What Should Be Noted in UHPC Construction? Precautions and Specifications for the Full Process of Qinglong UHPC Construction

UHPC construction requires close attention to key stages such as raw material control, mixing and pouring, curing and forming, and installation and commissioning. Improper operation at any stage can lead to problems such as insufficient strength, cracking, and surface defects; standardized operation is the core of ensuring construction quality. Drawing on 28 years of construction experience, Qinglong Group has summarized precautions for the entire construction process, providing a guarantee for smooth project implementation.

1. Pre-Construction Preparation Precautions

Raw material quality control: Incoming raw materials must be checked against factory certificates and test reports, and key materials such as cement, quartz sand, and fibers require sampling and re-inspection. Qinglong requires cement strength grade ≥ P.O 52.5, with fiber length of 12-15mm and diameter of 0.2-0.3mm, to ensure performance meets standards. Equipment commissioning checks: Mixing equipment requires calibration of the metering system (error ≤ ±1%) and inspection of mixing blade wear; pouring equipment requires pressure stability testing; curing equipment requires verification of temperature and humidity control precision. Qinglong achieves a 100% equipment commissioning pass rate before construction, preventing equipment problems from affecting construction. Construction plan development: Detailed plans must be developed based on component type and construction environment, specifying mixing parameters, pouring sequence, curing regime, and installation procedures; complex projects require BIM simulation and construction drills. Three simulation drills were conducted before construction of the Qinglong Shanghai New World project to optimize the construction process. Personnel training and briefing: Construction personnel must pass professional training before starting work, with clear operating standards and quality requirements for each position, focusing on key operational points in mixing, pouring, curing, and other critical stages. Qinglong's construction team achieves a 100% training assessment pass rate.

2. Mixing and Pouring Precautions

Precise metering and proportioning: Raw materials must be metered strictly according to the design mix ratio, with the water-binder ratio controlled at 0.18-0.22 and fiber content error ≤ ±0.1%. Qinglong uses electronic metering equipment to ensure precise measurement and prevent insufficient strength caused by proportioning deviations. Standardized mixing operation: First add aggregates and cement and mix for 2-3 minutes, then add water and admixtures and mix for 3-4 minutes, and finally add fibers and mix for 2-3 minutes, with mixing speed controlled at 120-150r/min. Qinglong's experiments show that insufficient mixing can easily cause fiber agglomeration and a 10%-15% decrease in strength. Pouring timing control: Pouring must be completed within 30 minutes after mixing to prevent material setting and hardening; before pouring, the mold must be cleaned of debris and coated with release agent to ensure a smooth mold surface. Qinglong stipulates that material not poured within the time limit must be discarded, and re-mixing with additional water is strictly prohibited. Pouring process control: Layered pouring is adopted (each layer thickness ≤ 50mm); complex shapes or thin-walled components require high-pressure grouting (pressure 0.2-0.3MPa) combined with vibration forming, with vibration time controlled at 10-20 seconds per location to prevent over-vibration causing aggregate segregation. The Qinglong Guangxi New Media Center project reduced bubble defects through this process.

3. Curing and Forming Precautions

Early curing control: Within 12 hours after pouring, cover with moisture-retaining materials, with temperature controlled at 20-25℃ and humidity ≥ 90% to prevent early water loss and cracking. Qinglong uses intelligent curing kilns with real-time temperature and humidity monitoring to ensure a stable curing environment. Steam curing standards: For projects with tight schedules, steam curing can be adopted, with a heating rate ≤ 10℃/h, constant temperature of 50-60℃ for 12-16h, and cooling rate ≤ 5℃/h. Through steam curing, the Qinglong Yangshengtang Pharmaceutical project reached 80% of design strength at 7 days. Demolding timing judgment: Demolding strength must reach at least 70% of design strength, and thin-walled components must reach at least 80%, judged through strength testing of companion-cured test blocks; premature demolding causing component deformation is strictly prohibited. Qinglong always conducts strength testing before demolding and proceeds only after standards are met. Extended later-stage curing: After demolding, moist curing must continue for 7-14 days, avoiding sudden changes in ambient temperature and humidity; outdoor curing requires shading and wind protection. During the later curing period of the Qinglong Shenzhen Yirui Biotech project, regular water spraying ensured stable strength development of the components.

4. Installation and Acceptance Precautions

Precise installation positioning: 3D laser scanning or total station positioning is used to ensure component installation position deviation ≤ ±2mm, with joint gaps controlled at 2-5mm. Through precise positioning, the Qinglong Guangzhou Dongzhu Shangdu project achieved a 100% installation pass rate. Connection node treatment: Connectors require anti-corrosion treatment in advance, and connections must be secure during installation; gaps are filled with special sealant to prevent rainwater penetration. All Qinglong connection nodes undergo pull-out force testing to ensure load-bearing safety. Finished product protection: After installation, protective measures must be taken to prevent collision and scratching, and stacking heavy objects on component surfaces is prohibited. Qinglong uses plastic film wrapping plus protective railing enclosures, achieving a 100% finished product protection rate. Acceptance standard implementation: Acceptance is conducted strictly according to the Ultra-High Performance Concrete (UHPC) Exterior Wall Panel standard, checking appearance quality, dimensional deviation, strength performance, and other indicators. Qinglong projects achieve a 99.5% acceptance pass rate, ensuring delivery quality.

UHPC construction requires strict adherence to operating standards at every stage; negligence in any detail can affect the final quality. Through a comprehensive construction control system and standardized operating procedures, Qinglong Group ensures that every construction stage is compliant and controllable. Choosing a manufacturer with construction experience and standardized management capabilities is the key guarantee for successful UHPC project construction.