. Portland Cement is one of the most important building materials in modern construction, and it's our leading non-fuel mineral product, accounting for about 10% of the total U.S. production. The major ingredient in Portland cement is crushed limestone, and in Texas that mostly comes from the Balcones Escarpment. Larger crushed rock from this area is used as a base layer for roads and buildings, to protect them from the shifting soils. Very pure limestone is procesed into lime, wich is then used in a wide variety of agricultural, industrial, and construction activities. Other rocks crushed for building materials include basalt, used for railroad track beds, and marble, used for fancy terrazzo floors. Texas is also a major producerof sand, gravel, and our infamous clay. Gypsum, an evaporite that accumulated when shallow inland seas got cut off from the oceans and evaporated out, is found in large quantities in Central and North Central parts of the state. Calcined gypsum, which has been heated in a kiln, is made into sheetrock and pllaster. Regular gypsum is used in Portland cement and as a fuel additive, amoung other things. ...
