What to Pay Attention to in UHPC Construction? Qinglong UHPC Full-Process Construction Precautions and Specifications

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 full-process construction precautions to safeguard the smooth implementation of projects.

I. Pre-Construction Preparation Precautions

Raw material quality control: Upon delivery, raw materials must be checked against factory certificates and test reports. Key materials such as cement, quartz sand, and fibers must be sampled and retested. Qinglong requires cement strength grade ≥ P.O 52.5, fiber length of 12-15mm, and diameter of 0.2-0.3mm to ensure performance compliance. Equipment commissioning and inspection: Mixing equipment must have its metering system calibrated (error ≤ ±1%) and mixing blade wear inspected; pouring equipment must be tested for pressure stability; curing equipment must have temperature and humidity control precision verified. Qinglong's pre-construction equipment commissioning pass rate reaches 100%, preventing equipment issues from affecting construction. Construction plan development: Develop detailed plans based on component type and construction environment, specifying mixing parameters, pouring sequence, curing regime, and installation procedures. Complex projects require BIM simulation and construction rehearsals—Qinglong conducted 3 simulation rehearsals before construction of the Shanghai New World project to optimize the construction process. Personnel training and briefing: Construction personnel must pass professional training before taking up their posts, with clear operational standards and quality requirements for each position, focusing on the key operation points of mixing, pouring, curing, and other critical stages. Qinglong's construction team training assessment pass rate reaches 100%.

II. Mixing and Pouring Precautions

Precise metering and proportioning: Raw materials must be metered strictly according to the design mix ratio. The water-binder ratio must be controlled at 0.18-0.22, and fiber dosage error must be ≤ ±0.1%. Qinglong uses electronic metering equipment to ensure accurate 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 easily causes fiber agglomeration and a 10%-15% reduction in strength. Timing of pouring: Pouring must be completed within 30 minutes after mixing to prevent the material from setting and hardening. Before pouring, molds must be cleared of debris and coated with release agent to ensure a smooth mold surface. Qinglong stipulates that materials not poured within the time limit must be discarded; adding water for re-mixing is strictly prohibited. Pouring process control: Adopt layered pouring (each layer ≤ 50mm thick). Complex shapes or thin-walled components require high-pressure grouting (pressure 0.2-0.3MPa) combined with vibratory forming, with vibration time controlled at 10-20 seconds per location to prevent aggregate segregation caused by over-vibration. Qinglong's Guangxi New Media Center project reduced air bubble defects through this process.

III. Curing and Forming Precautions

Early-age curing control: Cover with moisture-retaining materials within 12 hours after pouring, with temperature controlled at 20-25℃ and humidity ≥ 90% to prevent early-age water loss and cracking. Qinglong uses intelligent curing chambers that monitor temperature and humidity in real time to ensure a stable curing environment. Steam curing standards: For projects with tight schedules, steam curing can be adopted, with heating rate ≤ 10℃/h, constant temperature of 50-60℃ held for 12-16h, and cooling rate ≤ 5℃/h. Through steam curing, Qinglong's 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 specimens cured under the same conditions. Premature demolding that causes component deformation is strictly prohibited. Qinglong always conducts strength testing before demolding, proceeding only after standards are met. Continued 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 measures. During the later-stage curing period of Qinglong's Shenzhen Yirui Biology project, regular water spraying ensured stable strength development of components.

IV. Installation and Acceptance Precautions

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

UHPC construction must strictly follow operational 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 the successful construction of UHPC projects.