mainly used as a concrete admixture. It can also be used to make high-performance geopolymers. things.
Metakaolin amorphous silicon-aluminum compound in a metastable state, through the action of alkali or sulfate and other activators and hardeners, the silicon-aluminum compound will form a structure similar to some natural minerals in the earth's crust after depolymerization and repolymerization. Aluminosilicate network structure.
Metakaolin Cement is characterized by high early strength, strong corrosion resistance and good durability.
