(21)
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 x V / 2 g.
(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 X area drained in acres X rainfall in
inches per hour X impermeability factor).
LOESS:
Deposit of very porous and cavitated wind-blown silt and clay.
(22)
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 prestressing 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.
(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 traveled 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.
MOMENT CARRYING ABILITY OF REINFORCED CONCRETE BEAM (Nominal Strength,
Mn):
