Efficient pumping of concreteEfficient pumping of Light Weight Aggregate Concrete (Part I)

Jon Håvard Mork, Stefan Jacobsen

Oslo 20.05.2008

Background and goal

Background – Trend with light weight high performance pumpable products

to make constructions slimmer, lighter as for floating bridges and offshore constructions and still have good mechanical properties.

– New applications coming up as in sandwich constructions as for floating ships, storage tanks (LNG), heavy lifters etc.

– A need for light weight products in repair of existing buildings / constructions without excessive extra reinforcement and where existing buildings not can be removed.

– Efficient industrial application a prerequisiteObjectives– Study the rheological properties and pumpability mechanics

of high performance pumpable light weight concretes

Instrumentation (After pre-feasibility studies)

Laboratory tests 2007Program for developing 8 open, pumpable and basic recipes for further studies (Standard/LWA, 4/8mm, 30/60MPa)

Objectives:– 8 Open pumpable basic recipes for

• Further research in COIN• Student work at NTNU

– Feasibility study• Which further studies are most interesting to continue with• Needs for complimentary test methods and equipment?

maxit ton 915

Recipe1 Recipe2 Recipe3 Recipe4 Recipe5 Recipe6 Recipe7 Recipe8

Comment Reference LC 25/28

Reference 4mm 30MPa

Reference 4mm 60 MPa

Reference 8mm 30MPa

Reference 8mm 60 MPa

4mm 30MPa

4mm 60 MPa

8mm 30MPa

8mm 60MPa

Micro LWA X X X X X X X X Sand 4mm X X X X X X X X Sand 8mm X X LWA 0-3mm X X X X LWA 2-4mm X X X X LWA 8mm X X

Some pumpable mortar recipes Recipe1 Recipe2 Recipe3 Recipe4 Recipe5 Recipe6 Recipe7 Recipe8 Comment Reference 4mm

30MPa Reference 4mm 60 MPa

Reference 8mm 30MPa

Reference 8mm 60 MPa

4mm 30MPa

4mm 60 MPa

8mm 30MPa

8mm 60MPa

Micro LWA X X X X X X X X Sand 4mm X X X X X X X X Sand 8mm X X LWA 0-3mm X X X X LWA 2-4mm X X X X LWA 8mm X X

Materialer kg/m3 l/m3Norcem Standard FA 473,00 160,3Industri 0,00 0,0Silikastøv 0,00 0,0Flyveaske 0,00 0,0Micro LWA 41,00 15,8Kalksteinfiller 0,00 0,0Copoksylat 1,39 1,2TSS2 1,33 1,1Stabilisator 0,00 0,0Fritt vann 263,00 263,0Luftinnhold 50,00Sum pasta 779,7 491,4

Leca 2-4 mm 161,1 240,4Norstone Fillersand 563,7 212,7

Norstone Årdal 0-8 NSBR 0,0 0,0HF Leca 0-3 mm 80,5 55,5

Ingen 0,0 0,0Ingen 0,0 0,0

0,0 0,0Sum tilslag 805,3 508,6Prop. betongdens. (kg/m3) 1600 1000

Materialer kg/m3 l/m3Norcem Standard FA 550,00 186,4Industri 0,00 0,0Silikastøv 0,00 0,0Flyveaske 0,00 0,0Micro LWA 41,00 15,8Kalksteinfiller 0,00 0,0Copoksylat 4,40 3,7TSS2 0,00 0,0Stabilisator 0,00 0,0Fritt vann 240,00 240,0Luftinnhold 50,00Sum pasta 835,4 495,9

Leca 2-4 mm 0,0 0,0Norstone Fillersand 472,5 178,3

Norstone Årdal 0-8 NSBR 0,0 0,0HF Leca 0-3 mm 472,5 325,8

Ingen 0,0 0,0Ingen 0,0 0,0

0,0 0,0Sum tilslag 944,9 504,1Prop. betongdens. (kg/m3) 1813 1000

Materialer kg/m3 l/m3Norcem Standard FA 473,00 160,3Industri 0,00 0,0Silikastøv 0,00 0,0Flyveaske 0,00 0,0Micro LWA 41,00 15,8Kalksteinfiller 0,00 0,0Copoksylat 1,20 1,0TSS2 1,67 1,4Stabilisator 0,02 0,0Fritt vann 270,00 270,0Luftinnhold 50,00Sum pasta 786,9 498,5

Leca 2-4 mm 81,7 121,9Norstone Fillersand 245,1 92,5

Norstone Årdal 0-8 NSBR 163,4 61,7HF Leca 0-3 mm 204,3 140,9HF Leca 4-8 mm 122,6 84,5

Ingen 0,0 0,00,0 0,0

Sum tilslag 817,0 501,5Prop. betongdens. (kg/m3) 1633 1000

Materialer kg/m3 l/m3Norcem Standard FA 553,00 187,5Industri 0,00 0,0Silikastøv 0,00 0,0Flyveaske 0,00 0,0Micro LWA 41,00 15,8Kalksteinfiller 0,00 0,0Copoksylat 4,10 3,4Air entr 1,94 1,6Stabilisator 0,00 0,0Fritt vann 240,00 240,0Luftinnhold 50,00Sum pasta 840,0 498,3

Leca 2-4 mm 0,0 0,0Norstone Fillersand 282,1 106,5

Norstone Årdal 0-8 NSBR 188,1 71,0HF Leca 0-3 mm 282,1 194,6HF Leca 4-8 mm 188,1 129,7

Ingen 0,0 0,00,0 0,0

Sum tilslag 940,5 501,7Prop. betongdens. (kg/m3) 1813 1000

Conclusions

Pumpability has been achieved partly by increasing the paste volume and in LWA concrete to use high enough water content to assure excess of water after mixing and pumping as the LWA concrete under pumping matures and the LWA particles absorb water. The finished products are stable

LWA Concrete contra normal concrete

The LWA concrete proportioned in this way seems to have higher pump flow compared to traditional mortars at constant pump frequency.

Output volume

0,00

5,00

10,00

15,00

20,00

25,00

30,00

35,00

40,00

0 10 20 30 40 50 60

Time [s]

Volu

me

[l]

Recipe 1 Volume litreRecipe 2 Volume litreRecipe 3 Volume litreRecipe 4 Volume litreRecipe 5 Volume litreRecipe 6 Volume litreRecipe 7 Volume litreRecipe 8 Volume litremaxit ton 916 Volume litre

τ and µ

The LWA concrete mixes have lower initial yield stress and viscosity compared to the reference mixes

Tau and My

Reference 4mm 30 MPa

Reference 4mm 60 MPa

Reference 4mm 60 MPa

Reference 8mm 30 MPa

Reference 8mm 30 MPa

LWA 4mm 30 MPa

LWA 4mm 60 MPa

LWA 8mm 30 MPa

LWA 8mm 60 MPaLWA 8mm 60 MPa

maxit ton 915

maxit ton 915

Reference 4mm 30 MPa

Reference 8mm 60 MPaLWA 4mm 30 MPa

LWA 4mm 60MPa

-3,00

47,00

97,00

147,00

197,00

247,00

0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00 8,00 9,00

My

Tau

Reference 4mm 30 MPaReference 4mm 30 MPaReference 4mm 60 MPaReference 4mm 60 MPaReference 8mm 30 MPaReference 8mm 30 MPaReference 8mm 60 MPaReference 8mm 60 MPaLWA 4mm 30 MPaLWA 4mm 30 MPaLWA 4mm 60 MPaLWA 4mm 60 MPaLWA 8mm 30 MPaLWA 8mm 30 MPaLWA 8mm 60 MPaLWA 8mm 60 MPamaxit ton 915maxit ton 915

Motor effect pumpThe particular LWA concretes needed less energy in the pump engine, which can be explained by the mix design.

Effect motor

8

9

10

11

12

13

14

15

16

0 10 20 30 40 50 60 70

Time [s]

Effe

ct [A

]

Recipe 1 Current ARecipe 2 Current ARecipe 3 Current ARecipe 4 Current ARecipe 5 Current ARecipe 6 Current ARecipe 7 Current ARecipe 8 Current Amaxit ton 915 Current A

Pressure in hosesThe particular LWA concretes had less pressure in the hoses, which can be explained by the mix design.

Pressure between hoses

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

0 10 20 30 40 50 60 70

Time [s]

Pres

sure

[bar

]

Recipe 1 Pressure 2 barRecipe 2 Pressure 2 barRecipe 3 Pressure 2 barRecipe 4 Pressure 2 barRecipe 5 Pressure 2 barRecipe 6 Pressure 2 barRecipe 7 Pressure 2 barRecipe 8 Pressure 2 barmaxit ton 915 Pressure 2 bar

Theory and practice on outputThe theoretical output calculated with a simple analytical model combining the Hagen Poiselle flow and the Bingham rheology model, is in the same range as the measured, and by adjusting the viscosity from the BML viscometer slightly there will be a match. The necessary slight adjustment seems to vary randomly in addition or subtraction.

Correlation measured and theoretical values output

0,93; 1,04

1,82; 2,01

0,00

0,50

1,00

1,50

2,00

2,50

3,00

0,00 0,50 1,00 1,50 2,00 2,50 3,00

Calculated

Mea

sure

d

kg/s

l/s

Average

Average

⎟⎠⎞

⎜⎝⎛ −−= oconcx dx

dpaag τµ 3

28,

Overall Conclusions

It is possible to design a pumpable LWA concrete with dry aggregatesTheoretical models gives results in the same range as measuredFurther studies of pumping mechanisms and rheological properties are very interesting including simulations