Effects of lignin cellulose and expansive agent on microstructure and macro-property of polymer-modified mortar containing fly ash

Construction and Building Materials 23 (2009) 2467–2471

Contents lists available at ScienceDirect

Construction and Building Materials
journal homepage: www.elsevier.com/locate/conbuildmat

Effects of lignin cellulose and expansive agent on microstructure and
macro-property of polymer-modified mortar containing fly ash
Quan Liuquan a, Li Dongxu a,*, Li Zongjin b
a
b

College of Material Science and Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China
Department of Civil Engineering, The Hong Kong University of Science and Technology, Hong Kong, China

a r t i c l e

i n f o

Article history:
Received 14 July 2007
Received in revised form 3 July 2008
Accepted 4 July 2008
Available online 4 February 2009
Keywords:
Microstructure
Macro-property
Variance analysis
Lignin cellulose
Expansive agent

Polymer-modified mortar

a b s t r a c t
The influence of polymer-modified mortar with fly ash was researched, when lignin cellulose and calcium
sulphoaluminate expansive agent was added into mortar. The consistency, mechanical properties and
shrinkage performance of mortar were studied by orthogonal experiment. Lignin cellulose was wrapped
by the hydration products of binding materials. As the expansive agent and fly ash increasing, the
consistency of mortar can be improved. Moreover, the influence of cement-based self-leveling material
containing fly ash was also studied, when the different quantity of calcium oxide added into the material.
The proper added quantity of CaO can largely improve the mechanical property and restrain the shrinkage of self-leveling material.
Ó 2009 Published by Elsevier Ltd.

1. Introduction
Shrinkage of cement-based material is due to the loss of capillary water in the process cement harden, main including dry
shrinkage due to water evaporation and spontaneous shrinkage
due to chemical shrinkage [1]. When the shrinkage stress reaching
the some extent, cement-based material generate crack, so that the
mechanical property and durability would become bad. When fiber
added into cement-based material, the amount of crack will be significant reduced, meanwhile, the anti-crack, ductility and durability of material will be significant improved [2,3]. At present, there
are lots of researches about cement-based material with fibers,
these fibers including: nylon, polyethylene, polyamide fiber, polyester fiber and so on [4,5].
Fly ash is the type of admixture material possessing potential
hydration activity. Expansive agent is chemical material that can
react with cement and else gel, finally produce new substances
that can increase the volume of plaster [6,7]. The research of lignin
cellulose added into polymer-modified mortar, especially the research of polymer-modified mortar containing fly ash with both
lignin cellulose and expansive agent is few. In view of this, the performances of polymer-modified mortar with different quantity of
expansive agent, fly ash and lignin cellulose were studied in the
paper, moreover, the influences of cement-based self-leveling
material containing fly ash were researched, when added calcium

* Corresponding author. Tel.: +86 25 83587258; fax: +86 25 83588967.
E-mail address: (L. Dongxu).
0950-0618/$ - see front matter Ó 2009 Published by Elsevier Ltd.
doi:10.1016/j.conbuildmat.2008.07.005

oxide. Cement-based self-leveling material also belongs to polymer-modified mortar.
2. Materials and methods
2.1. Raw materials
Lignin cellulose (length is about 250 lm); calcium oxide expansive agent and
calcium sulphoaluminate expansive agent; methyl hydroxyethyl cellulose ether
(H300P2); redispersionable glue-powder (FL32); fly ash (the value of screen residue
is 0.4%, 0.08 mm); 52.5 grade Portland cement; fine sand and superfine sand; calcium lignosulfonate reducing agent; antifoamer. The chemical composition of cement and fly ash were showed Table 1.
2.2. The orthogonal experiment of polymer-modified mortar
The experiments were adopted by orthogonal design [8]. Orthogonal experiment is arranged many influence 4 shows the mixing proportions of self-leveling material adding calcium
oxide. The flowability, shrinkage and 24 h strength of self-leveling material was
tested by the Chinese standard JC/T985-2000 (cementitious self-leveling floor
mortar).

3. Results and discussion

(33), the experiment scheme was arranged, the programs of composition of mortar
were showed in Table 3. L9 (33) means that the number of levels and factors were
separate three, and the number of experiment group was nine.







Cement

preparation of mixes and of the drying process (2 days at 60 °C). In order to obtain
the original interfacial structure of images, the polished treatment was not adopted.
After metallization, the sections were examined in a SEM, where the secondary
electrons mode was used for imaging: compositions appear in white, and pores
in blank.

Table 3
L9(33)The programs of composition and the testing results

e¼

Serial
number

ð1Þ

The results of experiments were analyzed by variance analysis.
Table 5 shows the added dosage of expansive agent, lignin cellulose and fly ash can have some influence on the consistency of
mortar. The consistency of mortar can be improved by increasing
the added dosage of expansive agent and fly ash. But lignin cellulose has bad effect on the consistency of mortar. The optimum
mix proportion was M7 based on their consistency, from the results of experiments. The added dosage of fly ash and expansive
agent were more, but the added dosage of lignin cellulose was less
in M7 than others. The consistency of mortar can be improved by
adding with fly ash. The addition of fly ash can improve the fluidity
of cement paste, showing a water-reducing effect [10]. The physical and chemical characteristics of the fly ash, such as the grain
morphology, volcanic glass structure, density, specific area, and
grain diameter, have great influence on the water-reducing effect
of mortar. There were lots of spherical grains (glass micro bead)

in fly ash. But cement grains was irregular geometrically. These
glass micro beads play balls role in cement grains. The resistance
of slippage of cement grains was reduced, so that the consistency
of mortar was increased. The lignin cellulose was short rod structure, the length was about 250 lm. When lignin cellulose mixed
with plaster, they splice graft each other, so that lignin cellulose
has bad effect on the consistency of mortar. The testing of mortar
consistency was finished in very short time, after added water into
mixture. Therefore, the physics structure of materials makes great-

Annotate

e – the shrinkage ratio of cement mortar (10À4)
L0 – the initial length of mortar specimens (mm)
Lt – the length of mortar specimens every curing age (mm)
280 – the effective length of mortar specimens (mm)

2.4. The SEM of polymer-modified mortar
An approach of the microstructure can be made by means of image analysis. For
this purpose, images were obtained in three steps: the preparation of plaster specimens, the acquisition of images in the SEM, and the processing of images to obtain
binary images by thresholding. Specimens were obtained with a controlled time of

Table 5
Variance analysis of consistency

Expansive agent
Lignin cellulose
Fly ash
Error
Sum
*

SS

Degree of
freedom

MS

F

Significance

239.628
625.360
39.979
116.797
1021.765

2
2
2
2
8

119.8142
312.6800
19.9896
58.3987

2.05166

5.35423
0.34230

*

Show relatively significance influence factor.

*
*


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Q. Liuquan et al. / Construction and Building Materials 23 (2009) 2467–2471
Table 6
Variance analysis of flexural strength

Expansive agent
Lignin cellulose
Fly ash
Error
Sum
*

SS

Degree of
freedom

MS

F

Significance

1.70042
0.18389
1.43429
0.19876
3.51736

2
2
2
2
8

0.85021
0.09194
0.71714
0.09938

8.55534
0.92520
7.21635

*
*
*

Show relatively significance influence factor.

3.2. Results of shrinkage of polymer-modified mortar

Table 7
Variance analysis of compressive strength

Expansive agent
Lignin cellulose
Fly ash
Error
Sum
*
**

Al2O3 can react with Ca(OH)2, produced hydraulicity gel. The effect
of expansive agent and fly ash can exert, only when expansive
agent and fly ash react with Ca(OH)2. In the experiments, the mortar specimens were made by adding fly ash and expansive agent,
which equivalent replaced cement. When the added dosage of fly
ash and expansive agent to some degree, the quantity of Ca(OH)2
is not enough, expansive agent and fly ash effect would be not preferable exerted.

SS

Degree of
freedom

MS

F

Significance

50.18002
2.96949
32.28336
1.82802
87.26089

2
2
2
2
8

25.09001
1.48474
16.14168
0.91401

27.45044
1.62443
17.66026

**

*

Show relatively significance influence factor.
Show significance influence factor.

er influence on the consistency of mortar than the chemical property of materials. The fineness of expansive agent was very large.
When mixed with other materials, expansive agent fills in both cement grains and fly ash grains. The grain distribution of gel material was meliorated, so that the consistency of mortar was
improved.
Table 6 shows expansive agent, lignin cellulose and fly ash have
some influence on the flexural strength of mortar. Table 7 shows
according to the effects of composition on compression strength,
expansive agent was significance influence factor. Fly ash was relatively significance factor. Both flexural strength and compression
strength of M7 were biggest in all programs of composition.
Increasing the dosage of fly ash or expansive agent has bad effect
on the flexural strength and compression strength of mortar.
Table 8 shows when the interaction of both expansive agent and
fly ash being considered in variance analysis, both expansive agent
and fly ash played significance role on mechanical property of mortar. Moreover, the interaction of both expansive and fly ash was
relatively significance factor also. There was alunite, gypsum and
so on in calcium sulphoaluminate expansive agent. These chemical
substances can react with Ca(OH)2, producing AFm and AFt. Fly ash
is pozzolanicity admixture and have potential activity, SiO2 and

The shrinkage ratios of polymer-modified mortar are showed in
Table 9. The shrinkage ratios of mortar specimens were analyzed
by variance analysis. The research results show that significance
factors were alteration as the shrinkage of mortar specimens at different curing age. In response to the seventh day shrinkage ratios
of mortar s specimens, three influence factors (expansive agent,
lignin cellulose, fly ash) were all not significance. However, according to the 14th day shrinkage ratios of mortar specimens, three
influence factors were all significance influence factor. The phenomenon was largely related to the property of added materials
[11].
Fly ash was the type of admixture material possessing potential
hydration activity. In the prior period of hydration, the hydration
ability and surface energy of fly ash was low, the inter-particles

water was easy evaporated, so that the dry shrinkage of mortar
with fly ash was larger. In the final period of hydration, fly ash take
part in hydration with Ca(OH)2, which coming form the cement
hydration [12]. With the help of fly ash hydration, on the one hand,
the carbonization shrinkage was reduced, on the other hand, the
characteristics of mortar interface become dense, the loss of water
was reduced and the dry shrinkage ratio of mortar were decreased
[13]. So that the ratio shrinkage of mortar containing fly ash was
less than normal mortar’s in the final period.
There was alunite, gypsum and so on in expansive agent. These
compositions can react with cement hydration product, producing
possess of expansibility ettringite. The expansive effect of expansive agent was largely related to the quantity of cement hydration
products. In the prior period of cement hydration, the quantity of
cement hydration products was relatively few, So that the effect
of expansive agent was not exerted. In the final period of cement
hydration, the quantity of Ca(OH)2 was few also, because Ca(OH)2
reacted with fly ash, the effect of expansive agent was weakened.
The phenomenon was certified by variance analysis of the 28th
day shrinkage ratios, the expansive agent was not significance factor at the curing age.
According to 14th day shrinkage ratios of mortar specimens, lignin cellulose was significance factor. Lignin cellulose was wrapped
by the cement hydration products. The shrinkage and expansion of
mortar was controlled by the cohesive stress of between lignin cellulose and the hydrate of cement.

Table 8
Variance analysis of flexural strength when the interaction of both expansive agent
and fly ash was considered

Expansive
agent
Lignin

cellulose
Fly ash
Interaction
Error
Sum
*
**

SS

Degree of
freedom

MS

F

Significance

Table 9
The shrinkage ratios of polymer-modified mortar (10À4)

1.70042

2

0.85021

354.2546

**

Serial number

7d

14d

21d

28d

M1
M2
M3
M4
M5
M6
M7
M8
M9

2.29
0.64
À0.78
0.22
0.42
1.41
2.63
2.20

À0.05

2.33
À2.15
À1.36
À0.38
À0.71
2.48
0.29
2.27
À0.69

1.55
0.78
À1.98
À1.83
0.52
2.38
0.23
2.17
À0.60

3.14
1.26
À0.86
À1.49
À0.91
2.90
0.25
2.57

0.01

0.28722

2

0.14361

59.8374

1.43429
0.19635
0.00240
3.51736

2
1
1
8

0.71714
0.19636
0.00240

298.8102
81.8148

Show relatively significance influence factor.
Show significance influence factor.

*

**
*


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Q. Liuquan et al. / Construction and Building Materials 23 (2009) 2467–2471

3.3. The SEM of polymer-modified mortar
Fig. 1a shows that lignin cellulose (A) and aggregates (B) were
wrapped by the hydration products of binding material (C). The
bond of lignin cellulose and cement mortar matrix was better.
There was a good agreement with the result of Fig. 1b. Fig. 1a also
shows that there were a lots of C–S–H gel on the surface of aggregates. There was appreciable variance the microstructure of both
pure cement mortar matrix and cement mortar matrix with fly

ash [14]. There were lots of needle-volume hydration products in
the pure cement mortar matrix. The microstructure of pure cement
mortar matrix was relatively loose. The bond of needle-volume
hydration products was little. Fig. 1c shows that there were dense
flocculent gel in cement mortar matrix with fly ash, and the bond
of the gel.
3.4. Study of the property of cement-based self-leveling material
The results of flowability and mechanical property were
showed Table 10. When the added quantity of calcium oxide was
below 1%, the flowability of the material was better than normal
material’s. However, the added quantity of calcium oxide was
more than 1%, as the added quantity of calcium oxide increasing,

the flowability of material become badly. The added quantity of
calcium oxide had not largely related to the material flowability
loss, moreover, in some material mixing proportions, the 20 min’s
flowability of materials were better than the initial flowability.
Table 10 shows as the added quantity of calcium oxide increasing, even though the added quantity of calcium oxide was very low,
the mechanical property of cement-based self-leveling material
can be largely improved. When the added quantity of calcium
oxide was 1%, the flexural strength can improved 2.05 times than
normal material, and the compression strength can improved
1.92 times. After fly ash grinded, glass structure of fly ash was destroyed, active SiO2 was exposed from glass structure and the surface area of fly ash was increased also. This is due to grinded fly ash
that exhibits pozzolanic properties and packing effect. These characteristics tend to improve mortar strength as well as its density
[15]. The active SiO2 can react with Ca(OH)2, produced hydraulicity
gel [16]. As a result that calcium oxide can produce lots of Ca(OH)2
in relatively short time, the self-leveling material added CaO can
produce more hydraulicity gel than self-leveling material nonadded CaO. The early mechanical property of cement-based selfleveling material can be largely improved.
Table 11 shows as the added quantity of calcium oxide increasing, the shrinkage ratios of material were reduced. When the added
quantity of calcium oxide was 6%, the self-leveling material appears slightly expanse. When cement clinker react with water,
the absolute volume of the system of cement–water is decreased,

Table 10
The testing results of flowability and mechanical of self-leveling material
Serial
number

Flowability
(cm)

20 min
flowability (cm)

Flexural
strength (MPa)

Compression
strength (MPa)

1
2
3
4
5
6
7

11.7
12.7
11.0
10.2
10.3
8.5
8.0

12.0
12.4
12.3
10.0
9.1
9.1
9.6

0.38
0.78
1.25
1.35
1.90
2.09
2.05

1.3
2.5
3.6
5.0
7.2
6.7
7.7

Table 11
The ratios of shrinkage of self-leveling material (%)

Fig. 1. SEM micrographs of the plasters.

Serial number

7d

14d

21d

28d

1
2
3
4
5
6
7

À0.183
À0.168
À0.132
À0.112
À0.086
À0.044
0.166

À0.210
À0.185
À0.191
À0.146
À0.158
À0.065
0.090

À0.232
À0.220
À0.218
À0.180
À0.162

À0.122
0.026

À0.224
À0.218
À0.258
À0.222
À0.195
À0.133
0.020


Q. Liuquan et al. / Construction and Building Materials 23 (2009) 2467–2471

the phenomenon was said chemical shrinkage of material. In the
hydration progress of cement, the shrinkage ratio of material increased. When calcium oxide added into cement-based self-leveling material, calcium oxide reacted with water, producing
Ca(OH)2. In the progress, the volume of product increased 1.98
times than calcium oxide’s. The hydration rate of calcium oxide
was quick, so that the expanse effect of calcium oxide has greater
influence than the chemical shrinkage of cement hydration in the
prior period of hydration. The early shrinkage ratios of self-leveling
material containing calcium oxide appeared relatively small.
4. Conclusions

1. As expansive agent and fly ash increasing, the consistency of
polymer-modified mortar can be improved. Lignin cellulose
has bad effect on the consistency of polymer-modified mortar.
2. When fly ash and calcium sulphoaluminate expansive agent
were added into mortar together, fly ash have not obvious effect
on the final strength of mortar, at the same time, the expanse

effect of expansive agent was also restricted. This was not good
idea that both fly ash and calcium sulphoaluminate expansive
agent were added into mortar together.
3. Lignin cellulose not only has advantage on the strength of polymer-modified mortar, but also can effective control the shrinkage property of polymer-modified mortar.
4. The proper added quantity of CaO can largely improve the
mechanical property and restrain the shrinkage of material.

Acknowledgments
The authors gratefully acknowledge the financial support for
this research from the National Basic Research Program of China
(2001CB610703) and a National Starch & Chemical Business.

2471

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