What Should We Pay Attention to During Winter Concrete Mixing Plant Construction?

During winter construction at a concrete mixing plant, special attention should be paid to various aspects due to the low temperatures and slow cement hydration to ensure the quality of concrete and the smooth progress of construction. Here are some key considerations:

I. Raw Material Selection and Temperature Control

  1. Cement: Prefer Portland cement, ordinary Portland cement, and early-strength cement to improve the early strength of concrete and reduce the frequency of frost damage.
  2. Sand and Stone: Prioritize the use of stored sand, which has a relatively low moisture content, fewer frozen blocks, and stable performance. If newly arrived sand is used, its moisture content (below 4%) should be strictly controlled to reduce the chance of freezing and the frequency of adjusting the mix ratio. Similarly, gravel should be protected from rain and snow and covered with sand nets or blankets for insulation.
  3. Mixing Water: Use hot water for mixing, with a temperature controlled at around 60°C but not exceeding 80°C to prevent false setting of the concrete.
  4. Antifreeze Agent: Choose an antifreeze additive with antifreeze components that can lower the freezing point of water and allow concrete to hydrate under negative temperature conditions. The performance and dosage of the antifreeze must be strictly controlled to ensure its effectiveness.

II. Equipment Insulation and Heating

  1. Enclosure and Heating: Enclose the discharge ports of aggregate bins, additive tanks, and mixers, and set up heating points (such as stoves or electric heaters). If conditions permit, the mixing plant can use a boiler for heating, with heating pipes running through key areas to ensure normal concrete production.
  2. Mixer Truck Insulation: Wrap mixer trucks in insulation blankets before winter construction to reduce heat loss during transportation.

III. Production Process Control

  1. Mix Ratio and Mixing: Determine the mix ratio for winter construction concrete based on environmental temperature, raw materials, curing methods, and concrete performance requirements during construction through testing. Strictly control the certificates and test data of various raw materials to ensure their traceability. During mixing, the mixing time should be appropriately extended to ensure the uniformity of the concrete.
  2. Moisture Content and Temperature Testing: Quality inspectors should test the moisture content and temperature of sand and gravel every day, and increase the frequency of testing during rainy or snowy weather. Strictly control the temperature of mixing water to prevent false setting or excessively low temperatures in the concrete.

IV. Transportation and Pouring

  1. Transportation Route: Reasonably determine the concrete transportation route, choosing the shortest route for mixer trucks and ensuring smooth transportation with low traffic volume.
  2. Pouring Site: Maintain communication between the mixing plant and mixer trucks for unified command at the pouring site. During pumping construction, enhance the transportation speed of mixer trucks to reduce the residence time of concrete in the pump and pipeline, preventing excessive temperature drop and pipe blockage.
  3. Insulation and Curing: After concrete pouring, promptly cover it with plastic film and blankets for insulation and curing. In winter construction, concrete should not be watered for curing, and no stepping, formwork installation, or loading should be allowed on it until it reaches the required strength.

V. Safety Management

  1. Personnel Safety: Require all personnel entering the construction site to wear nonslip shoes, and high-altitude operators to wear nonslip shoes, protective gloves, and other nonslip and antifreeze equipment, while properly wearing safety harnesses. At the same time, take personal warmth measures to prevent frostbite.
  2. Electrical Safety: Power switches, control boxes, and other facilities should be uniformly arranged and locked for protection to prevent electric leakage and shock. Electrical equipment used outdoors should have rain and snow protection facilities.
  3. Equipment Safety: Regularly check the safety devices of equipment, such as protective covers and safety valves, to ensure their normal operation. During severe weather, such as violent storms or heavy snowfall, construction operations should be strictly prohibited.

During winter construction at a cement mixing plant, attention needs to be paid to raw material selection and temperature control, equipment insulation and heating, production process control, transportation and pouring, as well as safety management. Only by comprehensively considering and strictly implementing these measures can the quality of concrete and the smooth progress of construction be ensured.