1. After the concrete pouring of the beam body is completed, the bridge deck shall be closely covered with plastic film immediately (the concrete shall not be in direct contact with the concrete before the final setting. ) to prevent surface moisture evaporation, cover the curing hood for steam curing. In the curing process, in addition to placing embedded measuring points in the beam, thermometers should also be placed at both ends and middle sides of the curing shed to identify the temperature in the beam tarpaulin.
2. Steam curing can be divided into four stages: static stop, heating, constant temperature and cooling. Maintenance system: let stand for 4h, heat up for 6h, keep constant temperature 18, h, and cool down 12h. Constant temperature shall not be greater than 45℃; The temperature of beam core concrete should not exceed 60℃. During static shutdown, the ambient temperature shall be kept not lower than 5℃, the heating and cooling speed shall not be greater than 10℃/h, and the total curing time shall not be less than 40 hours.
3. During steam curing, ambient temperature and beam temperature shall be measured at any time. Observe the heating, cooling and constant temperature stages every half hour, and fill in the record form. Draw the beam temperature curve and ambient temperature curve in time, and pay attention to adjust the curing temperature at any time to ensure it is within the control range. When the temperature is abnormal, it should be reported to the relevant technicians immediately.
4. During steam curing, when removing thermal insulation facilities and templates, ensure that the temperature difference between concrete core and surface, inside and outside the box, and between surface and environment does not exceed 65438 05℃. Otherwise, measures should be taken to make it meet the standards before it can be removed.
5. During formwork maintenance, the beam should be watered and maintained 24 hours after concrete pouring to ensure the humidity of the beam.
6. The temperature difference between beam curing water temperature and beam surface shall not be greater than 65438 05℃.
7. During and after formwork removal, temporary sealing measures shall be taken for the reserved holes at both ends of the beam and box girder to prevent the beam from cracking under the influence of "through flow".
8, immediately after dismantling the template into the nature conservation. During natural curing, cover the beam surface with sacks and water it for curing. It is advisable to keep the concrete surface fully wet by sprinkling water on the beam. Generally speaking, it is 1 ~ 2 hours during the day and 4 hours at night. Natural conservation shall not be less than 14d. At the same time, the concrete specimen cured with the beam should be cured by spraying water, so that the strength of the specimen and the strength of the beam concrete increase synchronously. Water shall not enter the channel of the beam body to prevent the prestressed reinforcement from rusting.
9. When the day and night average temperature is lower than 5℃ or the minimum temperature is lower than -3℃ for three consecutive days, winter construction should be carried out, and curing agent should be sprayed on the beam surface, and sprinkling water on the beam is prohibited.
10. When using plastic film or spraying curing liquid for curing, ensure that the lap joint of the film is sealed or the spraying curing liquid does not leak.
1 1. When curing the beam concrete, observe whether there are cracks on the beam surface at any time. If there is any abnormality, report to the relevant technical personnel.
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