Cyclic Salt Damage to Coastal Buildings: Causes and Prevention

Cyclic salts (garam siklik) are crystalline deposits left behind when seawater evaporates on building surfaces. These salts—primarily chlorides, sulfates, and nitrates—drive a destructive cycle that degrades coastal structures.

The Damage Mechanism

1. Ingress: Seawater penetrates porous materials (concrete, brick, stone, mortar) via capillary action.
2. Crystallization: As water evaporates, salts crystallize within pores, generating immense pressure that exceeds the substrate's tensile strength.
3. Hydration Cycles: Salts repeatedly absorb atmospheric moisture (deliquesce) and recrystallize, progressively fracturing the matrix.
4. Corrosion: Chlorides reach steel reinforcement, destroying the passive layer and causing rust expansion that spalls concrete.

Visible Effects

• Spalling and scaling of concrete/masonry
• Efflorescence (white powdery deposits)
• Paint blistering and delamination
• Mortar joint deterioration
• Rebar corrosion and structural weakening

Prevention Strategies

• Use corrosion-resistant materials: stainless steel rebar, epoxy-coated rebar, FRP, sulfate-resistant cement.
• Apply protective coatings: silanes/siloxanes, epoxies, polyurethanes, cementitious waterproofing.
• Design for drainage and ventilation to reduce saturation time.
• Regular freshwater washing to remove surface salts.
• Cathodic protection for critical infrastructure.

Proactive design and maintenance are far cheaper than structural repair in aggressive marine environments.