chapter 6 Flashcards by moa diary

These are engineered surfaces constructed to support the movement of vehicles and pedestrians. They are designed to distribute loads, provide a
smooth and durable surface, and ensure
safe and efficient transportation.

Pavements

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Key Functions of Pavements

Load Distribution
Weather Resistance
Durability
User Comfort & Safety

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MAIN ROAD COMPONENTS

Sub-grade
Aggregate Sub-Base Course
Aggregate Base Course
Surface Course
Drainage Structures
Slope Protection/Retaining Structures
Miscellaneous Works

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This is the natural soil or prepared ground surface beneath a road or pavement structure. It acts as the foundation for the entire roadway system.

subgrade

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2 METHODS TO IMPROVE THE SUBGRADE

Removal and Placement
Additional base layers

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refers to the structural sub-layer material of a roadway placed directly on top of the sub-grade

Aggregate Subbase Course

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In flexible pavement, this is the load-carrying portion and provides the structural capacity to bituminous concrete slabs by carrying the load and distribute it to the soil under the layers of asphalt concrete.

aggregate base course

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Surface Courses

Bituminous Prime Coat
Bituminous Tack Coat
Bituminous Concrete Surface Course, Hot Laid

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This is an application of thin bituminous
material to a porous base before putting on a surface course. It serves to stabilize the base material and to plug the capillary voids in the pavement. It is applied only to dry or slightly moist surfaces.

Prime Coat

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This is an application of liquid asphalt on an existing pavement.

Tack Coat

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This is intended only to provide a “tacky” surface between the surfaces. It consists of a light application of asphalt material to an existing road surface before placing a Hot Mix Asphalt (HMA) course.

Tack coat

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This is constructed by casting in place, on a prepared foundation, a concrete slab with
the top finished to provide a smooth and durable wearing surface for traffic.

Portland Cement Concrete Pavement (PCCP)

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It is one of the two basic types of
pavement which is also called “rigid pavement”.

Portland Cement Concrete Pavement (PCCP)

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MATERIAL REQUIREMENTS FOR PCCP

Portland Cement
Fine Aggregate
Coarse Aggregate
Water

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This is used to grade concrete in such manner as to prevent segregation.

Screeder

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This is used after the concrete has been consolidated.

Longitudinal Float

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This is necessary for the hydration to take place.

Curing

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Used to protect the newly poured concrete pavement.

Pavement protection against rain

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Used to protect the newly poured concrete pavement at its early age.

Pavement protection against traffic

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These are gaps or separations intentionally placed in a road pavement (usually in concrete pavements) to control cracking, allow for expansion or contraction caused
by temperature changes, moisture variation, or load stresses without damaging the pavement, and help with construction sequencing.

Road joints

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TYPES OF ROAD JOINTS

Expansion Joints
Contraction (Control) Joints
Longitudinal Joints
Transverse Joints
Construction Joints

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Allow the pavement to expand during hot
weather. A gap filled with compressible material (like rubber or bitumen) is provided.

Expansion Joints

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Control the location of shrinkage cracks when concrete cools or dries. Usually formed by cutting or forming grooves
at regular intervals.

Contraction (Control) Joints

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Run parallel to the direction of traffic. Divide lanes and help control cracking
between lanes.

Longitudinal Joints

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Run across the pavement, perpendicular to the direction of travel. Control cracks across the width of the road.

Transverse Joints

Formed where one day’s work ends and the next begins. Provide a bond between old and new concrete.

Construction Joint

TYPES OF RE-BARS USED IN PCCP

Dowel Bars Tie Bars

are “plain round steel bars” generally coated with a thin file of bitumen to protect them against corrosion and to facilitate sliding in concrete

Dowel Bars

These are deformed bars used in construction joints and longitudinal joints together with keys to tie two slabs together. Its installation must be midway in the slab.

Tie Bars

TYPES OF PAVEMENTS

1. Portland Cement Concrete Pavement (PCCP) – Rigid Pavement 2. Asphalt Concrete Pavement (ACP) – Flexible Pavement

This is a pavement structure that uses Portland cement concrete (PCC) as the main material for the surface course.

Rigid pavement

It is called rigid because the concrete slab itself can carry and spread the traffic load due to its _________________.

high flexural (bending) strength

LAYERS OF RIGID PAVEMENT:

1. Concrete Slab 2. Subbase 3. Subgrade

Made of reinforced on plain concrete

Concrete Slab

Portion of the pavement structure between the subgrade and the slab

Subbase

Bottom portion of the pavement structure

Subgrade

FLOWCHART FOR PREPARATORY WORK FOR CONCRETE PAVING

Material Test > Design Mix and Trial Mix > Trial Paving > Approval of Design Mix and Methodology > Start Paving

The Engineer shall require that measures be taken into consideration to prevent the temperature of concrete mix from exceeding _______.

32°C

The primary purpose of this is to provide adequate means of channeling run-off and surface water to prevent damage by water which, either directly or indirectly, is the cause of many roadway failures.

drainage system

TYPES OF DRAINAGE STRUCTURES

Side Ditches (Open Drains) Culvert Canals or Lined Ditches Subsurface Drains (or Underdrains) Storm Drains and Catch Basins

open channels along the road that collect runoff

Side Ditches (Open Drains)

a tunnel-like structure that allows water to pass under the road (pipe or box type)

Culverts

These are larger, open drainage channels— sometimes made of concrete—that carry water from the side ditches or storm drains toward rivers or natural waterways.

Canals or Lined Ditches

These are pipes placed below the road surface. They remove water trapped underneath the pavement layers, preventing the road from weakening.

Subsurface Drains (or Underdrains)

This collects runoff and traps debris, while a storm drain is a larger underground pipe that carries water away.

Storm Drains and Catch Basins

These are engineering systems designed to prevent soil erosion, landslides, or slope failures on embankments, hillsides, and road cuts.

Slope protection structures

They stabilize the ground and protect roads, bridges, and other infrastructures built near or on sloping terrain.

Slope protection structures

TYPES OF SLOPE PROTECTION STRUCTURES

Riprap (Dry or Grouted) Gabion Walls Concrete Slope Protection Retaining Walls Sheet Piles Geotextile Mats/Erosion Control Mats Vegetative Cover (Bioengineering)

Large rock layers to prevent erosion.

Riprap (Dry or Grouted)

wire mesh boxes filled with rocks

Gabion Walls

reinforced concrete slabs or walls

Concrete Slope Protection

concrete or masonry structures holding back soil

Retaining Walls

steel or concrete sheets driven into the ground

Sheet Piles

synthetic mats that prevent soil washout

Geotextile Mats/Erosion Control Mats

using plants and grasses to hold the soil

Vegetative Cover

This is an ideal equipment to use in the excavation of foundation for grouted riprap.

backhoe

These are opening provided to permit draining of water in filter layer or soil layer from behind the structure.

Weep holes

These are structures that support soils at slopes steeper in their angle of repose and because of their resistance to earth pressure derived from their own weight they are also known as “gravity walls”.

Retaining Wall

Stones should have a thickness of not less than ___________.

150 mm

Face stones should be pitched to the line along the beds and joints. The maximum projection of rock faces beyond the pitch lines should not be more than _________.

50 mm

MISCELLANEOUS STRUCTURES

Curb and Gutter Sidewalk Road Sign Pavement Markings

is the raised rim which forms the edge of the sidewalk

Curb

is the lower horizontal paved portion of the sidewalk

Gutter

TYPES OF CURBS AND GUTTERS

Rounded Curbs Angled Type Square (90°-edge) Type

are used in many residential areas and are most often used at driveways

Rounded Curbs

is most often used on major suburban thoroughfares

Angled Type

is used in towns and cities as it is a straight step down and less to be tripped over by pedestrians

Square (90°-edge) Type

is typically 100 mm to 150 mm thick slab on grade and it is an important feature of the urban environment

Sidewalk

TWO CATEGORIES OF SIDEWALKS

1. Asphalt Sidewalk 2. Concrete Sidewalk

Majority of sidewalks are the rigid concrete slab-on-grade type as concrete sidewalks are more economical to construct with widths from ______________.

1.2 to 2.0 m

These are the oldest traffic control device used to guide the safe and orderly movement of traffic.

Road Signs

TYPES OF ROAD SIGNS

A. Regulatory Sign B. Warning Sign C. Informatory Sign

This is used to regulate the movement of traffic.

Regulatory sign

This is always triangular in shape with one vertical angle and dark blue symbol two borders one white and red with reflectorized white background. This is used to warn traffic of potentially hazardous conditions on or adjacent to the road.

Warning Sign

It informs and advices road users about the direction and distance of destination on the route they are following or along other roads which intersect their route. It supplies information to identify points of geographical or historical interest and give directions to rest, camping or parking areas.

Informatory Sign

This is an essential component of roadway for the guidance and control of vehicles and pedestrians. They take the form of lines, symbols, messages or numerals and may be set into the surface applied upon or attached to the pavement.

Pavement Markings

TYPES OF PAVEMENT MARKINGS

1. Longitudinal Lines 2. Edge Line 3. Lane Lines 4. Transverse Lines

are those laid in the direction of travel. These include: Center Line; Lane Line; Double Yellow Line; ‘No-Passing” Zone Markings; Pavement Edge Line; Continuity Lines; and Transition Line.

Longitudinal Lines

It is used to delineate the edge of the traveled way to distinguish it from the shoulder area. It is a solid white line between 100mm and 200mm wide.

Edge Line

these are 100 mm wide white stripes between contiguous lanes of pavement carrying traffic in the same direction

Lane Lines

are laid across the direction of travel or markings across the carriageway

Transverse Lines

Transverse lines should be solid stripes __________________ wide, of the color specified and placed at an angle to the direction of travel.

600 mm (24 inches)

Transverse lines may be classified into the following types:

Stop Line Yield (Give Way) Lines Pedestrian Crossing Markings

chapter 6 Flashcards

(83 cards)