What Are the Freeze-Thaw Resistance Indicators of GRC Materials? How to Test Them?

In the field of building materials, GRC (Glass Fiber Reinforced Concrete) is widely used in curtain walls, landscaping, decorative components, and other applications thanks to its advantages such as lightweight, high strength, and flexible shaping. Especially in cold regions or environments with significant seasonal temperature variations, the freeze-thaw resistance of GRC materials directly affects the durability and safety of building components. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group will analyze the core indicators and testing methods for the freeze-thaw resistance of GRC materials from a professional perspective, providing designers and owners with a scientific basis for material selection.

Analysis of Key Indicators for the Freeze-Thaw Resistance of GRC Materials

Freeze-thaw resistance is a core parameter measuring the ability of GRC materials to withstand freeze-thaw cycle damage in low-temperature environments. Its main evaluation indicators include frost resistance grade, mass loss rate, and strength loss rate. According to the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), the frost resistance grade of GRC materials must meet the requirements of the design service environment, typically classified into grades such as F15, F25, and F50, meaning that the material must withstand no fewer than 15, 25, and 50 cycles of freezing at -20℃ and thawing in water at 20℃, respectively. After the cyclic tests, the mass loss rate of the material should be no greater than 5%, and the compressive strength loss rate no greater than 25%, to ensure its structural stability.

In addition, saturated water absorption is also an important factor affecting freeze-thaw resistance. The lower the saturated water absorption of GRC materials, the denser the internal pore structure, the smaller the internal stress generated by water freezing and expanding during freeze-thaw cycles, and the stronger the freeze-thaw resistance. Through optimized mix design and production processes, Qinglong Group controls the saturated water absorption of its GRC materials below 8%, far below the industry average, providing reliable assurance for projects in cold regions. For more industry information: +WeChat qlfsbl123

Standardized Testing Procedure for the Freeze-Thaw Resistance of GRC

Scientific testing methods are key to verifying the freeze-thaw resistance of GRC materials. Based on national standards and industry specifications, Qinglong Group has established a comprehensive testing system, with main procedures including sample preparation, pretreatment, freeze-thaw cycle testing, and performance testing.

First, standard-size specimens (e.g., 100mm×100mm×100mm cubes) are randomly selected from production batches and undergo 28 days of standard curing to ensure that the material strength meets design requirements. The specimens are then soaked in distilled water at 20℃±2℃ for 48 hours to bring the material to a saturated water absorption state, at which point the initial mass and compressive strength are measured.

The freeze-thaw cycle test is conducted in specialized equipment: specimens are first frozen for 4 hours in a low-temperature chamber at -20℃±2℃, then thawed for 4 hours in water at 20℃±2℃, completing one cycle. After the specified number of cycles is reached, the specimens are removed, surface moisture is wiped off, and their mass loss rate and compressive strength loss rate are measured. If both indicators meet the standard requirements, the batch of GRC material is judged to have qualified freeze-thaw resistance. Qinglong Group's laboratory is equipped with fully automatic freeze-thaw cycle testing machines capable of testing multiple groups of samples simultaneously, ensuring the accuracy and timeliness of test data.

Core Technical Approaches to Improving GRC Freeze-Thaw Resistance

As a National High-Tech Enterprise and a participant in developing GRC industry standards, Qinglong Group improves the freeze-thaw resistance of GRC materials through three dimensions: material formulation optimization, production process upgrades, and quality control systems. In raw material selection, high-grade cement, alkali-resistant glass fiber, and premium mineral admixtures are used to reduce the number of capillary pores within the material; vacuum extrusion molding technology is employed to increase component density; during the curing stage, a combination of steam curing and natural curing is adopted to promote full hydration reactions and form a stable microstructure.

From the landscaping components of Harbin Ice and Snow World to curtain wall cladding panels in northern regions, Qinglong GRC materials have withstood real-world testing in hundreds of projects in cold regions, with their freeze-thaw resistance unanimously recognized by owners and designers. Moving forward, Qinglong Group will continue to deepen its expertise in the field of UHPC/GRC/GRG/GRP materials, guided by the mission of “Creating Beautiful Architecture”, providing global customers with green building material solutions that combine aesthetic value and durability. For more industry information: +WeChat qlfsbl123