Paving Bitumen – Specific Gravity Range (IS: 73–1992) According to IS: 73–1992 (paving bitumen), the specific gravity of paving grade bitumen lies between which of the following limits?

Introduction / Context:
Specific gravity (relative density) is a fundamental identification property for paving bitumen. It influences volumetric mix design, binder content calculations, and quality control in asphalt pavements. Standards such as IS: 73 specify practical ranges for paving grades to ensure consistency and performance.

Given Data / Assumptions:

• Material: paving grade bitumen (IS: 73–1992).
• Property: specific gravity at standard reference temperature.
• Objective: pick the correct typical range.

Concept / Approach:

Paving bitumen has a specific gravity slightly less than water, generally between about 0.97 and 1.02. Values far above 1.02 or below 0.97 would be atypical for standard paving grades and may indicate contamination or a different material class such as cutbacks/emulsions with significant volatile content.

Step-by-Step Solution:

Verification / Alternative check:

Laboratory data for various penetration/viscosity grades consistently fall near 1.00 ± 0.02, confirming the accepted range for paving bitumen at 27 °C.

Why Other Options Are Wrong:

• 1.10–1.06 and 1.06–1.02: Densities are too high for paving bitumen across the entire interval.
• 0.97–0.92: Too low; would suggest an unusually light, nonstandard binder.

Common Pitfalls:

Confusing specific gravity with bulk specific gravity of asphalt mixtures; not correcting for test temperature.

Final Answer:

1.02 and 0.97