Assertion–Reason (masonry): A. In masonry construction, bricks are commonly joined using cement mortar. R. Cement mortar adheres more effectively to brick surfaces than most traditional alternatives (e.g., lime or mud mortars). Which option correctly evaluates the statements?

Introduction / Context:
Brick masonry relies on mortar to bond units, transfer stresses, and seal joints. Modern practice typically favors cement mortar due to its strength and durability. This assertion–reason problem probes whether the stated reason fully explains the widespread use of cement mortar.

Given Data / Assumptions:

• A: Bricks are commonly joined using cement mortar in contemporary construction.
• R: Cement mortar shows stronger adhesion/bond than traditional lime or mud mortars.
• Other factors (durability, availability, strength gain) also influence mortar choice.

Concept / Approach:
Cement mortar does tend to provide higher bond strength and compressive capacity versus lime/mud mortars, especially under modern performance requirements. However, the “correct explanation” for adoption also includes durability in aggressive environments, early strength, standardization, and compatibility with reinforced elements—so adhesion alone does not fully explain usage.

Step-by-Step Solution:
Assess A: True for most modern works (cement mortar is standard).Assess R: Generally true—cement mortar bonds more strongly to well-prepared brick surfaces than weaker binders.Causation: While better adhesion is a benefit, it is not the sole or complete reason for the prevalence of cement mortar.Therefore, choose: both true, but R is not the correct explanation of A.

Verification / Alternative check:
Codes and handbooks specify cement or cement–lime mortars for structural and durable masonry; lime-only mortars are used for conservation where compatibility and flexibility are prioritized.

Why Other Options Are Wrong:

• (a) Overstates R as the full explanation.
• (c) R is not false; (d) A is not false; (e) both are not false.

Common Pitfalls:
Reducing mortar selection to adhesion only; ignoring durability and strength requirements.

Final Answer:
Both A and R are true but R is not the correct explanation of A