1. Gypsum is a monoclinic mineral, a hydrate whose main chemical component is calcium sulfate (CaSO4). Gypsum is a widely used industrial and construction material. It can be used as cement retarder, gypsum building products, model making, medical food additives, sulfuric acid production, paper filler, paint filler, etc.
2. Gravel solid soil: refers to solid or compacted clay, plate-shaped loess, dense and hardened alkaline soil , impurity clay containing less than 30% of crushed pebbles and a particle size of less than 3mm, and natural graded sand and gravel. wait. Identification method: Use picks and shovels for all, and use crowbars for a small amount to dig and identify.
3. Brick walls should be built in the form of or . The size of each balcony in the height direction should not exceed 300mm. Starting from the column base, the balconies should be stepped back first and then advanced.
4. The laying methods of roofing polymer modified asphalt waterproofing membrane include hot melt method, cold adhesive method and self-adhesive method.
5. The hot air welding method is a method of using preheated compressed air or inert gas to heat plastic welding parts and welding rods to make them reach a viscous state and perform welding under moderate pressure.
hot air welding method is mainly used for welding polyvinyl chloride , polyolefin , poly formaldehyde , nylon and other plastics. It can also be used for polystyrene , ABS, polycarbonate , chlorinated polyether , welding of plastics such as chlorinated polyethylene.
6. After the concrete pouring of the main structure is completed, it should be covered and watered within 12 hours.
7. The first-level welds shall not have defects such as undercuts, under-welding, and root shrinkage.
8. Soil loosenability: After natural soil is excavated, its volume increases due to loosening. Although it is vibrated and tamped, it still cannot completely return to its original volume. This property is called soil loosenability. It is an important parameter for calculating the productivity of earthmoving machinery when digging and filling earthwork, the amount of backfilled earthwork, the number of transportation equipment, the vertical design of site leveling planning, and the balance deployment of earthwork.
9. The load-bearing capacity of shaped steel concrete members can be more than twice that of reinforced concrete members with the same shape, so the member cross-section can be reduced.
10. If the concrete strength grade poured in winter is equal to or higher than C50, its critical freezing strength should not be less than 30% of the designed concrete strength grade value.
