At present, some prefabricated steel structure, lightweight high-strength, corrosion-resistant composite materials (such as FRP, commonly known as FRP) and concrete composite components are becoming a new research hotspot, the research results, foreign countries have been in the bridge and the old buildings in the reinforcement of the start Applied and promoted.
These structural systems have their own advantages such as light and beautiful, can speed up the construction schedule, but the concrete has good compression performance and corrosion resistance, but also irreplaceable. Taking into account the several forms of engineering applicability and cost, in the construction of China's market in the next few decades will be "flourishing, a hundred schools of thought" situation.
Secondly, some new types of concrete, such as smart concrete, fiber concrete, green high performance concrete (GHPC) and ultra-high performance concrete (UHPC), are also important in the field of research because of their good performance. The status. GHPC is the late engineer of the Academy of Engineering Wu Zhongwei has vigorously advocated, "green" means: save resources, energy; no damage to the environment, but should be conducive to the environment; sustainable development, to ensure that human descendants can be healthy and happy to survive.
GHPC should have the following characteristics:
① more to save clinker cement, reduce environmental pollution;
② more mixed with industrial waste-based fine admixture;
③ greater play to the advantages of high performance, reduce the amount of cement and concrete; expand the scope of application of GHPC.
UHPC (ultra-high performance concrete) from the last century 90's RPC (active powder concrete), due to RPC declared a patent, Europe and the United States in recent years in the RPC technology to further develop, and more and more use the term UHPC. The core of the concrete technology is to remove the large concrete aggregates in the conventional concrete and to make the concrete very dense with very low water and plastic, with very low porosity and bridging with steel fibers (single or multi-scale) Its tiny cracks in the body, and through the fiber and the relative relaxation of the matrix absorption, the concrete presents a similar to the metal material strain hardening characteristics, so that the fracture energy is also quite metal materials (steel, aluminum) Folding (anti-bending) strength also showed a great improvement. This combination of concrete and prestressed, in Germany, the United States and other countries have been used for highway bridges and other civil engineering structure of the new and old bridge transformation. Due to the excellent characteristics of UHPC, it can be used in some of the superstructure of civil engineering, reduce the size of the section and reduce the weight, thereby reducing the size of the lower structure, thereby reducing the amount of concrete and improve the durability of concrete to extend the service life of the structure.