For
‘J’
JOINT
SEALANT: A material used as a filler in concrete pavement joints to prevent
infiltration of water, soil and other fine particles.
JOIST: A
horizontal wooden, steel or precast concrete beam directly supporting a floor.
For
‘K’
KEYWAY: A
recess or groove in one lift or placement of concrete which is filled with concrete
of the next lift, giving shear strength to the joint, also called a key.
KINETIC
ENERGY: The energy of a moving body due to its mass and motion.
K.E. = W × V
/ 2 g.
For ‘L’
LAITANCE:
A layer of weak and non-durable cement concrete caused by bleeding as a result
of excessive vibration of concrete or over trowelling the mortar. It is weaker
than the rest of the concrete and should be cut away and covered with a pure
cement wash before laying more concrete on it.
LANDSLIP
OR LANDSLIDE: A sliding down of the soil on a slope because of an increase
of loading (Due to rain, new building, etc.), or a removal of support at the
foot due to cutting a railway or road or canal. Clays are particularly liable
to slips.
LEAN
CONCRETE BASE (LCB): A mixture of aggregate, cement and water used directly
under concrete pavement. The mixture has a lower modulus of rapture than the
concrete pavement, and a higher compressive strength than cement treated base.
LEDGE: A
horizontal projection or cut forming a shelf, cliff or rock wall.
LIME: Calcium
oxide (CaO).
LIQUID
LIMIT: The moisture content at the point between the liquid and the plastic
states of a clay.
LIQUIDATED
DAMAGES: The amount prescribed in the contract specifications, to be paid to
the State (Client) or to be deducted from any payments due or to become due the
Contractor, for each day's delay in completing the whole or any specified
portion of the work beyond the time allowed in the contract specifications.
LLOYD
DAVIES FORMULA: A method for calculating the run-off, from which the sizes
of sewers are calculated (Runoff water in cubic feet = 60.5 × area drained in
acres × rainfall in inches per hour × impermeability factor).
LOESS: Deposit
of very porous and cavitated wind-blown silt and clay.
LONG
COLUMN: A column which fails when overloaded, by buckling rather than by crushing.
In reinforced-concrete work this is assumed to happen when columns which are longer
than fifteen times their least dimension.
LONGITUDINAL
JOINT: A joint normally placed between traffic lanes in rigid pavements to control
longitudinal cracking.
LOSS OF
PRESTRESS: Losses of pre-stressing force after transfer arise mainly
through elastic shortening, shrinkage and creep of the concrete and creep of
the steel.
LOT: An
isolated quantity of material from a single source.
LUMINAIRE:
Complete lighting device for the highway.
For
‘M’
MARSHES: Low
lying wet land; swamp.
MATERIALS:
Any substance specified for use in the construction of the project and its appurtenances.
MAXIMUM
DRY DENSITY: The dry density obtained by a stated amount of compaction of a
soil at the optimum moisture content.
MEAN: An
arithmetic mean is an average in which all signs are taken as positive. In an algebraic
mean the signs of the quantities are considered and the mean may be either positive
or negative.
MEDIAN: That
portion of a divided highway separating the travelled ways for traffic in opposite
directions including inside shoulders.
MEMBRANE:
A thin film or skin, such as the skin of a soap bubble or a waterproof
skin.
MILLING: (1)
Removing a specified thickness of an existing pavement surface by grinding with
a milling machine. (2) Removing metal shavings from a surface by pushing it on
a moving table past a rotating toothed cutter.
MIST: Very
thin fog.
MOISTURE
CONTENT: The weight of water in a soil mass divided by the dry weight of
the solids and multiplied by 100.
MONOLITHIC
CONSTRUCTION: Constructed as one piece.
MORTAR: A
paste of cement, sand and water laid between bricks, blocks or stones.
MOVEMENT
JOINTS IN CONCRETE: Movement joints may be of five types, though it is possible
for one to combine the properties of one or more others. They reduce or prevent
cracking or buckling caused by temperature changes, shrinkage, creep,
subsidence and so on. Their location is important. Where possible, they should
be placed at points where cracking (or buckling) might start. The five types of
joints are: contraction, expansion, hinge or hinged joint, settlement and
sliding joints.
MULCH: Mixes
of wet straw and leaf peat.
MUNICIPALITY:
City, town or county.
For
‘N’
NEGATIVE
MOMENT: A condition of flexure (Bending) in which top fibers of a
horizontally placed member (Beam), or external fibers of a vertically placed
exterior member (Column), are subjected to tensile stresses.
NEOPRENE:
Synthetic rubber resistant to chemical compound, oil, light, etc.
NEUTRAL
SURFACE: In a beam bent downwards, the line or surface of zero stress,
below which all fibres are stressed in tension and above which they are
compressed. The neutral axis passes through the center of area of the section
(Centroid), if it is of homogeneous material.
For
‘O’
OFFSET: A
horizontal distance measured at right angles to a survey line to locate a point
off an edge line.
OPTIMUM
MOISTURE CONTENT: That moisture content of a soil at which a precise amount
of compaction produces the highest dry density. It is particularly important to
achieve this in soil stabilization before the road is completed. It is the
percentage of moisture at which the greatest density of a particular soil can
be obtained through compaction by a specified method.
OVERBURDEN:
Material of inferior quality which overlies material of desired quality and
which must be removed to obtain the desired material quality.
OVERLAY: One
or more courses of asphaltic concrete layers placed over existing worn or cracked
pavement.
For
‘P’
PARAPET: Any
protective railing, low wall or barrier at the edge of a bridge, roof, balcony
or the like.
PARKWAY: An
arterial highway for non-commercial traffic, with full or partial control of access,
usually located within a park or a ribbon of parklike development.
PASSIVE
PRESSURE: A pressure acting to counteract active pressure.
PAVEMENT:
The uppermost layer of material placed on the travelled way or shoulders.
This term is used interchangeably with surfacing.
PAVEMENT
STRUCTURE: The combination of sub-base, base course, and surface course placed
on a sub-grade to support the traffic load and distribute it to the sub-grade.
PEAT: Plant
material partly decomposed by action of water.
PEBBLES: Smaller
pieces of material (0.12 to 0.25 inch minimum size) which have broken away from
a bedrock..
PEDESTAL:
An upright compression member whose height does not exceed three times its average
least lateral dimension.
PERFORATED:
Pierced with holes.
PERMEABILITY:
That property of a material which permits a liquid to flow through its
pores or interstices.
pH VALUE:
An index of the acidity or alkalinity of a soil in terms of logarithm of
the reciprocal of hydrogen ion concentration (e.g., a pH indication of less
than 7.0 is acidic, whereas a reading of more than 7.0 is alkaline).
PIER: A
wide column or a wall of masonry, plain or reinforced concrete for carrying
heavy loads, such as a support for a bridge.
PIER CAP:
The top part of a bridge pier which uniformly distribute the concentrated
loads from the bridge over the pier .
PIER
SHAFT: The part of a pier structure which is supported by the pier
foundation.
PILE: A
long slender timber, concrete, or steel structural element, driven, jetted, or
otherwise embedded on end in the ground for the purpose of supporting a load or
compacting the soil.
PIT: Any
borrow pit, mine, quarry or surface excavation to obtain sand, clay, gravel,
etc.
PLANS: The
official project plans and Standard Plans, profiles, typical cross sections,
cross sections, working drawings and supplemental drawings, or reproductions
thereof, approved by the Engineer, which show the location, character,
dimensions and details of the work to be performed. All such documents are to
be considered as a part of the plans, whether or not reproduced in the special
provisions.
PLASTICITY:
The property of a soil which allows it to be deformed beyond the point of elastic
recovery without cracking or appreciable volume change.
PLASTICITY
INDEX (PI): Numerical difference between the liquid limit and the plastic
limit. This is an indication of the clay content on a soil or aggregate.
PLASTICIZER
OR WATER REDUCER: An admixture in mortar or concrete which can increase the
workability of a mix so much, that the water content can be low and the mortar or
concrete strength can thus be increased.
PLASTIC
LIMIT: The water content at the lower limit of the plastic state of a clay.
It is the minimum water content at which a soil can be rolled into a thread of
1/8 inch diameter without crumbling.
PLAT: A
small plot of land.
PORTLAND
CEMENT: A product obtained by pulverizing clinker consisting mainly of hydraulic
calcium silicates. Many different cements now use Portland cements or at least contain
some, the varieties include: Ordinary, Rapid-hardening, Ultra-high-early-strength,
Portland blast-furnace, Sulphate-resisting and Water-repellent cements, apart
from Colored cements.
POST-TENSIONING:
A method of pre-stressing concrete in which the cables are pulled or the
concrete is jacked up after it has been placed. This method is usual for
bridges and heavy structures which are placed in place.
POTABLE
WATER: Drinking water.
POTENTIAL
ENERGY: Energy due to position such as the elevation head of water or the elastic
energy of a spring or structure caused by its deformation.
PRECISION:
Of a measurement, the fineness with which it has been read, therefore, precision
is different from accuracy.
PRECAST
CONCRETE: Concrete beams, columns, lintels, piles, manholes, and parts of walls
and floors which are cast and partly matured on the site or in a factory before
being placed in their final position in a structure. Where many of the same
unit are required, pre-casting may be more economical than casting in place,
may give a better surface finish, reduce shrinkage of the concrete on the site
and make stronger concrete.
PRESSURE:
A force acting on a unit area.
PRESTRESSING:
A process of preparing concrete slabs and beams for extra strength by placing
the mix over tightly-drawn special steel wire rope or rods which are later
released to provide strong dense concrete. Pre-stressing accomplished by
applying forces to a structure to deform it in such a way that it will
withstand its working loads more effectively or with less total deflection.
When concrete beams are pre-stressed they deflect upwards slightly by an amount
about equal to their total downward deflection under design load. Downward deflection
is thus less than half that of a reinforced-concrete beam of the same shape.
The struts or braces to deep excavations in bad ground are pre-stressed to
prevent settlement of the surface and damage to neighboring structures.
PRESTRESSED
CONCRETE: Concrete in which cracking and tensile forces are eliminated or
greatly reduced by compressing it by stretched cables, wires or bars within it.
Two main methods for pre-stressing are: post-tensioning and pre-tensioning. Pre-stressed
concrete is economical for spans which are large or where the beam depth must
be reduced to a minimum.
PRIME
COAT: The initial application of a low viscosity bituminous material to an
absorbent surface, preparatory to any subsequent treatment, for the purpose of
hardening or toughening the surface and promoting adhesion between it and the
superimposed constructed layer.
PROFILE
GRADE: The trace of a vertical plane intersecting the top surface of the
proposed wearing surface, usually along the longitudinal centerline of the
roadbed. Profile grade means either elevation or gradient of such trace
according to the context.
PROFILOGRAPH:
An instrument for measuring smoothness of a surface (as of metal casting,
or a highway or road) by amplification of the minute variations from the plane
or arc of smoothness.
PROJECT: The
specific section of the highway together with all construction to be performed
thereon under the contract.
PROPOSAL:
The offer of a bidder, on the prescribed forms, to perform the work and to furnish
the labor, equipments and materials at the prices quoted.