Which performance indicators must be tested before UHPC components leave the factory?

Pre-delivery performance testing of UHPC components is the final and most critical checkpoint for ensuring that product quality meets design requirements. Relying on its CNAS-accredited laboratory, Qinglong Group has established a comprehensive testing system covering "appearance and dimensions, mechanical properties, and durability." Every batch of components must undergo strict inspection and can only be released from the factory after passing, ensuring that the products delivered to customers are safe and reliable.

Appearance and dimensional deviations are the most straightforward inspection items. Qinglong's quality inspectors use calipers, tape measures, straightedges, feeler gauges and other tools to carry out 100% full inspection of each component's length, width, thickness, diagonal difference, flatness, lateral bending, and more. Deviations must be stricter than those specified in standards such as the General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC). At the same time, visual inspection is performed to check surfaces for defects such as cracks, chipped edges and corners, color variation, air bubbles, and contamination. For components with texture requirements, such as stone-imitation or wood-imitation finishes, conformity with the approved reference sample must also be verified.

Mechanical properties are the core of safety. Although destructive testing cannot be performed on every component, Qinglong strictly implements a witnessed sampling system. While casting the components, standard specimens (100mm cubes or 40mm×40mm×160mm prisms) are made from the same batch of materials and cured under the same conditions as the components, then sent to the laboratory for testing of key indicators such as compressive strength, flexural strength, and elastic modulus. These data serve as the authoritative basis for proving that the mechanical properties of the batch meet design requirements. For example, our UHPC is typically required to have a compressive strength of no less than 120MPa and a flexural strength of no less than 15MPa.

Durability and related physical properties safeguard long-term quality. Tests such as water absorption, freeze-thaw resistance (e.g., F300), and chloride ion diffusion coefficient are conducted regularly on specimens to verify UHPC's long-term performance in harsh environments. In addition, for components with embedded inserts, pull-out tests are required to check whether the anchorage strength of the inserts meets standards. This complete testing system is the solid backbone behind the high quality of Qinglong's UHPC components.