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Technical requirements for construction of refractory castables

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One. Inspection of castable before construction:

Check the surface and cleanliness of the equipment to be poured, and the construction surface must be clean.

Check the intact condition of the construction equipment. There must be intact spare parts for mixing and vibrating tools.

Check the shape, size, layout and welding quality of the anchor. The metal anchor must be compensated for expansion (coated with asphalt or other measures).

Check the surrounding refractory brick lining and insulation layer to prevent the castable from losing water.

Check the packaging and delivery date of the castable, and conduct a pre-test to check whether it is invalid.

Check the construction water, the water quality must meet the drinking water standard.

When the above items fail to pass the inspection, they should be processed before being qualified. The expired castables should not be used. During the construction of the castables, it is necessary to ensure that there is no power outage and construction must not be interrupted.

two. Matters needing attention during construction:

Formwork: The formwork for castable construction can be made of steel plate or hardwood plate (plywood). The formwork should have sufficient strength, good rigidity, no deformation, no displacement, no leakage, and the formwork should be coated with release agent, wood formwork To apply water repellent, the reused template must be cleaned before painting. The inspection holes and cleaning holes should be made of wood to form a regular mold. The metal tie bars supporting the wooden magic board should be more than 4 per square meter (to prevent strong heat transfer) and the tie bars should be welded based on the anchor (that is, the tie bars of the template should be welded to the anchor).

Water-cement ratio: The amount of water added when stirring the castables must be strictly controlled in accordance with the instructions, and should not exceed the limit. On the premise of ensuring the construction performance, the amount of water added should be less or not more.

Mixing: The mixing time of the castable should be no less than 5 minutes (subject to the requirements of the instructions), and a forced mixer is required for operation. When mixing, it is advisable to dry mix first, then add 80% of water to mix, and then, depending on the degree of dryness and wetness, slowly add the remaining water and continue to mix until a suitable working level is obtained. Mix the different castables and clean the mixer.

Use of castables: The castables must be used in whole barrels and bags. The stirred castables must generally be used within 30 minutes. In a high-temperature and dry operating environment, this time must be shortened appropriately. It has already set or even agglomerated. The casting material should not be poured into the mold frame, and it should not be used after stirring with water.

Vibration: The castable poured into the mold frame should be immediately layered and compacted with a vibrating rod, the height of each layer should be no more than 300mm, and the vibration spacing should be around 250mm. When vibrating, try to avoid touching the anchor, do not damage the insulation layer, and do not vibrate or re-vibrate at the same position for a long time. After seeing the surface of the castable, the vibrating rod should be slowly pulled out to avoid segregation and appearance of the castable Hollow.

Large-area construction: In the large-area construction process, the construction should be divided into blocks. The area of each pouring area is about 1.5m2. Expansion joints should be retained according to the design requirements and must not be omitted. Expansion joints should be left at the anchor interval In the middle position, 6 ~ 8mm thick planks can be used for the expansion joint. The distance between the cross section of the plank and the formwork should be 40 ~ 60mm. The planks for expansion should be effectively fixed to prevent translocation during the construction of the castable.

Regarding the welding of anchors: draw a grid line on the working surface (according to the requirements of the drawing), weld the anchor at the position of the grid line contact, and the welding of the root of the anchor should be fully welded.

The casting body after the construction of the casting material is completed shall not be subjected to pressure or shock before solidification.

three. Maintenance inspection after construction:

After the surface of the castable is dry, the part exposed in the air should be tightly covered with plastic film or straw bag. After the initial setting, it should be regularly sprinkled with water to maintain the surface moist. The curing time should be at least two days. The first day should be Sprinkle water frequently. After the casting material is finally set, the formwork can be removed to continue sprinkling and curing, but the load-bearing formwork must be removed after the strength reaches 70%.

After the formwork is removed, the casting body should be inspected in time, and quality problems such as honeycomb, peeling and voids should be dealt with and repaired in time. When the problem is serious, the defective part should be chiseled to expose the anchor, and then filled with the same quality tamping Tampering, continue to maintain, it is strictly forbidden to smooth the problem with cement mortar to cover up the problem.

four. Precautions for construction in winter, rainy days and days:

1. Winter refers to construction when the ambient temperature is between + 5 ° C and -5 ° C. When the temperature is below -5 ° C, construction can only be carried out after reliable cold protection measures have been taken.

2. During winter construction, winter construction technical measures must be adopted, and the work environment must be well sealed, windproof, heated, and warmed to ensure that the temperature of the lining after masonry is above + 5 ℃.

3. During the construction of castables in winter, the dry materials should be stored in the heating room. Stir with warm water (about 25 degrees) during construction to prevent the use of higher temperature water to avoid rapid coagulation of the castables. The temperature of the mixture should be kept above 10 ℃ . It is not easy to add a chemical accelerator or antifreeze.

4. When constructing in the furnace in winter, the insulation layer should be built first to improve the anti-freezing ability of the refractory layer. After construction, the masonry should be covered with plastic cloth and then covered with hay curtains. For newly built kilns, the heat preservation time shall not be less than 10 days, and it is strictly forbidden to expose the built masonry to the cold atmosphere.

5. It should be transferred to indoor operation during rainy construction. All materials, means of transport, work sites and masonry must be protected from rain. Cover the building, plug holes and plug leaks for the completed building. The upper opening of the completed furnace should be closed. The finished ground prefabricated parts should be raised and covered, and it is strictly forbidden to soak in water.

6. When the ambient temperature is greater than 30 ° C, it can be regarded as a construction day. During summer construction, the water temperature and material temperature should be controlled below 30, and the materials under the hot sun should be cooled before use.

7. In the summer, the castable should be arranged as day or evening as possible. After pouring, it should be covered with grass curtains in time, water should be sprayed frequently to cool down, and the water should not be allowed to flow onto the refractory bricks.

Inspection and acceptance of castable construction:

1. During the construction of castables, a set of test blocks shall be reserved for every 20m2 of engineering volume, so as to check the main properties such as its strength.

2. All covered concealed works should be checked and accepted by the concealed works before entering the next process. The inspection items are as follows:

Insulation and anchoring bricks, formwork, etc. (check at any time)

Anchor and anchoring device

Water loss prevention measures

Embedded facilities

After the inspection of concealed works, the acceptance form for concealed works should be filled out, and after the visa approval of the construction unit, it should be used as one of the completion materials.

3. After the completion of the sub-projects, the intermediate hand-over inspection should be carried out. The inspection items are as follows:

Masonry dimensions, lining thickness and centerline

Material usage

Expansion joints, brick joints, levelness, verticality and surface flatness

Construction of technological facilities and technological holes

Appearance inspection

After the inspection of the partial projects, the acceptance checklist for the partial projects shall be filled out, which shall be regarded as one of the completion documents after being approved by the construction unit visa.

six. Upon completion and acceptance, the contractor shall submit the following materials to the contractor, general contractor, and owner:

1. Delivery acceptance certificate

2. List of completed projects

3. Opening and completion report

4. Completion drawing with design changes

5. Business contact list (including rationalization suggestions)

6. Material inspection report (provided by the unit when supplied by the general contractor)

7. Process handover certificate (proposed by the general contractor)

8. Concealed engineering acceptance slip, intermediate delivery acceptance slip and quality inspection inspection record

9. Handling documents for major engineering problems

Construction records for winter, rain and weather

Other related matters

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