Examples are given to illustrate the development of civil engineering materials.

A: Since modern times, the changes in social system, the development of economy, science and technology, and the improvement of people's ideological consciousness have also affected the development of civil engineering materials. 1842, Joseph Astin, an Englishman, obtained a patent for producing Portland cement. Because the hardened color of this cement is very similar to Portland limestone at that time, it is called Telan cement. The appearance and application of Portland cement is undoubtedly an important milestone in the history of modern civil engineering materials, and cement has been used to this day. At present, there are about 200 kinds of cement in the world. Cement is a kind of hydraulic cementing material with wide sources and low price. Its combination with active mixed materials can also improve its performance. Active mixed materials are basically recyclable industrial waste, which just conforms to the theme of contemporary environmental protection and waste utilization. Cement mortar is also widely used in modern buildings, including building cement, decorative cement, road cement and so on. In addition, since the advent of 1824 concrete, concrete has been widely used and become the most used civil engineering material. Concrete is an engineering material with strength after hardening, which takes cement aggregate and water as the main raw materials, supplemented by additives and mineral admixtures. Because concrete accounts for a small proportion, but steel bars account for a large proportion, but they are in tension rather than compression. They have their own advantages and disadvantages, and they are used in combination, so the birth of reinforced concrete perfectly solves the problems of compression and tension. Because of the advantages of convenient construction, adjustable performance and wide sources of raw materials, reinforced concrete has been widely used in modern construction projects, making it possible to build many buildings with complex structures and strange shapes that could only exist in imagination. Compared with concrete, wood and other civil engineering materials, steel has many advantages in performance. Steel has uniform texture, strong shear, tensile and compressive strength, good plastic toughness and certain formability, and is widely used in building bridges and railway projects. China's famous Water Cube and Bird's Nest are also examples of artistic and practical steel structures. 1889 The Eiffel Tower, built in Ares Square, Paris, France, is also a typical application of steel and steel structure, and its beautiful structural modeling perfectly expresses the romantic plot of the French. Modern civil engineering materials pay more attention to material properties, so many composite materials have been developed, such as reinforced concrete, polymer concrete, PVC steel plate, glass fiber reinforced plastic, asphalt mixture and so on.