What to Note in UHPC Construction: Four Core Stages and Qinglong Construction Specifications

The success or failure of UHPC construction hinges on "attention to detail" — every stage, including mixing, pouring, curing, and installation, has strict requirements, and any improper operation can lead to problems such as insufficient strength, cracking, and poor compactness. Drawing on 28 years of construction experience, Qinglong has summarized four core precautions to safeguard construction quality.

Precaution 1: Precise mixing parameters to ensure uniform dispersion. UHPC mixing requires control of three key parameters: First, raw material metering accuracy — the metering error for cement, quartz sand, fibers, and admixtures must be ≤±1%; Qinglong uses an automated batching system to avoid the errors of manual batching. Second, mixing sequence and time — first dry-mix the cement and quartz sand for 2-3 minutes, then add water and admixtures and wet-mix for 3-4 minutes, and finally add fibers and mix for 3-5 minutes, with a total mixing time of 8-12 minutes to prevent fiber clumping. Third, mixing equipment selection — twin-shaft forced mixers with a rotation speed ≥800r/min must be used; ordinary concrete mixing equipment cannot meet fiber dispersion requirements. After mixing, the spread of the mixture must be tested (≥750mm); if it fails, the admixture dosage must be adjusted — never add water arbitrarily.

Precaution 2: Proper pouring timing and methods to ensure compactness without defects. Before pouring, pay attention to the following: First, mold pretreatment — molds must be coated with a special release agent to ensure a smooth surface; Qinglong uses polyurethane molds, achieving a surface flatness of ≤±1.5mm/m after demolding. Second, pouring timing — pouring must be completed within 30 minutes after the mixture leaves the mixer to prevent initial setting from affecting flowability. Third, pouring methods — flat panels are poured by pumping; components with a thickness ≤50mm use high-pressure spray pouring; special-shaped components use layered pouring (each layer ≤50mm thick); vibration is performed with high-frequency vibrators (frequency ≥100Hz) to ensure compactness free of bubbles and voids. The UHPC wood-effect translucent panels at Shanghai New World achieved precise fixing of the light-transmitting rods and component compactness through layered spraying plus manual vibration assistance.

Precaution 3: Strict curing conditions to avoid insufficient strength and cracking. UHPC curing is critical and must meet the following: First, curing temperature — components must enter a constant-temperature curing kiln within 2 hours after pouring, with the temperature controlled at 90-95℃ to avoid temperature fluctuations caused by natural curing. Second, curing duration — constant-temperature curing for 12-16 hours ensures full cement hydration, with strength reaching 80% of the design strength at 7 days. Third, post-curing — after leaving the kiln, avoid exposure to direct sunlight and rain, and air-cure for 7 days while keeping the surface moist; Qinglong uses moisture-retention film covering plus mist-spray curing to prevent surface cracking caused by water loss. The UHPC exterior wall panels at the Yangshengtang Pharmaceutical Industrial Park, through strict curing, achieved a 28-day compressive strength of 160MPa, far exceeding the design requirement of 150MPa.

Precaution 4: Installation precision and fixing to ensure structural safety. During installation, pay attention to the following: First, hangers and connectors — use 304/316L stainless steel, with hanger spacing ≤400mm and no fewer than 4 hangers per panel; Qinglong's back-bolt connection provides a pull-out bearing capacity ≥6kN. Second, installation positioning — use laser rangefinders and total stations for precise positioning with an installation error ≤±2mm, avoiding internal stress caused by forced joining. Third, flexible connections — install elastic shims between hangers and components to allow ±10mm thermal deformation, preventing cracking caused by rigid restraint. Fourth, sealing — joints are sealed with neutral silicone weatherproof sealant, filled densely to prevent rainwater penetration. The UHPC curtain wall installation at the Shenzhen Pingshan High-tech Zone Comprehensive Service Center, following the above standard procedures, achieved "zero-error" joining and long-term stability.

The core of UHPC construction lies in "standardization and refinement." Qinglong's construction specifications cover the entire process from mixing to installation, ensuring every stage meets requirements through professional equipment, technical teams, and strict controls. For construction teams, following specifications and paying attention to detail are the keys to achieving high-quality UHPC construction. Qinglong also provides full-process technical guidance to help customers overcome construction challenges.