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RHEOLOGY MODIFYING ADMIXTURES
FOR CONCRETE
TAKEN FROM NATURE
Wolfram Schmidt1, Inès L. Tchetgnia Ngassam2,
Rose Mbugua3, Kolawole A. Olonade4
1 BAM Bundesanstalt für Materialforschung und –prüfung2 University of Cape Town3 Tshwane University of Technology4 Obafemi Awolowo University
21.02.2017
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Co-authors
2
Rose Mbugua
Tshwane University of
Technology, ZA
Inès Tchetgnia Ngassam
University of
Cape Town, ZA
Kolawole A. Olonade
Obafemi Awolowo
University, NG
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Introduction
3
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
‒ Strength evolution
Introduction
Relevance of rheology modifying admixtures
0
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250
0
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900
Co
mp
ress
ive
str
en
gth
[M
Pa]
Spre
ad fl
ow
dia
me
ter
[mm
]
Self-levelling
Flowable
Soft
Plastic
Stiff
UHPC
HPC
Normalstrength
0
50
100
150
200
250
0
100
200
300
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900
Co
mp
ress
ive
str
en
gth
[M
Pa]
Spre
ad fl
ow
dia
me
ter
[mm
]
Self-levelling
Flowable
Soft
Plastic
Stiff
UHPC
HPC
Normalstrength
0
50
100
150
200
250
0
100
200
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500
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900
Co
mp
ress
ive
str
en
gth
[M
Pa]
Spre
ad fl
ow
dia
me
ter
[mm
]
Self-levelling
Flowable
Soft
Plastic
Stiff
UHPC
HPC
Normalstrength
Lignosulfonates
Naphthalene sulfonates
Melamin sulfonates
Polycarboxylates
Vinyl copolymers
4
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
‒ Strength evolution
‒ New casting technologies
Introduction
Relevance of rheology modifying admixtures
5
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
‒ Strength evolution
‒ New casting technologies
‒ New architecture
Introduction
Relevance of rheology modifying admixtures
phænoby Zaha Hadid, Source: Wikipedia
www.bewegteflaeche.de
6
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
‒ Strength evolution
‒ New casting technologies
‒ New architecture
‒ Special applications
Introduction
Relevance of rheology modifying admixtures
Source: BAM
7
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
‒ Strength evolution
‒ New casting technologies
‒ New architecture
‒ Special applications
‒ Sustainability and environmental
friendliness
Introduction
Relevance of rheology modifying admixtures
Source: BAM
8
WWF, 2008
Barcelo et al., 2014
Rheology modifyingadmixtures are the key to
sustainable, and innovative construction.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance of rheology modifying
admixtures in Africa
9
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Economy and society
10
• Africa‘s economies grow at rapid pace.
• Investment in construction ensuresongoing growth and triggers newdevelopments.
• The most crucial challenges are:
• Infrastructure
• Housing
• Construction business allows thepopulation to participate in economicgrowth, and thus ensures social stability.
• Admixtures support efficient andsustainable construction.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Affordable construction
11
• Cement is extremely expensive.
• Alternatives do exist, e.g.:
• Rice husk ashes
• Cassava peel ashes
• Bagasse ashes
• But pozzolanic materials typicallyrequire admixtures to compensate forthe higher water demand.
Msinjili, 2015 Olonade, 2015 Wikipedia
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Sustainability
12
• Admixtures help to minimise the cementcontent as well as the w/c.
• Therefore today, the correlation between high cement content and good concrete does not hold true anymore.
Aitcin, 2000
Morgan Stanley Research, 2015
CEMNET, 2013
Admixtures
required to avoid
the hump
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Global effects
13
• Hence, admixtures are of enormousrelevance for the African continent.
• However, they are also extremelyimportant for the global environment, since reasonable concrete technology will achieve the greatest momentum today in Africa.
• Sustainable concrete technology pays back a multiple due to the rapid cement marketgrowth, to the benefit of:
• The environment
• Local markets
• Global markets
International EnergyAgency
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Admixture shipments to Africa
14
• Admixture supply from outside, and mainly coastal regions.
www.maps.google.de
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Admixture shipments to Africa
15
• Admixture supply from outside, and mainly coastal regions.
• Alternatives are required.
• Africas strength is agriculture.
• 600 Million ha of unused agriculturalareas (Perry 2016).
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Relevance for Africa
Admixture shipments to Africa
16
• Admixture supply from outside, and mainly coastal regions.
• Alternatives are required.
• Africas strength is agriculture.
• 600 Million ha of unused agriculturalareas (Perry 2016).
• Local plants and local agriculturalwastes can be used, like
• Acacia gum
• Lignosulfonate
• Starch
• Nkui
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
17
Cement, 20 µm
PCE
GAK, LS
Amylopectin
NkuiEttringite
Cement, 5 µm
Relevance for Africa
Comparison
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Acacia gum as superplasticizer
18
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Acacia gum
Origin
19
• Acacia gum can be obtained from the stem, e.g. from Acacia Karoo Hynes
• One tree can be harvested for 15 years
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Acacia gum
Influence on rheology
20
• An increasing dosage of GAK (Acacia gum from the Karoo) can significantly enhance the slump of concrete.
• Set retardation could be observed, but it was not dramatic and caneven be positive high temperature conditions.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Acacia gum
Influence on rheology
21
• An increasing dosage of GAK (Acacia gum from the Karoo) can significantly enhance the slump of concrete.
• Set retardation could be observed, but it was not dramatic and caneven be positive high temperature conditions.
• In future research the use ofGAK as admixture for SCC in East Africais observed in cooperation betweenTshwane University of Technology, the Pan-African University at Kenyatta University and BAM.
see MSc thesisCaroline Mwende
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Acacia gum
Influence of solid volume fraction on GA
w/c = 0.3
0.35% GA
w/c = 0.4
0.35% GA
w/c = 0.3
0.35% PCE
w/c = 0.4
0.35% PCE
w/c = 0.3
w/c = 0.4
22
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Lignosulfonate
23
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Lignosulfonate
Peculiarities of lignosulfonate
24
Lignosulphonates are typicallyconsidered as plasticizer.
• Waste product of cellulose industry
• More water required than with PCE
• More complex adjustment.
Lignosulfonates pointed out toperform very well in conjunction withporous surfaces such as rice huskashes.
• For further information, please seeNsesheye Susan Msinjili
100
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260
0,0% 1,0% 2,0% 3,0% 4,0%
Past
e sp
read
flo
w d
iam
eter
[m
m]
Dosage of superplasticizer [% of cement]
PCE; w/b=0.31
LS; w/b=0.31
LS; w/b=0.6
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Lignosulfonate
Potentials
25
Components to be added [kg/m³]
Water 238
Aggregate [2 – 16 mm] 613
Slump flow ~ 30 min: 635 mm
28d compr. strength: 56.2 MPa90d compr. strength: 68.4 MPa
Compound: Mineral components [kg/m³]
OPC 399
Pozzolan (Uganda) 80
Fine sand [0 - 2 mm] 972
Compound: Admixtures [% of cem.]
Lignosulfonate SP (Powder) 1.96%
De-foaming agent (Powder) 0.75%
Nigerian cassava starch (Powder) 0.004%
• SCC with lignosulfonate is possible.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava starch/starch
26
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava starch
Origin
27
• Cassava, manioc, tapioca or yuca.
• Food: Staple crop of over 200 million people in Africa alone
• Animal Feed
• Industrial usage
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava starch
Projection
28
• Cassava is an important resource in Africa.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava starch
Versatility
29
• Cassava is an important resource in Africa.
• Chemically it is similar to potato.
• 80% by mass Amylopectin
• 20% by mass Amylose
• After modification it can be extremely versatile.
For more information,
see: Eleni Vasiliou
ICBBM, Clermont Ferrand, 2017
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava
Sustainability
30
Food
Admixture
Energy
Waste
Olonade, 2015
Boiling
SCM
http://www.arte.tv/guide/de/063945-041-A/xenius
Msinjili, 2015
Fuelling
Usage of ashes
Peeling
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Cassava
Potentials for sustainability
31
• Cassava starch is also a waste from Gari production.
https://www.youtube.com/watch?v=kDkxk64dRHA
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
32
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
Origin
33
• Nkui is a traditional dish of the Bamilekein Cameroon.
• A gum inside the barks of Triumfettapendrata A. Rich is responsible for the very peculiar consistency.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
Consistency
34
• The sticky consistency can possibly be used to stabilise cementitious systems effectively and provide for special consistency.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
Effect on instable cementitious systems
35
• The sticky consistency can possibly be used to stabilise cementitious systems effectively and provide for special consistency.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
Effect on superplasticised systems
36
• The sticky consistency can possibly be used to stabilise cementitious systems effectively and provide for special consistency.
• In combination with PCE, the performance can be interesting.
w/c = 0.3
w/c = 0.3
0.35% PCE
w/c = 0.3
0.08% Nkui
w/c = 0.3
0.35% PCE
0.08% Nkui
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Nkui
Effect on superplasticised systems
37
• The sticky consistency can possibly be used to stabilise cementitious systems effectively and provide for special consistency.
• In combination with PCE, the performance can be interesting.
w/c = 0.3
0.35% PCE
0.08% Nkui
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Rheometric comparison
38
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Rheometric comparison
Experimental setup
Aggregate, 16 mm
• Water cement system• Solid volume fraction = 0.48• Viskomat NT• Cement paste stirrer
39
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Rheometric comparison
Experimental setup
Aggregate, 16 mm
• Water cement system• Solid volume fraction = 0.48• Viskomat NT• Cement paste stirrer• Measurement regime allows saving materials
40
0
20
40
60
80
100
120
140
0
40
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240
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320
360
400
0 4 8 12 16 20 24 28 32 36 40
Torq
ue
[Nm
m]
Ro
tati
on
al s
pee
d [
rpm
]
Rotational velocity [rpm]
Torque [Nmm]
No admixtures
Admixture addition
Admixture addition
Admixture addition
Admixture addition
Admixture addition
Admixture addition
Admixture addition
two-spot flow curve
two-spot flow curve
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
41
0
20
40
60
80
100
120
140
160
0.00% 0.25% 0.50% 0.75% 1.00%
Torq
ue
[Nm
m]
Polymer addition [% by weight of powder]
Polycarboxylate ether
Hydroxypropylated potato starch
Untreated boiled cassava starch
Karoo gum
Lignosulphonate
Rheometric comparison
Results at constant rotational speed 240 rpm
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
42
Rheometric comparison
Results at 240 rpm and 120 rpm
-10
0
10
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90
100
110
120
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150
160
0 40 80 120 160 200 240
Torq
ue
[Nm
m]
Rotational speed [rpm]
Reference without polymer
Polycarboxylate ether
Karoo gum
Lignosulphonate
Hydroxypropylated potato starch
Untreated boiled cassava starch
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Summary
43
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Summary
Nkui
Aggregate, 16 mm
44
• Cement and concrete construction are of enormous importance for SSA.
• All over the world we need more sustainable concrete technologies.
• Admixtures are the key.
• In Africa the supply chains for chemical admixtures are not well developed.
• Nature based chemical components can be used effectively to fill the gap.
• Some potentially promising materials were presented, but further research is required.
If natural polymers point out to bepromising, this can trigger more
sustainable admixtures all over the world.
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Announcement
KEYS – Knowledge exchange for young scientists
45
Speakers:
• Prof. Billy BoshoffUniversity of Stellenbosch, South Africa
• Prof. Elsabe KearsleyUniversity of Pretoria, South Africa
• Prof. Ephraim SenbettaAddis Ababa University, Ethiopia
• Dr. Soumen MaityDevelopment Alternatives, New Delhi, India
• Prof. Marco MenegottoSapienza University of Rome, Italy
• Dr. Mike OtienoUniversity of the Witwatersrand, South Africa
• Prof. Mitchell GohnertUniversity of the Witwatersrand, South Africa
• Prof. Viktor MechtcherineTechnical University of Dresden, Germany
• Prof. Violeta Bokan BosiljkovUniversity of Ljubliana, Slovenia
• Dr. Dipl.-Ing. Wolfram SchmidtBAM, Germany
Next symposium: Johannesburg, SA
Deadline for abstract: 28. Feb. 2017
Selected authors attend for free
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Announcement
UNEP report – Eco-efficient cements
46
http://lmc.epfl.ch/files/content/users/184559/files/2016-UNEPReport-Complete4.pdf
21.02.2017Rheology modifying admixtures for concrete taken from nature | 26. Kolloquium | Rheologische Messungen an mineralischen Baustoffen | OTH Regensburg | [email protected]
Thank you very much for your kind attention!
47
Niwega!
Asante sana!Siyabonga!
Meu lap‘teu! E sé ún púpò!
Danke!