Aggregates Ppt - Aa

8/12/2019 Aggregates Ppt - Aa

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AUYONG SIOK MAY SANDRA

AYE AYE AUNG

BEH HOOI WOON

CHAN NGET LOONGCHEN DEJUN

CHEN KANG

CHEN XINCHEN LEI


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IntroductionBenefits of Aggregate

Factors affecting Strength of Concrete

Classification of Aggregate (Size, Source, Density)

Aggregate Production

Sampling of Aggregate

Properties of Aggregate

(to be filled by the rest of team for individual sections)


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Composition of ConcreteAirPortland CementGravel of Crushed Stone (Coarse Aggregate)Sand (Fine Aggregate)

Water

At least three-quarters of the volume of concreteis occupied by aggregates

Aggregate is importance because it influencesthe performance of concrete


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Cheaper use of coarser aggregates lowers cost of

concrete mix by reducing cement requirements economical filler of 60-80% by volume in

concrete Higher volume stability Rigid and strong compared to cement paste

Better durability

Provides ductility in concrete


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Strength of the aggregate(e.g. surface texture, cleanness, particleshape, maximum size)

Shrinkage and creep(e.g. stiffness, grading)

Abrasion(hardness)


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SIZE

Coarse aggregates (>5mm) Fine aggregates (


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Maximum aggregate size: The largest sieve size thatallows all the aggregate to pass through

Nominal maximum aggregate size: The sieve sizethat less than 10 % of aggregate retain on it


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Quarrying Crushing

Primary: Jaw crusher

Secondary: Gyratory, roller, impact

Screening or Sieving


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Heavyweight Aggregate 4,000 - 8,500 kg/m3 Use in production of concrete for radiation

shielding

Normal Aggregate 2,300 2,500 kg/m3 Use in normal concrete

Lightweight Aggregate 350 1,100 kg/m3 Use in lightweight concrete production that provide

thermal insulation and fire resistance properties


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Get the sample randomly from entire width ofstock pile i.e. from top, middle & bottom atseveral locations

Use splitting or quartering Method until toget the required amount of aggregate samplefor testing


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Aggregate properties are used to determine:Suitability for a particular application

Specific concrete mix design


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Shape and Texture Soundness & Durability

Hardness and abrasion resistance

Absorption Specific gravity

Strength

Gradation

Cleanness and deleterious materials Alkali-aggregate reactivity


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Particle shape affect the workability of freshconcrete

Higher surface to volume ratio: require morecement paste to coat aggregate surface

Irregular particles: Greater interaction betweenaggregate particles and reduce workability offresh concrete

Rounded particle shape need less cement pastethan angular shape at same workability.


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Beh Hooi Woon Pg22-30


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Chen Nget Loong Pg31-39


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Chen Dejun Pg40-48


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Chen Kang Pg49-57


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Chen Xin Pg58-66


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Chen Lei Pg67-74


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THANK YOU

Aggregates Ppt - Aa

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