Advanced

Betong till 3D-printning - egenskaper i färskt och hårdnat tillstånd

Hamelius, August LU and Ehrensvärd Backebjörk, Mikael (2015) In TVBK-5247 VBK920 20151
Division of Structural Engingeering
Abstract
Question formulation: The construction process today is slow, costly and generates large amounts of waste and emissions. In order to meet housing needs of the rapidly growing population in a sustainable way, the technology must evolve; it must be faster and more cost-effective. New technology, where concrete is manufactured by automated and computer-controlled 3D-printing, can possibly streamline the entire concrete building process.
3D-printing with concrete is a layer on layer based manufacturing process that follows a pre-programmed pattern. The concrete is extruded (ejected) from a nozzle mounted on a robot. The concrete is pressed, screwed or pumped out of the nozzle, and it must be self-supporting in order to build layer by layer.... (More)
Question formulation: The construction process today is slow, costly and generates large amounts of waste and emissions. In order to meet housing needs of the rapidly growing population in a sustainable way, the technology must evolve; it must be faster and more cost-effective. New technology, where concrete is manufactured by automated and computer-controlled 3D-printing, can possibly streamline the entire concrete building process.
3D-printing with concrete is a layer on layer based manufacturing process that follows a pre-programmed pattern. The concrete is extruded (ejected) from a nozzle mounted on a robot. The concrete is pressed, screwed or pumped out of the nozzle, and it must be self-supporting in order to build layer by layer. The manufacturing technology and the need for a self-supporting mass create high demands on the fresh concrete. Good balance between buildability and workability has to be established for the concrete mass to be useful. When designing and building elements or entire structures with 3D technology strength values of the concrete such as compressive strength, tensile strength and modulus of elasticity has to be evaluated.
Purpose: The report helps to streamline the construction industry using 3D-printed concrete. The objectives of this work are to:
• Acquire knowledge of 3D printed concrete
• Comparing production of 3D-concrete with conventional concrete and shotcrete
• Investigate the properties of the concrete in the fresh state
• Examine the hardened characteristics that can be expected of 3D-concrete
Method: A literature study was made to investigate the demands on the concrete. The technology and the used concrete mass were compared to conventional cast concrete and shotcrete to obtain knowledge of the concrete components and material properties.
Laboratory investigations were conducted to explain how material properties of concrete changes with the addition of different additives, both in fresh and hardened state
Conclusions: The study showed that the concrete composition depends not only on the structures to be built, but also on the design of the robot's nozzle. A recipe that works with all types of nozzles is therefore impossible to determine.
The consistency of the concrete cannot be too rigid, then it cannot be extruded, and it should not be too loose, then it does not achieve reasonable buildability. Reasonable buildability means that the lower layers are not noticeably deformed by the weight of the upper layers. With the nozzle and the concrete used a good balance, between workability and buildability, is achieved if the concrete in the fresh state has shear strength (consistency) between 0.6-1.0 kPa. To achieve good texture the recipes include retarder and very high levels of cement.
The consistency proved to be very sensitive to small variations in water content; this allows different types of mixers/mixing methods to also affect the consistency. Stiff texture of the concrete made it possible to build even layers. An early developed stiffness of the concrete mass resulted in that a number of layers could be constructed on top of one another without notable deformation of the lower layers.
The recipe developed provides a concrete strength in the same order of magnitude as high performance concrete. The involvement of plastic fiber has not given any verifiable increase in concrete strength, neither for 1 day or 28 days. The high compressive strength is a result of the low water/binder ratio required to obtain an extrudable and buildable consistency.
Keywords: Concrete for 3D-printing, 3D-printed concrete, concrete, additive manufacturing, freeform construction, Contour Crafting, high performance concrete (Less)
Abstract (Swedish)
Problemformulering: Byggprocessen är idag långsam, kostsam och genererar stora mängder spill och utsläpp. För att kunna möta bostadsbehovet från den snabbt växande befolkningsmängden måste tekniken utvecklas, den måste bli snabbare och mer kostnadseffektiv. Med ny teknik där betongelement tillverkas genom automatiserad och datorstyrd 3D-printning kan eventuellt hela betongbyggnadsprocessen effektiviseras.
3D-printning med betong är en lager på lager baserad tillverkningsteknik som följer ett förprogrammerat mönster. Betongen extruderas (matas ut) ur ett munstrycke som är monterat på en robot. Massan trycks, skruvas eller pumpas ut ur munstycket och den måste vara självbärande för att kunna byggas lager på lager. Tillverkningstekniken och... (More)
Problemformulering: Byggprocessen är idag långsam, kostsam och genererar stora mängder spill och utsläpp. För att kunna möta bostadsbehovet från den snabbt växande befolkningsmängden måste tekniken utvecklas, den måste bli snabbare och mer kostnadseffektiv. Med ny teknik där betongelement tillverkas genom automatiserad och datorstyrd 3D-printning kan eventuellt hela betongbyggnadsprocessen effektiviseras.
3D-printning med betong är en lager på lager baserad tillverkningsteknik som följer ett förprogrammerat mönster. Betongen extruderas (matas ut) ur ett munstrycke som är monterat på en robot. Massan trycks, skruvas eller pumpas ut ur munstycket och den måste vara självbärande för att kunna byggas lager på lager. Tillverkningstekniken och en självbärande massa ställer höga krav på betongen i färskt tillstånd. En god balans mellan byggbarhet och arbetbarhet måste fastställas för att betongmassan skall kunna vara användbar. För att kunna dimensionera och bygga element eller hela byggnader med 3D-teknik måste tryckhållfasthet, draghållfasthet och elasticitetsmodul för betongen vara tillräckliga.
Syfte: Rapporten avser att bidra till en effektivisering av byggnadsbranschen med hjälp av 3D-printad betong. Målen med detta arbete är att:
• Införskaffa kunskap om 3D-printad betong
• Jämföra 3D-tillverkning av betong med konventionell betong och sprutbetong
• Utreda betongens egenskaper i färskt tillstånd
• Undersöka vilka härdade egenskaper som kan förväntas av 3D-betong
Metod: En litteraturstudie gjordes för att utreda de krav som ställs på betong till 3D-printning. Tekniken och betongmassan som används jämfördes med konventionellt gjuten betong och sprutbetong för att erhålla kunskap om betongens beståndsdelar och materialegenskaper.
Laborationsundersökningar utfördes för att redogöra hur materialegenskaper hos betongen förändras vid tillsats av olika tillsatsmedel och tillsatsmaterial, både i färskt och hårdnat tillstånd
Slutsatser: Studien visade att betongsammansättningen inte bara beror på de konstruktioner som ska byggas utan även på utformningen av robotens munstycke. Ett recept som fungerar med alla typer av munstycken går därför inte att fastställa.
Konsistensen för denna betong kan inte vara för styv, då går den inte att extrudera, och den får inte vara för lös, då uppnås inte rimlig byggbarhet. Rimlig byggbarhet innebär att de undre lagren inte deformeras märkvärt av tyngden från de övre lagren. Med munstycket och betongen som använts uppnås god balans, mellan arbetbarhet och byggbarhet, om betongen i färskt tillstånd har en skjuvhållfasthet (konsistens) mellan 0,6-1,0 kPa. För att uppnå god konsistens innehåller recepten bland annat mycket retarder och höga halter av cement. Konsistensen visade sig vara mycket känslig för små variationer i vattenhalt, detta gör att olika typer av blandare/blandningsmetoder också påverkar konsistensen. En styv konsistens gjorde det möjligt att bygga jämna lager. Den tidiga strukturutvecklingen hos betongmassan resulterade i att ett flertal lager kunde byggas ovanpå varandra utan märkbar deformation av de undre lagren.
Receptet som tagits fram ger en betong med hållfastheter i samma storleksordning som högpresterande betong. Inblandningen av plastfiber har inte gett någon verifierbar ökning av betongens hållfasthet, varken efter 1 dygn eller 28 dygn. Den höga tryckhållfastheten är en effekt av det låga vattenbindemedelstal som krävs för att få en extruderbar och byggbar konsistens.
Nyckelord: Betong till 3D-printning, 3D-printad betong, betong, additiv tillverkning, friformframställning, högpresterande betong (Less)
Popular Abstract (Swedish)
Byggindustrin kan effektiviseras med hjälp av 3D-printningsteknik. Avancerad datorstyrd tredimensionell teknik har redan revolutionerat många andra industriella tillverkningsprocesser. Med högpresterande betong och robotteknik är det nu möjligt att 3D-printa hela hus i betong.
Please use this url to cite or link to this publication:
author
Hamelius, August LU and Ehrensvärd Backebjörk, Mikael
supervisor
organization
alternative title
Concrete for 3D-Printing - properties in fresh and hardened state
course
VBK920 20151
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
high performance concrete, Contour Crafting, freeform construction, additive manufacturing, concrete, 3D-printed concrete, Concrete for 3D-printing, högpresterande betong, friformframställning, additiv tillverkning, betong, 3D-printad betong, Betong till 3D-printning
publication/series
TVBK-5247
report number
LUTVDG/TVBK-15/5247
ISSN
0349-4969
language
Swedish
additional info
Examinator: Eva Frühwald Hansson
id
7853408
date added to LUP
2015-09-03 11:14:26
date last changed
2015-09-03 11:14:26
@misc{7853408,
  abstract     = {Question formulation:	The construction process today is slow, costly and generates large amounts of waste and emissions. In order to meet housing needs of the rapidly growing population in a sustainable way, the technology must evolve; it must be faster and more cost-effective. New technology, where concrete is manufactured by automated and computer-controlled 3D-printing, can possibly streamline the entire concrete building process.
3D-printing with concrete is a layer on layer based manufacturing process that follows a pre-programmed pattern. The concrete is extruded (ejected) from a nozzle mounted on a robot. The concrete is pressed, screwed or pumped out of the nozzle, and it must be self-supporting in order to build layer by layer. The manufacturing technology and the need for a self-supporting mass create high demands on the fresh concrete. Good balance between buildability and workability has to be established for the concrete mass to be useful. When designing and building elements or entire structures with 3D technology strength values of the concrete such as compressive strength, tensile strength and modulus of elasticity has to be evaluated.
Purpose:	The report helps to streamline the construction industry using 3D-printed concrete. The objectives of this work are to:
•	Acquire knowledge of 3D printed concrete
•	Comparing production of 3D-concrete with conventional concrete and shotcrete
•	Investigate the properties of the concrete in the fresh state
•	Examine the hardened characteristics that can be expected of 3D-concrete
Method:	A literature study was made to investigate the demands on the concrete. The technology and the used concrete mass were compared to conventional cast concrete and shotcrete to obtain knowledge of the concrete components and material properties.
Laboratory investigations were conducted to explain how material properties of concrete changes with the addition of different additives, both in fresh and hardened state
Conclusions:	The study showed that the concrete composition depends not only on the structures to be built, but also on the design of the robot's nozzle. A recipe that works with all types of nozzles is therefore impossible to determine.
The consistency of the concrete cannot be too rigid, then it cannot be extruded, and it should not be too loose, then it does not achieve reasonable buildability. Reasonable buildability means that the lower layers are not noticeably deformed by the weight of the upper layers. With the nozzle and the concrete used a good balance, between workability and buildability, is achieved if the concrete in the fresh state has shear strength (consistency) between 0.6-1.0 kPa. To achieve good texture the recipes include retarder and very high levels of cement.
The consistency proved to be very sensitive to small variations in water content; this allows different types of mixers/mixing methods to also affect the consistency. Stiff texture of the concrete made it possible to build even layers. An early developed stiffness of the concrete mass resulted in that a number of layers could be constructed on top of one another without notable deformation of the lower layers.
The recipe developed provides a concrete strength in the same order of magnitude as high performance concrete. The involvement of plastic fiber has not given any verifiable increase in concrete strength, neither for 1 day or 28 days. The high compressive strength is a result of the low water/binder ratio required to obtain an extrudable and buildable consistency.
Keywords: 	Concrete for 3D-printing, 3D-printed concrete, concrete, additive manufacturing, freeform construction, Contour Crafting, high performance concrete},
  author       = {Hamelius, August and Ehrensvärd Backebjörk, Mikael},
  issn         = {0349-4969},
  keyword      = {high performance concrete,Contour Crafting,freeform construction,additive manufacturing,concrete,3D-printed concrete,Concrete for 3D-printing,högpresterande betong,friformframställning,additiv tillverkning,betong,3D-printad betong,Betong till 3D-printning},
  language     = {swe},
  note         = {Student Paper},
  series       = {TVBK-5247},
  title        = {Betong till 3D-printning - egenskaper i färskt och hårdnat tillstånd},
  year         = {2015},
}