1- HIGHWAY MATERIALS 2024

What was the California Bearing Ratio (CBR) test used for?

To evaluate the mechanical strength of subgrade and base courses.

What are the main types of road pavements mentioned?

Earth road, Graveled surface, Flexible pavement, Rigid pavement, Interlocking block pavement.

What does HMA stand for in road paving materials?

Hot Mix Asphalt.

According to the Malaysian road system, how many kilometers of federal roads are there?

20,039 km.

What are the four pavement layers listed?

Wearing course, Binder course, Road base, Subbase.

What influences the suitability of subgrade materials?

Soil type, compaction, moisture content, and CBR properties.

What does the Plasticity Index (PI) measure in terms of subgrade materials?

It indicates the plasticity characteristics of the soil.

What are the two types of bitumen mentioned?

Tar and Bitumen.

What percentage of the pavement should the wearing course binder's bitumen range between?

3.5% to 5.5%.

Which method is used to determine the proportion of fine dust in aggregates?

Sand Equivalent Test.

What was John Macadam's contribution to road engineering?

Developed a surface course with specific grading for stones.

What is the primary purpose of aggregate in road construction?

To carry traffic load and provide main interlocking structure.

What is the difference between Coarse and Fine aggregates?

Coarse aggregates are larger than 2.36mm, while Fine aggregates range from 2.36mm to 75 microns.

What type of road material is unsuitable for subgrade?

Silt, peat, logs, stumps, and toxic materials.

What is the significance of the 'flakiness index' in aggregates?

It measures the shape and surface texture, affecting interlocking and resistance to sliding.

What type of highway construction would benefit from Interlocking block pavement?

High volume, low speed roads.

How does the presence of moisture affect asphalt binder performance?

It can lead to stripping and reduce adhesion between aggregate and binder.

What is the key function of a baseline subgrade material in the pavement layers?

To provide consistent strength and stable support for the pavement structure.

How is the mechanical strength of subgrade layers assessed?

Through the California Bearing Ratio (CBR) test.

What is the main component of hot mix asphalt (HMA)?

Bitumen, which binds the aggregates.

Which test is done to measure the resistance of aggregates against wear?

Los Angeles Abrasion Value (LAAV) test.

What is the impact of temperature changes on asphalt performance?

It can affect viscosity and susceptibility to fatigue cracking.

What is a characteristic feature of rigid pavements?

They distribute loads through bending action over a large area.

What qualities are essential for bitumen to perform optimally in asphalt mixtures?

High stiffness, good workability, and resistance to temperature variations.

Why is it important to manage moisture content in subgrade materials?

Excess moisture can weaken the structural integrity and affect compaction.

What factors affect aggregate durability in pavements?

Resistance to disintegration under weathering and impacts from traffic loads.

What is the purpose of a surface dressing in road paving?

To provide a skid-resistant surface and improve riding quality.

What should be the minimum California Bearing Ratio for subbase materials according to JKR specifications?

30%.

What type of bitumen emulsion is typically compatible with siliceous aggregates?

Anionic emulsion.

What does the grading system for bitumen correlate with?

The temperature ranges expected for the pavement.