How to Prevent Cracking of GRC Components During Setting? Anti-Cracking Technology and Qinglong Group's Whole-Process Control Solution

Preventing cracking of GRC components during the setting process is key to ensuring long-term durability, which requires establishing a four-dimensional prevention and control system of "material optimization, process control, curing management, and structural design". Based on 28 years of crack-resistance research and practice, Qinglong Group has summarized the core control indicators: during the plastic shrinkage stage (before final setting), surface evaporation cracks are prevented through wind speed control (<5 m/s) and mist curing (humidity ≥90%); during the hardening shrinkage stage (days 1-7), polypropylene fibers (0.9 kg/m³) are added and the drying shrinkage rate is controlled (≤0.06%); during the long-term service stage, temperature stresses are addressed through properly spaced joints (spacing ≤6 m) and reinforcing ribs. In the Nanning Wuxiang China Resources MixC One project, by adding internal curing agents (saturated lightweight aggregate) and early film-covered curing, we achieved zero cracking during the setting period for 20,000 square meters of GRC decorative moldings. Crack resistance is the combination of materials science and construction artistry.

Precise Raw Material Control Is the Foundation

Low-heat cement (such as sulphoaluminate cement) is used to reduce hydration heat; fly ash (20-30%) is added to optimize particle grading; polypropylene fibers (12 mm in length) suppress plastic shrinkage cracks. Through extensive testing, Qinglong Group has determined the optimal fiber content, shifting crack control from "passive repair" to "active suppression".

Fine-Tuning Process Parameters Is the Key

Mixing speed is controlled (60-80 rpm) to prevent the introduction of large air bubbles; the drop height during pouring is kept ≤0.5 m, with chutes used to reduce impact; vacuum dewatering time is ≥3 minutes (vacuum degree -0.07 MPa). In the production of ultra-thin panels (12 mm) for the Shenzhen Yirui project, we adopted a layered pouring process to effectively avoid settlement cracks.

Scientific Execution of Curing Procedures Is the Guarantee

Plastic film is applied immediately after final setting to keep the surface moist for 24 hours; humidity is maintained at ≥95% for 7 days to prevent early drying shrinkage. During steam curing, the temperature rise and fall rate is controlled (≤15°C/h) to avoid thermal stress cracks. Qinglong Group's intelligent curing kiln enables fully automated monitoring throughout the entire process.

Preemptive Structural Design Is Fundamental

Component shapes are optimized to avoid abrupt cross-section changes; deformation joints are properly arranged (spacing 4-6 m); reinforcing fiber mesh is placed in stress concentration areas. Our detailed design team uses finite element analysis to predict crack-prone areas in advance.

Crack control is the lifeline of GRC quality. Through refined whole-process management and control, Qinglong Group ensures that every component can withstand the test of time.