I. preparation and perfusion process of RPC cover material
In the mixing process of cement concrete raw materials and added materials, the mixing folding shall be a forced mixer, and the mixing speed shall not be lower than 45 revolutions per minute.
2. The water-glue ratio of RPC cover material should not be greater than 0.2.
3. In the configuration of RPC cover plate material stirring the mixture, the dosage of cement, special 傪 material dry state are calculated in accordance with the quality, weighing should be accurate to plus or minus 1%, aggregate using dry aggregate, dosage according to the quality plan, weighing should be accurate to plus or minus 2%. The quantity of water and additives should be accurate to plus or minus 5% according to the quality calculation.
4. For the process that the feeding sequence of precast RPC cover plate should be aggregate, steel fiber, cement, composite admixture, water and chemical reinforcing agent, dry materials should be pre-stirred for 4 minutes, and water and chemical reinforcing agent should be added for 4 minutes.
5. Slump of mixed active powder concrete materials should be controlled at 140-180 mm.
6. The mixture should be poured within 20 minutes, and a single member should be cast and formed by RPC cover mold in one time.
7. Stirring, transportation, pouring and stalling of RPC materials shall be completed at a temperature above 10 ℃.
8. During the pouring of RPC cover plate components, RPC cover plate material test pieces should be made randomly. The molding mold is made of RPC cover plate mold made of ABS plastic.
9. The compressive strength, tensile strength, elastic modulus, impervious grade, chloride permeability coefficient and frost and thaw resistance of
RPC cover material should meet the following design requirements:
The compressive strength of RPC cover is greater than or equal to 130MPa, the flexural strength is greater than or equal to 16MPa, the elastic modulus is greater than or equal to 46GPa, the permeability level is greater than or equal to P50, the chloride ion permeability is less than or equal to 40Coul, and the frost resistance number is greater than or equal to F600.
II: RPC cover maintenance
The curing of the formed RPC cover plate is divided into four stages: static stop, primary care, final care and natural care. The temperature during orderly maintenance is automatically controlled by the following specific requirements:
1. Stop statically. The ambient temperature of the formed components is above 10 degrees Celsius, and the relative humidity is 60%.
2. Initial incubation. Steam curing was conducted for RPC cover after static stopping, and the temperature rise rate was controlled within 12 ℃ / hour.
3. Mold removal and mold removal shall be carried out after initial incubation. It can be said that the plastic mold of RPC cover plate is placed on the vibration table for mold removal.
4. After final care, the RPC cover plate after demodulating needs to undergo three curing stages: temperature rise, constant temperature and temperature drop. The temperature rise rate should not be more than 12 ° c per hour, the temperature drop rate should not be more than 15 ° c per hour, and the constant temperature should be controlled between 65 ° c and 75 ° c, and the constant temperature curing time should not be less than 48 hours.
5. Natural maintenance: the maintenance environment is higher than 10 ℃, and the RPC cover plate is sprayed with water for maintenance. The time is no less than 7 days.