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Updated by Ben Pilkington on 25th September 2019
The main application of calcium aluminate cements (CACs) is as a binder in monolithic refractories. Other applications include industrial flooring products (such as cast house floors), chemical resistant mortars and concretes, sewer applications, expansive grouts, floor screeds, tile adhesives, protective coatings and building chemistry products (where OPC, ordinary portland cement, is combined with CACs to give desired setting times).
Monolithic refractory binder
One of the major applications of CACs is as a binder in monolithic refractories, in particular, refractory castables. Typically, a cement with higher alumina content is used. The cement bonds precision graded aggregates together in the green state. Following the subsequent heat up of these materials, the cement sinters with the aggregate forming a refractory matrix. Many different refractory aggregates are used in castables, such as tabular alumina, bauxite, chamotte and silicon carbide. They are selected on the properties required by the application. These products have applications in the iron and steel industry, non-ferrous metallurgical industries, preheaters of cement kilns, and in incinerators.
The CAC used in this application is selected on its alumina content; the higher the alumina content the higher the temperature of application the cement may be used in (pyrometric cone equivalent).
Building chemistry products
Building chemistry products include products such as tile adhesives, tile grouts, rapid floor screeds and floor levelling compounds, sealers, bedding mortars and repair mortars. These diverse products are all composed of a mineral base which is a mixture of calcium aluminate cement and Portland cement. The mixture may then have various materials added to it including gypsum, lime, fine calcareous material, slag, admixtures and polymers.
Since liquid waste is becoming more and more concentrated with the rise in city populations around the world, more resistant construction materials are required. Calcium aluminate cements contain no free lime, which is prone to attack by sulfates. In addition to this, CACs provide greater resistance to abrasion and biogenic corrosion.
Chemical resistant concretes
Concretes produced from calcium aluminate cement have a lower porosity matrix and greater resistance to both sulfate attack and abrasion and are favored in the formulation of chemical resistant concretes. These types of products mainly include industrial floorings such as cast house floors.
The rapid strength development and the high final strength of calcium aluminate cements make them a good choice for mining applications. Also, the excellent abrasion and impact resistance makes calcium aluminate cement very suitable for this application. A composition of calcium aluminate cement, ALAG (aluminous aggregate) and corundum tends to be used in a shotcrete form, a specialized concrete formulation which can be easily pumped to the site of application then sprayed out through a nozzle.
Refractory concretes are manufactured and assembled into a metal enclosure. These are then finished with conventional wood, masonry materials and facades, which give them the appearance of traditional masonry fireplaces. This type of refractory concrete is produced from lightweight aggregate and high alumina cement.
References and Further Reading