Technical knowledge that kiln manufacturers must see before pouring concrete construction

(1) The following contents should be strictly checked before the construction of castables:

1) Check the shape and cleaning of the equipment to be poured.

2) Check the integrity of the construction equipment, vibrating tools, etc. must have good spare parts.

3) Check the anchor type, size, arrangement and welding quality. The metal anchors must be compensated for expansion.

4) Check the surrounding refractory brick lining and insulation layer to prevent water loss measures of castables.

5) Check the packaging and date of manufacture of the castable and conduct a preliminary test to check for failure.

6) Check the construction water, the water quality must reach the quality of drinking water.

Where the above items are unqualified, they shall be processed before they can be qualified. Expired materials may not be used. In the construction of castables, it is necessary to ensure no power cuts and no interruption in construction.

(2) The template for castable construction can be made of steel plate or hard wood board, and the surface should be smooth. The template should have sufficient strength, good rigidity, no shape, no displacement, no leakage, and the template should be firmly fixed to avoid the rise of the mold due to vibration. The gap of the template is small to avoid the slurry. The steel formwork should be coated with a release agent, and the wooden formwork should be painted with a waterproof paint. The used template should be cleaned before painting and then used.

(3) The amount of water to be poured shall be controlled strictly in accordance with the instructions for use and shall not exceed the limit. Under the premise of ensuring the construction performance, the amount of water should be less and less.

(4) The mixing time of the castable should be no less than 5 min. Use a forced blender when operating. When mixing, it is advisable to dry mix beforehand, then add 80% water to stir, then slowly add the remaining water according to the dryness and wetness, and continue to stir until the proper working consistency is obtained. The mixer should be cleaned before mixing different castables.

(5) The castables shall be used in whole bags. The stirred castables are generally used up within 30 minutes, and the amount of time is shortened in a high-temperature dry working environment. Castables that have been initially condensed or even agglomerated shall not be poured into the mold frame, and shall not be mixed with water.

(6) The pouring material poured into the mold frame should be layered and shattered immediately by the vibrating bar. The height of each layer is not more than 300mm, and the vibration spacing is about 250mm. Try to avoid touching the anchor when vibrating, and do not vibrate and re-vibrate in the same position. After seeing the surface of the castable, the vibrating rod should be slowly extracted to avoid segregation and voiding in the castable layer, and ensure the gas in the castable. After the pouring is completed, the cast body can no longer be pressed and oscillated before solidification.

(7) When pouring large areas, it is necessary to divide the blocks. The area of each casting area is about 1.5m. Generally, 3-5mm plywood is used as the expansion joint. The plywood should be placed on the working surface of the castable. The expansion should be designed according to the design and should not be missed. The depth of the expansion joint should be poured. Preferably, about one-half of the thickness of the material is used. If the castable height is low at one time, an expansion joint shall be left between 1.2 and 1.5 m, and the expansion joint shall be left at the position where the anchor is spaced.

(8) Immediately after the surface of the castable is dry, cover the exposed part of the air with a plastic film or a straw bag. After the initial condensation arrives, it should be regularly sprinkled and maintained to keep the surface moist. The maintenance time is at least two days, and the water should be sprinkled during the first day. After the castable is finally set, the side mold can be removed and the water spray can be maintained. However, the load-bearing formwork needs to be 70% of the strength to be demoulded.

(9) The castable should be inspected in time after the template is removed. It is found that quality problems such as honeycomb, spalling and voids should be handled and repaired in time. When the problem is serious, the defect part should be cut away to expose the anchor, and then the same quality of the solid material should be used to fill the tamping, and the maintenance should be continued. It is forbidden to use the cement mortar to level the problem to cover up the problem.