Stone Testing – Purpose of Dorry’s Testing Machine In standard laboratory evaluation of building stones, the Dorry’s testing machine is specifically used to determine which property relevant to road and floor stones?

Introduction:
Different stone tests target different failure mechanisms. The Dorry’s testing machine is a classic apparatus used to rank stones for wear resistance—critical for road metal, flooring, and pavements subjected to traffic abrasion.

Given Data / Assumptions:

• Specimens are stone discs or cylinders prepared to standard sizes.
• Machine applies abrasive action under load using standardized materials.
• Loss in weight or thickness indicates wear.

Concept / Approach:

Hardness in this context reflects resistance to abrasion. Dorry’s test simulates grinding action, producing a quantifiable wear index. Materials with better hardness show less loss and are favored for surfacing where polish and durability matter.

Step-by-Step Solution:

Verification / Alternative check:

Materials testing manuals group Dorry’s test with other abrasion tests (e.g., Los Angeles) for comparative assessment of wear resistance.

Why Other Options Are Wrong:

Crushing, impact, and water absorption are measured via distinct apparatuses and procedures; Dorry’s machine is not designed for these properties.

Common Pitfalls:

Confusing abrasion tests with impact or compression tests; mislabeling the wear index as strength.

Final Answer:

Hardness/abrasion resistance of stone surfaces