Concrete - Student

8/10/2019 Concrete - Student

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CONCRETEPrepared by: Siti Khadijah Bt Hubadillah

CHAPER


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BASIC PROPERTIES OFCONCRETE-Materials in concrete mixture(_________________________________________

_______________________________________).

- Concrete strength according to materials composition.

- Differentiate concrete from other _________________________.


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DEFINITION OF CONCRETE

Concrete is a ______________________________________________________

_______________are mixed and blended according to mix ratio allowed toharden to form a structural member.


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MATERIALS OF CONCRETEMIX


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CEMENT

It is a basic ingredient of _________, _________, and _________.

Material produced by burning a mixture of _________ and _______.

Is the product obtained by grinding clinker formed by burning raw-materials(argillaceous and calcareous) primarily consisting of lime (CaO), silicate(SiO2), alumina (Al2O3), and iron oxide (Fe2O3).

Have two type is _________ or non _________.


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Argillaceous + Calcareous Silica Lime Alumina

Ferum Oxide Argillaceous Clay, sandstone, shale

Calcareous limestone, chalk

Hydraulic cement able to set and harden under water e.g. OPC, SlagCement, ggbs

Non-Hydarulic cement will not set and harden under water but require airto harden e.g. lime, gypsum


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AGGREGATEClassified by ASTM C33 is fine and coarse.

Fine Aggregate

Consists of source is river sand, mining sand and sea sand.

Size less than 5mm (___________________)


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Coarse Aggregate.

Consists of source is lime stone, granite and sand stone.

Size more than 5 mm. (_________________)


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AGGREGATE _________ sharp angular,

particles, fro quarry, rough surface,good bond strength, low workability

_________ round shapes, smoothsurface, from river, low bondingproperties, high workability


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Water

Materials of _________________.

Clean no (__________________________________)

Water cement ratio (BS 0.45 0.65)

Purpose For hydration and workability Washing Curing


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ADMIXTURE

Material added to concrete or mortar to _________________________atthe fresh / hardened.

Purpose Increased plasticity, accelerating the setting, improving the strength development, and

reducing the heat of hydration Some modify workability characteristics and setting rate of fresh concrete, others change the

properties both at mixing and hardened stages.

Introduced before, during or after mixing


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ADMIXTURE

______________________ _______________________


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CONCRETE STRENGTH ACCORDING TO MATERIALS

COMPOSITIONQuality material material used. ______________.

Grading of ______________.

Volume of water used.

Compaction when placed in the mold.Preservation are carried out ______________.

_____________ and transport.

Curing.


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BASIC KNOWLEDGE OFCEMENT __________ of cement in the market.

Chemical composition of __________.

_________________of water in cement.

Function of chemical substances in cement.


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INTRODUCTION OF CEMENT

Cement is a _____________ produced by _____________________________. Properties of cement is cohesive andadhesion, which enable it to bind the component materials

_________________________ to be compact.


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TYPES OF CEMENT

________________________(OPC)

Rapid Hardening Portland (_______)

Low Heat Portland Cement (LHPC)

_________________________(SRPC)

___________ Portland Cement (MPC) __________________________(PBC)

High Aluminium Portland Cement (HAPC)


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ORDINARY PORTLANDCEMENT (OPC)

By far the most common cement used in general concrete constructionwhen there is no exposure to sulphates in the soil or groundwater.

Minimum ________________ m2/kg.

Rate of hardening is _______________.

Standards; BS 12, MS 522


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RAPID HARDENINGPORTLAND CEMENT (RHPC) ______________ gain due to higher C3S content (70%).

Minimum fineness of _____________.

_______________is to be removed early for reuse or where sufficientstrength for further construction is required quickly.

Should not be used in mass concrete construction or in large structuralsections because of its higher rate of heat development.

For construction at low temperatures, the use of ______ may provide asatisfactory safeguard against early frost damage.

The setting time and chemical composition of _____ and ____ is reativelythe same.


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CONT.

For construction at low temperatures, the use of RHPC may provide asatisfactory safeguard against early ________________.

The setting time and chemical composition of ______ and _______ isrelatively the same.


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LOW HEAT PORTLANDCEMENT (LHPC)

Cement is used to prevent cracks due to the increase in ___________________ during _____________.

This cement has a slower rate of increase in strength but did not change its _________________.

Cement was used to build large structures.


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MODIFIED PORTLANDCEMENT

Cement produces less heat than normal Portland cement, sulphateresistant to the attack is simple.

__________________________is modified by adding chemicals to beadjusted to the use.


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PORTLAND-BLASTFURNACECEMENT (PBC)

Made by intergrinding or blending Portland cement clinker with granulatedblastfurnace slag.

Known as ______________.

Slag contains _____, _______ and ________, but did not in the sameproportions as in Portland cement.

Minimum fineness of _____ m2/kg.

Early strength are generally lower than OPC but later strength are similar oreven higher.


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HIGH ALUMINIUM PORTLANDCEMENT (HAPC)

Contain high ________, called ________________.

Be resistant to ______________, quickly hardened.

The slow freezing of the OPC, but the freeze will apply immediately for afour to five hours and thirty minutes to freeze expired.


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FACTORS THAT CAN AFFECT


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FACTORS THAT CAN AFFECTTHE COMPRESSIVE STRENGTHOF CONCRETE.1. Quality of Raw Materials:

Cement: Provided the ____________________ standard and it has beenstored correctly (i.e. in dry conditions), it should be suitable for use inconcrete.

_______________: Quality of aggregates, its size, shape, texture, strength

etc determines the strength of concrete. The presence of salts (chlorides andsulphates), silt and clay also reduces the strength of concrete.

Water: This criterion though is not absolute and reference should be madeto respective codes for testing of _______________________.


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2. Water / Cement Ratio:

The _________ the water/cement ratio, the greater the initial spacingbetween the cement grains and the greater the volume of residual voids notfilled by hydration products.

3. Coarse / fine aggregate ratio:

If the proportion of fines is increased in relation to the ______________, theoverall aggregate surface area will increase.

If the surface area of the aggregate has increased, the water demand willalso increase.

Assuming the water demand _______________ , the water cement ratio willincrease.

Since the water cement ratio has increased, the compressive strength willdecrease.


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4. Compaction of concrete:

Any entrapped air resulting from inadequate compaction of the plasticconcrete will lead to a reduction in strength.

If there was ___% trapped air in the concrete, the strength will fall down inthe range of __________%.

5. Relative humidity:

If the concrete is allowed to dry out, the hydration reaction will stop. Thehydration reaction cannot _________________.

6. Curing:

It should be clear from what has been said above that the detrimental effectsof storage of concrete in a dry environment can be reduced if the concrete isadequately cured to _________________________.


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HYDRATION PROCESS

CEMENT

WATER

HYDRATIONPROCESS

PASTACEMENT

AGGREGATE(FINE &

COARSE)

CONCRETE


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HYDRATION PROCESSCYCLEWhen the materials are mixed water and cement together through achemical process called _____________ and produce a _____________.Cement paste acts as a binder with ____________ to produce a

__________.


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CHEMICAL COMPOSITION INCEMENT

Compound ChemicalFormula

Abb. Percent (range) Rate of reactwith

Tricalcium silicate 3CaO. SiO2 C3S 35-65% Medium

Dicalcium Silicate 2Cao.SiO2 C2S 15-40% Slow

Tricalcium Aluminate

3CaO.Al2O3 C3A 0-15% Fast

Tetracalcium Aluminoferrite

4CaO.Al2.Fe2O3 C4AF 6-20% Medium


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CHEMICAL FUNCTIONS

C3S for faster gain in __________ and produces higher _______________.

C2S reacts slowly, provide later strength, highly chemical resistance(sulphate, chloride)

C3A is __________, contribute little or nothing to the strength of cementexcept at early ages.

C4AF does affect the __________________hydration significantly.


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CEMENT

23cm

1 m @5 feets


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FINE AGGREGATE ANDCORASE AGGREGATE

Criteria of __________.

_____________ of aggregate


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CRITERIA OF AGGREGATE

Size

Shape

Surface Texture

Grading


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PROPERTIES OF AGGREGATES

A number of physical and ____________________affect _________, _________, and ____________ of construction products manufacturedusing aggregates.

The aggregates particles should retain their strength, ________, andtexture when used with materials such as _________.


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MECHANICAL Compressive strength

Specific gravityBulk density

Porosity

Voids

Absorption

Modulus of elasticity

Moisture content

Shrinkage

Grading and fineness

Chemical reactivity


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QUALITY OF WATER INCONCRETE MIXTURE

The water used for mixing and curing should be clean and free from ________, acid, _______, salt, ________, organic materials.

________ is filt drink or taken from an approved source.

The pH value of water should be not less ________.


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THE ROLE OF WATER INCONCRETE MIXTURE

spreading ____________ (or lime) for each item covered by the meetingstone.

Water to give _______________ on concrete mix.

Water is a __________________ of the cement to bind all the stones in theconcrete mix.


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BASIC CONCRETE OFCONCRETE MIX

Define of concrete mixture.

Types of ___________.

Relation of mix ratio and strength.

Types of mixture :

i. Standard Mix/ Fixed Mixii. Design Mix

iii. Nominal Mix


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CONCRETE MIXTURE

Define

Concrete mix design is a _____________________________________________

_____________________________________________________________ _____________________________________________________________ _________.


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THE RELATION OF MIX RATIO


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THE RELATION OF MIX RATIO AND STRENGTH

Concrete Grade Strength (N/mm 2) Uses

7 7 Concrete withoutreinforcement10 10

15 15 Reinforced concrete withlightweight aggregates

20 20 Reinforced concrete with

aggregate volume25 2530 30 First reinforced concrete

40 40 Stressed reinforced conc

50 50


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STANDARD MIX

Mixing based on the weight.

Refer specification on BS (CP 110)

At the construction site contractor must be followed the consultant basedthe BS (CP 110)


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DESIGN MIX

Mixing rate ______________.

The contractor is responsible for _______________________ for thestrength and level of work performed.

Some of the mixture should be modified in the mix.


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NOMINAL MIX

Mixing based on the __________ and ___________.

Mix set was to have only _________________.

Not recommended at construction site.

Can be carried out with the weight if the density have given.

Density (D) = ____________ / _____________


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EXAMPLE 1

Calculate the mass of material which is needed for nominal mix with ratio 1 :2 : 4 based on 150 kg cement, where mixing is done based on mass :

Given the density of materials :

Cement = 1440 kg/m3

Fine aggregate = 1640 kg/m3

Coarse aggregate = 1390 kg/m3


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FRESH CONCRETE

Describe fresh concrete and workability The factor influencing workability :

a) Water / cement ratiob) Aggregates / cement ratioc) Shape and textured) Additives substance


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FRESH CONCRETE

concrete mix design is a process of selecting the materials in concrete mixand can be ____________________________________.


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WORKABILITY

Work from mixing to placed concrete in the mould. It represent the ability of concrete to be

_________________________________.

FACTORS INFLUENCING


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FACTORS INFLUENCINGWORKABILITY

Water / cement ratio To produce concrete mixes that are plastic and easily worked.

Water should be used more than the limit, ____________________ ofconcrete is reduced.

If the water used ____________, the concrete will be difficult to do and the

hydration process is not perfect.Relationship between the _____________________ in the concrete mix isknown as the ratio of water cement.


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Additives substance


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Additives substance

additive can given mixed into the __________ during the mixing progress.

to increase or modify the ____________ on the concrete.

both these materials, _____________ and ingredients added to theconcrete advantages.

ADDITIVES (ADMIXTURE) IN


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ADDITIVES (ADMIXTURE) INCONCRETE MIXTURE

Define of admixture. Types of admixturea. Catalyzing Substances.b. Retarding Substances.c. Water Decreasig Substances.d. Plasticizing Substancese. Air Trapping Additives


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DEFINE OF ADMIXTURE

Agent chemical are include in concrete or mortar to change the propertiesat the fresh and hard concrete.

Have ___ group is chemical and mineral.

Function :

i. To modify the workability characteristic.

ii. To setting (hydration) rate of fresh concrete.

iii. To change the properties of concrete.


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Water decreasing substances


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admixture is ___________.

To increase the workability so that placing the concrete it ease.

to increase the volume of _______ in concrete mix. Designed to resist ________.

Plasticizing Substances

Active at the ________ that helps cement the more effective spread in the

______. When the material is blended in the concrete it will speed up the propertiesof cohesion.

small quantities have to use ____ % by ______ of cement.


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SUPER PLASTICIZERS ___________________ (superplasticizers)are surface-active chemicals. It can separatethe ___________ particles by increasing thestatic charge on the _______________ andthus releasing the water _________ bycement particle clusters (see Figure). Morewater is then available to __________ themix.

Function:To produce high strength concrete at w/c

ratio in a range of ___________.

To create "flowing" concrete with highslumps in the range of ____________.

____________ and retarder are ____________ that can be added to the


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concrete mix to modify certain characteristic of the mix.

accelerator retarder

It has the added benefit of

increasing the rate ofstrength development.

Retarders cannot alter

weather conditions such ashigh temperature, wind orlow humidity, all of whichgreatly affect plasterperformance.

Accelerators can shorten theperiod between rodding andfloating or finish texturing.

They slow the hydrationprocess, they do not insurethe retention of the mixwater.

Air Trapping Additives


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As small quantity include in mixture.

This agent can shape are bubble to

i. Increase the workability.

ii. Reduce of bleeding and segregation.

iii. Improve the strength of concrete.

Materials of agent is :


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a) Natural materials (wood resin)

b) Oilly plant (___________________)

c) Fresh agent (alkali salt & organic sulphate)

d) ________________(resin acids & fat acids of plants)

e) Sodium salt of ______________ (petroleum, hydrogen peroxide andaluminium)

CONCRETE TEST


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CONCRETE TEST

Destructive test:will render the part unusable for its intended purpose (e.g. it is cut up for

analysis, or fatigue tested for life).

Non Destructive Test

Estimating the in-situ compressive strength

Estimating the uniformity and homogeneityEstimating the quality in relation to standard requirement


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Laboratory testing for coarse aggregate

Si (P i l Si Di ib i )


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Sieve test (Particle Size Distribution)

SLUMP TEST


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SLUMP TESTThe slump of concrete carriageway is purposely specified to be a relatively lowvalue, i.e. ______. For concrete carriageway, traffic loads directly act onconcrete pavement surface and therefore the ________ is detrimental to itsfuture performance.

In freshly placed concrete, segregation (may be in the form of bleeding) occurswithin the mixture of ______________ and __________. The degree ofresistance to segregation is related to _____________ of concrete.

If substantial ___________ is allowed to take place, then the relatively porousand weak laitance layer will be formed on the carriageway surface and the

____________ will concentrate in the bottom. Hence, concrete which hasinsignificant bleed possesses a stronger surface layer and is

___________________. Consequently, a small slump value is specified toincrease the wearing resistance of concrete and to achieve a suitable

______________ of concrete pavements.

Therefore, high slump concrete is _______________for a structure that iscontinuously exposed to the external load on its surface, for example,

READY MIX CONCRETE


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READY MIX CONCRETE

Advantage:Speedy construction through continuous

_______________________________

Disadvantage:

Since RMC is a bought ____________________ by about 10 to 15% thanconcrete mixed at site

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Concrete - Student