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8/13/2019 Aggregates for Concrete and Road Construction Materials
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Group 8 Do Quoc Toan
Phu Xuan Thai Nguyen Cong Tan
Nguyen Thanh Trung
Timo Trautwein
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Aggregates
for MaterialsNaturalaggreg
ates
Manufactured
aggregates
Reused
By-
products
Recycled
aggregates
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8/13/2019 Aggregates for Concrete and Road Construction Materials
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2.1. Foamed blastfurnace slag (FBS)
2.2. Fly ashaggregates (FAA)
2.3.Manufactured
sand (MS)
2.4. Polystyreneaggregate (PA)
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Description Applications and limitations
- A by-product of iron slag
- Was produced fist in Germany
- Not available in Australia
- Used as aggregates in
concrete block and in
insulating concrete
- Foamed slag (2000 kg/m3) =>
concrete 30 Mpa- Production contributes less to
the air pollution than the
normal does
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Description Applications and limitations
- An industrial by-product
(which is recognized as an
environmental pollutant)
- Several lightweight concreteaggregates can by product
from fly ash
- Small density: 1740-1840
kg/m3 (contain fly ash)
compared with 2400 kg/m3
(natural aggregates)
- Spend more cement to reach
the same structure grade (25
Mpa)
- Elastic modulus: 14-17 Mpa
compared with 28-30 Mpa
- Pelletizing and firing fly ash at
controlled temperature ->
synthetic aggregate
- Synthetic aggregate has
specific gravity:+1.20-1.47
+bulk density: 650-790 kg/m3
+water absorption: 16-24.8%
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Description Applications and limitations
- A purpose-made crushed fine
aggregate produced from a
suitable source material
- The research of CCAA: the
specification of manufactured
sands in term of density,grading, particle shape
- The R&D project of RTA:
specification for natural and
manufactured sands for
asphalt and concrete mixes
- Concrete 1 (fine sand :
manufactured sand = 1:1)
more workable than Concrete
2 (natural sand)
- Manufactured sand can be
used to replace a majorproportion of natural sand
with no significant loss of
performance
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Description Applications and limitations
- Used in combination with
normal weight aggregates to
produce lightweight concrete
- Concrete using PA : 1600-2000
kg/m3; higher elastic
modulus; density and creep
are inverse ratio
A comprehensive range of
engineering properties of
concrete made with such
aggregate and many examples oftheir applications in Australia
have ben reported
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1.Recycled concrete aggregate(RCA)
2.Recycle concrete and mansonry(RCM)
3.Reclaimed aggregate(RAP)
4.Reclaimed asphalt pavement(RAP)
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Description
+ RCA is produced by crushing sound,clean demolition waste of at least 955 by concreteweight and have total contaminant level typically lower than 1% of bulk mass.
+ Gravel,crushed stone,hydraulic-cement concrete or suitable combination for premixconcrete production.
Application:
+ Replacement for virgin materials(up to 30% of coarse RCA) for non-strctural concrete.
+ Stabilization base and sub base. Advantages:
+ The same carbonation rate
+ Lower specific weight than control concrete
+ Save cement and natural material
+ Similar flexural strength
Disadvantages:
+ Higher permeability ,water absorption, dry shrinkage and creep
+ Higher chloride ion absorption and gas permeability.
+ Lower compressive strength
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Description
+ RCM is graded aggregatee conducted from sorted and clean waste concreteand masonry.
+ The material may contain small quantities of brick,gravel,crushed rock or otherforms of stony.
Application:
+ Road sub-base applications. Advantages:
+ Lower specific weight than control concrete
+ Save cement and natural material
Disadvantages:
+ Higher chloride more swelling and creep+Lower workability.
+ Lower compressive strength than RCA concrete.
+ Difficulty in controling water content because of high water absorption.
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Description
+ Aggregates can be obtained by saparating aggregates from water-cement slurry.
+ Must be handled to avoid segregation.
Application:
+ replacement in a new mix.(100% RA can be used for 32 Mpaconcrete)
+ Partial replacement for natural aggregate in HSC.
Advantages:
+ Enhance the strength
+ Save cement and natural material
Disadvantages:
+Lower workability.
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Description
+ RAP is reuse of old asfalt concretes as the aggregates base for newasphaltic concrete.
Application and limitations:
RTA QA Spec R116 Asphalt permits the use of up to 15% reclaimed asphaltpavement.
Increases in recycled content will be considered when performance
implications of the current amendment are demonstrated.