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THE CLO3 was comprised of this major topic:
Module 3: Basic Service Requirements of Highway
This module covers the different traffic studies to conduct level of service analysis on highways.
Study Guide # 1
a. Introduction to Transportation Planning & Engineering
b. Transportation as a System
c. Urban Transportation Planning Concepts
Study Guide # 2
a. Philippine Transportation System
b. Transportation Safety & Economics
c. Transportation Policy Analysis and Planning/Technical Tour
Study Guide # 3: Introduction to Travel Demand Forecasting (Classic Four- Step Forecasting Model)
Study Guide # 4: Traffic Impact Assessment
Module 3: Basic Service Requirements of Highway
This module covers the different traffic studies to conduct level of service analysis on highways.
MAJOR CAUSE OF PAVEMENT FAILURES:
1. Rutting due to high variation in ambient temperature
2. Uncontrolled heavy axle load
3. Inadequate stability
4. Loss of binding action
5. Poor Design and Fabrication
DIFFERENT TYPES OF CRACKS:
a. Fatigue Cracking – is sometimes called alligator’s skin.
Possible Causes: Weakened Base or Subgrade, Not enough pavement thickness, Poor Drainage Remedy: Full Depth Patch
b. Block Cracking - is a series of large (typically one foot or more), rectangular cracks on an asphalt pavement’s surface.
Possible Causes: Shrinkage of asphalt due to temperature changes, placing of mix too dry, poor choice of asphalt binder
Remedy: Cracks < 0.5in or less can be sealed with bitumen to prevent water seepage. For wider cracks, layer be replaced with an overlay.
One concrete application of this third-course learning objective would be in terms of VOLUME STUDY. In particular, the Average Annual Daily Traffic (AADT). The terminology refers to the average of 24-hour counts collected every day of the year. In this particular work, we were tasked to determine the AADT on a rural primary road that has the volume distribution characteristics shown in the tables that the class discussed. At first, it was quite challenging because I don't know how to find the date, but in the end, I was able to find out which is which and be able to realize that it's just easy to find the data given that there are many formulas to be familiarized.
As for the detailed procedure to conduct level of service analysis, it is reflected in mine that the level of service at a roundabout is determined by calculating or measuring the control delay of each movement on the minor street. As a result of different conditions and driver's perception, level of service is different at the signalized and unsignalized intersections.
It is evident that I determined the basic service requirements of highway and detail the procedure to conduct level of service analysis.
c. Longitudinal Cracking – these occur parallel to the center of the asphalt or laydown direction.
Possible Causes: Shrinkage of asphalt, poorly constructed joint, reflective cracking, poor paver operation
Remedy: Cracks < 0.5in or less can be sealed with bitumen to prevent water seepage. For wider cracks, layer be replaced with an overlay.
d. Transverse Cracking – these occur parallel to the center of the asphalt or laydown direction.
Possible Causes: Shrinkage of asphalt, poorly constructed joint, reflective cracking, poor paver operation
Remedy: Cracks < 0.5in or less can be sealed with bitumen to prevent water seepage. For wider cracks, layer be replaced with an overlay.
e. Edge Cracking – these are longitudinal cracks that occur within a foot or two of each other on the outer edges of the asphalt.
Possible Causes: poor drainage on sides or pavement, lack of support on the edge of pavement, heavy vegetation along the side of the pavement, heavy traffic
Remedy: provide proper drainage, remove vegetation, small gaps be filled to make pavement impermeable
f. Reflection Cracking – happens because of asphalt pavement overlays that have been placed over a pavement structure that has been cracked or jointed.
Possible Causes: movement of old pavement
Remedy: Cracks < 0.5in or less can be sealed with bitumen to prevent water seepage. For wider cracks, layer be replaced with an overlay.
g. Slippage Cracks – crescent shaped cracks
Possible Causes: weak asphalt mix or poo bonds between pavement layers
Remedy: partial or full depth patch]
h. Depressions – also called bird baths; these are pavement areas that have lower elevations than surrounding area
Possible Causes: not enough or not uniform compaction
Remedy: removal of layer and an overlay Less severe depression can be rectified by thin surface patch
i. Rutting – longitudinal depressions in the wheel tracks or in the direction of the traffic flow.
Possible Causes: insufficient pavement thickness, lack of compaction, poor grade of bitumen, moisture infiltration
Remedy: underlying layers be removed and replace with good quality base sub-base material following asphalt layer as well.
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