In lime technology for mortars and hydraulic binders, what is the property called by which certain limes can set and harden under water (not only in air)? Select the correct term used in civil engineering.

Introduction / Context:
Lime binders are broadly classified into fat (non-hydraulic) and hydraulic types. Hydraulic limes set even in submerged or damp conditions due to hydraulic compounds formed during burning. Recognizing this property is essential when selecting lime for wet foundations, retaining walls, or marine works.

Given Data / Assumptions:

• Hydraulic set occurs via hydration of reactive calcium silicates and aluminates.
• Non-hydraulic limes harden by carbonation only and require air access.
• Terminology distinguishes process steps: calcining, slaking, setting.

Concept / Approach:

Hydraulicity is the inherent capability of a lime to set under water. It arises from clayey impurities in the parent limestone that, upon burning, form hydraulic compounds. Such limes do not rely solely on carbonation with atmospheric CO2, unlike fat limes.

Step-by-Step Solution:

Verification / Alternative check:

Standards for natural hydraulic lime specify performance in water, confirming the definition.

Why Other Options Are Wrong:

Slaking: a preparatory reaction. Calcining: manufacturing step. Carbonation only: describes non-hydraulic lime behavior.

Common Pitfalls:

Assuming any lime sets underwater; only hydraulic limes and cements reliably do so.

Final Answer:

Hydraulicity