Impact of Guar Gum Derivatives on Properties of Freshly-Mixed Cement-Based Mortars

(1)

HAL Id: emse-01250110

https://hal-emse.ccsd.cnrs.fr/emse-01250110

Submitted on 4 Jan 2016

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Impact of Guar Gum Derivatives on Properties of

Freshly-Mixed Cement-Based Mortars

Alexandre Govin, Marie-Claude Bartholin, Barbara Biasotti, Max Giudici,

Valentina Langella, Philippe Grosseau

To cite this version:

Alexandre Govin, Marie-Claude Bartholin, Barbara Biasotti, Max Giudici, Valentina Langella, et al.. Impact of Guar Gum Derivatives on Properties of Freshly-Mixed Cement-Based Mortars. Caijun Shi; Yan Yao. 14th International Congress on the Chemistry of Cement (ICCC 2015), Oct 2015, Beijing, Italy. The 14th International Congress on the Chemistry of Cement - ICCC Proceedings, 2015. �emse-01250110�

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Impact of Guar Gum Derivatives on Properties

of Freshly-Mixed Cement-Based Mortars

Alexandre Govin

1 , Marie-Claude Bartholin

1 , Barbara Biasotti

2 , Max Giudici

2 ,

Valentina Langella

2 , Philippe Grosseau

1

1 _{SPIN-EMSE, CNRS:UMR5307, LGF, École des Mines de Saint-Étienne, 42023 Saint-Etienne, France}

2 _{Lamberti SpA, 21041 Albizzate, Italy}

Conclusions

Water Retention

 HPGs are good water retention agents

 Huge impact of HPG chemical composition

  MS

_HP

promotes WR by  [HPG]

 Hydrophobic side chain promotes WR by  C*

Chemical composition of HPGs is a key parameter of mortar formulation

Rheological properties

 HPGs act as VEA

  “Classical” HPGs  the stability of mortars by 



₀

 Hydrophobically modified HPGs  the resistance to the flow of admixed

mortars by  K

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Introduction

Results

Facade render

Masonry

Adhesive mortar

Sand

Admixture

Cement

Water Retention Agent

(polysaccharide)

Most widely used admixture:

Cellulose Ethers

~ 1/3 of raw materials cost for only

0,5 wt%

Desired

Effect

Water Retention

= Capacity of fresh mortar to keep its mixing water

Without

Water Retention Agent

Absorption of water by the substrate

Mortar

Support

Mixing water stay into the

fresh mortar

 Good Mechanical and

adhesive properties

With

Water Retention Agent

Adhesion

failure

Cracking

Mortar

Support

Mortar

Polysaccharides are

also expected to act

as VEA

Major drawback:

Cement hydration

delay

Study of bio-based Water Retention and VEA admixture :

Hydroxypropyl Guar (HPG)

1 hole 6 holes 12 holes 18 holes 24 holes 30 holes 36 holes 42 holes48 holes 8x8.75mm Filter paper Depretion of 50mm of mercury (6,6 kPa)

Standard ASTM C 1506-09:

Water Retention

70

75

80

85

90

95

100 0.00%

0.05%

0.10%

0.15%

0.20%

WR

(

%

)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

HPG 4

HPG 5

Herschel-Bulkley model:









_K





n

0 

₀

: yield stress

K: consistency coefficient

n: fluidity index

Rheological properties of mortars

20

40

60

80

100

120

140 0.00%

0.05%

0.10%

0.15%



0

(P

a)

Polymer dosage (% bwob)

20

40

60

80

100

120

140 0.00%

0.05%

0.10%

0.15%



0

(P

a)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

HPG 4

HPG 5

Yield Stress (



₀

)

0

5

10

15

20

25 0.00%

0.05%

0.10%

0.15%

K (

P

a.s

n

)

Polymer dosage (% bwob)

20

40

60

80

100

120

140 0.00%

0.05%

0.10%

0.15%



0

(P

a)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

HPG 4

HPG 5

Consistency (K)

0

0.2

0.4

0.6

0.8

1

1.2 0.00%

0.05%

0.10%

0.15%

n

Polymer dosage (% bwob)

20

40

60

80

100

120

140 0.00%

0.05%

0.10%

0.15%



0

(P

a)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

HPG 4

HPG 5

Fluidity Index (n)

 

%

100

0

1

0 





W

WR

Excepted

GG

,

HPGs improve

the WR capacity of mortars

Positive impact

of the additional

alkyl chain

 Adsorption compensated by  in coil overlapping

concentration

 MS

_HP

improves

the WR capacity

MS

_{HP HPG 1}

< MS

_{HP HPG 2}

<

MS

_{HP HPG 3}

Thanks to  Adsorption and thus  [HPG] in pore

solution

 DS

_AC

slightly

reduces

the WR capacity

<

DS

_{HP HPG 5}

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2 0.00%

0.05%

0.10%

0.15%

0.20%

m

g

p

o

ly

m

er

ad

so

rb

ed

/g

b

in

d

er)

Polymer dosage (% bwob)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2 0.00%

0.05%

0.10%

0.15%

0.20%

m

g

p

o

ly

m

er

ad

so

rb

ed

/g

b

in

d

er)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

100% adsorption

HPG 4

HPG 5

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2 0.00%

0.05%

0.10%

0.15%

0.20%

m

g

p

o

ly

m

er

ad

so

rb

ed

/g

b

in

d

er)

Polymer dosage (% bwob)

HPG 1

HPG 2

HPG 3

GG

HPG 4

HPG 5

100% adsorption

Adsorption

Hydrophobic alkyl chain:

Low  Adsorption

Change in conformation of HPG

(Simon et al.)

Alkyl chains inside the coils / Hydrophilic groups at the

outskirt of the coils

 MS

_HP

:  Adsorption

because of  free -OH and polarity

TOC - Centrifugation - Depletion method

Low dissolution kinetics of GG





₀

with HPGs

1 ,

2 ,

3 Bridging flocculation



K

and

 n

with HPGs ,

5  MS

_HP

 adsorption 

bridging compensated by

 η

₀

and [HPG]

Rheological behavior of mortars imposed by the

more and more shear thinning behavior of pore

solution

Materials

Seed

Endosperm

Grinding

HPG preparation

HPG Studied

HPG

O

HO

O

OH

O

OH

HO

OH

O

HO

H

₂

C

CH

₃

HO

H

₂

C C

CH

3 HO

H

Native guar gum obtained

without chemical treatment

O

OH

HO

O

OH

HO

O

OH

HO

OH

HO

Thermomechanical

extraction

Cyamopsis

tetragonolobus

India

Irreversible

nucleophilic

substitution

 A native Guar Gum (

GG

) + 3 HPGs + 2 hydrophobically

modified HPGs



Roughly the same molecular weight (≈ 2.10

6 _Da)

H

ydroxy

P

ropyl

G

uars

 Water-to-Binder ratio: W/B = 0.22

Admixtures in addition to the binder: 0.05%

– 0.15% bwob

Mortar Formulation

Sample

MS

_HP

Additional

Substitution

DS

AC

HPG 1

Low

-

HPG 2

Medium

-

HPG 3

High

-

HPG 4

High

Short alkyl chain

HPG 5

High

Short alkyl chain Higher than HPG 4

GG

-

Component

CEM

II/B-LL 32.5R

Lime CaCO

3 CaMg(CO

3 )

2 Water

% mass of