If aggregate size of 50 – 40 mm is to be tested for finding out the portion of elongated aggregates using length gauge, the slot length of the gauge should be

This question was previously asked in

ESE Civil 2014 Paper 1: Official Paper

Option 1 : 81 mm

CT 3: Building Materials

2894

10 Questions
20 Marks
12 Mins

__Concept:__

An aggregate is said to be flaky if its** least dimension** (thickness) is **less than** **0.6 times the mean sieve size.**

An aggregate is said to be **elongated** if its** greatest dimension** is **greater than 1.8 times the mean dimension.**

**Note:**

Flaky means have less thickness, elongated means having more length.

**Calculation:**

Slot length for elongated aggregate

= 1.8 × mean dimension

\(= 1.8 \times \left( {\frac{{50 + 40}}{2}} \right) = 81\;mm\)

For flakiness index, the slot size

\(= 0.6 \times \left( {\frac{{50 + 40}}{2}} \right) = 27\;mm\)