Concrete grade designation — permissible compressive strength for M 200 In the traditional kg/cm² notation, what is the permissible (characteristic) compressive strength associated with concrete grade M 200?

Introduction / Context:
Concrete grades are commonly designated by their characteristic compressive strength at 28 days. While modern codes typically use MPa (e.g., M20 = 20 MPa), older or alternate conventions may be expressed in kg/cm². Recognizing the equivalence helps prevent confusion across specifications and textbooks.

Given Data / Assumptions:

• M 200 grade uses kg/cm² notation.
• Characteristic strength is defined at 28 days on standard specimens.

Concept / Approach:
The grade number directly matches the characteristic compressive strength in the same unit system. Thus, M 200 indicates a characteristic strength of about 200 kg/cm². In MPa terms this corresponds roughly to M20 (since 1 MPa ≈ 10.2 kg/cm²), with minor rounding differences depending on the reference used.

Step-by-Step Solution:

Verification / Alternative check:
Conventional grade tables show: M 100, M 150, M 200, M 250, etc., each corresponding to the same numeric strength in kg/cm².

Why Other Options Are Wrong:

• 100, 150, 250, 300 kg/cm² correspond to other grades (M 100, M 150, M 250, M 300) and not M 200.

Common Pitfalls:
Confusing kg/cm² with MPa; mixing up grade designations when switching unit systems.

Final Answer:
200 kg/cm²