Question

The following observations are made while testing aggregate for its suitability in pavement

construction:

(i) Mass of oven-dry aggregate in air = 1000g

(ii) Mass of saturated surface-dry aggregate in air = 1025g

(iii) Mass of saturated surface-dry aggregate under water = 625 g

Based on the above observations, the correct statement is
1. bulk specific gravity of aggregate = 2.5 and water absorption = 2.5%
2. bulk specific gravity of aggregate = 2.5 and water absorption = 2.4%
3. apparent specific gravity of aggregate = 2.5 and water absorption = 2.5%
4. apparent specific gravity of aggregate = 2.5 and water absorption = 2.4%

Answer 1

Correct Answer - Option 1 : bulk specific gravity of aggregate = 2.5 and water absorption = 2.5%

Mass of oven dry aggregate, A = 1000 gm

Mass of saturated surface dry aggregate, B = 1025 gm

Mass of saturated surface dry aggregate under water, C = 625 gm

Bulk Specific gravity

\(\Rightarrow \frac{{Wt.\;of\;solids}}{{Wt.\;of\;equivalent\;vol.\;of\;water}}\)

\(\Rightarrow \frac{A}{{B - C}} = \frac{{1000}}{{1025 - 625}}\) = 2.5

Water absorption \(\Rightarrow \frac{{1025 - 1000}}{{1000}} \times 100\) = 2.5%