transportation , railway, airport Flashcards
Tractive efforts by locomotivess
F = .0016W +.00008W.V +.0000006W.v^2 +W tan(θ) +.0004D°.W
transition curve locus in railway
y = x^3 /R.L
gradient provided in station yard
1/1000 min
1/400 max
martins formula for max speed
V= 4.35* sqrt(R-67) V= 4.58 sqrt(R) for high speed track
radius of railway curve defined in degree
1720 /D°
Length of cross over of track
S= (D-G)N - G* sqrt(1+N^2) L = 4.G.N +S
Defects in bitumin road
SURFACE DEFECTS
- fatty surface
- smooth surface
- streaking
- hungry surface
CRACKS
- hair line cracks
- alligator cracks (map cracking)
- longitudinal crack
- edge crack
- shrinkage crack
- reflection crack
DISINTEGRATION
- stripping
- ravelling
- pot hole
- edge breaking
- loss of aggrigades
DEFORMATIONS
- slippage
- rutting (longitudinal depression)
- shoving(movement within the layer = localized bulging )
- shallow depression (settlement of lower layers)
CBR test
california bearing ratio
soil sample 150mm =dia , h= 127mm
standard sample results
at 2.5mm penetration =1370 kg (70kg/sq.cm)
at 5mm penetration =2055 kg (105kg/sq.cm)
plate bearing test
applicable in rigid and flexible both pavements
std dia of plate = 75 cm
seating load = 320 kg
K= p/0.125
material test acceptence limits for base course and surface course
abression, crushing and impact
test – base course– surface course
L.abression – 50% – 30%
crushing val. – 45% – 30%
agg impact – 40% – 30%
soundness test key points
resistence of aggrigade to weathering action
<12% -sodium sulphtae
<18% - magnisium sulphate
material test acceptence limits flackiness/elongation angularity water absorption stripping value
flackiness/elongation <15%
angularity 0-11
water absorption <0.6%
stripping value < 25%
bitumin penetration test
100g needle applied for 5 sec
penetration = 1/10 th of grade
type and grade of bitumin - their use
30/40 - high volume traffic
60-70 - high traffic in normal summer
emulsion - premix, surface dressing in cold weather, wet condition, maintenance work
cut back -grades, uses
Cutback Bitumen is a type of bitumen which is obtained when viscosity of bitumen is reduced by volatile dilutent. It is generally used in colder regions.
Different types of cutback bitumen are:
(i) Rapid Curing Cutback (RC): In this, bitumen is fluxed with NAPTHA / GASOLINE.
(ii) Medium Curing Cutback (MC): In this, bitumen is fluxed with KEROSENE.
(iii) Slow Curing Cutback (SC): In this, bitumen is fluxed with high boiling point dilulent.
suffux 0,1,2,3,4 for viscosity
eg MC-0 (least viscous, medium curing)
RT1 lowest viscosity used for surface painting
RT4 may be used for premix macadam
RT5 for grouting
Marshall mix design test specification
stability = 340 kg
flow val = 8-16 units
penetration = 3-5 mm
VFB = 75-85 %
Group index formula
G.I = 0.2a +0.005ac +0.01bd
effect of addition of lime to soil
PL increases
type of road construction - binder content
bituminous macadam = 3-3.5%
dense bituminous mac = 4-4.5%
bitumin concrete = 4.5-6%
bitumin mastic = 8-15%