Road Surfaces Flashcards
Pavement Definition
Structure Consisting of super imposed layers of processed materials above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade.
Pavement Requirements (6)
Sufficient Thickness
Adequate Coefficient of Friction
Smoothness
Dust proof Surface
Impervious Surface
Long life, low maintenance
Pavement Types
flexible Pavements
Rigid Pavements
Rigid Pavements
reenforced Concrete slabs
Subject to cracks and temp
Have contraction joints
Slow Curing (14 Days)
High Friction
Flexible Pavements
Elastic Deformation
Constructed in Layers
Easy repair
No stress from temp
Lower Friction
quick curing / turn around
BINDER TYPES
SEAL COAT - Thin surface treatment, waterproof and provides friction
Tack Coat - Acts as a binder for binder course and surface course layers. Thin, diluted asphalt
PRIME COAT - Low viscouse bitchumen. Binding between base and binder course
Flexible Pavement Construction Layers
Surface Course - 25-50
Binder Course - 50-100
Base Course - 100-300
Subbase Course - 100 - 300
Compacted Subgrade - 150-300
Surface Course
Layer 1
Direct contact with traffic
Dense graded asphalt
meets expectaction of a surface
Binder Course
Layer 2
Bulk of Asphalt sstructure
Load distribution
Base Course
Layer 3
Additional load distribution
Crushed rock
First level of no asphalt
Sub-base Course
Layer 4
Structural Support
Optional
Sub-Grade
Layer 5
Natural Soil prepared for road
Rigid Pavement
COncrete Slab 150-300 resting on sub-base
reenforced by steel
Large distribution of loads
Contraction Joints
Control movements
Controls cracking
Allows for expansion and contraction due to heat.
