كيف تحسن الإضافات أداء GRC؟ وما الإضافات الممنوعة؟

Admixtures are the "regulators" of GRC performance. Proper use can improve workability by 30%, strength by 15%, and durability by 50%. However, improper use will lead to catastrophic consequences; chloride-containing and alkali-containing admixtures in particular must be strictly prohibited.

In the Shenzhen Yirui Biotechnology Building project, Qinglong achieved a performance breakthrough through scientifically formulated admixtures: polycarboxylate superplasticizer (water reduction rate 30%) lowered the water-binder ratio to 0.30; hydroxypropyl methylcellulose (viscosity 40000mPa·s) retained water and prevented cracking; redispersible latex powder (dosage 2%) increased bond strength by 40%; and an organosilicon defoamer controlled air content to ≤3%. This formulation enabled the GRC panels to reach a flexural strength of 25MPa with a softening coefficient of 0.85, while the water permeability coefficient dropped to 1×10⁻¹²m/s. Calcium chloride early-strength agents, nitrate antifreeze agents, strong alkali activators and the like are strictly prohibited, as these components will cause fiber corrosion and durability deterioration.

Functional Admixture Applications

Water reducers lower the water-binder ratio to improve density. Water-retaining agents reduce plastic shrinkage cracks. Toughening agents increase fracture energy to 1500J/㎡. Waterproofing agents reduce water absorption to ≤6%.

Workability Modifiers

Retarders control setting time within 1-2h. Accelerators bring final setting time to ≤40min. Air-entraining agents improve frost resistance (bubble spacing factor ≤200μm). Viscosity modifiers adapt to the spraying process.

Durability Enhancers

Corrosion inhibitors improve rebar protection. Shrinkage-reducing agents reduce drying shrinkage by 30%. Anti-carbonation agents extend the time to neutralization. Preservatives inhibit microbial attack.

Strictly Prohibited Blacklist

Chloride-containing salts (CaCl₂, NaCl). Strong alkali activators (water glass, NaOH). Ammonium salt expansion agents. Formaldehyde-based preservatives.

Admixture use requires systematic verification. The Qinglong GRC laboratory has a comprehensive admixture evaluation system.