Friday, October 21, 2022

Technical Questions for civil engineer

1.What is the minimum CBR of subgrade   soil ?

As per IRC 58-2015 Clause 5.7.3.6 , a minimum CBR of 8 % is recommended for 500 mm of selected soil used as subgrade.

2. What is code reference from which you are performing CBR test with 3 energy level as per MORTH 5 revision ?

AASHTO Designation: T 193-99 -2003

3. What is the limit of Air Voids , flow & VFB in Dense Bituminous Macadam mix design ?

The limit of Air voids , flow & VFB is 3 -5% , 2- 4 mm & 65-75% simultaneously.

4.What should be the minimum required density of Subgrade soil as per MORT&H 5th revision ?

17.5 KN/m³ or 1.78 gm /cc

5.What is the softening point of VG 30 & VG40 grade bitumen ?

The softening point of VG30/VG 40 grade bitumen is 47 ºC / 50ºC

6.What will be the maximum allowable size of granular material for subgrade soil as per MORT&H specification ?

Allowable size of granular material in subgrade is 50 mm

7.What is the maximum Liquid Limit & Plasticity Index allowed in earth work in embankment/subgrade soil ?

Clay should have Liquid Limit less than 50 % & PI should always be less than 25 %.

8.What is the frequency of taking core for BM/DBM/BC for checking of compaction & thickness of laid layer as per MORT&H 5th revision ?

One core at 700 m²

9.What is the maximum Aggregate Impact Value of aggregate allowed for Bituminous concrete(BC) work in flexible pavement ?

AIV should not be more than 24%.

10.What is the minimum cement content & maximum W/C ratio for M 25 RCC concrete for moderate condition as per MORT&H 5TH Revision ?

Minimum Cement Content 340 Kg & Maximum W/C ratio is 0.45

11.What is the density frequency of compacted layer in Embankment & subgrade/Shoulder ?

1 set of 10 test for 3000 m² of Embankment / 1 set of10 test for 2000 m² of Subgrade/Shoulder.

12.What is difference between Specific Gravity & Density ?

Bulk density is the ratio between soil weight to the total volume of the soil but Specific Gravity (G) is the ratio of the weight in air of a given volume of soil solids at a stated temperature to the weight in air of an equal volume of distilled water at that temperature . Specific gravity has no unit and it is generally used in design of concrete/bituminous mix.

13.What is the maximum Aggregate Impact Value of aggregate for concrete work ?

45%

14.What is the rate of spray of Prime Coat over WMM ?

0.7 -1.0 kg/m²

15.Which IS code specified the specification of aggregates ?

IS 383-2016

16.How much Kinetic Viscosity of VG 40 bitumen is ?

The Kinematic Viscosity of VG 40 grade bitumen is 400 cst minimum at 135 º C

17.What is the dry density of WMM & GSB material in your project ?

The density of WMM/GSB in our project is 2.23 /2.24 gm/cc

18.What is the minimum cement content & maximum W/C ratio for Pile concrete as per IRC 78 -2014 Cl 709.1.9 ?

 Minimum amount of cement content 400 kg/m³ & maximum W/C ratio is 0.40

19. What will be the minimum cement content as per IRC SP 49 2014 for DLC mix design ?

140 kg / m³

20.How many samples you take for 900 m² of DLC laying ?

3 samples (9 Cubes)

What is the Nominal size of aggregate for grade 1 Bituminous Concrete?

19 mm

What is the maximum limit of FI+EI for Dense Bituminous Macadam as per MORT& H 5th revision ?

Maximum FI+EI limit is 35%

What is setting time RS1 & SS1 Emulsion?

15 to 30 minutes for RS1 & 24 hours for SS1  

How many cube mould required for 110 m³ concrete ?

4 +1+1=6 samples means 18 cubes as IS 456-2000

As per MORT&H 5th revision how many grades of GSB are there?

Six grades are there.

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