Stone, Concrete, Ceramics, and Glass

Stone, Concrete, Ceramics, and Glass


The stone, concrete (cement mixed with gravel or crushed rock), ceramics, and glass industries represent human creativity and resourcefulness in using material from the earth to create things that can make our lives easier. From the earth come all the elements needed to construct objects such as roads, buildings, bathroom fixtures, and rocket components.

Natural materials from which stone, concrete, ceramics, and glass are extracted have been in the earth for millions of years, and humans have utilized them since prehistory. Thousands of years ago, people made functional articles from simple earthen materials, usually clay hardened by heat. As early as 6500 B.C., the ancient Sumerians made bricks and pottery. Stone and concrete also have been used for thousands of years as building materials. Ancient Egyptians built many structures of brick and stone. The Romans developed natural cement materials to erect many of their public structures and aqueducts; they introduced masonry construction to the rest of Europe and made innovations in bricklaying, including the use of mortar and different types of patterns. An 18th century English engineer developed cement that set under water. The first Portland cement mixture was made in 1824 by burning and grinding together limestone and clay; it soon became the most widely used cement because of its strength and resistance to water.

The oldest known piece of man-made glass dates from about 7000 B.C. By 1500 B.C., Egyptians were making colored beads and containers entirely out of glass; the glass industry flourished in Egypt for the next 300 years. By 500 B.C., Syria and other Mediterranean countries also became glass manufacturing centers. Early glassmaking was slow, costly, and painstaking. Glass items were sculpted from solid blocks, until it was discovered that extreme heat allowed glass to be worked more easily. Heating methods, however, were often insufficient because furnaces were small, and the clay pots used to heat the sand mixture were of poor quality. The technique of glassblowing changed that. Historians believe that glassblowing was invented in Syria around 50 B.C. by the Phoenicians. The first golden age of glass, from 100 to 400 A.D., occurred when the art of glassblowing flourished in the Roman Empire. Glass was no longer the luxury it had once been.

The second golden age of glass began around 1200. Crusaders returning from the Middle East brought some of the best glassmakers to Venice, where there were large quantities of high-quality sand and other necessary raw materials. To keep the skills of their craft secret, Venetian glassmakers at one time were forbidden to leave Venice and tell anyone of their techniques, except to pass them down to their children or apprentices. By the late 1400s and early 1500s, glassmaking had become an important industry in Germany and other northern European countries for manufacturing containers and drinking vessels. The invention of lead crystal marked the beginning of modern glassmaking.

Glassmaking was one of the first industries in the United States. A glass production house was built at Jamestown, Virginia, where raw materials and fuels were available. In the early 1800s, the greatest demand on the glass producers was for window glass. In 1825, the Boston and Sandwich Glass Company heralded a new machine that pressed glass into what came to be called sandwich glass; it allowed for cheaper and faster production of glass in different sizes and shapes. Plate glass was developed for mirrors and other products needing high-quality, flat glass.

Specialized glass emerged as needs arose or changed. Heat-resistant glass, insulated glass, and shatterproof glass all became part of manufacturers' product lists. In the 1930s, the Corning Glass Works and Owens-Illinois Glass Company developed fiberglass, which consists of tiny, solid glass rods that are usually much finer than human hair. It is heat-resistant, incombustible, and a nonconductor of electricity. Applications for fiberglass now range from aircraft parts to insulation to fiber optics. In 1970, Corning Glass Works fabricated fused silica glass fibers as a light wave conduit, and fiber optics emerged. The use of fiber optics has since created revolutions in computers, data transmissions, data storage, and telephone and radio communications.

The understanding of fundamental principles of bonding mechanisms (how atoms are held together in a solid) and the resulting properties of certain materials spurred the development of vastly improved clay- and sand-based substances-refractories (materials that are resistant to heat), cements, and especially glass. In addition, the relatively new industry of ceramics science developed.

The ceramics industry is more difficult to trace than the stone, concrete, and glass industries. From 1500 to 1000 B.C., the Chinese produced high-quality ceramic articles. In the late 1800s, scientists learned more about the nature of chemical bonding, providing explanations for the difference in properties between metals and ceramics, especially the high-temperature properties for which ceramic materials are known. Technological advances of the past 150 years have helped ceramics engineers and scientists better understand the nature of earthen materials. The discovery and application of X rays, for example, enabled ceramics engineers to understand the crystal structure of materials.

Pressure to develop new ceramic materials unknown in nature has come from various sources, such as manufacturers of jet aircraft, automobiles, space missiles, nuclear power plants, electronics, and communications equipment. For example, a ceramic tile was developed to protect the exterior surface of the space shuttle from searing heat during reentry into Earth's atmosphere. In the electronics industry, ceramics engineers and physicists combined their efforts to produce very pure crystals of silicon, the basis of the entire transistor industry. This allowed miniaturization of all electronic circuitry, resulting in low-cost pocket calculators, digital watches, and small computers. The material in the emission-control system of a modern automobile is a ceramic that must withstand sudden changes in temperature as well as a very corrosive environment.

As the ceramics industry has developed, so have new products, such as glass with very low thermal expansion that can withstand sudden changes in temperature. Other new products include unbreakable dinnerware and glass engineered to be crystalline that has unusual strength. Other areas that benefit from ceramics include medicine, nuclear science, electronics, and computer technology.