Aggregates for Concrete and Road Construction Materials

8/13/2019 Aggregates for Concrete and Road Construction Materials

1/19

Group 8 Do Quoc Toan

Phu Xuan Thai Nguyen Cong Tan

Nguyen Thanh Trung

Timo Trautwein


2/19

Aggregates

for MaterialsNaturalaggreg

ates

Manufactured

aggregates

Reused

By-

products

Recycled

aggregates


3/19


4/19


5/19


6/19


7/19


8/19

2.1. Foamed blastfurnace slag (FBS)

2.2. Fly ashaggregates (FAA)

2.3.Manufactured

sand (MS)

2.4. Polystyreneaggregate (PA)


9/19

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


10/19


- 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%


11/19


- 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


12/19


- 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


13/19

1.Recycled concrete aggregate(RCA)

2.Recycle concrete and mansonry(RCM)

3.Reclaimed aggregate(RAP)

4.Reclaimed asphalt pavement(RAP)


14/19

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


15/19


16/19

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


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.


17/19


18/19

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


Disadvantages:

+Lower workability.


19/19

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.

Aggregates for Concrete and Road Construction Materials

Documents