Beijing PVC Structural Joints Board, Beijing Structural Joints Board Manufacturer. Concrete structural joints are one of the common issues in construction projects, posing serious threats to the building's usability and the economic interests of the constructors. This article delves into the measures for preventing and controlling concrete structural joints during on-site construction and briefly introduces the remedial methods for structural joints.
1. Pouring Operation: During pouring, the vibrator should be inserted quickly and withdrawn slowly. Properly control the vibration time according to the different slump of concrete to avoid over-vibration or missed vibration. It is recommended to adopt double vibration and double finishing techniques to exclude bleeding, moisture within the concrete, and air bubbles.
2. Concrete Curing: In the prevention of cracks in concrete structures, the early curing of freshly poured concrete is particularly important to minimize shrinkage as much as possible in the early stages. Mainly, it involves maintaining the components in a moist environment. For large-volume concrete, it is advisable to use water storage or running water curing if possible. The curing period is 14-28 days.
3. Concrete Temperature Control and Insulation: For thick, large-volume concrete, the heat of hydration of cement should be fully considered during construction. Necessary cooling measures (such as buried heat dissipation holes, water circulation for heat dissipation, etc.) should be taken to avoid the concentration of the peak heat of hydration and reduce the peak value. After casting and shaping, necessary water retention and insulation measures should be taken, such as covering the surface with film, wet burlap, etc., for maintenance to prevent temperature structural cracks caused by excessive temperature differences between the inside and outside of the concrete.
Avoid watering concrete during rain or strong winds.
5. Early backfilling of soil is beneficial for reducing structural cracks in underground concrete structures.
6. During summer, attention should be given to the pouring temperature of concrete. Use low-temperature molds and maintenance, and if necessary, ice blocks can be used after testing to lower the temperature of the concrete raw materials.
In addition, to prevent cracking in concrete structures, preventive measures should be taken in aspects such as the production and manufacturing of concrete, construction, and structural design. For instance, under the premise of reasonable design, the concrete mix ratio should also be appropriate, especially using the correct construction methods during construction. This is the only way to effectively prevent cracking.