How to Make Prefabricated Beam Cement for Houses

The construction of cement for prefabricated beams in houses mainly involves the concrete pouring process, which requires selecting an appropriate pouring method based on the beam structure and strictly controlling key construction points.

I. Selection of Pouring Methods

1. One-time Pouring: Suitable for small prefabricated beams or simple structures, with fast construction speed and simple operation. However, large or complex structures are prone to quality issues due to excessive internal temperature and shrinkage stress in the concrete.
2. Layered Pouring: Pour concrete into the mold in layers, and vibrate each layer densely after pouring, suitable for large or complex structures. It is necessary to reasonably design the thickness of each layer (generally ≤30 cm) and the vibration method to control internal temperature and stress distribution and improve overall quality.
3. Segmental Pouring: Divide the prefabricated beam into several segments for pouring separately, suitable for extremely long or wide beams. It is necessary to precisely control the length of each segment (e.g., 4-6 meters) and the pouring time interval to ensure tight connections between segments, uniform quality, reduced temperature and shrinkage stress, and improved durability.

II. Key Construction Points

1. Transportation and Pumping

   • The transportation capacity of the concrete tanker must meet the pouring time requirements, and continuous pumping is required when using a拖泵 (trailer pump) to avoid excessive slump loss.
   • The retention time of concrete should be ≤1 hour, and the pouring interval should be ≤2 hours; if the pump is stopped for more than 15 minutes, it should be started every 4-5 minutes for forward and reverse rotation and stirring to prevent segregation.
   • Before use, lubricate the conveying pipe with cement mortar, with the initial horizontal section ≥15 meters. Except for the outlet, no hoses or tapered pipes should be used, and direct contact with formwork and reinforcement should be avoided.

2. Material Distribution and Pouring

   • Place the material distributor at the 1/4-3/4 span on the same side of the beam, pour from the web plates on both sides at one end, and advance towards the other end; when 6 meters from the end, change to pouring from the end towards the mid-span to avoid concentrated slurry.
   • Pouring sequence: first at the chamfer of the bottom web plate, then the bottom plate, and then the web plate, with the heights of the web plates on both sides being consistent.

3. Pouring Process

   • Adopt a continuous pouring method with oblique segments (length 4-6 meters) and horizontal layers (thickness ≤30 cm), with a total pouring time ≤6 hours and a process inclination of about 15 degrees.
   • Vibrate while pouring: use an immersion vibrator for the bottom and top plates, and mainly an immersion vibrator supplemented by an attached vibrator for the web plates, with vertical point vibration to avoid over-vibration or missed vibration.

III. Other Key Requirements

• Preliminary Preparation: Organize drawing reviews, prepare technical disclosure documents, and clarify quality control points; determine the concrete mix ratio through experiments, and add high-efficiency water reducers and fly ash to optimize performance.
• Site and Materials: Harden the prefabrication site and set a drainage slope; raw materials such as reinforcement, cement, and aggregates must meet standards.
• Equipment Configuration: Reasonably equip concrete mixing plants, tankers, vibrating rods, and other equipment to ensure construction continuity.