Materials and Method Notes1

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Material and Method:

Excavation and Embankment:

The foundation are of a damn is the valley floor and terraces on which the embankment will be constructed.

Excavation :

It is the process to remove soil from the ground.

Embankment :

It is the process to fill a hole in the ground with soil and rocks.

Rocks :

Rocks must be protected against both CHEMICAL and MECHANICAL erosions.Rock surface must be clean of all loose rocks.

loose rocks can be removed by hand wedging = they are called rock knobs ( its all the pieces that extend beyond the surface of the rock).

Blastering with light charges : this option should be used only as a last resort becouse it creates disturbance.

Exposed cracks and crevices should be cleared of soil or loose rocks by using water jets or air jets.

Fissures should be filled with GROUT ( its made of cement, sand and water).

Mortar = Grout.

Grout is thinner than Mortar.

Mortar contains less water than Grout.

As a conclusionmortar is used to construct things where as grout is used to fill in fissures or cracks.

Grout = Cement + sand + water.

Concrete = Grout + gravel.

Cut-Off or Seepage barrier :

It is the process to prevent leaking.

An excavated trench cut through the Previous strata and backfilled with compactedImprevious strata.

Previous Starta : It allows the water to flow through.

Like for example Sand and Clay.

Imprevious strata : It doesnt allow water to flow through.

Like for example Rock.

Excavation Equipments :

Power Shovel :

It is used to excavate and load trucks. It has a tractor tires. Tractor tires are better than ruber tires because it gives a better grip and it can go

anywhere no matter the compositionof the surface ( rocky , sandy...)

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Draglines and Clamshell :

Clamshell :

A clamshell is also called an orange peal. It is used mainly to remove rocky materials like for example rocks. It is very effectivein removing

soil under water.

Draglines:

A dragline is very similar to a clamshell but it can only be used in soft materials like for example Sand. It is a sort of big shovel dragged on

the surface of the ground by a crane in order to collect soil.

Side Delivery loaders :It is used mainly to load trucks. This machine can be used in excavation but only in flat areas with a soft soil. Some side delivery holders have a

backhoe holder ( its a shovel in the back) used to excavate narrow trenches.The side delivery loaders have robber wheels which give them more

speed on flat areas.

Scrappers :

It is also called a Bulldozer, it has a small shovel at the bottom and a container on its back used to fill the soil removed. Its a machine that can

perform both excavation and hauling unit ( push material from one place to another) and backfilling .

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Gradders :

Its similar to a scrapper but it has a flat shovel used to grade the soil at the same level. Gradders can't excavate.

Hammer :

It breaks rocks. It can be placed instead of a shovel. The layer of its head is made of diamond ( anti-scratch).

Tunnel Boring Machine :

Also called Disc cutter or Discs. Its a machine used to construct tunnels. It is placed on tracks and pushed into the mountain to dig a tunnel through.

When the disks rotates, the unit rotates and cuts, it is generally used for long tunnels.

Hauling equipment :

They are equipment that can move materials from one place to another.

Like for example :

Scrappers : they push earth and rock away by scrapping the surface.

Bottom, side, end dump trucks.

Maximum truck capacity may reach 60 m3, with tunneling trucks up to 230 m3.

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The excavated volume can be estimated from counting the number of filled trucks.

A bobcat or also called a skid steer loader : this equipment is a combinationof both excavation and hauling unit. Bobcat is generally used in

thight locations. It can do any sort of work like for example : excavate small trenches,move materials, hammer some rocks.....

On a Excavation site water is used to reduce the dust.

Dexpan Powder :

It is a powder mix, after mixing it with water it expands and create pressures that can break concrete and rock.

Compaction Equipments :

Most common are the sheepsfootroller also called the tamping roller and the pneumatic-tiredroller. The main objectiveof the compaction

equipment is to decrease the settelmentand stabilize the soil.

Sheepsfoot roller :

The Sheepsfootroller is better than the steel wheel roller because it has sharp edges that can break down large pieces of soft soil.

It performsmore pressure on the soil than the steel wheel roller.

It requires 10 passes per 30 cm lift. Its speed range between 5 to 8Km

h. Its pressure range between 690 to 3450 KPa or (

KN

m2).

Pneumatic-tired roller :

Its pressure range between 345 to 1380 KPa KNm2

).

It is faster than the sheepsfootroller and it requires fewer passes. It is only used on asphalt.

Vibrating steel-wheeled roller :

It is used after the passes of the sheepsfootroller.

Its speed range between 1.6 to 2.5

Km

h .It creates more pressure.

It requires 4 passes per 30 cm lifts.




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Portable impact or also called compactor :

Segmented-steel-wheel roller :

Segmentsgo through the soil and break pieces of rock. the surface of contact is very small so this will create more pressure on the soil.

Embankment stabilization :

Required where steep slopes exists that are subjected to heavy storm water runoff.

Definitions :

Sand = has a high frictiton, is non cohesive( ne colle pas a d'autre materiels ) . Its diameter ranges from 0.05mm< < 2mm.

Clay = also called hydrated silicates of aluminium, has low friction and is cohesive.Its diameter varies between 0 < < 0.002mm. All

plants live in clay.

Silt = sedimentaryfine mineral particles. Its diameter varies between 0.002mm < < 0.05mm.

Loam = It is formed of sand, clay, silt and organic material .

Saturated clay = its clay with a degree of saturation equal to 100 %.

Organic material = It is material that contains carbon. This kind of material is harmless to the environmentand it can disapear with time.

The higher the friction the better the material is less cohesive( se colle les uns aux autres ).

Clay < Silt < Sand.

- Clay has low friction and is cohesive.

- sand has high friction and in non cohesive.

Clay is more impermiablethan sand, which means clay can block and reserve the water more than the sand. Saturated clay is not a good material it is

consideredas a poorly graded soil and its not good to use it in embankment.

Just to protect the environmentit is beter to take the sand from mountains rather from the beach, because destroyingthe shores can cause the loss ofmany things.

Slopes :

From the steepestslope to the lowest slope :

a) Gravel 1:1

b) Dry sand 3:1

c) Loam 2.5:1




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d) Compacted clay 1.25:1

e) Saturated clay 5:1

In order to protect the natural slope we should cut in stepped manner.

General case = a:b

Stabilization method :

0.1. Rip-Rap protection : Its a way to place stones one above the other. Its function is to stabalize the soil.

0.2. Rip-Rap protection with sand-cement bags : It is often used near culvert crossing ( big pipe made of cement ). This method of protection is

often used when there is water involved its way stronger than the stone method. The cement with water will harden. Cement will dry and

harden under any circumstance.On top of the rip-rap we construct a cap ( CAPITAL ) to hold the cement bags together and to make the

system stronger.

0.3. Articulated concrete block: Its a block of concrete allowed to move. Under the articulated concrete block we place a filter fabric. The main

function of the fabric is to protect the soil and to prevent it to move. This fabric allows water to flow through.

0.4. High Strength fabric filled with pumped concrete ( armor form ) : Its is formed with two layers of fliter fabric filled with concrete.On the

top layer of the fabric we find weep pores which allow the water to flow through.

0.5. Reinforcing geo-grids : The company that construct them is called TENSAR. It reinforcesthe soil and it is also called plastic reinforcment.




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0.6. Gabion : Its rocks protected by steel grids. It is done on the side of roads.There is two types of gabions :

- Rectangularbasketstockedon top ofeach other.

- Steppedstacking method.

0.7. Soil Nailling : It is in situ reinforcingof the soil while it is excavated from the top down. Any array of soil nails which are passive inclusions

are installed in a grid that functions to create a stable mass of soil. Soil nailling is a rapid and economicalway of constructingexcavations

support systemsand retaining wall. The nails hold the filter fabric placed on the soil then we spray concrete on top of the filter fabric. In

order to make it stronger we place reinforcingstell bars on the fabric. This system is like constructinga wall on the soil.

0.8. Shot creet : It is the concrete sprayed at high pressure. It is this type of concrete that we use in soil nailling. Shot creet is generally used when

we construct somethingtemporary.

Foundations :

Footings :

Foundations are used to support buildings. There are 2 types of foundations:




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- Footings : element that have a large area that support a lot of load.

- Piles : vertical membersthat is shoved in the soil.

Many true statments about footings and piles :

- Bulidings and bridges may be supported by piles or footings.

- In very weak soils and limited land area, piles should be used.

- A pile exists that supports a building by both bearing pressure and friction.

- The constructionprocedure for footingsrequires more available equipment than the procedure for piles.

- Footings support loads by bearing pressure, piles support load by friction.

- The weaker the soil the wider the footing is because it reduces stresseson the soil.

1. Spread footings = Individual footings.It supports only one colomn. Refer to photo (b) page5.

2. Matt Footing = raft foundation. It is one foundation for the entire building. It supports more than one colomn. It is the best type of footing in case of

an earthquake. Refer to photo (g) page5.

3. Wall footing = Continuous footing. It is generally constructedunder a wall. Refer to photo (a) page5.

4. Combined footing : It is when we combine two colomns and support them by one footing. 1 footing = 2 colomns. Refer to photo (e) page5.

5. Steeped or Pedestral footing : It is the strongesttype of footing. It prevent punching of the footing by the colomn because of its thickness.Refer to

photo (c) page5.




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- Large sizes require heavy and expensivehandling and driving equipment.

- Its constructioncan delay the project.

- possibilityof breakage of the pile while handling.

Cast in Place :

There is 2 principal method of constructing:

- Driving a mettalic shell, leaving it in the groung, and filling it with concrete.The concrete inside the shell is called mandrel.

- Driving a mettalic shell and filling it with concrete as the shell is pulled from the ground.

- The mattalic shell is generally corrogated because a pile with a corrogated surface creates more friction with the soil.

Prestressed concrete : It is a precast concrete with steell bars stressed.after pouring the concrete we relieve the steell which will lead to the

compactionof the concrete.

Equipment used in Pilling :

Drilling machine : The machine drill a hole in the ground and then the pile is placed in that hole. The part that drills is called an augre.

Pile hammers = PUSHER : The function of pile hammer is to furnish the energy required to drive a pile. They are choosedaccording the

type and size of the pile.

Vibratory pile drivers : They are effectivein speed and more economicalin driving piles into certain soils. It is more effectivewhen the pile

is driven into water saturated non-cohesicesoils. It may find some difficulty in driving piles into soil that does not respond to vibration like

dry sand.

Jetting pile : The use of water jet assist in driving piles into sand or fine gravel frequently will speed the driving operation. The water keeps

the soil arround the pile in agitation thereby reducing the resistancedue to skin friction.




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Drainage :

It is the process of water disposal, normally rainwater runoff (storm water).

Drainage system is placed on low level on the roof to make sure that all water goes through.

For a drainage system in the toilet we construct a trap. A trap is a trap to block water and prevent odors to come through the toilet seat. We

place also a vent to eliminate the odors from waste water. A pipe should always have a slope in order to facilitate the water flow.

Roof crossection :

The slope in the roof should be minimum of 1 %.

2 roofs configurations :

7.5.

7.6.

Catch pits or drainage inlet also called a catch bassin : is only function is to catch the water.




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A manhole : a hole that connectspipes together. it facilitate maintenanceof the pipes becouse a man can go in and repare the pipes.

In roadways the slope is 0.3% (slope along the road). There is also a cross slope of 2 %. Drainage is important in roofs , roadways ...

French- Drain or exfiltration trench :

A French drain, drain tile, perimeter drain or land drain is a trench covered with gravel or rock that redirects surface and groundwater away from an

area. A French drain can have perforated hollow pipes along the bottom (see images) to quickly vent water that seeps down through the upper gravel

or rock. French drains are common drainage systems,primarily used to prevent ground and surface water from penetrating or damaging building

foundations.Alternatively,the French drain technique may be used to distribute water, such as that which flows from the outlet of a typical septic

tank sewage treatment system. French drains are also used behind retaining walls to relieve ground water pressure.

This system can only be used when we have pervious concrete or asphalt. This system can also be placed accross a roadway or parallel to it.

Structural materials :

Concrete :

Materials necessaryfor the manufacture of cement are:

7.7. Lime ( calcaire ).

7.8. Silica : It is found in sand and clay.

7.9. Iron oxide ( rust ).

7.10. Alumina : found in clay.

7.11. Magnesium oxide.

Theese ingredientsare mixed in proper and closely controlled proportions.this mixing gives us the cement knows today and we call it PORTLAND

CEMENT. All the mixing is burned at 1450C to form the CLINKER which has particles diameter varies form 0.5cm to 3 cm.

The clinker looks like gravel but it is ground into powder to become cement.

The finer the cement powder is the stronger the concrete will be because it fills the voids. The size of a cement particle should not exceed 0.02mm.

The concrete sets within 45 min, it turns into a solid state after about 10 hours and its design strength is gained at 28 days. but the concrete remains

getting stronger even after 5 years or more.

The time between the mixing of the concrete and the pouring of the concrete should not exceed 11

2hours. It is better to have the mixing plant near

the constructionsite or we can add water just before 30 min of the pouring time.

The cement will harden under any circumstances( rain, wind, sun, under the ocean...).

The chemical water that occurs right after adding the water, release heat. no matter what circumstancesthe chemical water should not be stopped or

accelerated or even disturbed because it will give us a poor concrete with a strenght less than the design strenght.

Chemical reaction = crystallization,hydration of lime always present.

Cement is packed in 50Kg bags. It should be used from 3 months up to maximum 6 months after production because humidity in the air can spoil

the cement. the humidity will force the reaction to begin while the cement is still in the bags.

When concrete is poured we face the problem of shrinkage. the concrete will change weight due to water evaporation. This is why we should put

water on the concrete after 45 min to prevent the water insude it to evaporate. Whereas the concrete poured under water ( TREMIE concrete)

increases in volume.




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It gains strenght rapidly, it sets very fast.

In 3 days = 70% f 'c is gained whereas for type 1 it takes 7 days to gain 70% f 'c.

Type 4 : Portland cement is generally known for its low heat of hydration :

This causes the heat given off by the hydration reaction to develop at a slower rate. However, as a consequencethe strength of the concrete

develops slowly. After one or two years the strength is higher than the other types after full curing. This cement is used for very large

concrete structures, such as dams, which have a low surface to volume ratio. This type of cement is generally not stocked by manufacturers

but some might consider a large special order. In this type we get less cracks and shrinkage so we can use this type in foundations.

Type 5 :

is used where sulfate resistanceis important.Thistype is used in concrete that is to be exposedto alkali soil and ground water sulfates which

react with (C3A) causing disruptive expansion.In general this type of cement is poured under water.

White cement :

White Portland cement differs physically from the gray form only in its color, and as such can fall into many of the above categories (e.g.

ASTM Type I, II and/or III). However, its manufacture is significantlydifferentfrom that of the gray product, and is treated separately. this

type is very similar to type 1 cement but it cost twice more.

Composite cement :

Today, other type of cement ar being manufactured, called COMPOSITE CEMENT having a new chemical compositionand include special

additives like :

Fly Ash ( small in size which reduces the voids. it has the property of adhesion ).

Ground blast furnace slag ( ashes from steel ).

Silica fumes ( dust that comes from sand ).

pozzolan ( it acts as a binder. it binds sand and gravel together ).

Rice hull ash.

Lime ( Calcaire ).

All those material increase the compressivestrenght ( f 'c ) of the concrete.

Micro silica = Silica fumes : it increases the strenght of concrete and extends its durability. Micro silica is highly actice pozzolan.

Cementitiousmaterial = cement, micro silica, Ground blast furnace slag , Fly Ash.

Slump test :

In constructionand civil engineering,the Concrete slump test (or simply the slump test) is an in situ test or a laboratory test used to determineand

measure how hard and consistenta given sample of concrete is before curing.

The concrete slump test is, in essence,a method of quality control. For a particular mix, the slump should be consistent.A change in slump height

would demonstratean undesired change in the ratio of the concrete ingredients;the proportionsof the ingredientsare then adjusted to keep a concrete

batch consistent.This homogeneityimproves the quality and structural integrity of the cured concrete.

This test tests the workability of the concrete whether it firm, flowable, soft or plastic. It is better for the concrete to be firm. The slump test doesntgive us the % of water in the concrete.If the concrete didnt settle a lot this means that the concrete is good.

Concrete testing :

The concrete should be tested in order to make sure that the material proportionsare controlled.It is better to do all testing after 7 days because if

somethingis wrong it can be easily destructed.The test sample should show strengthsgreater than the required strength after 28 days. The core

samples should be taken from place located away from the steel. This test is called DESTRUCTIVE STRUCTURE.

- fct = 0.33 f 'c ( tensile strenght of concrete ).

- 0.10 * f 'c < fct < 0.20 * f 'c ( roughly tensile strenght of concrete ).




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- fr = 1.09 * fct ( rupture ).

1 MPa = 145 psi = 10.19Kg

cm2

Schmidt hammer :

A Schmidt hammer, also known as a Swiss hammer or a rebound hammer, is a device to measure the elastic propertiesor strength of

concrete or rock, mainly surface hardness and penetration resistance.The hammer measures the rebound of a spring loaded mass impacting

against the surface of the sample. The test hammer will hit the concrete at a defined energy. Its rebound is dependenton the hardness of the

concrete and is measured by the test equipment. By referenceto the conversionchart, the rebound value can be used to determinethecompressivestrength. When conducting the test the hammer should be held at right angles to the surface which in turn should be flat and

smooth. The rebound reading will be affectedby the orientation of the hammer, when used in a vertical position (on the underside of a

suspendedslab for example) gravity will increase the rebound distance of the mass and vice versa for a test conducted on a floor slab. The

Schmidt hammer is an arbitrary scale ranging from 10 to 100.

Concrete mixing :

Ready mixed : mixing completleythe concrete in a stationary mixer and transporting it in a truck mixer called also an agitator.

Shrink-mixedor also called transit-mixed: materials are batched at a central plant and are completelymixed in the truck in transit.

Frequently, the concrete is partially mixed in transit and mixing is completedat the jobsite. Transit-mixingkeeps the water separate from

the cement and aggregates and allows the concrete to be mixed immediatelybefore placement at the constructionsite. This method avoids

the problems of premature hardening and slump loss that result from potential delays in transportation or placement of central-mixed

concrete. Additionally,transit-mixingallows concrete to be hauled to constructionsites further away from the plant. A disadvantage to

transit-mixedconcrete,however, is that the truck capacity is smaller than that of the same truck containing ready-mixedconcrete.

Dry-mixed : all material is mixed in a stationary mixer and water is added at the site.

Concrete properties :

If we increase the cement and gravel content the strength will increase, whereas if we increase the water and sand (that contains clay )

content the strength will decrese and we will have a poor concrete.

The strenght of the concrete dependson the type of gravel. If we get strong gravel we will get strong concrete.

The quantity of sand is very important in concrete mixed, because the sand fills in the voids. if we add a lot of sand, the sand will tend to fill

the voids and push the gravel away from each other. This will lead to a poor concrete.

The proportionsin a concrete mixed is very important because we dont want shrinkage and cracks. More cement will lead to more cracks.

Important questions :

Filter fabric is a special type of fabric placed arround a french drain.

a pneumatic-tiredroller is used to compact roadways only.

A dragline can perform similar function as a bull dozer.

Sheet piles can be made out of plastic, can be vertical placed along a river, can replace soil nailing, can resist lateral soil pressure, are

connectedto each other, can be stronger is U-shaped...butthey cant replace cylindrical piles.

1 short ton = 0.9072 metric tons.

20 days per months

7 hrs per day.

Gradeall = flattening embankment

modular channel = inlet.

wall footing = continuous foundation.

trenchlesstechnology= placing pipe.

limerock base = crushed surfacing course.

fluted shell = taper section.




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auger = rotary drilling

vibratory soil densifier= compaction.

Drop hammer = H-pile.

mechanical trawel = helicopter.

A screed is a layer of concrete placed to drain the slab.

A catch basin is used to drain roadways and yards.

A segmentedsteel wheeled roller is used to compact weak soils.

A power shovel can perform similar functions as a loader.

A mat foundation can be used in the case we have a weak soil.

A fieldstonedrywell is a bassin that dissipatesthe runoff.

The common item between a septic tank and an exfiltration trench is they are both used to dissipate a flow.

A rammer compactor is used to compact small surfaces like trenches.

A hydrolic pile hammer perform similar fumctionsas a pusher.

Caissons may be drilled while the shell driven arround it at the same time.

Articulated concrete block are permeable, are connectedby steel cables, help release the pressure due to water behind them, are method of

soil stabilization...

Rigid pavement should be used when the traffic count is high.

the subbase is the existing grade ( transportation ). The logitudinal slope of a roadways is maximum equal to 2%.

Runnway = rigid pavment



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