Question

The specific gravity of ferrocement is

• A. 2.4 -- 2.6
• B. 2.8 -- 3.0
• C. 2.0 -- 2.1
• D. 3.1 -- 3.3

Hint:

Specific gravity is a unitless ratio. For comparison: Aluminum is ~2.7, Steel is ~7.8, and Fiberglass (GRP) is ~1.5 -- 1.9. Ferrocement falls between concrete and aluminum.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Ferrocement is a construction material consisting of a thin shell of cement mortar reinforced with layers of continuous and relatively small diameter wire mesh. In fisheries, it is used for building small to medium-sized fishing boats, fish tanks, and silos because it is relatively cheap, durable, and easy to repair.
Detailed Explanation:
The specific gravity (density relative to water) of any composite material depends on the proportions of its constituents.
- Cement mortar (sand and cement) has a specific gravity of roughly 2.2 -- 2.3.
- Steel (the mesh reinforcement) has a specific gravity of approximately 7.8.

In ferrocement, the volume of steel reinforcement is much higher than in standard reinforced concrete, but it still makes up a small percentage of the total volume. The combination of high-density mortar and the dense mesh network results in a specific gravity typically ranging from 2.4 to 2.6. This makes it slightly heavier than standard concrete but much lighter than a solid steel hull of the same thickness. This density range ensures sufficient structural weight for stability in boats while remaining light enough for buoyancy.

Step 2: Final Answer:
The standard specific gravity for ferrocement construction is 2.4 -- 2.6.