Problem1：Sand freezing block
Reason analysis: due to the local materials used in the project construction, river sand and so on, and the water content is large, the sand and the water freeze and condense together at low temperature, and the temperature continues to be cold, the sand agglomeration will become larger and more many.
Treatment plan: Use a seamless steel pipe to lay a warm steam pipe row near the sand yard. The pipe size is Φ105×5, the distance between the pipe and the pipe is 500mm, the pipe row size is 20m×20m, and the sand is stored on this pipe row. Then covered with colored strips to prevent heat loss and snow from mixing into the sand. Then the steam from the start boiler room is circulated in the tube row to heat and heat the sand to prevent the sand from freezing. This insulation pipe row can store 1200m3 sand, which can continuously meet the production volume of 2100m³ concrete.
Effect verification: After adopting this program to heat and store the sand, no agglomeration or freezing °Ccurs in the sand. The temperature of the sand stored on the heating pipe is measured many times. When the temperature is -30°C, the temperature of the sand is above 20°C.
Question 2: Admixture (liquid) agglomeration
Reason analysis: According to the regulations of the industry standard “Concrete Antifreeze” (JC 475-2004), the minimum prescribed temperature of antifreeze is -15°C, while the average winter temperature in Hulunbeier is -20 °C, which is far lower than the prescribed temperature of antifreeze. The admixture (liquid) is stored in a bare tank without any heat preservation measures, so when the temperature is lower than the specified temperature of the admixture, the admixture will often appear on the site of the freezing bl°Ck, resulting in the performance of the admixture being reduced or invalid.
Treatment scheme: use four layers of materials such as “insulation blanket-electric blanket-insulation blanket-waterproof tarpaulin” to insulate the admixture tank, and use the electric blanket to heat the tank body (Figure 3); heat is stored to prevent heat loss; waterproof tarpaulin Prevent snow from contacting the insulation blanket (figure 4), so that the snow melts into water and freezes, reducing the insulation effect.
Effect verification: After adopting this treatment plan, through continuous heating for 2 days, the temperature of the additive in the tank was tested multiple times. The measured temperature of the additive and the ambient temperature in the tank were both above 10 °C.
Question three: The silo outlet of the mixing station is blocked
Reason analysis: Because the temperature of the silo wall is extremely low, the sand sticks to the wall, and the accumulation is more, and the sand has agglomeration phenomenon, which makes the silo outlet easy to bl°Ck and affects the production progress of concrete.
Treatment plan: Install a steam heating pipe on the inner wall of the lower part of the silo to heat the silo wall to prevent the sand from sticking to the wall. At the same time, the sand can be “secondarily heated” to improve the concrete production schedule and construction quality.
Effect verification: After adopting this treatment plan, there is no sticky sand or clogging at the exit of the silo, which ensures the timely supply of sand and the continuous production of concrete.
Question 4: Low temperature of stirring water
Reason analysis: due to low weather temperature, the temperature of the mixing water is generally around 0°C, which is easy to make the concrete mixing uneven and the quality is unqualified.
Treatment plan: use hot water to stir. Install a 2t hot water boiler (outlet temperature 70°C, working pressure 0.7MPa) near the mixing building, and directly supply the concrete mixing water with a water pump after the header. All pipes are insulated with 200mm thick r°Ck wool and linoleum paper to prevent Hot water temperature loss. Install a water temperature meter near the water supply pipeline of the mixer to detect the water temperature in time.
Effect verification: After adopting this treatment plan, the stirring water was measured several times, and the measured water temperature was above 55°C.
Question 5: The mixer is difficult to operate or unable to operate
Reason analysis: Because the mixing plant is exposed equipment, affected by the low ambient temperature, the electrical components, mixing micoComputer, pneumatic system, mechanical operation and other components of the mixing plant cannot operate or malfunction, resulting in difficulty or inoperability of the mixer.
Treatment plan: 100mm thick color steel plate is used to fully close the mixing host, belt feeding part of the mixing building, and the key parts such as the pneumatic butterfly valve, limit switch, cylinder, etc. are electrically heated with tungsten iodine lamp to make it sensitive and reliable. ; Install a steam heating piece near the closed mixing host and belt feeding; the above heating facilities use steam from the startup boiler room for heating.
Effect verification: After adopting this scheme, the ambient temperature of the mixing host, feeding system and other parts are kept above 5°C. The mixing building is operating normally, the electrical components are sensitive, and the pneumatic components operate in a timely and reliable manner, ensuring the continuity of concrete production.
In addition, the water used for concrete production is hot water, but the cement cannot be directly mixed with hot water higher than 80°C, so the concrete must be mixed according to the following feeding methods: first, the sand and stone are added with 90% water for 1min; then the cement, The admixture is mixed into the mixer for more than 1.5 minutes and the remaining 10% of water is added; at the same time, it should be noted that the sand and the cement and the admixture are fed separately to prevent the cement and admixture from contacting the hot water to cause the cement “false setting” phenomenon; Prolonged mixing time. After adopting the above scheme, the mixing plant is operating normally, the production and supply of concrete in winter is timely, the temperature of the concrete is about 15°C, and the quality of the concrete meets the requirements