Electric heat tracing technology has the advantages of safety and reliability, fast construction speed, etc. It has been widely used in petrochemical, steel, construction and other fields. The use of electric heat tracing technology for the maintenance of cast-in-place concrete in winter can effectively shorten the curing time of concrete in the winter construction process in northern China. Under the conditions of low temperature, tight construction period and high quality requirements, electric heating Maintenance technology has advantages over traditional conservation methods and has certain promotion and application value.

The bearing capacity and impact resistance of ultra-high performance concrete poles (wall thickness less than 30mm) with different spiral rib diameters, different spiral rib spacings and different erect spacings were studied. The effects of spiral rib diameter, spiral rib spacing and erection ring spacing on the bearing capacity and impact resistance of ultra high performance concrete poles are discussed. Tests show that increasing the diameter of the spiral ribs and reducing the spacing of the spiral ribs can improve the bearing capacity and impact resistance of the ultra-high performance concrete poles, and reducing the spacing of the erecting rings can improve the impact resistance of the ultra-high performance concrete poles.

The effects of mineral admixture content, water reducing agent dosage, water-to-binder ratio and steaming system on the properties of concrete and the effect of cement content on the chloride ion permeability of concrete were studied. And the basic mix ratio of PHC pipe pile concrete is obtained: the cement dosage is ≥360kg/m3, the mineral admixture content is 22%, the water-binder ratio is ≤0.24, and the sanding rate is 0.36. The concrete thus prepared satisfies the working performance requirement, and the strength of 1d is 84.6 MPa under normal pressure steam curing conditions.

The reinforced concrete (RC) column is an important force-bearing member in the structure. Therefore, it is necessary to study the displacement response of the RC column under impact load. In order to correctly understand the performance and characteristics of the RC column under the horizontal impact load, and provide reference for the improvement of the RC column impact design. A finite element model of RC column was established by using the finite element software ANSYS/LS-DYNA. Four kinds of internal factors such as column height, longitudinal reinforcement ratio, concrete strength and axial compression ratio were discussed in the horizontal impact load. The effect of the displacement response of the RC column under action. The results show that the displacement response of the RC column under horizontal impact loads can be reduced by increasing the longitudinal reinforcement ratio and increasing the axial compression ratio within a certain range.