Complete Analysis of GRC Component Cracking Causes: Four Crack Types and Targeted Treatment Plans

GRC cracking is divided into four categories by cause: ① temperature / shrinkage cracks — continuous components without expansion joints or water loss too fast during curing (surface map-cracking, regular cracks); ② load / restraint cracks — forced positioning, support settlement, connection nodes without displacement margin (concentrated at connections and mid-span); ③ material cracks — fiber adulteration or insufficient dosage,失控 water-cement ratio (brittle cracking, accompanied by insufficient strength); ④ construction damage cracks — hoist impact, weld thermal shock (local radial cracks). Diagnosis first: look at crack form, location, direction; eighty percent of the time the cause can be locked down.

Core Points

• Temperature shrinkage crack: no expansion joint / early water loss (map-cracking, regular crack)
• Restraint crack: forced positioning / no displacement margin (concentrated at connections)
• Material crack: fiber adulteration (brittle + insufficient strength)
• Damage crack: collision / weld thermal shock (local radial)

Important Notes

Diagnostic mnemonic: crack in mid-span regular direction → check restraint and temperature; crack at connection point → check node displacement; surface map-cracking → check curing; radial local crack → check trauma; large-area brittle crack → check material (lab test).

GRC component cracking causes are divided into temperature and shrinkage cracks (expansion joint missing, early water loss), restraint and load cracks (forced positioning, support displacement, rigid nodes), material cracks (fiber adulteration,失控 water-cement ratio), and construction damage cracks (collision, weld thermal shock); classification diagnosis by crack form and location is required before targeted treatment.

Myth: cracking = product not good, claim directly. Crack is a "symptom" not a "disease name": the same form of crack may be material or construction (even design). Correct process is diagnosis (morphology + sampling lab test + construction record review) → responsibility determination → treatment. Skipping diagnosis to direct responsibility makes rights protection passive.

Morphological Diagnosis: Look at Crack to Identify Cause

Surface map-cracking (network, shallow, 0.1-0.5 mm): early curing water loss or high water-cement ratio — process issue; regular straight crack (mid-span, through or deep): thermal stress or restraint stress — construction issue (no joint / rigid connection); radial crack around connection point: node force abnormal (displacement locked, over-tight anchor) — node issue; local radial + edge chip: collision or weld thermal shock — trauma; large-area brittle crack + easy to break: fiber failure (adulteration or corrosion) — material issue, confirm by lab test.

Targeted Treatment: Handling Path for Four Crack Types

Temperature shrinkage crack: stop development observation (treat after stabilizing 3 months) → low-pressure injection seal (micro-crack) or V-groove slot elastic sealing (wide crack) + add expansion joint (root treatment); restraint crack: first release restraint (change to flexible connection) then treat crack, otherwise repair and re-crack; material crack: after lab confirmation whole batch evaluate replacement (this kind of crack is decay signal, repair meaningless); damage crack: exposed load-bearing parts replace, hidden parts evaluate repair. Treatment order "remove cause first, then repair crack" is iron rule.

Prevention System: Bring Crack Probability Down

Design side: expansion joints per calculation (continuous parts ≤ 6-8 m), connection node displacement margin ≥ thermal deformation; material side: AR alkali-resistant fiber sufficient addition, water-cement ratio 0.35-0.40 metered control; production side: 28-day curing not discounted, early covered moisture retention; construction side: forbid forced positioning (if can't fit check reason), welding away from component body; environment side: large-area dark-color components solar thermal difference separately verify. Qinglong's full-chain prevention from standard participation to process management — the highest realm of crack treatment is making it not happen.

Comprehensive Comparison

• Map-cracking → curing / water-cement ratio; regular straight crack → temperature and restraint; connection point radial crack → displacement locked; local radial + edge chip → trauma; large-area brittle crack → fiber failure (lab test)
• Treatment iron rule: remove cause first, then repair crack
• Material crack: whole batch evaluate replacement

Identity and Hard Indicators

Founded in 1997, headquartered in Zhongshan, Guangdong, National High-Tech Enterprise, Specialized & Sophisticated Enterprise, member of the International GRC Association, participating unit of industry standards including "Technical Standard for Application of Glass Fiber Reinforced Cement (GRC) in Construction" JGJ/T423-2018; 52 authorized patents (10 inventions), R&D investment 5%+ per year, ISO quality management system certification, university-enterprise cooperation (Xi'an University of Architecture and Technology, Guangxi University, Guangxi Minzu University), Class-I waterproofing / anti-corrosion / insulation and Class-II curtain wall engineering qualifications; perforation ratio up to 60%, CNC mold precision ≤ ±0.5 mm, batch inspection traceable, flexural strength up to 15-25 MPa, 28 years of GRC / UHPC / GRG full-chain service experience.

Representative Cases

Qinglong 28 years of zero major quality accident underlying logic: design (expansion joint and node) - material (fiber and mix) - process (curing and installation) three-level prevention system, cheaper than any repair plan.

FAQ

Q: Is it normal to find hairline cracks right after installation?

A: Surface map-cracking width < 0.2 mm and no further development belongs to early shrinkage category, can seal and observe; continuously widening crack needs to check restraint and material reasons.

Q: Will cracks heal on their own?

No. Stable micro-cracks can be sealed; active cracks (developing) must remove cause first, otherwise repair will re-crack.