PIC Materials Testing & Asphalt Composition 4

Question 1

Stone Matrix Asphalt (SMA) differs from conventional dense-graded HMA primarily because SMA relies on:

Accepted Answer

A coarse aggregate stone-on-stone skeleton with a rich binder-filler mastic

Answer

SMA uses a gap-graded aggregate skeleton where coarse stones interlock to carry load, while voids are filled with a thick mastic of binder, filler, and fibers.

Question 2

What is the purpose of adding cellulose or mineral fibers to an SMA mix?

Accepted Answer

To prevent binder drain-down during transport and placement

Answer

Fibers in SMA absorb and retain the high binder content, preventing binder drain-down from the mix during hauling and before compaction.

Question 3

The ignition oven test (AASHTO T 308) is used to determine:

Accepted Answer

The asphalt binder content of a mix by burning off the binder

Answer

The ignition oven burns off the asphalt binder at high temperature, and the binder content is calculated from the weight loss of the mix sample.

Question 4

Which test evaluates an asphalt binder's resistance to rutting by measuring its complex shear modulus (G*) and phase angle (δ)?

Accepted Answer

Dynamic Shear Rheometer (DSR) test

Answer

The DSR measures G*/sin(δ), which is the rutting factor for unaged and RTFO-aged binders, with higher values indicating better rutting resistance.

Question 5

An inspector notices bleeding or flushing on an asphalt pavement surface. This defect most likely indicates:

Accepted Answer

Excess asphalt binder content causing binder to migrate to the surface

Answer

Bleeding occurs when excess binder migrates to the pavement surface under traffic, creating a shiny, slick appearance and reducing skid resistance.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Materials Testing & Asphalt Composition 4