Abstract
This article introduces the technology of steel bars in pre-stressed concrete. It consists in three parts. The first part introduces the characteristics of steel bars in pre-stressed concrete, namely, the tensile strength, elastic modulus and so on. The second part gives the structure of steel bars for pre-stressed concrete and its performance tests. The third part focuses on the application and research trends of steel bars for pre-stressed concrete.
Introduction
Steel bars are an important component of pre-stressed concrete, which are used to provide tensile strength, elastic modulus and maintain the stability of concrete structures. Steel bars have a significant impact on the performance of pre-stressed concrete and its durability. The standard of steel bars in pre-stressed concrete is YB/T111-1997.
Characteristics of Steel Bars in Pre-stressed Concrete
Steel bars used in pre-stressed concrete have various characteristics. The tensile strength of steel bars used in pre-stressed concrete should meet the requirements of YB/T111-1997. Generally, the tensile strength of steel bars used in pre-stressed concrete should be greater than or equal to 510 MPa and should be suitable for the temperature and environment of the place of application. The elastic modulus of steel bars used in pre-stressed concrete should meet the requirements of YB/T111-1997. Generally, the elastic modulus of steel bars used in pre-stressed concrete should not be less than 210000MPa. The ratio of tensile strength to elastic modulus of steel bars used in pre-stressed concrete should also meet the requirements of YB/T111-1997. Generally, the ratio of tensile strength to elastic modulus should not exceed 108%. In addition, the chemical composition of steel bars used in pre-stressed concrete should also meet the requirements of YB/T111-1997.
Structural Features of Steel Bars for Pre-stressed Concrete
The structure of steel bars for pre-stressed concrete includes three parts: the head, the body and the tail. The head is an important component of pre-stressed steel bars. It has two functions, one is to connect the anchor, the other is to ensure that the cracks of the steel bars are not widened or changed shape during the tension process. The body of steel bars is composed of a tensile-resistant material, which has greater tensile strength than the non-tensile materials. The body of steel bars is also required to have good plasticity and high resistance to corrosion. The tail of steel bars is another component of pre-stressed steel bars, which is used to form a connection between the steel bars and the concrete component.
Performance Test of Steel Bars for Pre-stressed Concrete
The performance tests of steel bars for pre-stressed concrete mainly include tensile strength test, fatigue test, corrosion resistance test, stress relaxation test and so on. According to the YB/T111-1997 standard, the tensile strength test should be carried out to ensure the ultimate tensile strength of the steel bars for pre-stressed concrete, which should be greater than or equal to 510 MPa. The fatigue test is mainly used to evaluate the durability of the steel bars and should be carried out according to the conditions of the place of application. The corrosion resistance test should be carried out to ensure that the steel bars have good corrosion resistance and can be used in pre-stressed concrete structures. The stress relaxation test should also be carried out to ensure that the steel bars are not easily influenced by the tension after stress reduction.
Application and Research Trends of Steel Bars for Pre-stressed Concrete
Steel bars for pre-stressed concrete have been widely used in various fields, such as bridges, tunnels, buildings and other civil engineering projects. With the development and innovation of pre-stressed concrete technology, the application of steel bars for pre-stressed concrete is more and more extensive.
In the future, the research on steel bars for pre-stressed concrete will be focused on the development of new types of steel bars and testing technologies. For example, the development and application of micro-alloyed steel bars, the development of high-strength special-purpose steels, the application of non-destructive testing technology, etc. In addition, research and development of new welding technology and the combination of steel bars with other materials will also be a research direction in the future.
Conclusion
In general, steel bars are an important component of pre-stressed concrete. The structure and performance of steel bars should meet the requirements of YB/T111-1997. With the development and innovation of pre-stressed concrete technology, the studies of different kinds of steel bars and testing technologies will be more abundant.
