Refractory testing: the cold crushing strength (CCS) of a refractory brick is an intrinsic material property. Which factor listed below does CCS not depend on, assuming standard specimen preparation and testing conditions?

Introduction / Context:
Cold crushing strength (CCS) is a fundamental quality-control parameter for refractories. It measures a brick’s resistance to failure under compressive loading at room temperature and is widely used to judge suitability for furnace linings, regenerators, and other high-temperature structures. Understanding what CCS represents—and which variables it depends on—prevents misinterpretation of test results and poor material selection.

Given Data / Assumptions:

• Standardized test specimen with specified dimensions (e.g., core drilled or sawed prisms).
• Ambient-temperature test; no thermal gradients.
• Proper drying/conditioning before test per specification.
• Comparison among: shape, composition, firing (burning) temperature, and texture.

Concept / Approach:
CCS is a material property reflecting bonding, porosity, grain size distribution, and degree of vitrification or sintering. These are dictated by raw mix composition, additives, firing schedule, and resulting microstructure (texture). The external macroscopic shape of a brick is not an intrinsic material variable. In standardized CCS testing, samples are machined to a specified geometry to remove shape effects; hence CCS does not depend on the brick’s original shape.

Step-by-Step Solution:

Verification / Alternative check:
Materials testing standards require trimming/coring to specified sizes to normalize geometry. If two differently shaped bricks of identical composition and firing yield the same standardized specimens, CCS results coincide within test scatter, confirming independence from original shape.

Why Other Options Are Wrong:

• Composition: dictates phase assemblage and bonding; CCS is sensitive to it.
• Firing temperature: governs sintering/vitrification; higher proper firing generally increases CCS until over-firing causes bloating.
• Texture: grain size, packing, and bonding directly affect CCS.
• Moisture content: improper drying reduces CCS due to pore pressures and weak interfaces.

Common Pitfalls:
Comparing CCS of different shapes without standardizing specimens; ignoring moisture conditioning; extrapolating CCS to hot strength without considering refractoriness-under-load or creep.

Final Answer:
Shape