In reinforced cement concrete (R.C.C.) construction, which grade/type of steel is most commonly used for reinforcement in general building practice?

Introduction / Context:
R.C.C. (reinforced cement concrete) combines concrete in compression with steel in tension. Examinations often ask which steel is generally used in everyday building work, focusing on practicality, economy, and code traditions rather than specialty applications.

Given Data / Assumptions:

• Question targets “generally used” reinforcement for common R.C.C. work.
• Special steels like stainless or very high-carbon types are available but expensive or unsuitable for routine use.
• Answer is framed for typical building structures under standard codes and budgets.

Concept / Approach:
Mild steel (including deformed mild-steel-based bars in older practice) has long been the staple reinforcement owing to its ductility, weldability, and cost-effectiveness. Although modern practice frequently uses high-yield strength deformed (HYSD) bars (often low-alloy, not the “high-carbon” option shown), traditional objective-type questions usually mark “mild steel” as the general-purpose answer for R.C.C. reinforcement in buildings.

Step-by-Step Solution:
List options and identify the one most associated with everyday, economical R.C.C.: mild steel.Exclude specialty or unsuitable steels for routine work (stainless/high-carbon).Recognize that “high-tensile alloy steel” is used in prestressing, not ordinary R.C.C. bars.Select: mild steel.

Verification / Alternative check:
Textbook summaries of traditional R.C.C. practice emphasize mild steel (and later HYSD) as the common reinforcement choice for slabs, beams, and columns in buildings, due to cost and ductility advantages.

Why Other Options Are Wrong:

• Stainless steel: corrosion-resistant but too expensive for general use.
• High-carbon steel: too brittle; poor ductility for R.C.C. detailing.
• High-tensile alloy steel: typical of prestressed concrete tendons, not ordinary R.C.C. reinforcement.

Common Pitfalls:
Confusing prestressing steel with reinforcement for conventional R.C.C.; selecting an exotic material based on corrosion resistance without considering cost/practice.

Final Answer:
Mild steel