Bituminous materials are used in highway construction primarily because of their
The group index of a soil sub-grade is 7. The sub-grade soil is rated as
Rapid curing cutback bitumen is produced by blending bitumen with
Rapid curing cutbacks are bitumens, fluxed or cutback with a petroleum distillate such as neptha, or gasoline which will rapidly evaporate after using in construction, leaving the bitumen binder.
Main drawback of CBR method is that it
Bitumen is derived from
Bitumens are derived from the destructive distillation of crude petroleum oils that give substantial amounts of heavy residue, typically from 10–50%, although crude oils giving a greater yield of residue are sometimes used.
Emulsions are used as binder mainly for
Seal coat is provided to
Aggregate used in road construction should have flakiness index not more than
Which one of the following premix methods is used for base course?
Bituminous carpet: surface course
Mastic asphalt: Surfacing for bridge deck slabs
Sheet Asphalt: wearing or surfacing course
Bitumen Bound Macadam: base course
What is the recommended grade of tar of grouting purpose?
Among the five grades of tar RT-1 has least viscosity and then viscosity increases with number,
RT-1 : Surface painting under cold weather
RT-2 : Surface painting under Indian conditions
RT-3 : Surface painting, renewal coats and premixing chips for top course and light carpets
RT-4 : Premixing tar macadam in base course
RT-5 : Has highest viscosity and used for grouting
Which one of the following is the correct statements:
Penetration to know bitumen grade is measured in:
Penetration test determines the hardness or softness of bitumen by measuring the depth in tenths of a millimetre to which a standard loaded needle wilt penetrate vertically in five seconds.
A typical Marshall test graph is shown in the given figure. The variable on the X-axis is % binder content by weight of total mix. The variable on the Y-axis for the given graph will be
Flow value is the deformation of specimen in 0.25 mm units up to the maximum load. It should be between 8 to 16.
Marshall stability value is the maximum load in kg before failure. Its minimum specified value is 340 kg. The stability first increases and then decreases with increase in bitumen content.
Unit weight also increases initially and then decreases.
Percentage of voids in total mix always decrease with increase in bitumen content.
The percentage of voids filled with bitumen increase with increase in bitumen content. But the graph is convex upward.
The plasticity index of the fraction passing 425 micron IS sieve in case of sub-base/base course should be
According to iS:2720 the Plasticity Index (PI) of binding material in WBM for base/subbase should be less than 6%.
Which one of the following diagrams illustrates the relationship between VMA and % bitumen content (BT) in -Marshall test?
Curve (a) → % air voids in total mix (Vv) Curve (b) → VMA ( % voids in mineral agg)
Curve (c) → unit weight (g/cc)
Curvo (d) → Flow value
Bitumen grade 80/100 indicates that under the standard test conditions, penetration value of bitumen would vary from
Penetration = (1/10) x reading on scale.
The best binder material to be used with stone aggregates for patch repair work, is patch pot holes on wet pavements during the rainy season when the traffic is also heavy, is
The most common type of failure that occurs on a flexible pavement is
In which of the following types of bituminous constructions is proportionating of materials determined from laboratory tests?
Which of the following tests measures the toughness of road aggregates?
The binder normally used in flexible pavement construction is