Recently, the Hainan Regional Team of the Structural Building Materials Business Division of China Resources Building Materials Technology Holdings Limited (CR Bldg Materials Tech) successfully completed the entire fair-faced concrete supply for the Meiyijia (Hainan) Industrial Park project, delivering a total of approximately 5,000 m³ of C40 fair-faced concrete. Located in Ding’an County, Hainan Province, the project is one of the county’s key projects launched in the fourth quarter of 2025. The project features fair-faced concrete columns with a cross-section measuring 1.2 m × 1.2 m and a height of 11.5 m. Each column requires approximately 16.6 m³ of concrete, making it a typical mass concrete structural element.

Faced with Hainan’s hot and humid climate, as well as the dual technical challenges posed by ultra-high columns and mass concrete construction, CR Bldg Materials Tech delivered the project to the highest standards of fair-faced concrete, achieving the goal of “the structure itself serving as the finished architectural surface” through customized mix design, refined construction management, and full-process technical services, contributing to the construction of key projects in the Hainan Free Trade Port.

Customized Mix Design Balances Strength and Crack Resistance

Fair-faced concrete demands exceptionally high standards for surface color uniformity and compactness, while mass concrete structures face additional challenges from concentrated hydration heat and an elevated risk of thermal cracking. Meanwhile, Hainan’s high-temperature environment further increases the risk of material performance fluctuations, placing higher requirements on the adaptability and stability of the concrete mix.

The technical team worked closely with the admixture supplier to conduct dedicated trial mixes, optimizing the cementitious material system and aggregate gradation while incorporating high-quality fly ash and ground granulated blast-furnace slag to reduce the peak hydration heat. This ensured both the required C40 strength and the volumetric stability of the concrete. In addition, aggregate storage areas were thoroughly cleaned, and admixtures were stored in dedicated tanks to eliminate cross-contamination of raw materials, ensuring consistent and reliable quality for every batch of concrete.

Plastic-coated Formwork and Water-based Release Agent

To achieve a uniform and refined fair-faced finish on the concrete columns, the project adopted customized plastic-coated formwork combined with a water-based form-release agent. This effectively minimized surface air bubbles, avoided the reflective appearance associated with conventional mirror-finish formwork, and presented the simple, natural aesthetic characteristic of fair-faced concrete architecture.

For the construction of the 11.5-meter-high columns, the technical team developed a systematic construction solution. Mortar sealing was applied at the bottom of the formwork to prevent grout leakage, while a 30-centimeter-thick layer of mortar with the same strength grade was placed as the base to prevent honeycombing at the column foot. Five high-frequency vibrators were used to continuously consolidate the concrete at the four corners and the center of each column, eliminating even the smallest air bubbles.

The formwork support system was strengthened with reduced spacing, and concrete was placed in 3-meter lifts with intermittent intervals to gradually release lateral pressure and effectively prevent formwork blowout. At the same time, for the mass concrete temperature rise, the team carefully controlled lift thickness and optimized placement intervals to ensure the orderly dissipation of hydration heat.

Internal Circulating Water and Full Film Covering Ensure High-quality Curing

All integrally cast columns were fully covered with protective film, while water pipes were installed inside the columns to provide circulating-water curing. This approach combined moisture retention and temperature control, effectively reducing the temperature difference between the interior and exterior of the concrete, preventing thermal cracking, and ensuring a durable, uniform surface color.

The successful completion of this project fully demonstrates CR Bldg Materials Tech’s comprehensive technical expertise in fair-faced concrete mix design, ultra-high column construction, and architectural surface quality control. Looking ahead, the company will continue to strengthen research and innovation, drive high-quality industry development through technology, and make greater contributions to the construction of the Hainan Free Trade Port.