UHPC Casting Methods and Construction Key Points Explained

What Are the UHPC Casting Methods and Key Construction Points Explained

In the field of contemporary architecture, Ultra-High Performance Concrete (UHPC), with its outstanding mechanical properties and design flexibility, is becoming the material of choice for landmark buildings and complex structures. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group has always taken "creating beautiful architecture" as its mission, deeply involved in every step from detailed design to construction implementation. This article provides a systematic analysis of UHPC's core casting processes and key construction points, offering professional technical reference for designers and engineering parties.

I. UHPC Casting Process System: From Material Properties to Construction Method Innovation

The ultra-high strength of UHPC material (compressive strength ≥150MPa) and its low water-binder ratio characteristics determine that its casting process must balance fluidity and density. Currently, mainstream casting methods can be divided into three major categories:

1. Conventional casting method: Suitable for flat components and simple shapes. Based on Qinglong's self-developed self-compacting UHPC formula (water-binder ratio 0.18-0.22), the mold is filled by natural gravity flow, combined with high-frequency vibration (vibration frequency ≥150Hz) to eliminate air bubbles. This process accounts for 60% of the 600,000㎡ annual capacity at the Nanning production base, and is widely used in municipal bridge deck panels and architectural cladding panels.

2. Spray casting method: For curved shapes and complex nodes, high-pressure spraying equipment (working pressure 8-12MPa) is used to inject UHPC mix into the mold at high speed. In the translucent concrete project at Century Plaza on Nanjing East Road, Qinglong achieved a hyperboloid shape with a minimum curvature radius of 300mm using this process, winning the AALBORG WHITE Cup UHPC Construction Engineering Innovation Award.

3. Combined precast and cast-in-place process: Leveraging Qinglong's BIM detailed design capabilities, large components are broken down into precast modules and joined on-site with UHPC grouting material (fluidity ≥300mm). This method, applied in the Dongguan Women and Children's Activity Center project, kept the installation precision of the GRC/UHPC composite curtain wall within ±2mm, winning the Silver Award of the GRC Engineering Innovation Award.

II. Key Control Points in UHPC Construction: From Material Preparation to Quality Acceptance

1. Material preparation: Strictly control raw material temperature (aggregates ≤25℃) and mixing time (≥5 minutes in a dedicated mixer). Qinglong's self-built provincial-level R&D center can monitor fiber dispersion in real time (steel fiber volume content 2-3%) to ensure stability of mechanical properties.

2. Casting process control: High-precision steel molds are used (surface flatness ≤0.5mm/m). When casting thickness exceeds 500mm, layered casting is implemented (each layer ≤300mm), with secondary vibration before initial setting. For mass components, Qinglong's original embedded circulating water cooling system controls the temperature difference between interior and exterior within 25℃.

3. Curing process innovation: A combined "steam curing + natural curing" approach is adopted. During the steam curing stage, the heating rate is controlled at ≤20℃/h with a constant temperature of 80-90℃ to ensure that 28-day strength meets standards. Practice from Qinglong's overseas projects (such as a landmark building in Malaysia) shows that this curing process can increase UHPC early strength by 40%.

4. Quality acceptance standards: Following the "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)", which Qinglong helped develop, key inspections focus on apparent density (≥2400kg/m³), flexural strength (≥12MPa), and chloride ion penetration coefficient (≤10⁻¹²m/s), with RFID chips enabling full life-cycle quality traceability.

III. Industry Practice and Technology Trends: Qinglong's Full-Chain Solutions

As a national "Specialized, Refined, Distinctive, and Innovative" enterprise, Qinglong integrates UHPC technology with GRC/GRG/GRP material systems to form differentiated competitive advantages. For example, in a commercial complex project, a UHPC and GRG composite ceiling system achieved an unsupported curved shape with a 12-meter span, meeting both fire performance requirements (Class A non-combustible) and acoustic requirements (NRC ≥0.8).

In the future, with the combination of 3D printing technology and UHPC materials, Qinglong is exploring a new "digital casting" model, in which parametric design directly drives concrete printing nozzles, shortening the production cycle of complex components by 50%. This technical path has been piloted in a cultural center project in Saudi Arabia, setting a technical benchmark for the industry.

From material R&D to project implementation, Qinglong always maintains a meticulous and excellence-driven attitude, providing global customers with full-chain UHPC/GRC/GRG/GRP solutions. Whether you are a designer pursuing ultimate shapes or an owner focused on engineering quality, choosing Qinglong means choosing the professional assurance built on 28 years of accumulated industry experience. Let us join hands to create the beauty of architecture and explore the infinite possibilities of material technology.