Curing practice in building construction: For traditional lime mortar used in masonry or plastering, what is the typical (normal) period over which the work should be kept moist and protected to ensure proper setting and strength gain?

Introduction / Context:
Curing is the controlled maintenance of moisture and temperature after laying mortar or concrete. For lime mortar, adequate curing is vital because setting occurs primarily by carbonation and, in hydraulic limes, by hydration reactions. This question asks the normal period recommended to keep lime mortar moist so that it achieves intended bond, density, and durability.

Given Data / Assumptions:

• Lime mortars may be fat (non-hydraulic) or hydraulic, but routine site guidance specifies a minimum curing period.
• Ambient conditions are typical (not extremely hot/windy).
• Objective: select the commonly accepted “normal” curing period used in practice and standard MCQs.

Concept / Approach:
Lime mortars gain strength slower than neat cement mortars. A practical site norm is to keep the work damp for about one week to avoid early drying and shrinkage, allowing hydration (if hydraulic lime) and carbonation to proceed. Prolonged gentle moisture helps prevent cracking and dusting, especially in plaster.

Step-by-Step Solution:

Verification / Alternative check:
Construction handbooks and traditional specifications for lime mortars cite keeping the work damp for about a week under moderate climate; hotter or windy weather may need longer curing, while cool-humid conditions may suffice with similar or slightly shorter periods.

Why Other Options Are Wrong:

• One day / 3 days: too short; risk of shrinkage and poor strength.
• 10 days / 14 days: sometimes used in harsh climates, but the common “normal” site practice is 7 days for typical conditions.

Common Pitfalls:

• Confusing cement-mortar curing guidance with lime mortar; lime often benefits from equal or longer moist protection.
• Allowing surfaces to dry out quickly due to sun or wind exposure.

Final Answer:
7 days