What is the primary ingredient in cement?

The primary ingredient in cement is limestone, which is composed mainly of calcium carbonate. Limestone is heated with clay or shale at high temperatures to produce clinker, which is then ground into a fine powder and mixed with gypsum to create cement. Cement is a key component of concrete, which is used extensively in construction for buildings, roads, and bridges. Its strength, durability, and versatility make cement a cornerstone of modern infrastructure.