Cement is made in a wide variety of compositions and is used in many different ways. The best-known cement is Portland cement, which is bound with sand and gravel to create concrete. Concrete is used to unite the surfaces of various materials and to coat surfaces to protect them from various chemicals. Portland cement is almost universally used for structural concrete. It is manufactured from lime-bearing materials, usually limestone, together with clays, blast-furnace slag containing alumina and silica or shale. The combination is usually approximately 60 percent lime, 19 percent silica, 8 percent alumina, 5 percent iron, 5 percent magnesia, and 3 percent sulfur trioxide. To slow the hardening process, gypsum is often added. In 1924, the name "Portland cement" was coined by Joseph Aspdin, a British cement maker, because of the resemblance between concrete made from his cement and Portland stone. The United States did not start producing Portland cement in any great quantity until the 20th century. Hydraulic cements are those that set and harden in water. Clinker cement is an intermediate product in cement manufacture. The production and consumption of cement is directly related to the level of activity in the construction industry.
Prices - The average value (F.O.B. mill) of Portland cement in 2007 rose +0.5% yr/yr to $102.00 per ton, which was a new record high.
Supply - World production of hydraulic cement in 2007 rose +2.0% yr/yr to a new record high of 2.600 billion metric tons. The world's largest hydraulic cement producers are China with 50% of world production in 2007, India (6%), U.S. (4%), and Japan (3%).
U.S. production of Portland cement in 2005 (latest data available) rose +1.6% yr/yr to a new record high of 93.904 million tons. U.S. shipments of finished Portland cement from mills in the U.S. in 2007 fell -1.5% to 92.073 million metric tons, falling farther below the 2005 record high of 95.588 million metric tons.
Demand - U.S. consumption of cement in 2007 fell -9.3% to 115.000 million tons, falling farther below the 2005 record high of 128.280 million tons.
Trade - The U.S. relied on imports for 17% of its cement consumption in 2007. The two main suppliers of cement to the U.S. are Canada and Mexico. U.S. exports of cement in 2007 rose 22.5% yr/yr to a record high of 1.850 million tons.