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VOLUME STABLE CONCRETE USING SHRINKAGE REDUCING AND EXPANSIVE AGENTS -
APPLICATION IN STRUCTURES WITH SENSITIVE CRACKING BEHAVIOR
Kaspars KravalisProduct manager joint-less floors
New ideas in concrete
industry
Additive producers,
scientists
Contractors, end
users
Sometimes only for
lab, even perfect
Only what needed,
economical
Volume stable, shrinkage free
concrete
History of shrinkage reduced, compensated concrete
2000 years – expanding agents
50 years – expanding cements
40 years – SRA agents
15 years – combination of expanding agents and SRA
now – combination of all known + fibers = standards?
SHRINKAGE
Plastic reduced by SRA
Autogenousreduced by SRA and expanding additive
Chemical and dryingsmall reduction by SRA
Thermalcontrol with good mix design and reinforcement
Challenges before
Practically complicated
and....
PriceSRA agents historically used in dosages 2-5% from cement weight
Tasks we got from concrete industry in Scandinavia
To find best effect/cost margin for SRA agent use
To reduce thicknesses of slabs up to 20-30% due to less shrinkage
To make solution for use in joint-free slabs, bridge decks, tunnel walls, water dams, etc.
MAPEI answer to market questions and needs
Process of Mapecrete SRA-N behaviour
Shrinkage with increasing dosages of Mapecrete SRA-N
Around 40-50% shrinkage reduction using only SRA
How to get away even up to 70% of shrinkage?
Mapecrete® System - technology leans on the synergetic effect between an expansive agent (EXPANCRETE) and a shrinkage reducing admixture (MAPECRETE SRA-N)
+
Mix design
Material Dosage
Sand 0-8mm 64% of total aggregate
Stone 8-16mm 36% of total aggregate
Cement 315 kg/m3
Water 175 kg/m3
Superplasticiser (Dynamon XTend) 0,9% of cementweight
Expancrete 15 kg/m3
Mapecrete SRA-N 3,2 kg/m3
Steelfibre DE 50/0,75 N 35 kg/m3
Results – synergetic effect
ESEM
Reference concrete Mapecrete SRA-N + Expancrete
• Concrete is more dense• Less gaps between grains
Possibilities with Mapecrete system
If shrinkage is eliminated up to 50-70% and using proper slab calculation guidelines like TR34 (British):
Slabs can be reduced in thickness up to 30%
Max joint space for internal slabs – up to 50mMax for external – up to 30m
Joint free slab
Traditional slab 6*6m cut
Less concrete, less CO2 footprint
Around 400 000 m3 of concrete produced in last years all
around Scandinavia and Baltics using Mapecrete system for shrinkage reduction
Application – retail centers
COOP Bygg, Stavanger, Norway
Application – industrial floors
Warehouse Helsingborg, Sweden
Application – parking decks
Parking, Jesheim, Norway
Application – airport decks
Airport Lulea, Sweden
Application – decorative floors
Car showroom, Gislaved, Sweden
Application – bridge decks
Mosetertoppen, Hafjel, Norway
Application – special architectural concrete
Kodasema thin wall cabin houses in Estonia
Design awards in New York, London, etc.
Application – bridge pillar repair
Used also already in Lithuanian projects
• MEGA shopping center parking Kaunas
• Klaipeda sea port
• SANITEX projects
• many more
CONCLUSIONS
It is possible to reduce up to 70% from total
shrinkage
Mix designs contain around 0,7-1,5% SRA and 4-6%
expanding agents
System has been approved nicely in last years in
Scandinavian sites
Thank You for your attention!