Plain concrete refers to a concrete structure without or without reinforcing steel bars. Plain concrete is an important part of reinforced concrete structure. It is made of cement, sand (fine aggregate), stone (coarse aggregate), mineral ginseng, admixture, etc., mixed with a certain proportion and then mixed with a certain proportion of water. . Ordinary concrete has an apparent density of 1900 to 2500 kg/m3 and is made of natural sand and stone. When the reinforcement ratio of the component is less than the minimum reinforcement percentage of the longitudinally stressed steel bar in the reinforced concrete, it should be regarded as the plain concrete structure. This material has high compressive strength and low tensile strength, so it is generally used in structural members mainly composed of pressure, such as column piers and foundation walls.
When the appropriate amount of steel is added to the concrete, it is reinforced concrete. The reason why the physical and mechanical properties of steel and concrete are very different can work together effectively, mainly because of the cohesive force between the two, and the coordinated deformation after the load. In addition, the temperature linear expansion coefficients of the two materials are close, and the concrete between the steel bars and the concrete edges acts as a protective layer of the steel bars, so that the steel bars are not corroded and the fire resistance of the components is improved. Because the reinforced concrete structure makes reasonable use of the performance characteristics of both steel and concrete, it can form a structure with high strength and high rigidity, which has good durability and fireproof performance, good moldability, flexible structure, and integrity and ductility. Good, reduce its own weight, suitable for seismic structures, etc., and thus widely used in building structures and other civil engineering. Concrete manufacturer
It refers to the configuration of stressed prestressing tendons, and the prestressed concrete structure is established by tension or other methods.
The prestressed concrete is subjected to the high-strength prestressed steel bar in the concrete before the concrete structural member is subjected to the load, so that the pre-stressed stress can offset most or all of the tensile stress caused by the external load. , which also improves the crack resistance of structural members. This aspect of the prestressed concrete cracks or cracks due to a small width, so that it is larger than the corresponding cross-sectional rigidity of reinforced concrete, the deformation is smaller; on the other hand that the prestressed structural member or the deformation of the outer load The resulting deformation direction is opposite (accustomed to be called "reverse arch"), which can offset part of the latter deformation, making it easy to meet the structural requirements for deformation, so prestressed concrete is suitable for the construction of large-span structures. The higher the strength of the concrete and the prestressed steel bars, the greater the prestress value that can be established, and the better the crack resistance of the components. At the same time, due to the rational and effective use of high-strength steel, it saves steel and reduces the structural weight. Due to its high resistance to cracking, hydraulics, water storage and other non-leakage structures can be constructed. Concrete company