Difference between Quick sand and Quick soil

 

Quick Sand	Quick Soil
Quick sand is a hydraulic condition, not a type of soil	Quick soil is a type of soil
Definition At critical condition, effective stress being zero, shear strength of cohesionless soil becomes zero hence, soil behaves like a boiling liquid.	Definition A soil deposit that is reasonably stable if undisturbed, but suddenly becomes loose when disturbed. Or When sensitivity of soil > 16
Observed in fine sand and silt	marine clay
Also known as Quick condition, Boiling condition	Also known as Highly sensitive, quick clay

What is the difference between unit dry density and unit weight of soilds Γ_dry  vs Γ_solid?
Γ_{dry    =   Weight of soil solids / Total volume}  
Γ_{solid  =  Weight of soil solids / Volume of soil solids}

But dry weight of soil and weight of soil solid are the same. 

Γ_{solid is always greater than} Γ_dry.Why?

_{In case of}  Γ_{solid calculation only volume of soil solid is taken, which yields constant values where as} 

_In Γ_{dry Total volume is taken including Volume of voids, Volume of water present in pores,Volume of Soil solids. So the denominator value increases and so does the value of} Γ_dry.

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Difference between Isotropy and Anisotropy

 

Anisotropy	Isotropy
Property of material depends on direction	Property of material is independent of direction
Particle substance do not have same mechanical and thermal properties in every direction	Particle substance have uniform mechanical and thermal properties in every direction
Different properties in different direction	Same properties in different direction
More than one refractive index	Only one refractive index
Examples Wood, composite material, All crystals except cubical crystals	Examples Crystals with cubic symmetry , metals, glass

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Difference between Crystalline and Amorphous structure

Crystalline	Amorphous
Well defined edges and faces	Irregular surface
Has definite pattern, regularly arranged	No definite pattern, irregular arrangement
These have a long range order meaning- there is a regular pattern of arrangement of particles which repeats itself periodically over the entire crystal.	These have short range order meaning- regular predictable arrangement of the atoms are seen over a short distance
Sharp melting point	Has varying range of melting point
When cut with a sharp-edged tool, they split into two pieces with plain and smooth surfaces.	When cut with a sharp-edged tool, they cut into two pieces with irregular shapes.
Anisotropic in nature	Isotropic in nature
Also known as true soilds	Also known as pseudo-solids or supercooled solids
Examples Diamond, Ice, Sugar, Metals	Examples Rubber, Plastic, Gel, Glass

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Difference between Helical and Leaf springs

Helical Spring	Leaf Spring
	Source Wikipedia
It is made by winding a constant diameter wire in the form of helix.	It is made by clamping series of flat plates of varying length one above another.
Spreads the load to a single point	Spreads the load more widely over the vehicle's chassis
Resulting shape of helical spring is cylindrical	Resulting shape of leaf spring is semi-elliptic.
It offers small amount of flexibility in transverse direction.	It does not offer flexibility in transverse direction.
Load bearing capacity of this type of spring is comparatively lower.	Load bearing capacity of this type of spring is much higher.
It is light weight and cheaper.	It is heavy and costly.
It tends to absorb shocks and vibrations and thus provide a comfortable ride.	Leaf spring tends to lift of the vehicle body when it experiences bumps hence uncomfortable ride.
Common application areas Spring balance, shock absorbers in motor bikes, pens etc	Common application areas Vans and Trucks, SUVs etc

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Difference between close coiled and open coiled spring

Close Coiled Spring	Open Coiled Spring
Spring is wound tightly with no gap between two adjacent coils.	Spring is wound with sufficient gap  between adjacent coils.
Helix angle is less than 10°	Helix angle is greater than 10°.
Pitch of spring wire is smaller due to small helix angle.	Pitch of spring wire is comparatively larger as a result of larger helix angle.
Designed to undergo axial tension	Designed to undergo axial compression
Common application areas Spring balance Bike or cycle stand spring	Common application areas Spring-operated ball point pen Shock absorber in Vehicles

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Other test on bricks

1. Water absorption test – The bricks should not absorb more than 20% of water when immersed in water. It is calculated by the ratio between the dry weight of the brick to the weight of the saturated brick. The test ensures the quality of the bricks by wetting it for 24 hours and measuring the dry weight to its saturated brick weight.

2. Soundness test – A good brick should give a clear metallic ringing sound when struck with another brick. We have discussed the whole brick quality check process.

3. Shape and Size test – It is a visible test. The brick should have a straight and sharp edge. It helps to avoid the extra cost spending on cement mortar. Uneven bricks impact the width of the wall. We may need to apply extra mortar thickness to cover up the bricks to the proper thickness.

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Normal consistency of Cement 
Initial and Final setting of Cement
Compressive strength of Cement Sample
Specific Gravity of fine aggregate 
Grain Size distribution of fine aggregate
Grain Size distribution of coarse aggregate 
Crushing Value of aggregate
Impact Value of aggregate
Compressive strength of Concrete Cube
Fineness of cement
Compressive strength of cement
Specific Gravity of cement
Soundness of cement
Fineness Modulus of fine and Coarse Aggregrate
Specific Gravity, Void ratio, porosityand Bulk density of fine and Coarse aggregrate
Bulking of Sand
Slump test-Workability test
Compaction factor test- Workability test
Flow table test- Workability test
Water absorption test of aggregrate

Ductlity of Bitumen

AIM 

To determine the ductility of distillation residue of cutback bitumen, blown type bitumen and other bituminous products as per IS: 1208 - 1978.

THEORY
The ductility of a bituminous material is measured by the distance in cm to which it will elongate before breaking when a standard briquette specimen of the material is pulled apart at a specified speed and a specified temperature.

APPARATUS

1)Standard mould
2) Water bath
3) Testing machine
4) Thermometer - Range 0 to 44⁰C , Graduation 0.2⁰C

 

PROCEDURE
1) Completely melt the bituminous material to be tested by heating it to a temperature of 75 to 100⁰C above the approximate softening point until it becomes thoroughly fluid.

2)Assemble the mould on a brass plate and in order to prevent the material under test from sticking, thoroughly coat the surface of the plate and the interior surfaces of the sides of the mould with a mixture of equal parts of glycerine and dextrin. While filling, pour the material in a thin stream back and forth from end to end of the mould until it is more than level full. 

3) Leave it to cool at room temperature for 30 to 40 minutes and then place it in a water bath maintained at the specified temperature for 30 minutes, after which cut off the excess bitumen by means of a hot, straight-edged putty knife or spatula, so that the mould is just level full.

4) Place the brass plate and mould with briquette specimen in the water bath and keep it at the specified temperature for about 85 to 95 minutes. Remove the briquette from the
plate, detach the side pieces and the briquette immediately.

5) Attach the rings at each end of the two clips to the pins or hooks in the testing machine and pull the two clips apart horizontally at a uniform speed, as specified, until the briquette ruptures. 

6)Measure the distance in cm through which the clips have been pulled to produce rupture. While the test is being done, make sure that the water in the tank of the testing machine covers the specimen both above and below by at least 25mm and the temperature is maintained continuously within ± 0.5⁰C of the specified temperature.

Result
A normal test is one in which the material between the two clips pulls out to a point or to a thread and rupture occurs where the cross-sectional area is minimum. Report the average of three
normal tests as the ductility of the sample, provided the three determinations be within ± 0.5 percent of their mean value.

If the values of the three determinations do not lie within ± 0.5 percent of their mean, but the two higher values are within ± 0.5 percent of their mean, then record the mean of the two higher values as the test result.  

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Specific gravity of Bitumen
Bitumen content test
Marshall stability test
Flash and fire point test
Softening point test
Ductility of Bitumen test
Penetration test on Bitumen