What Risks Require Key Control in Mass UHPC Construction? Thermal Crack Prevention and Qinglong Group's Engineering Management System

Mass UHPC construction requires focused control of three core risks: thermal cracks, shrinkage cracks, and layer segregation, which stem from its material characteristics of low water-binder ratio, high binder content, and concentrated hydration heat. In super-large-volume projects such as the 12,000 m³ cast-in-place roof at the Hainan International Convention and Exhibition Center and the 9,000 m² precast panel installation at the Wuhan Hanxiu Theater, Qinglong Group applied a system of 'material cooling + layered pouring + intelligent temperature control' to keep the peak core temperature within 70°C, the internal-external temperature difference ≤20°C, and the crack occurrence rate below 0.5%, achieving safe construction of mass UHPC.

Thermal crack prevention is the top priority. We adopt measures such as low-heat cement (sulphoaluminate cement), adding ice water (placing temperature ≤15°C), and embedding cooling water pipes (spacing 1 m) to reduce temperature rise. The temperature monitoring system deploys one monitoring point every 50 m² with real-time alerts. In the construction of a foundation slab in Shenzhen, by optimizing the mix proportion (binder content ≤800 kg/m³), the peak temperature was reduced from 85°C to 65°C, preventing thermal cracks.

Shrinkage cracks require comprehensive control. Magnesium oxide expansion agent (dosage 6-8%) is added to compensate for cooling shrinkage; post-cast strips (spacing ≤20 m) are set to release restraint stress; and thermal and moisture curing (film covering + water spraying) is maintained for 14 days. We developed an internal curing technology by adding saturated lightweight aggregate (3%), reducing 28-day shrinkage to 200 μm/m. Layered pouring prevents segregation: each pour thickness ≤500 mm with intervals ≤2 h, using high-frequency vibration to ensure compaction.

Risk management must cover the entire process. Qinglong Group establishes dedicated construction plans and performs thermal calculations and crack prediction. Through 28 years of practice, we have developed a mature mass UHPC construction guide to provide technical assurance for our clients.