Calcium carbonate is used as a high quality filler in the concrete market for paving stones, tubes and sewage tanks, as well as in ready-mixed and pre-cast concrete. In cement, the mineral speeds up the hydration of the cement matrix and increases durability of the product through better permeability, while calcium carbonate’s light colour makes it ideal for applications in architecture.
In concrete roofing tiles, which must conform to standards such as water permeability, freeze-thaw performance and strength, calcium carbonate increases the density of the concrete matrix, while iron oxide pigments are added for colour.
The growth of the clay tile and brick market has also led to growth in calcium carbonate’s use as a filler for its chemical properties and as a pigment. Advantages of adding calcium carbonate to clay mixtures include lightening the colour of the natural clay, decreasing shrinkages, and decreasing air contamination during the clay burn process.
The mineral also finds applications in asphalt, manufactured from a blend of bitmen, calcium carbonate filler, gravel and sand. Calcium carbonate improves the workability of the mixture as well as its mechanical resistance by acting as a sand modifier.