Top 120 Technical Interview Question for civil Engineers
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.
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
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
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
What is the softening point of VG 30 & VG40 grade bitumen ?
The softening point of VG30/VG 40 grade bitumen is 47 ºC / 50ºC
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
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 %.
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
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%.
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
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.
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.
What is the maximum Aggregate Impact Value of aggregate for concrete work ?
45%
What is the rate of spray of Prime Coat over WMM ?
0.7 -1.0 kg/m²
Which IS code specified the specification of aggregates ?
IS 383-2016
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
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
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
What will be the minimum cement content as per IRC SP 49 2014 for DLC mix design ?
140 kg / m³
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.
From which IS code concrete mix design is being done ?
IS 10262 -2009 now the latest revision introduced IS 10262-2019
On what temperature Kinetic Viscosity test of any bitumen is being done ?
At 135 º C
What is minimum bitumen content as per MORT&H 5th revision in DBM & BC for grade 1 mix ?
DBM 4.0 % & BC 5.2 % Minimum for the aggregate having specific gravity below 2.7.
What is Compaction parameter of Bituminous Concrete ?
Relative density minimum 92% of Gmm of that day
How much water can reduce the Superplasticizer ?
Practically more than 30 %
What is the relation between Air Voids & Density ?
Air voids is inversely proportional to Density i.e If Air Voids are increasing density will be decreasing & reverse versa
In tack coat which type of emulsion is used?
RS1
What is the minimum rolling & laying temperature for VG grade 30 DBM/BC mix ?
Minimum laying temperature for laying is 140 º C & minimum rolling temperature is 90 º C.
In prime coat what type emulsion is used as per MORT&H 5th revision in Indian condition ?
SS1
What is the minimum sand equivalent value of crusher dust if to be used in Bituminous work ?
50 %
What does mean by VG 40 Bitumen ?
Kinematic viscosity at 135º C, is 400 cSt, min.
What is the minimum rolling & laying temperature for VG grade 30 DBM/BC mix ?
Minimum laying temperature for laying is 140 º C & minimum rolling temperature is 90ºC.
In prime coat what type emulsion is used as per MORT&H 5th revision in India ?
SS1
What is the minimum sand equivalent value of crusher dust if to be used in Bituminous work ?
A50 %
What does mean by VG 40 Bitumen ?
Kinematic viscosity at 135 º C, is 400 cSt, min
Can you tell the name of IRC SP guide line for Quality System for road construction highway & Road bridge ?
IRC SP 57 – 2000 but now latest revision with change the name also is IRC SP 112 -2017 & IRC SP 47-1998 for Road Bridge
Which apparatus is used for softening point ?
Ring & ball apparatus
What is the Rate of spread of Prime coat/Tack Coat ?
Three test per day
Why you want to leave your present company?
1.I’d really love to be part of your project from beginning to end, and I know I’d have that opportunity here.
2. In my current role, I’ve learned many new skills. I’m looking for a position in which I can continue to grow that skill set in new circumstances.”.
3. I’ve learned a lot in my current role, but I’m looking for an opportunity that provides more challenges as I continue developing my skills and abilities.”
Tell me your 5 strong point?
Flexibility to handle any situation
2. Good Communication
3.Work under pressure
4.Dedication
5.Honesty
Tell me your achievement in your carrier?
1.Re-organized something to make it work better
2.Identified a problem and solved it
3.Developed or implemented new procedures or systems
What types of pavement is there?
Flexible /Rigid pavement.
What is the crust thickness of pavement in your project?
650 mm(GSB 250 mm,CTB 200 mm,WMM (Crack Relief Layer)100 mm, DBM 50 mm & BC 50mm). For service road 330 mm- CTGSB 180 mm , WMM 100 mm (Crack relief layer )& BC 50 mm.
How much quantity of Earth work, GSB, WMM & Bituminous work is there?
Earth Work -3000000 m³, GSB 200000 m³, CTB 170000³ ,WMM 100000 m³ & DBM/BC 140000m³ or whatsoever in your project.
What is difference between Flexible Pavement & Rigid pavement?
FLEXIBLE PAVEMENT
- Deformation in the sub grade is transferred to upper layers.Have low flexural strength.
- Have low completion test but high repairing cost.
- Damaged by oil and chemicals.
- Design Based on load distribution factor
RIGID PAVEMENT
- Deformation in the sub grade
- is transferred to subsequence Layers.
- Have high flexural Strength.Have low repairing cost but high completion cost.
- No damage by oil or Greece.Design based on Flexural strength or slab action
How much staff is working under you , draw the organization chart & show your position ?
4 staffs are working under me and draw the Organization chart on your own , show your position.
What is difference between OGL & NGL?
The first level taken of the natural ground without using any mechanical means is called NGL whereas the level taken after preparation of bed by using mechanical means Grader ,Doze, JCB & Roller is called OGL.
What do you know about this company?
As being an experienced candidate in this sector I’ve heard a lot about your organization.Your organization’s fame and prestige is what drove me here to apply for the position when your job vacancy was posted on your site. I know that your company has been in business for over xyz years, with an excellent reputation in successful completion of highway project .Your company is providing good opportunities to new coming member owing to that I am sitting infront of you.
Why dowel bar is being provided PQC pavement?
Dowel bars are required at expansion joints to transfer wheel loads to the adjacent slab. It is provided in the wheel paths only, it links the two adjacent structures by transferring loads across the joints.
What is land width of shoulder in plain & rolling terrain?
Land width of shoulder will be either 2.0 m or 3.5 m depending upon the situation.
What do you understand by Sub-base & base course in flexible pavement ?
Sub – base course is the first layer which is constructed immediately after the subgrade after the subgrade such as GSB & WBM etc.Base course is sandwich layer between wearing course and sub-base course.Base can have multiple layer such as CTB & WMM etc.
What is the vertical clearance of LVUP VUP & CUP?
The vertical clearance of VUP,LVUP and CUP are 5.5 m,3.5m and 3.0 m simultaneously.
What is the Minimum Right of way should be available (ROW) for 4 laning & 6 laning project?
A minimum Right of Way (ROW) of 60 m should be available for development of a 4 laning and 6 laning project as per IRC SP 84-2014 and IRC SP 87-2013.
What is the role of tie bar?
Tie bar is placed across longitudinal joints at the mid-depth of the slab .It prevent lanes from separation and differential deflections & transverse cracking These are installed by providing appropriate chair or these are installed by providing appropriate (drilled) holes in the side forms depending on the size and spacing of bars. Generally 16 mm dia bar is being used.
What is the role of joint sealant?
It seals the joint width and prevents water and dirt from entering the joint which causing dowel bar corrosion and unexpected joint stress resulting from restrained movement.
What is the minimum relative percentage compaction requirement for embankment and subgrade ?
For embankment 95% & for subgrade 97 % relative compaction is required.
What is the role of PVC dowel sheet ?
It serves to facilitate the movement of dowel bar.On one side of the joints,the dowel bar is encased in concrete.On the other side, however, the PVC dowel sleeve is bonded directly to concrete so that movement of dowel bar can take place.
Tell the level tolerance in Subgrade (For flexible Pavement) ?
Sub grade +/- 20 mm.
What is bumping or pumping in subgrade & why occur?
A bumping/pumping in subgrade is similar to the concept to trying to compact something on matress means when soil compactor rolls over a prepared subgrade soil . it got compacted with staggered line but when roller cross over, soil returns to its original position . This type of phenomena occurs when excess moisture is present in the prepared bed.
What do you understand by carriage way?
It is the width of the road which is used by the traffic for moving on it.It is generally central portion of the total land width and is paved and surfaced with the bituminous concrete for service to the road users.
What is hard shoulder?
The hard shoulder is the area at the side of a motorway or other road where we are allowed to stop if our car breaks down.It is generally separated by white line.
Why the saw cut joint is provided in road kerb?
Saw cut helps control cracking occurs due to shrinkage in Kerb.
What is the role of separation member in Rigid Pavement?
The separation membrane between concrete pavement slab and sub-base has mainly 4 function:
- It avoids the possibility of active aggressive agents from soil water being attached to the concrete slab.
- It prevents the loss of cement and water in immature concrete which significantly affects the strength and durability of hardened concrete.
- It reduces friction between concrete and sub-base.
- It avoids the mixing up of sub-base materials and freshly placed concrete.
What is the median width in raised condition in plain & Mountainous and Steep terrain?
In plain area generally 5.0 m but in built up area 2.5 m.In mountainous & steep terrain it is always 2.5 m.
What is minimum bitumen content in DBM & BC for grade 1?
DBM 4.0 % & 5.2%
Tell me the difference between Slope and Camber?
Slope is an area of ground that tends evenly upward or downward while camber is a slight convexity, or curvature of a surface of the road , so that water will flow off the sides .Camber is the transverse slope provided to the road surface for the drainage of the rainwater for the better performance of the road. Camber can be written as 1 in n or x%.
What is the reason for rutting?
There are 5 main reason for rutting
- Heavy traffic axle.
- High temperature & using VG30 bitumen.
- Higher bitumen content.
- More fines.
- Less air voids in bituminous surface.
For how many period flexible pavement design should be done?
Flexible pavement shall be designed for a minimum design period of 15 years or operation period, whichever is more
For how many period rigid pavement design should be done?
Rigid pavement shall be designed for a minimum design period of 30 years or operation period, whichever is more.
ln tack coat & Prime coat which type of emulsion is used as per MORT&H 5th revision?
In tack coat RS1 & in prime coat SS1
How much minimum longitudinal slope is required for lined drains and unlined drains ?
As far as possible, longitudinal slope shall not be less than 0.3 percent for lined drains and 1.0 percent for unlined drains.
What should roughness Index be of finished wearing course?
Not more than 2000 mm/km for each lane in a km length.
What will the minimum thickness of bituminous overlay for pavement strengthening ?
The thickness of bituminous overlay for pavement strengthening shall not be less than 50 mm bituminous concrete after attending to the requirements of profile corrective course.
What is the advantage of Cement Treated Base ?
There are so many advantages of using CTB :
- CTB provides a durable, long-lasting base in all types of climates.
- Can speed up the Project Completion
- Can reduced thickness of pavement.
- Reduced Project Cost (approx. 8 to 10 thousand rupees per metre)
- Reduced consumption of aggregate.
- Reduced consumption of bitumen.
What will be the cross fall on straight sections of road carriageway, paved shoulders of bituminous surface and paved portion of median for concrete surface in National Highway project?
The cross fall on straight sections of road carriageway, paved shoulders and paved portion of median will be 2.5% for bituminous surface and 2.0% for the cement concrete surface.
What is the justified minimum design speed for service road ?
A minimum design speed of 40 km/h shall be adopted for service roads.
In open country, on what space median openings shall be provided?
In open country, median openings shall not be spaced closer than 2 km. Additional controlled openings can be provided for inspection and diversion of traffic during repair and rehabilitation.
In built area, on what space median openings shall be provided?
In built up area, median opening shall be provided as per site requirement and the spacing between two medians opening in built up area shall not be less than 500 m.
As per IRC what is the minimum dia of new pipe culvert, cushion & class to be used in National Highway?
As per IRC SP 84-014 minimum dia of new pipe culvert should not be less than 1200 mm & pipe should be NP4 pipe. Minimum depth of earth cushion over pipe excluding road crust shall not be less than 600 mm for new,reconstructed and retained culverts constructed in National Highway projects.
What is the output of excavator having 1 m3 bucket?
60 m3 /hour
Why the mastic is being provided on deck slab ?
In most cases the protective layer is a Mastic Asphalt layer. This layer also serves as a second waterproofing layer. The non-porous mastic asphalt is usually used for the protective layer of the bridge pavement.
What is your weakness?
- The first is my inability to share responsibilities.
- I lose my patience when I suspect that the other person isn’t doing it right. I’ve discussed these weaknesses with my supervisor as areas I’d like to improve.
- The third is I easily trust on anyone.
Why you want to leave your present company?
You can tell any of the following points:
- I would really love to be part of your project from beginning to end, and I know I’d have that opportunity here.
- In my current role, I’ve learned many new skills. I’m looking for a position in which I can continue to grow that skill set in new circumstances.”
- I’ve learned a lot in my current role, but I’m looking for an opportunity that provides more challenges as I continue developing my skills and abilities.”
Tell me your 5 strong point?
Tell the following points with cleverness:
- Flexibility to handle any situation.
- Good Communication.
- Work under pressure.
- Dedication.
- Honesty
Tell me your achievement in your carrier?
Tell any of the below point confidently:
- Re-organized something to make it work better
- Identified a problem and solved it
- Come up with a new idea that improved things
- Developed or implemented new procedures or systems
- Worked on special projects
- Received awards/Certificates
What is your salary expectation?
This is your most important negotiation. Never tell lie about what you currently having, but feel free to include the estimated cost of all your fringes, which could well tack on 25 -30% more to your present “cash-only”salary.
How much time you required to join?
Ans: Always says one month but handle this situation very calmly, if you are ideal & have no job, can say within 7 days.
Quality Records are documented evidence that construction conformed to requirements of contract as well as design specifications. Quality Records include:
- Test and inspection reports
- Monthly Reports
- Material and equipment certificates required by specification
- Equipment maintenance/preservation records
- Acceptance and test data results
- Non conformance’s
- Corrective action ordered/taken
- Audit reports
- Project activity
- Amount and type of material used
- Frequency and accountability of submission
What is the IS code for Plain and Reinforced Concrete
IS :456
What are the standard american codes for steel and concrete
ACI and AISC
What is the code of practice for General Construction in steel
IS :800
What is the code of Practice for loads
IS : 875 part 1 – Dead Loads
IS :875 part 2 – Live Loads
IS :875 part 3 – Wind Loads
IS :875 part 4 – Snow Loads
What is the IS code for Earthquake /Seismic
IS :1893
What does M and 25 mean in M25 grade of concrete
M refers to the Mix and 25 is the characteristic compressive strength of 15 cm cube at 28 days in N/sq.mm
Basic Design philosophy followed
Working Stress and Limit State method
What is the standard size of brick
19 cm x 9 cm x 9 cm
What is the purpose of providing frog on brick
It is form key for holding mortar and joint to another brick above
What are initial and Final setting times of cement
Initial setting is about 30 min and final setting time is about 10 hrs.
What are basic Admixtures used for concrete
Acclerators : – To shorten the setting time Eg – Calcium chloride
Retarder : – To delay the setting time Eg – Carbohydrate derivatives
Which type of cement is used is construction of massive Dam structures
Low heat cement
What is the bending stress equation
M/I = fb/y =E/R where
M -Bending Moment
I – Moment of Inertia
fb – Bending Stress
y – Distance from Neutral axis to the load
E – Modulus of elasticity
R — Radius of gyration
What is effective cover
Distance from face of concrete to Centre of gravity of steel bars.
What is singly reinforced beam
If reinforcement is provided only on single face then it is singly reinforced beam.
What is balanced section
If stress in concrete and steel reach their maximum values simultaneously then its balanced section.
What is the minimum reinforcement in beams
Ast/b*d = 0.85/ fy
What is the maximum reinforcement in beams
0.04*b*d
What is the minimum reinforcement in slabs
0.12 % of gross area
What is the minimum reinforcement in columns
0. 8% of area
What is the maximum reinforcement in columns
4%
What are various checks in footing design
Bending, shear,overturning and sliding
Where is critical section for one way shear in footing
At a distance “d” from face of column
Where is critical section for two way or punching shear
At a distance d/2 from face of column
Where is the section for bending considered
At the face of column
What is the maximum no of steps in a flight
12
What are various limit states of strength
Flexure, Compression, shear and torsion
What are various limits states of serviceability
Deflection, cracking and Vibration
What is the slenderness limit for column
Less than 12 , it is short column
More than 12 , it is Long column
What are the minimum no of bars to be provided in rectangular column
4
What are minimum no of bars to be provided in circular column
6
What are various losses in prestressing
a) Elastic deformation of concrete
b) Shrinkage of concrete
c)Creep of concrete
d) Relaxation of stress in steel
Vicats apparatus is used for
Consistency test
Le chatliers apparatus is used for
Soundness test
when is masonry wall is said to be short wall
If slenderness ratio is less than 8
What is elastic limit
If a body regains to original position after removal of load is elastic limit
The shear stress on principal planes is
Zero
Which is more elastic mild steel or Rubber
Mild steel
What is Rate of change of shear force
Load
What is rate of change of bending Moment
Shear force
What are different methods of calculating deflection
a) Conjugate Beam method
b)Moment area method
c)Strain energy method
d)Double integration method
What is shear center in steel beam
It is point or axis through which load acts
What is Strut
Struct is a compression member
What is Modular ratio
It is the ratio of Modulus of elasticity of steel to Modulus of elasticity of concrete
What is the minimum diameter of bar used in column
12
What are bearing piles
Bearing piles transfer the loads to the hard strata
What are friction Piles
Friction piles transfer the loads by friction between surface of pile and soil.
What are the functions of a column in a building?
A column is used to support the weight of the roof and/or the upper floors. Nowadays, many columns are used for decorative purposes. A column along with load bearing beams can support a lot of weight.
What are the uses of Groynes?
They prevent, or slow down erosion, and stop the longshore drift. This, however, can have bad knock-on effects somewhere near.
What are the strongest shapes in the building?
The pillars
How many feet are in 4 square yards?
There are 9 square feet in a square yard, therefore, there are 36 square feet in 4 square yards.
What is the average density of soil?
For purposes of civil engineering, an average soil will have a density of about 100 to 110 pounds per cubic foot. (This can vary a little depending upon how well compacted the soil is)
What is the ratio of Grades M5, M7.5, M10, M15, M20, M25, M30, M35, M40?
M5 – 1:5:10
M7.5 – 1:4:8
M10 – 1:3:6
M15 – 1:2:4
M20 – 1:1.5:3
M25 – 1:1:2
M30, M35, M40 – Design Mix Followed
How do you compute the volume of airflow?
Orifice meter is used for measuring flow rate air.
Who designed the city of Washington DC?
Pierre L’Enfant
How do you maintain water pressure?
If you have water pressure and wish to maintain it, do not cause flow in the line, which will reduce pressure due to friction. To keep the pressure up, reduce friction by increasing the line size or eliminating some other restriction.
The mixture of different ingredients of cement is burnt at
1400°C
The foundations are placed below ground level, to increase
stability of structure
The portion of a brick cut across the width is called
Bat
The concrete slump recommended for beams and slabs; is
30 to 125 mm
In jack arch floor, the rise is kept
1/12th of the span
What is absolute pressure?
Absolute pressure is simply the addition of the observed gauge pressure plus the value of the local atmospheric pressure.
What is the meaning of soil reinforcement?
Soil reinforcement is the act of improving soil strength to enable it support or carry more load.
Minimum size of the particles of silt soil, is
0.002 mm
Under reamed piles are generally
bored piles
Describe briefly the various methods of concrete curing.
Curing is the process of maintaining the moisture and temperature conditions for freshly deployed concrete. This is done for the small duration of time to allow the hardening of concrete. The methods that are involved in saving the shrinkage of the concrete includes:
(a) Spraying of water: On walls, and columns can be cured by sprinkling water.
(b) The wet covering of surface: can be cured by using the surface with wet gunny bags or straw
(c) Ponding: The horizontal surfaces including the slab and floors can be cured by stagnating the water.
(d) Steam curing: Prefabricated concrete units, steam can be cured by passing it through the units that are under closed chambers. It allows faster curing process and results in faster recovery.
(e) Application of curing compounds: Compounds having calcium chloride can be applied on curing surface. This keeps the surface wet for a very long time.
Sometimes the side of concrete bridges is observed to turn black in color. What is the reason for this phenomenon?
In some cases, it may be due to the accumulation of dust and dirt. However, for the majority of such phenomenon, it is due to fungus or algae growth on concrete bridges. After rainfall, the bridge surface absorbs water and retains it for a certain period of time. Hence, this provides a good habitat for fungus or algae to grow. Moreover, atmospheric pollution and proximity of plants provide nutrients for their growth. Improvement in drainage details and application of painting and coating to bridges help to solve this problem.
What reinforcements are used in the process of prestressing?
The major types of reinforcements used in prestressing are:
(a) Spalling Reinforcement: The spalling stresses leads to stress behind the loaded area of the anchor blocks. This results in the breaking off of the surface concrete. The most likely causes of such types of stresses are Poisson`s effects strain interoperability or by the stress trajectory shapes.
(b) Equilibrium reinforcements: This type of reinforcements are required where several anchorages exist where the prestressing loads are applied in a sequential manner.
(c) Bursting Reinforcements: These kinds of stresses occur in cases where the stress trajectories are concave towards the line of action of load. In order to reduce such stresses, reinforcements in the form of bursting are required.
What are the functions of grout inside tendon ducts?
Grout in prestressing works serves the following purposes:
(i) Protect the tendon against corrosion.
(ii) Improve the ultimate capacity of the tendon.
(iii) Provide a bond between the structural member and the tendon.
(iv) In a case of failure, the anchorage is not subject to all strain energy.
What is the different type of slump test indications?
Slump tests are performed to empirically measure the workability of fresh concrete. It is used to measure the consistency of the concrete. In general, there are three different types of slumps that occur in slump tests. They are as follows:
(i) True Slump
(ii) Shear Slump
(iii) Collapse Slump
(i) True Slump: This type of slump is characterized by the general drop in the concrete mass evenly without visible signs of deterioration or disintegration. Shear Slump: It indicates that the concrete mix is deficient in cohesion. This type of slump leads to segregation and bleeding. Henceforth, in the long run, affecting the durability of the concrete.
(ii) Shear Slump: It indicates that the concrete mix is deficient in cohesion. This type of slump leads to segregation and bleeding. Henceforth, in the long run, affecting the durability of the concrete. Collapse Slump: This type of slump is indicates that the mix of concrete is simply too wet. The mix is considered to be harsh and lean.
(iii) Collapse Slump: This type of slump is indicates that the mix of concrete is simply too wet. The mix is considered to be harsh and lean.
Is it worthwhile to carry out tests on particle density of soil particles for geotechnical design?
Particle density of soils is defined by the ratio of soil particle mass and soil particle volume. Depending on soil types, the range of variation of soil particle density varies not significantly, i.e. by 4%. Therefore, it may not be worthwhile to order laboratory tests and incur additional expenditure just to determine the particles density by recognizing that the variation of particles density is not significant.
What are the main reasons for conducting pull-out tests for soil nails?
There are mainly four reasons for this test: (i) To check and verify the bond strength between soil and grout adopted during the design of soil nails. This is the main objective of conducting soil nail pull-out test. (ii) To determine the bond strength between soil and grout for future design purpose. However, if this target is to be achieved, the test nails should be loaded to determine the ultimate soil/grout bond