Home > Documents > Mortar rheology

Mortar rheology

Date post: 12-Jan-2017
Category:
Author: voque
View: 238 times
Download: 1 times
Share this document with a friend
Embed Size (px)
of 32 /32
Rheology of fresh concrete Influence of superplasticizers dr. Luka Zevnik, Vesna Jereb Regensburg 2013
Transcript
  • Rheology of fresh concreteInfluence of superplasticizers

    dr. Luka Zevnik, Vesna Jereb

    Regensburg 2013

  • Air-migration The undesirable condition in which entrapped air in fresh SCC migrates tothe top surface causing a bubbling or boiling appearance. This is an indication of unstable airand a low viscosity mortar. Air-popping is another term used for this occurrence.

    Bleeding The water that appears to rise to the surface of concrete subsequent toplacement. ACI defines bleeding as the autogenous flow of mixing water within, or itsemergence from, newly placed concrete or mortar; caused by settlement of solid materialswithin the (concrete) mass.

    Blocking The condition in which coarse aggregate particles combine to form elementslarge enough to obstruct flow of the fresh concrete between reinforcing steel or otherobstructions in the concrete formwork. This property is of increased importance in SCCbecause of the absence of vibration energy to dislodge these blockages.

    Cohesiveness The tendency of SCC to stick together, resulting in resistance to segregation,aggregate settlement, and bleeding.

    Dynamic stability The characteristic of a fresh SCC mix that ensures uniform distributionof all solid particles and air voids as the SCC is transported and placed.

    Filling ability The ability of SCC to flow under its own weight (without vibration) into andfill completely all spaces within formwork containing obstacles such as reinforcement.

    Finishability The ease with which SCC can be finished to achieve the desired surfaceflatness and smoothness on that portion of an element that must be finished. Finishabilitydoes not refer to formed surface finish quality.

    Passing ability The ability of SCC to flow through openings approaching the size of the mix s nominal max size aggregate without segregation or aggregate blocking

    Pumpability The ability to pump without significant degradation of fresh concrete properties.Sumpflow t500Stability the ability of fresh SCC to remain homogeneous during mixing, transportation, handling, placement, finishing, curing.Static stability The charactaristic of concrete to maintain a uniform distribution of all solid particles and air voids once all placement operation are complete. Stickiness Adherance to finishing toolsViscosityWater sensitivity The amount of free water variation witin the mixture change the stability (and other SCC properties) of concrete from accaptable to unaccaptable range.

    Introduction

    Definitions and terms Relating to SCC [http://www.na.graceconstruction.com/custom/concrete/downloads/tb_1501b.pdf]

  • How could we evaulte superplasticizer influence on concrete rheology(robustness etc)?

    Numerous investigations on job sites, and long term use in practice Is there any other option? Could we predict the concrete rheology with mortar or paste

    experiments?

    Superplasticizer influence on concrete rheology

    Concrete Mortar PasteCEqM MEqP

  • Superplasticizer influence on concrete rheology

    020406080

    100% (dry solids)/powder mat.

    consistency loss

    robustness

    min. powder content/m3

    water reductionlow critical shear rate

    low shear thickening

    low concr. viscosity

    static seggreg. resistence

  • 0,50 0,45 0,40 0,35 0,30 0,25 0,20 0,15water/powder

    pote

    ntia

    l pro

    blem

    s w

    ith c

    oncr

    ete

    rheo

    logy

    Flowable concrete, SCC, HPCC30/37 S4C25/30 S3

    0,50 0,45 0,40 0,35 0,30 0,25 0,20 0,15water/powder

    pote

    ntia

    l pro

    blem

    s w

    ith c

    oncr

    ete

    rheo

    logy

    Flowable concrete, SCC, HPCC30/37 S4C25/30 S3

    Normal use of usual PCE...

    Superplasticizer influence on concrete rheology

  • 0,40 0,35 0,30 0,25

    PCE 3

    PCE 2

    water/powder

    pote

    ntia

    l pro

    blem

    s w

    ith c

    oncr

    ete

    rheo

    logy

    Flowable concrete, SCC, HPCC30/37 S4C25/30 S3

    PCE 1

    Superplasticizer influence on concrete rheology

  • Concrete rheology evaluation

    Important rheological concrete parameters

    Cohesivity

    Bleeding

    Seggregation at rest

    Seggregation at pumping

    Slump shape

    Sound at mixing (air content)

    Most advanced concrete rheometer

    My collegue Vlado10.000+ concrete mixes

  • Concrete rheology evaluation standard investigations

    Concrete PCE Concrete Ph

    CEM II A-M (LL-S) 42,5R 420 kg 420 kg

    Limestone filler 90 kg 90 kg

    Crushed aggregate 0/2, Soa 842 kg 842 kg

    Natural aggregate 4/8, Soa 258 kg 258 kg

    Natural aggregate 8/16, Soa 592 kg 592 kg

    w/c 0,44 0,44

    Air content 1,6 % 2 %

    PCE (dry content) 0,21% /

    Ph (dry content) / 0,63%

    Cohesivity Slumpflow, t500 V - funnel

  • Concrete PCE Concrete Ph

    CEM II A-M (LL-S) 42,5R 420 kg 420 kg

    Limestone filler 90 kg 90 kg

    Crushed aggregate 0/2, Soa 842 kg 842 kg

    Natural aggregate 4/8, Soa 258 kg 258 kg

    Natural aggregate 8/16, Soa 592 kg 592 kg

    w/c 0,44 0,44

    Air content 1,6 % 2 %

    PCE (dry content) 0,21% /

    Ph (dry content) / 0,63%

    flow 680 mm 670 mm

    t500 4,0s 2,2s

    V funnel 9,3 s 6,5 s

    L box (H1/H2) 91% 89%

    cohesivity ***** *****Overall filing Quite good Good

    Concrete rheology evaluation standard investigations

  • Mortar PCE Mortar Ph

    CEM II A-M (LL-S) 42,5R

    600 g 600 g

    Limestone filler 177 g 177 g

    Quartz sand 0-1 775 g 775 g

    Quartz sand 0,5-1 87 g 87 g

    w/c 0,475 0,480

    Air content 2% 2%

    PCE 0,24% /

    Ph / 0,65%

    Mortar rheology standard investigations

    Cohesivity- mortar Slumpflow - mortar

  • Mortar PCE Mortar Ph

    CEM II A-M (LL-S) 42,5R

    600 g 600 g

    Limestone filler 177 g 177 g

    Quartz sand 0-1 775 g 775 g

    Quartz sand 0,5-1 87 g 87 g

    w/c 0,475 0,480

    Air content 2% 2%

    PCE 0,24% /

    Ph / 0,65%

    flowminicone 39,5 cm 36,5 cm

    t 250 4,7 s 2,6 s

    t final 50 s 20,5 s

    Cohesivity ***** *****Overall filing Bad Very good

    Mortar rheology standard investigations

  • Vogel [Ein Messezell fur Specialmortel, www.vogel-labor.de]type measuring body. [www.schleibinger.com]

    Rheology of mortar =Viscomat NT + Vogel cell

    Calibration (TKK)

    /N = 0,447 [min]/[s] crit-/( /pl) = 0,321

    cK = 0,868 /T = 0,76 [Pa]/[mNm]

    0 1 2 3 40

    10

    20

    30

    40

    50

    60

    70

    N (RP

    M)

    time (min)

    A typical speed profile.

    Mortar rheology rheological experiments

  • Mortar SCC and Mortar Ph

    0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    Mortar rheology rheological experiments

    = 10 1/s = 1 1/s = 0,1 1/s

  • 0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar PCE Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology rheological experiments

  • 0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 7 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar PCE Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology rheological experiments

  • 0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar SCC Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology rheological experiments

  • 0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar SCC Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology rheological experiments

  • 0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar SCC Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology rheological experiments

  • 0,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

    parameter Mortar SCC Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit] 1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    0 5 10 15 20 250

    50

    100

    150

    200

    250

    (P

    a)

    (1/s)

    mortar PCE mortar Ph

    Mortar rheology rheological experiments

  • Mortar PCE Mortar Ph

    flowminicone 39,5 cm 36,5 cm

    t 250 4,7 s 2,6 s

    t final 50 s 20,5 s

    Cohesivity ***** *****Overall filing Bad Very good

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1]

    1,7 4,2

    Shear thinning [@1]/[@crit]

    1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

    Mortar rheology standard vs. Vogel rheology

    Stand. e xp.Vogel rh eology

  • Paste rheology standard experiments

    Paste PCE Paste Ph

    CEM II A-M (LL-S) 42,5R

    600 g 600 g

    Limestone filler 177 g 177 g

    w/c 0,45 0,45

    PCE 0,24% /

    Ph / 0,65%

    flowminicone 29,5 cm 26,5 cm

    Cohesivity ? ?Overall filing ?? ??

  • parameter Paste PCE Paste Ph

    crit 4,3 s-1 12 s-1

    @crit = (min. ) 0,89 Pas 1,09 Pas

    Shear thinning [@0,1]/[@1] 2,26 4,85

    Shear thinning [@1]/[@crit] 1,29 3,7

    Shear thickening [@crit]/[@20]

    0,58 0,77

    0 5 10 15 20 250

    5

    10

    15

    20

    25

    30

    35

    (Pa

    )

    (1/s)

    paste PCE paste Ph

    0,1 1 100,1

    1

    10

    (P

    as)

    (1/s)

    paste PCE paste Ph

    Paste rheology rheological experiments

  • Paste rheology vs. Mortar rheology

    parameter Paste PCE

    Paste Ph

    crit 4,3 s-1 12 s-1

    @crit = (min. ) 0,89 Pas 1,09 Pas

    Shear thinning [@0,1]/[@1] 2,26 4,85

    Shear thinning [@1]/[@crit] 1,29 3,7

    Shear thickening [@crit]/[@20]

    0,58 0,77

    0,1 1 100,1

    1

    10

    (P

    as)

    (1/s)

    paste PCE paste Ph

    parameter Mortar SCC

    Mortar Ph

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 Pas

    Shear thinning [@0,1]/[@1] 1,7 4,2

    Shear thinning [@1]/[@crit]

    1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,870,1 1 10

    6

    10

    100

    mortar PCE mortar Ph

    (P

    as)

    (1/s)

  • Concrete rheology vs. Mortar rheology

    Concrete PCE

    Concrete Ph

    flow 680 mm 670 mm

    t500 4,0s 2,2s

    V funnel 9,3 s 6,5 s

    cohesivity ***** *****

    Mortar PCE Mortar Ph

    flow 395 mm 365 mm

    t250 4,7s 2,6s

    t final 50 s 20,5 s

    cohesivity ***** *****

    crit 7 s-1 11 s-1

    @crit = (min. ) 8,5 Pas 6,2 PasShear thinning [@0,1]/[@1]

    1,7 4,2

    Shear thinning [@1]/[@crit]

    1,35 2,3

    Shear thickening [@crit]/[@20]

    0,625 0,87

  • PCE (pure) superplasticizers: Mortar rheology

    0,1 1 10

    10

    100

    PCE 1 PCE 2 PCE 3

    (P

    as)

    (s-1)

    parameter PCE 1 PCE 4 PCE 1 PCE 2 PCE 3

    Mortar 1: agg. Size 0-1mm, w/c=0,475 Mortar 0: agg. Size 0-2mm, w/c=0,50

    Flow 39,5 cm 37 cm 37 cm 33,5 cm 35 cm

    Dosage (dry solids) 0,24 % 0,35 % 0,24 % 0,32 % 0,36 %

    crit 7 s-1 7,5 s-1 10,2 s-1 10 s-1 10,6 s-1

    @crit = (min. ) 8,5 Pas 6,6 Pas 7,6 Pas 10,7 Pas 8,5 Pas

    Shear thinning [@0,1]/[@1]

    1,7 2,5 3,0 3,50 3,53

    Shear thinning [@1]/[@crit]

    1,34 1,72 1,76 1,87 2,04

    Shear thickening [@crit]/[@20]

    0,63 0,75 0,85 0,87 0,87

    0,1 1 10

    10

    100

    PCE 1 PCE 4

    (P

    as)

    (1/s)

  • Superplasticizer formulations: mortar rheology

    Mortar No

    PCE 1 LSb w/c Flow Cohesivity

    Bleeding

    Seggreg

    Overall filling

    1 0,24% 0,00% 0,475 43 cm ***** *** *** very bad

    2 0,24% 0,09% 0,50 44,5 cm ***** *** *** bad3 0,24% 0,18% 0,50 42,5 cm ***** *** *** ok4 0,24% 0,27% 0,50 39 cm ***** *** *** good5 0,24% 0,36% 0,53 40,5 cm ***** *** *** excelen

    t

    0 2 4 6 8 100

    10

    20

    30

    40

    50

    60

    70

    80 LS 0% w/c=0,475 LS 0,09% w/c=0,50 LS 0,18% w/c=0,50 LS 0,27% w/c=0,50 LS 0,36% w/c=0,525

    (Pa

    )

    (1/s)0,1 1 7 10

    5

    10

    15

    20

    25

    30 LS 0% w/c=0,475 LS 0,09% w/c=0,50 LS 0,18% w/c=0,50 LS 0,27% w/c=0,50 LS 0,36% w/c=0,525

    (P

    as)

    (1/s)

  • parameter Mortar 1 Mortar 2 Mortar 3 Mortar 4 Mortar 5w/c 0,475 0,50 0,50 0,50 0,53PCE (dry solids) 0,24% 0,24% 0,24% 0,24% 0,24%LS (dry solids) 0,00% 0,09% 0,18% 0,27% 0,36%Flow (minicone) 43 cm 44,5 cm 42,5 cm 39 cm 40,5 cmCohesivity ***** ***** ***** ***** *****Bleeding *** *** *** *** ***Segregation *** *** *** *** ***Overall filling very bad bad ok good excellent

    crit 4 s-1 8 s-1 7,4 s-1 9,1 s-1 11 s-1

    @crit = (min. )

    6,6 Pas 3,8 Pas 5 Pas 4,8 Pas 3,8 Pas

    Shear thinning [@0,1]/[@1]

    1,34 1,30 1,75 2,39 2,52

    Shear thinning [@1]/[@crit]

    1,12 1,31 1,58 1,81 1,95

    Shear thickening [@crit]/[@20]

    0,61 0,72 0,72 0,85 0,90

    Superplasticizer formulations: mortar rheology

  • parameter Mortar 1 Mortar 2 Mortar 3 Mortar 4 Mortar 5w/c 0,475 0,50 0,50 0,50 0,53PCE (dry solids) 0,24% 0,24% 0,24% 0,24% 0,24%LS (dry solids) 0,00% 0,09% 0,18% 0,27% 0,36%Flow (minicone) 43 cm 44,5 cm 42,5 cm 39 cm 40,5 cmCohesivity ***** ***** ***** ***** *****Bleeding *** *** *** *** ***Segregation *** *** *** *** ***Overall filling very bad bad ok good excellent

    0,0 0,1 0,2 0,3 0,40,47

    0,48

    0,49

    0,50

    0,51

    0,52

    0,53

    0,54

    max w/c

    max

    w/c

    % LSds

    0,0 0,1 0,2 0,3 0,43

    4

    5

    6

    7

    8

    9

    10

    11

    12

    min vis. gamma crit

    visc

    osity

    (Pas

    ), cr

    itica

    l (P

    a)

    0,0 0,1 0,2 0,3 0,41,0

    1,5

    2,0

    2,5

    3,0

    shear thinn 0,1/1 shaat thinn 1/gamma cr.

    shea

    r thi

    nnin

    g

    % LSds

    0,0 0,1 0,2 0,3 0,4

    0,6

    0,7

    0,8

    0,9

    % LSds

    % LSds

    shaer thick.

    shea

    r thi

    cken

    ing

    Superplasticizer formulations: mortar rheology

  • parameter Mortar 1b Mortar 4b

    w/c 0,50 0,525

    PCE (dry solids) 0,24% 0,24%

    LS (dry solids) 0,00% 0,27%Flow 10 min 10 min 40 cm 35 cmCohesivity 10 min ***** *****Bleeding 10 min *** ***Segregation 10 min *** ***Flow 60 min 60

    min38 cm 41 cm

    Cohesivity 60 min ***** *****Bleeding 60 min *** ***Segregation 60 min *** ***

    Superplasticizer formulations: workability vs. time

  • parameter Mortar 1 Mortar 2 Mortar 3 Mortar 4 Mortar 5w/c 0,475 0,50 0,50 0,50 0,53PCE (dry solids) 0,24% 0,24% 0,24% 0,24% 0,24%LS (dry solids) 0,00% 0,09% 0,18% 0,27% 0,36%Flow (minicone) 43 cm 44,5 cm 42,5 cm 39 cm 40,5 cmCohesivity ***** ***** ***** ***** *****Bleeding *** *** *** *** ***Segregation *** *** *** *** ***Overall filling very bad bad ok good excellent

    0 12 24 36 48 60 720

    1

    2

    3

    q (m

    W/g

    sam

    ple)

    t (h)

    Mortar No.1 Mortar No.2 Mortar No.3 Mortar No.4 Mortar No.5

    0 12 24 36 48 60 720

    5

    10

    15

    20

    25

    30

    Mortar No.1 Mortar No.2 Mortar No.3 Mortar No.4 Mortar No.5

    Q (m

    Wh/

    g sam

    ple)

    t (h)

    0 20 40 60 80 100 120 140

    -1

    0

    1

    2

    3

    4

    5

    6

    7

    8

    9

    q (m

    W/g

    cem

    ent)

    t (min)

    Paste 1 Paste 2 Paste 3 Paste 4 Paste 5

    0 2 4 6 8 10 12 14 16 18 20

    -1

    0

    1

    2

    3

    4

    5

    6

    7

    8

    9

    Paste 1 Paste 2 Paste 3 Paste 4 Paste 5

    q

    (mW

    /gce

    men

    t)

    t (min)

    Superplasticizer formulations: hydration reaction

  • parameter Mortar 1 Mortar 2 Mortar 3 Mortar 4 Mortar 5PCE (dry solids) 0,24% 0,24% 0,24% 0,24% 0,24%LS (dry solids) 0,00% 0,09% 0,18% 0,27% 0,36%

    020406080

    100% (dry solids)/powder mat.

    low consistency loss

    robustness

    min. powder content/m3

    water reductioncohesivity

    dynamic segr. Resitence

    low concr. viscosity

    static segreg. resistence

    Superplasticizer formulations: overall aspect on concrete rheology

    Valid fo r flowa ble co ncrte ( SC

    C)

    Not prooved experimentaly

  • parameter Mortar 1 Mortar 2 Mortar 3 Mortar 4 Mortar 5PCE (dry solids) 0,24% 0,24% 0,24% 0,24% 0,24%LS (dry solids) 0,00% 0,09% 0,18% 0,27% 0,36%

    Superplasticizer formulations: overall aspect on concrete rheology

    0,40 0,35 0,30 0,25

    PCE 3

    PCE 2

    water/powder

    pote

    ntia

    l pro

    blem

    s w

    ith c

    oncr

    ete

    rheo

    logy

    Flowable concrete, SCC, HPCC30/37 S4C25/30 S3

    PCE 1

    Our pre sentatio n at Sc hleibin ger 201 4


Recommended