CCIL Advanced Aggregate Characterization 5

Question 1

What is the significance of determining the clay content of aggregate using the methylene blue value (MBV) test?

Accepted Answer

It quantifies swelling clay minerals that can harm concrete durability and workability

Answer

The methylene blue value detects and quantifies swelling clay minerals like montmorillonite, which absorb water, swell, and reduce concrete durability and workability.

Question 2

In the context of hot mix asphalt aggregate specifications, what does the sand equivalent (SE) value measure?

Accepted Answer

The relative proportion of clay-like material to sand-sized particles in fine aggregate

Answer

The sand equivalent value (ASTM D2419) measures the relative proportion of fine clay-like or plastic fines to sand-sized particles in aggregate; higher values indicate cleaner aggregate.

Question 3

The 10% fines value (TFV) test is an alternative to the aggregate crushing value and is particularly useful for evaluating which type of aggregate?

Accepted Answer

Weak or porous aggregates prone to crushing at lower loads

Answer

The 10% fines value is specifically useful for weak aggregates that would yield very high ACV values, providing a more sensitive measure of strength at lower force levels.

Question 4

Which standardized test method is used to evaluate the susceptibility of aggregates to polishing under traffic, relevant to skid resistance of asphalt pavements?

Accepted Answer

ASTM D3319 Accelerated Polishing Test (British Pendulum)

Answer

The polished stone value (PSV) is determined using the British accelerated polishing machine followed by pendulum friction measurement, assessing resistance to traffic polishing.

Question 5

When evaluating recycled concrete aggregate (RCA) for structural concrete use, which property typically causes the most concern compared to virgin aggregate?

Accepted Answer

Higher absorption and lower specific gravity due to adhered mortar

Answer

RCA contains adhered cement mortar on particle surfaces, which increases absorption rates and lowers specific gravity compared to virgin aggregate, affecting mix design and durability.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Advanced Aggregate Characterization 5