What Mold Materials Are Commonly Used for UHPC Components and What Are Their Advantages? Mold Selection Guide and Application Analysis

The material of UHPC component molds directly affects product precision, appearance quality, and production efficiency. Molds made of different materials suit different component types and production needs. Selecting the right mold material is key to ensuring UHPC production quality. Drawing on 28 years of UHPC production experience, Qinglong analyzes common mold materials and their core advantages.

1. Steel Molds: The Choice for High Precision and High Durability

Steel molds are the material of choice for high-precision UHPC components, with core advantages of high precision and long service life. Fabricated from welded Q235 steel plates with surfaces milled, ground, and polished, they achieve a flatness error of ≤0.5mm/m and can accurately reproduce complex shapes, making them suitable for large irregular components. For the UHPC wood-grain translucent panels at the Shanghai New World Nanjing East Road Century Plaza, Qinglong used steel molds to ensure precise dimensions of the 12㎡ oversized components. Steel molds are extremely durable and can be reused more than 200 times, making them ideal for mass production projects. For example, for the 12,000-square-meter UHPC components of the Yangshengtang Pharmaceutical Hangzhou Industrial Park, steel molds effectively reduced unit production costs. In addition, steel molds offer good thermal conductivity and are compatible with steam curing processes, which can accelerate component strength development and further shorten production cycles.

2. GRP Molds: The Preferred Choice for Complex Shapes and Lightweight Applications

With their excellent moldability, GRP molds (fiberglass-reinforced plastic molds) are a core choice for complex curved UHPC components. Made from glass fiber reinforced resin, they can accurately reproduce complex shapes such as curves and openwork patterns, with high mold conformity and smooth surfaces that reduce bubbles and blemishes on UHPC component surfaces. In the UHPC perforated panel project for the Ouargla Hotel in Algeria, Qinglong achieved precise shapes with a perforation rate of over 50% using GRP molds. GRP molds are lightweight (density only 1/4 that of steel molds), easy to handle and assemble, and especially suitable for work at heights; their short fabrication cycle, about 1/3 that of steel molds, enables a quick response to customized needs. However, they can be reused approximately 50-80 times, making them suitable for small-to-medium batch production of complex components.

3. Wooden Molds: Suited to Low Cost and Rapid Iteration

Wooden molds use plywood as the core material, with advantages of low cost and short fabrication cycles, making them suitable for simple shapes and sample production. Raw materials are readily available and easy to process, allowing molds to be quickly made and modified—ideal for the project development stage or small batches of simple components such as flat panels and straight lines. Qinglong often uses wooden molds during the project sampling stage to quickly verify design solutions. To improve durability, wooden mold surfaces need to be coated with epoxy resin to enhance water resistance and surface smoothness and reduce UHPC slurry adhesion; however, wooden molds can only be reused 10-20 times, are prone to deformation from moisture, and are difficult to control for precision, making them unsuitable for high-precision or large-batch production projects—only serving as a low-cost temporary solution.

4. Silicone Molds: Specialized for Fine Textures and Artistic Shapes

Silicone molds are designed specifically for UHPC artistic components, with core advantages of high texture replication precision and good flexibility. Made from high-elasticity silicone rubber, they can accurately reproduce fine textures such as stone-like and wood-grain patterns, achieving a fidelity of over 95%. In the public art project for the Shanghai Astronomy Museum, Qinglong used silicone molds to perfectly present the complex textures on sculpture surfaces. Silicone molds are highly flexible, easy to demold, and unlikely to damage component edges and fine details, making them suitable for irregular artistic components and small-batch customized products; however, they are costly, can be reused about 30-50 times, and have poor heat resistance, making them incompatible with high-temperature steam curing processes. They are mainly used for the production of indoor artistic components and decorative pieces.