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Along with the development, large-scale projects are increasing. In the design of these works, large block concrete construction methods are required such as large foundation blocks for hydroelectric dams, works, road and bridge projects,…
In the following article, Hoa Binh Construction will provide you with the most general information about the method of mass concrete construction as well as the necessary requirements and requirements of this stage. See now!
What is large blocks concrete?
Massive concrete is a concrete structural block with the smallest side (a) and height (h) greater than 2m.
When constructing large concrete blocks, the construction unit needs to achieve the density, waterproofing, strength … according to the design requirements. After construction, the concrete block is guaranteed not to crack due to the hydrothermal effect of the cements in the concrete.
Construction methods of large block concrete
1. Before the construction of large concrete blocks
Before taking measures to construct large concrete blocks, it is necessary to check the following issues:
What is the condition of the insulation materials to be used for the building?
The condition of materials such as cement, sand, stone is suitable for large concrete blocks or not.
Carefully check the cement content in the concrete.
Check the temperature of the concrete mix before pouring (must be less than 25 degrees Celsius).
Prepare measures to prevent cracking, layer height and pour.
Check the formwork condition.
To ensure the continuous application of layers and batches, the condition of the construction equipment should be carefully checked.
If there are ductwork units, it is necessary to check the installation status of the duct systems and test them.
The moisture curing regime by watering also needs to be carefully checked so that heat is quickly released.
The insulation coating construction method is also important to be checked prior to the mass concrete application.
2. Massive concrete construction methods
Step 1: Transporting concrete
Concrete used in the project will be transported to the construction site by a mixer truck.
Step 2: Pour and compact the concrete
For mass concrete construction methods, concrete will be poured and compacted according to the method used for conventional heavy concrete. At the same time, the construction contractor needs to ensure the following requirements:
Height of pouring layer: The height of each layer should not exceed 50cm. The turnaround time for layers should be less than 1 hour in summer and 2 hours in winter. The pour layers of concrete should be poured and compacted continuously and rotated until the full height of a pour is reached.
Surface treatment of precast concrete: Before pouring the next batch of concrete, the concrete surface of the previous batch needs to be roughened and washed, watered and cemented or some admixtures.
Step 3: Curing concrete
Concrete curing is an indispensable step in the method of mass concrete construction. Generally, there are two ways to cure concrete:
Curing concrete with insulation: you can wrap around the pour with Polystyrene or Polyurethane foam sheets
Curing concrete by watering is carried out according to the requirements of TCVN 5592-1991: if curing in this way, you must meet the requirement for rapid heat dissipation from the concrete mass. Therefore, for the watering cycle, you need to ensure that the concrete surface is always wet.
Massive concrete construction methods
Construction units can refer to the method of mass concrete construction according to the following steps for the best construction quality:
Step 1: Carrying out transporting concrete: The concrete used in the project will be transported to the construction site by a mixer truck.
Step 2: Pour and compact concrete: Concrete will be poured and compacted according to the method used for conventional heavy concrete. In addition, the construction unit must also meet the following requirements:
Height of pouring layer: The height of each pour layer does not exceed 50 cm, the rotation time of pouring layers is less than 1 hour in summer and 2 hours in winter. The layers of concrete should be poured and compacted continuously and rotated until the full height of a single pour is reached.
Before placing the next concrete, the previously poured concrete surface needs to be roughened and washed, watered and cemented with some additives.
Step 3: Curing Concrete: There are two ways to cure bulk concrete:
Curing concrete by watering is carried out according to the requirements of TCVN 5592-1991: The construction unit must meet the requirements of fast heat dissipation from the concrete block. Therefore, for the watering cycle, it is necessary to ensure that the concrete surface is always wet.
Curing concrete with insulation: The construction unit can wrap around the pouring block with Polystyrene or Polyurethane foam sheets
Requirements for the method of mass concrete construction
The construction contractor taking measures to construct large-sized concrete needs to ensure that the concrete achieves firmness, waterproofing, strength, etc., as required by the design; After construction, it is necessary to ensure that the concrete does not crack due to the hydrothermal effect of the cements in the concrete.
For the purpose of preventing concrete from cracking, construction units need to fully prepare the following measures: design concrete components, prepare adequate construction materials, methods of transportation, mixing, and compaction. and curing of mass concrete.
Hopefully, through this article of Contractors San Antonio, readers will have useful knowledge to apply in real work as well as work quality monitoring activities in the future.