experimental and numerical techniques to characterize ... · overview • contour crafting •...

18
Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete Concrete Tony Di Carlo, PhD candidate Anders Carlson, S.E., Ph.D. Behrokh Khoshnevis, Ph.D. University of Southern California Daniel J. Epstein Department of Industrial and Systems Engineering

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Page 1: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Experimental and Numerical Techniques to Characterize Structural Properties of Fresh

ConcreteConcrete

Tony Di Carlo, PhD candidate

Anders Carlson, S.E., Ph.D.

Behrokh Khoshnevis, Ph.D.

University of Southern California

Daniel J. Epstein Department of Industrial and Systems Engineering

Page 2: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Overview

• Contour Crafting• Properties of Fresh Concrete• Experimental Techniques• Experimental Techniques• Numerical Techniques• Fresh Concrete Stacking Regimens• Fresh Concrete Stacking Test• Opportunities for Research

Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 2May 30, 2012

Page 3: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Contour Crafting - Intro

• Computer-controlled layering of cementitious materials

• A special mixture of extrudable mortar• Successive layers accrete from the bottom up• Successive layers accrete from the bottom up• Process is formless; fresh mortar is shape stable• Green strength to match substantial and unprecedented fabrication loads

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 3

A prototypical structure and its fabrication tool path

(Zhang 2009)

Page 4: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Contour Crafting - Motivation

• Reduce the time and cost of fabrication• Automation → affordable high quality dwellings• Material savings (less waste and formwork)• Material savings (less waste and formwork)• Less labor, fewer construction-related injuries• More design freedom

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 4

Page 5: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Contour Crafting - Evolution

Un

cure

d C

era

mic

Ma

teri

als

(K

wo

n 2

00

2)

RapidSet Cement AllUltimax

Cement 35.3%Sand 40.6%Bentonite 2.5%

Water 21.6%(% by weight)

SikaRepairM

elt

ed

Po

lyst

yre

ne

(R

uss

ell

19

99

)

Un

cure

d C

era

mic

Ma

teri

als

(K

wo

n 2

00

2)

Co

ncr

ete

wit

h C

lay

VM

A (

Hw

an

g 2

00

5)

Plasterand Clay

Ultimax

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 5

Me

lte

d P

oly

sty

ren

e (

Ru

sse

ll 1

99

9)

Un

cure

d C

era

mic

Ma

teri

als

(K

wo

n 2

00

2)

Co

ncr

ete

wit

h C

lay

VM

A (

Hw

an

g 2

00

5)

'99 '00 '01 '02 '03 '04 '05 '06 '07 '08 '09 '10'98

Page 6: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Contour Crafting in Action

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 6

Page 7: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Contour Crafting – Fabrication Scenario

• Goal: a house in a day• Mortar stacking rate...

H

H=96” (8 feet)h=3”

n=94/3=32t= 8 hrs = 480 min

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 7

h

t= 8 hrs = 480 min

n/t = 32/480 n/t = 1 road / 15 min

Page 8: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Mix Design ↔ Stacking Regimen

Lightweight

Early Strength

Workability

ClayFly AshExpanded Glass

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 8

Internal curing (Green) Shape Stability

Page 9: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Properties of Fresh Concrete

Development of Compressive Strength of Extruded Cement

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 9

Development of Compressive Strength of Extruded Cement

Mortars (Voigt 2005)“at birth”† structural

properties of concrete

† credit: Mario Ucci

After Carino (2001) and Freiesleben (1985) the gradual strength development

during setting can be modeled with an exponential function:

y =Cemt

Page 10: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Experiments with Fresh Concrete

Bin to hold sand used to charge the

loading device.

Dummy specimen used to zero

extensometer.

6 in.x12 in. cylinder guided laterally and suspended by springs. The

cylinder collects sand flowing in at a constant rate from above. This charge stretches the suspension

system, and is considerably larger than the resistance exerted by the

compressed fresh mortar specimen - this disparity assures nearly constant axial strain rate.

Ram used to extrude

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 10

Digital weighing platform to measure

applied force.

Extensometer to measure slump and

axial deflection. Vibration table used to consolidate test specimens inside extrudable

cylindrical mold.

Ram used to extrude test specimens.

Page 11: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Stacking Strength

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 11

Page 12: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Stacking Regimen

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 12

0.0

10.0

20.0

0 100 200 300

Exponential Growth

F = Cemt

Time After Mixing [min.]

Ma

xim

um

Fo

rce

[l

bf]

Page 13: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Stacking Simulation

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 13

Page 14: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Numerical Methods for Fresh Concrete

Analysis of Fabrication

Scenarios, and In-Situ Health

Monitoring

Modulus

[psi]

Poisson’s

ratio, ν

Angle of

Friction

Initial Hydrostatic

Tension Strength

Dilation

Angle

Yield Stress

[psi]

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 14

[psi] ratio, ν Friction Tension Strength Angle [psi]

5 0.2 45 0.2 45 0.3

Typical Drucker-Prager parameters for a Contour-Craftable

mortar 30 minutes after mixing

Page 15: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Research Opportunities

• Varying temperatures • Varying moisture contents

• Analysis of creep• Analysis of autgeneous shrinkage cracking of the

monolithic structure• Optimize grading (including large aggregate) improve

shape stability and green strength• …

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 15

• …

Page 16: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Thank You for you Kind AttentionThank You for you Kind Attention

[email protected]

www.contourcrafting.org

Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 16May 30, 2012

Page 17: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Maison en Pise’ (Rammed Earth)

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 17

Ref. 1: « traité de construction en terre » CRATerre ed parenthèses, 1995, p. 207)

Ref. 2: « Architecture et Terre en SYRIE , une tradition de onze Millénaires » par Mahmoud BENDAKIR ed CRAterre. 2008.

Page 18: Experimental and Numerical Techniques to Characterize ... · Overview • Contour Crafting • Properties of Fresh Concrete • Experimental Techniques • Numerical Techniques •

Green Strength Test - Results

4.0

4.5

5.0

Dia

l Tur

ns (

1 re

volu

tion

= 0

.1 in

ches

)

5

6

0:060:11

Time AfterMixing

[hh:mm]

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Dia

l Tur

ns (

1 re

volu

tion

= 0

.1 in

ches

)

2

3

4

For

ce [l

bf]

0:110:180:220:260:310:470:520:581:041:131:241:32

May 30, 2012 Experimental and Numerical Techniques to Characterize Structural Properties of Fresh Concrete 18

Unconfined Compressive Strength of a Contour-Craftable Mortar

0.0

0.5

1.0

1.00 3.00 5.00

Raw Scale Reading [lb]

0

1

0.00 0.05

Strain [%]

1:321:391:491:543:283:314:434:48