Cement

Cements are made in a wide variety of compositions and are 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 in a combination of 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 2002 was $76.00 per ton, down from $76.50 in 2001. That was well above the 10-year average price of $71.50.

Supply – World production of hydraulic cement in 2002, the latest reporting year, reached a record high of 1.80 billion metric tons. The world’s largest hydraulic cement producer is China with 39% of world production, followed by India with 5.6%, the US with 5.1%, and Japan with 4.0%. Other large producers include South Korea, Germany, and Brazil. US mills produced approximately 90.78 million metric tons of Portland cement in 2003, which was a record high and up from 86.97 million in 2002 and 88.12 million in 2001.

Demand – US consumption of cement in 2002 fell to 110.02 million tons from 112.81 million in 2001.

Trade – US exports of hydraulic and clinker cement rose to 834 million tons in 2002 from 746 million in 2001. The major suppliers of cement to the US are Canada, Thailand, China, Venezuela, and Greece. The US exports only a very small portion of cement, less than 1% of production.