latest developments in concrete admixtures
DESCRIPTION
Latest developments in concrete admixturesTRANSCRIPT
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Latest developments i t d i tin concrete admixtures
29th October 200829th October 2008
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Programme
Intro to concrete admixturesI Self-compacting concrete
History, testing, project references Latest developments in SCC Latest developments in SCC
QuestionsQ
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Introduction to concrete admixturesconcrete admixtures
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History of admixture developments
ConcreteConcrete
History of admixture developments
development of VEAsdevelopment of VEAs
performanceperformance
PolyacrylatesPolyacrylatesPolycarboxylatesPolycarboxylates
development of VEA sdevelopment of VEA s
Hyper-plasticiser
NaphthalenesulphonatesNaphthalenesulphonatesMelaminesulphonatesMelaminesulphonates
Super-plasticiser
1950 1970 1980 1990 2008
LignosulphonatesLignosulphonatesPlasticiser
Plasticconcrete
Rheoplasticconcrete
Self compactingconcrete
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Admixture performanceAdmixture performance
Type Typical dosage % % water brandby weight of cement reduction name
Modified Lignosulfonate (MLS) 0.2 - 0.6 < 10 Pozzolith
NaphthaleneSulfonate (BNS) 0.8 - 1.5 < 26 Rheobuild
Polycarboxylic ether (PCE) 0.5 - 1.3 > 40 Glenium
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Performance of plasticising admixtures
8090
100
Polycarboxylate
40506070
o
w
[
%
]
Lignosulphonate
Melaminesulphonate
10203040
F
l
o
Polyacrylates
Naphthalenesulphonate
010
0 30 60 90 120 150 180
Time [min]Time [min]
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Self-compacting concreteconcrete
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ContentsContents
Why do we need it?
History & Definition of SCC
Testingg
Opportunities & benefits
Job references / case studies
Next generation SCC
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The problem
Inadequate & incomplete compaction dramatically lowers
The problem
Greatly reduced strength (1% voids reduces 28 days strength by
Inadequate & incomplete compaction dramatically lowers the quality of concrete:
more than 5%)
Lack of compaction of surface layer leads to poor durabilityperformance (durability closely associated with the permeabilityperformance (durability closely associated with the permeabilityof the surface layer of a concrete structure)
Poor appearance (surface finish)( ) Cube results not representing actual castings Inconsistent hardened properties (different permeabilities) in Inconsistent hardened properties (different permeabilities) in
various locations, enhancing the ingress of aggressive substances.
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FACTSFACTS
More than 90% of repair materials go to new construction sites
Ab t 100 000 t 200 000 Dh f i t i l About 100,000 to 200,000 Dhs of repair materials are consumed in a 40 story tower, on vertical elements alone.
On average the cost of repairs (in materials only) adds about On average, the cost of repairs (in materials only) adds about 20 to 30 Dhs/ m3 of concrete.
5 Million Dhs were consumed in a single project for repairs.5 Million Dhs were consumed in a single project for repairs.
40% of consultants time and efforts dedicated to inspection of repairs.p
End of Service life : When you start making the first repair
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The solutionThe solution
Design the concrete mix so thatNO NO
external compaction is required !
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What is SCC?What is SCC?
Definition:Definition:Definition:Definition:
highly flowable, yet stable concrete that can spread readilyinto place and fill the formwork without any consolidationand without undergoing any significant separation.g g y g p(by Khayat, Hu and Monty: Proc. 1st. Intl. RILEM Symposium, SCC, Stockholm 1999)
Flowing concrete without segregation and bleedingFlowing concrete without segregation and bleeding,capable of filling spaces and dense reinforcement orinaccessible voids without hindrance or blockage.(by EFNARC, Technical Committee, Self Compacting Concrete, London 2000)
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Types of SCCTypes of SCC
A.A. PowderPowder typetype Optimising the concrete structureby increasing the fines (
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The European Guidelines for Self-Compacting ConcreteSelf-Compacting Concrete(Specification, Production & Use)
In order to enhance the acceptance of SCC a joint project groupconsisting of :
BIBM (European Precast Concrete Organisation), CEMBUREAU (European Cement Association), ERMCO (European Ready-mix Concrete Organisation)ERMCO (European Ready mix Concrete Organisation), EFCA (European Federation of Concrete Admixture Association) and EFNARC (European Federation of Specialist Construction Chemicals
and Concrete Systems)
Published the "European Guidelines for Self-CompactingConcrete in 2005.
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EN206-9 & EN12350-8 to 12EN206-9 & EN12350-8 to 12
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Test MethodsTest Methods
Characteristic Test method(s)
Flowability and filling ability Slump-flow test (EN12350-8)
Viscosity T500 Slump-flow test or V-funnel test(EN12350 8 9)(EN12350-8 or 9)
Passing ability L-box test (EN12350-10)
Segregation Segregation (sieve) stability testSegregation Segregation (sieve) stability test(EN12350-11)
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Consistence classesConsistence classes
Slump-flow Slump-flow in mmSlump-flow Class
Slump-flow in mm
SF1 550 to 650SF1SF2SF3
550 to 650660 to 750760 to 850
Viscosity V-Funnel Time (s)Class
VF1 < 9VF2 9 to 25
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SCC vs. high slump concrete
Fill Box
g p
Fill BoxNormal Concrete (high slump, 200 mm+)
Fill BFill BoxSCC
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Testing SCCTesting SCC
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Where can SCC be used?
PilesPiles
Columns
Beams
Slabs
Precast
Rafts
Heavily reinforced elements
Areas of limited accessAreas of limited access
Anywhere that concrete is required !
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SCC Project Referencesj
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SCC Project ReferencesSCC Project References
1st SCC pour in the UAE
February 2001
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DXB International Airport,T i l 3Terminal 3
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Why SCC?Why SCC?
- The main contractor was looking for means to enhance his work programme and for early completion of the project.
- Reduction in concrete repairs was also another aim.
Cylinder strength No. of columns Volume
45/20 180 2 500 345/20 180 2,500 m360/10 62 2,000 m380/20 78 2 500 m380/20 78 2,500 m3
7,000 m3
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Advantages Offered:Advantages Offered:
Speed of construction: The use of SCC reduced the columns ti l f 7 d ( i i l d i t t i 3 l )casting cycle from 7 days (original design to cast in 3 layers),
to one day.
No remedial works required, therefore additional savings in manpower and materials.
The client was sure of the high quality and durability of the columns.
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Marina Heights Tower-DubaiBasement walls
Consultant: RMJMConsultant: RMJM
Contractor: Dutco Const.Co.
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Grosvenor House HotelTransfer beams (heavily reinforced)
C lt t A hConsultant: ArchonContractor: Nasa Multiplex
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Sewage Treatment PlantEmirates Hills
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Pump inletPump inlet
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Palm JumeirahSewage Treatment Works
Consultant: Ace ConsultantsContractor: Target Engg.
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SCC pumped from the side walls and flowing upwardsupwards.
Consultants: De Leuw Cather IntlConsultants: De Leuw Cather Int l
Contractor: Al Muheiry
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SCC raft
12,500m3 (3 pours of 2,300m3 + 1 pour of 5,600m3)
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Current status
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SCC raft pourSCC raft pour
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Value Engineering-Value EngineeringSummary:
To RMC To Contractors To Clients/Engineers
Efficient Fleet Utilisation. Speed of construction Early completion.
To RMC To Contractors To Clients/Engineers
Less wear & tear onequipment.
Less wear & tear onEquipment.
Enhanced durability,extended service life.q p
(concrete pumps)
Market Differentiation.
q p
Optimisation & reduction ofmanpower
Design benefits (on elements sizes).Market Differentiation. manpower
Savings in repair costs
(on elements sizes).
Noise reduction & environmental benefits
Savings in vibrators cost
environmental benefits.
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The next generation of gself-compacting concrete
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Smart Dynamic Concrete (SDC)For a new generation of highly fluid concretes
Solving the dilemmaSolving the dilemma
Self-compaction Robustness
Costeffectiveness
Obj ti f th j tTraditionallyVibrated Concrete (TVC)
Self-CompactingConcrete (SCC)
Objective of the project was to develop SCC mixes with cement Concrete (TVC) Concrete (SCC)
Robust mix No vibration
contents of 350- 400 kg/m3so as to be used in normal
ready mixed concreteLow stickiness
Good price
High speed
Great surface
SDCready mixed concrete.
Good price Great surface
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Fields of Application Made for day-to-day use
TVC SDC SCCApplications for fits to the following applicationsTVC SDC SCC
Special
Applications for: fits to the following applications
vertical: walls & columns (W)driver: surface quality
n
t
y
p
e
W
C
20% driver: surface quality
horizontal: floors (C) and
A
p
p
l
i
c
a
t
i
o
F
80%SDC
horizontal: floors (C) and foundations (F)
driver: labour productivity
Slump100-125 150-175
driver: labour productivity
Use SDC to convert high slump to true self-compacting concrete
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Construction Benefits
B fit
Adding value to concrete
M lti i it ti
Specifier + general contractor
BenefitsEconomical Savings in cement
U t 40% f t l i
Multi-win situation
ContractorReady-mix producer
Up to 40% faster placing Up to 5x higher labour productivity Easy to produce
Ecological Less cement, less CO2 Higher durability Specifier + general contractorg e du ab ty
Ergonomic No vibration No noise Low stickiness
Contractor
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Features & CostsMaterial cost in % per m3 concrete
FeaturesFeatures
Fines: Cement content >350 kg Slump flow: 60-70 cm
125%
150% 134%
Strength: C35 C50 Robust mix-design with
day-to-day raw material 75%
100%
125%100% 108%
day-to-day raw material
Self-compacting25%
50%
75%
M i l l i0%
TVC SDC SCC
Fi & Ad i t A t
SDC
Material cost analysis
TVC: reference SDC: 8% higher
Fines & Admixtures Aggregates SCC: 34% higher
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Cost savingsg
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Smart Dynamic ConstructionFull cost analysis
ApproachApproach
Stop-watch all activities Full cost analysis
5 process steps1. Outside formwork2 Reinforcement2. Reinforcement3. Inside formwork4. Concrete placing5 Remove formwork5. Remove formwork
Target Material cost impact (incl equipment cost) Material cost impact (incl. equipment cost) Labour cost impact
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Process Step 1 Placing outside formwork
TV Difference between TVC and SDCC
Formwork savings (less wear and tear)
Re-use of shutters increased by 5x
SDC
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Process Step 2Reinforcement
TV
Difference between TVC and SDC Same activities
C Same materials
Impact on total wall cost Material cost: 0 Dhs
SDC
Labour cost: 0 Dhs
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Process Step 3Placing inside formwork
TV Difference between TVC and SDCC
e e ce be ee C a d S C
Formwork savings (less wear and tear)
Re-use of shutters increased by 5x
SDC
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Process Step 5Removing formwork
TV
Difference between TVC and SDC Less cleaning with SDC
C Much higher surface quality with SDC For fair faced concrete: remedial work
savings of 25-75%savings of 25 75%
Impact on total wall cost
SDC
Reduced labour (no. & time)Reduced repairs (material & time)
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Full Cost Analysis Summary
300 TVC SDC Labour cost impact: -6%
200
250
- 3%
p
Material cost impact: -6%Plus:
100
150 + 8%
- 43%
0% Improved surface quality Higher safety
Faster constr ction
50Formwork Reinforcement Concrete Placing
- 43% Faster construction
In horizontal applications, the benefits of SDC pay off even better!
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Smart Dynamic ConcreteSmart Dynamic Concrete
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Summary
Technology Features Benefits in the field ofTechnology Robust mix design Tailor-made superplast. Exclusive VMA
Features Fines < 400 kg 60-70cm slump flow Self-compacting
Benefits in the field of Economics Ecology Ergonomics Exclusive VMA Self-compacting Ergonomics
Smart Dynamic Construction
New:
SDC makes unique mix-design optimization possible
SDC combines the advantages of both, TVC and SCC
RheoMATRIX is the key to solve paradox requirements: robustness (stability) + fluidity
SDC is cost effective: it saves labour and material costs
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Summaryy
Development of admixturesTh d f SCC
I The need for SCC Testing of SCCest g o SCC
SCC in use
SDC and RheoMATRIX
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Ultimate labour savingUltimate labour saving
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Chemistry-based innovationsf th t ti i d t
Thank you for for the construction industryyour attention!