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CONSTRUCTING THE ROAD BED
Transcript of CONSTRUCTING THE ROAD BED
Types of Base Course
1. Granular base course
is a road surface of untreated soil mixture described as gravel road
A gravel road is a type of unpaved road surfaced with gravel that has been brought to the site from a quarry or stream bed. They are common in less-developed nations, and also in the rural areas of developed nations such as Canada and the United States.
7.4 Grading and Maintaining of Untreated Surface
CONSTRUCTING THE ROAD BED
as presented by YLA Valencia
1. Sub-grade or Sub-base
2. Base Course
A pavement is only as strong as its foundation. Without an adequate base or foundation, a road simply cannot stand up to long-term traffic volumes, increasing vehicle weights and speeds, and the assault of the elements.
Sub-Grade or Sub Base
Fajardo : supporting structure on which the pavement surface and its special under-courses rest
Grading in civil engineering and construction is the work of ensuring a level base, or one with a specified slope, for a construction work such as a foundation, the base course for a road or a railway, or landscape and garden improvements, or surface drainage.
North American: the hard surface of a road or street.
British: a sidewalk.
Pinoy: the material laid over the base course consisting of asphalt concrete or portland cement concrete.
Fajardo: mixed with asphalt binders, consist of crushed stone or gravel.
- sub-layer material of an asphalt roadway
- is placed directly on top of the undisturbed soil
- to provide a foundation to support the top layer(s) of the pavement.
- a specific type of construction aggregate
- is placed by means of attentive spreading and compacting to a minimum of 95% relative compaction
CONSTRUCTION & MATERIAL REQUIREMENTS
Stable to support loads, without detrimental deformation
Shed large portion of water off the surface
Consist of < 1 in. dia. rocks/stones
Has clay portions in its composition.
must maintain its damp quality
cost effective & economical
use local materials
Treated Base Course
7.5 DPWH Standard Specifications on Aggregate Sub-Base Course
7.6 Clearing and Grubbing
7.8 Free Haul - Overhaul
7.9 CONSTRUCTION OF FILLS & EMBANKMENTS
7.10 SUB GRADE PREPARATION
7.11 COMPACTION & STABILIZATION
Properties to consider
1. soil must have adequate strength
2. relatively incompressible to avoid insignificant future settlement.
3. must be stable against volume change as water content vary.
4. must be durable and save against deterioration
5. must possess proper permeability.
Equipments for Compaction
Pnuematic or Rubber Tired Rollers
cap. 20 - 200 tons
Drum Type Roller
Light Drum Roller
describes the stages in land development in which vegetation is removed (known as clearing), and then a root rake or a similar device is use to remove the roots that remain in the dirt (referred to as grubbing).
1. cleared all protrusions, and surface obstructions.
beyond 90 cm, need not to remove.
not more than 15 cm above ground level
slope: should be cut flush with or below the surface line
burning should be supervised and monitored.
Methods of Measurements
1. Area Basis
2. Lump Sum Basis
3. Individual Unit Basis
is the process of loosening and removing earth or rock from its original position in a cut and transporting it to s fill or to waste deposit.
Roadway Excavation Classification
is paid for at a fixed price per yard or any other agreed unit regardless if it is common or rock excavation.
all hard, compacted, cemented material are removed by means of blasting or ripping of using machines.
are those that are not included in the list of quotations under rock excavation
removal of saturated or unsaturated mixture of soil and organic matter not suitable for foundation materials regardless of moisture content.
excavation and utilization of approved materials for the construction of embankment or other portions of work.
case 1: materials obtained from sources designated by the plan.
case 2: materials obtained from sources provided by the contractor
6. Backfill for Structures
aggregates + binders
Asphalt -> waterproofing
aggregate + sand + clay
Lime -> conveniet availability of material
1. removal and replacement method
2. Displacement methods
Vertical Sand Drain