Approach

Mechanism of action

Advantages

Limitations

Autogenous healing

Continued hydration, carbonation and deposition of products in the crack

Low cost, natural mechanism

Limited crack width, dependence on moisture

Crystalline admixtures

Formation of insoluble crystalline products in capillaries and cracks

Constructability, applicability in monolithic concrete

Correct dosage and mix control are required

Microcapsules

Capsule rupture during crack opening and release of a healing agent

High local activity

Cost, possible influence on concrete structure

Biomineralization

CaCO3 precipitation as a result of microbiological processes

Promising for sustainable construction

Limited practical applicability and environmental requirements

Integrated system

Combination of admixtures, external protection, waterstops, drainage and monitoring

Higher reliability due to multiple barriers

Higher initial cost