High-speed railway box girder concrete pouring and maintenance operation instructions

I. Importance and goals of high-speed railway box girder concrete pouring and maintenance

The importance of high-speed railway box girder concrete pouring and maintenance is self-evident, which directly affects the strength, durability and service life of the box girder. The goal of pouring and maintenance is to ensure that the box girder concrete has excellent physical and mechanical properties and meets the requirements of high-speed railways for safety, stability and comfort.

 

II. Preparation before pouring

1. Material selection: Select concrete raw materials that meet national standards and design requirements, including cement, aggregates, admixtures, admixtures, etc.

2. Equipment inspection: Conduct a comprehensive inspection and commissioning of the pouring equipment to ensure that the equipment has good performance, safety and reliability.

3. Formwork preparation: Check the flatness, rigidity and stability of the formwork to ensure that the formwork is installed firmly and without gaps.

 

III. Detailed concrete pouring process and precautions

1. Pouring sequence: Pour in accordance with the predetermined pouring sequence, generally from one end to the other, to avoid excessive pressure on the concrete in the formwork.

2. Pouring speed: Control the pouring speed to avoid too fast or too slow, and ensure that the concrete fills the formwork evenly and continuously.

3. Avoid cold joints: Ensure good contact between the concrete poured before and after to avoid cold joints.

4. Vibration: Use appropriate vibration methods and equipment to ensure that there are no bubbles and looseness inside the concrete.

 

IV. Maintenance methods and steps

1. Insulation covering: After the concrete is poured, cover the insulation material in time to reduce the change of concrete surface temperature and avoid the generation of temperature cracks.

2. Steam curing: Use steam curing according to environmental conditions to accelerate the hardening and strength development of concrete.

3. Natural curing: Under suitable environmental conditions, natural curing can be used to keep the concrete surface moist by appropriate sprinkling.

 

V. Analysis and solutions to common problems

1. Surface defects: such as honeycombs, pockmarks, etc., the causes should be analyzed and appropriate repair measures should be taken, such as using cement mortar for plastering.

2. Insufficient strength: If the concrete strength does not meet the design requirements, the reasons should be analyzed and strengthening measures should be taken, such as increasing the curing time and strengthening the vibration.

 

VI. Quality inspection and acceptance standards and processes

1. Quality inspection: Inspect the concrete strength, size, appearance, etc. in accordance with national standards and design requirements to ensure that the box girder quality meets the requirements.

2. Acceptance process: Organize professional personnel to conduct acceptance and rectify unqualified box girders until they meet the requirements before they can be delivered for use.

 

VII. Safety production requirements and preventive measures

1. Safety production requirements: Comply with safety production laws and regulations to ensure the safety of operators; conduct regular inspections and maintenance of equipment to ensure that the equipment is safe and reliable.

2. Preventive measures: Formulate safe operating procedures and strengthen operator training; set up safety warning signs and protective measures; pay attention to fire prevention, electric shock prevention and other safety issues during concrete pouring and curing.