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International Journal of Civil Engineering and Technology (IJCIET) Volume 7, Issue 6, November-December 2016, pp. 400–407, Article ID: IJCIET_07_06_044

Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=6

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication

MECHANICAL PROPERTIES OF LATEX MORTAR

FOR BRICK MASONRY

Vincent Sam Jebadurai S

Department of Civil Engineering, Karunya University, Coimbatore, Tamilnadu, India

Dr. Tensing D

Department of Civil Engineering, Karunya University, Coimbatore, Tamilnadu, India

ABSTRACT

Experimental results on the investigation done to study the behavior of brick masonry with latex

modified mortar subjected to compressive strength is presented in this paper. Three mix ratios of

mortar for considered for the experimental investigation. The cube compression strength of mortar

without rubber latex and with rubber latex in various proportions was tested for 7 days strength.

The mortar strength was found to increase when the percentage latex was 20%. For various

proportions of latex, the strength properties of the brick prisms and ductility were observed. A

formula to calculate the strength of brick masonry including optimum latex percentage is proposed.

Key words: Mortar, latex modified, ductility factor, Regression analysis, compression strength.

Cite this Article: Vincent Sam Jebadurai S and Dr. Tensing D, Mechanical Properties of Latex

Mortar for Brick Masonry. International Journal of Civil Engineering and Technology, 7(6), 2016,

pp.400–407.

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1. INTRODUCTION

The widely utilized material for construction in India is brick masonry, due to its advantages like ease of

construction, high sound and thermal insulation properties etc. Brick masonry has been widely used for

load bearing construction and for infill walls. However, the drawback of masonry construction is that it has

loose components and has low tolerance to oscillations as compared to other materials like Reinforced

cement concrete. Though codal provisions have suggested the usage of reinforced brick masonry, the

adoption to the technique is limited. In this research, an attempt has been made to incorporate natural latex

in mortar to enhance the bonding and in turn the compressive strength and ductility of masonry.

Rajni et al., 2006; Haggam et al., 2014have presented that inclusion of polymeric substances was

responsible for enhancing general performance of concrete, especially cement and asphalt concretes.

Ohama, 1995published the first patent with the concept of polymer latex-modified system with Lefebvre

and Natural Rubber Latex (NRL). Since then, many investigations on potential natural rubber (Mathew et

al., 2001; Qi et al., 2014) and synthetic latexes (Barluenga and Hermandez-Olivares, 2004) have been

conducted. At present, many effective polymer systems for cement, concrete and mortar have been

developed and are already in use in various applications of concrete and mortar (Pieming and Wang, 2007;

Ohama, 2007). Bala in 2009has recommended that elastomeric latexes are the most frequently used among

the various polymeric substances used in practice. India being the third largest producer of rubber in the

Mechanical Properties of Latex Mortar for Brick Masonry


world next to Thailand and Indonesia the use of latex in mortar can be explored for better performance of

the brick masonry structures. This paper presents results of experimental investigation to study the

performance of mortar and brick masonry with natural latex in varying proportions.

2. EXPERIMENTAL INVESTIGATIONS

2.1. Compressive Strength of Cement Mortar

Experimental Investigation was carried out to determine the compressive strength of mortar with natural

latex in various proportions. Ordinary Portland Cement (OPC) as a binder and local river sand for the fine

aggregate were used to prepare the mortar specimens. The properties of OPC cement used and fine

aggregates are given in table 1 and table 2.

Table 1 Physical properties of OPC

OPC Properties Test Results

Specific gravity 3.15

Initial and Final setting time in min 28 min and 560 min

Table 2 Properties of Fine aggregate

Properties Values

Specific gravity 2.89

Fineness modulus 3.6

Silt content % 2.1

Bulking of sand % 18

The various percentages of natural latex used for experimentation is given in table 1. Water cement

ratio was taken as 0.5. Latex was replaced as percentage volume of water. Three mix ratios of mortar was

taken for the study, namely, 1:3, 1:4,1:5. 3 mortar cubes were cast for each proportion.

Table 1 Proportions of Natural Latex in cement mortar

Mix

Number

Mix Latex Mix

Number

Mix Latex Mix

Number

Mix Latex

M1 1:3 0% M8 1:4 0% M15 1:5 0%

M2 1:3 5% M9 1:4 5% M16 1:5 5%

M3 1:3 10% M10 1:4 10% M17 1:5 10%

M4 1:3 25% M11 1:4 25% M18 1:5 25%

M5 1:3 20% M12 1:4 20% M19 1:5 20%

M6 1:3 25% M13 1:4 25% M20 1:5 25%

M7 1:3 30% M14 1:4 30% M21 1:5 30%

Mortar cubes of size 70.7mm x 70.7 mm x 70.7 mm was used for the test. The mortar was placed in the

mould and vibrated for 2 min at a speed of 12,000 ± 400 per minute. Specimens were left in the mould

inside the moist room (temperature 27±2 °C and relative humidity 65% ±5) for a period of 24 h. The

specimens were kept in the curing tank for 7 days. Computerized Universal Testing machine of 100 T

capacity was used to determine the compressive strength of mortar cubes.

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2.2. Compressive Strength of Brick Masonry

Brick masonry is a resultant of combination of bricks and mortar and hence the strength of the brick

masonry depends of both brick and Mortar. When the brick masonry is subjected to compressive force,

shear stress is formed at the mortar brick interfac

direction. Brickprism of size 500 mm x 200 mm x200 mm

brick masonry with latex mortar.

was 12%. Figure 1 shows the experimental set up of the brick prism. The various proportions of mortar

used was the same as given in table 1. The tests were conducted on 100T UTM.

Figure 1

3. RESULTS AND DISCUSSION

3.1. Compressive Strength of M

The various proportions of latex for the mortar cube to determine the c

table 1. The values of compressive strength for various mixe

total of 63 cubes were tested with three samples for each mix

Table 2

Mix Latex

M1 0%

M2 5%

M3 10%

M4 25%

M5 20%

M6 25%

M7 30%

Vincent Sam Jebadurai S and Dr. Tensing D

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Brick Masonry



shear stress is formed at the mortar brick interface. Thus, the mortar will be subj

rism of size 500 mm x 200 mm x200 mm was used to test the c

brick masonry with latex mortar. Compressive strength of bricks was 5.45 N/mm

12%. Figure 1 shows the experimental set up of the brick prism. The various proportions of mortar


Experimental setup for Prism test on Brick Masonr

DISCUSSION

Mortar Cubes

The various proportions of latex for the mortar cube to determine the compressive strength

table 1. The values of compressive strength for various mixes of latex are given in table 2 to table 4.

were tested with three samples for each mix.

Table 2 Compressive strength of Mortar cubes (1:3)

Latex Peak load

(kN)

Compressive strength

(N/mm2)

0% 107.7 21.55

5% 113.4 22.69

10% 67.2 13.44

25% 108.6 21.73

20% 119.4 23.89

25% 102.6 20.53

30% 70.2 14.04

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e. Thus, the mortar will be subjected forces in three

was used to test the compressive strength of

5.45 N/mm2 and Water absorption

12%. Figure 1 shows the experimental set up of the brick prism. The various proportions of mortar


Experimental setup for Prism test on Brick Masonry

ompressive strength are presented in

are given in table 2 to table 4. A

Compressive strength




Mix Latex Peak load (kN) Compressive strength

(N/mm2)

M8 0% 80.5 16.10

M9 5% 82.5 16.50

M10 10% 68.5 13.70

M11 25% 95 19.01

M12 20% 97 19.41

M13 25% 86 17.21

M14 30% 77 15.40


Mix Latex Peak load (kN) Compressive strength

(N/mm2)

M15 0% 66.99 13.40

M16 5% 53.4 10.68

M17 10% 49.2 9.84

M18 25% 53.4 10.68

M19 20% 72.1 14.44

M20 25% 52.2 10.44

M21 30% 46.8 9.36

From tables 2 to 4 it can be observed that the addition of natural latex does not increase compressive

strength to a great extent, however in all the three cases it was observed that mortar cube with 20% latex

had the maximum compressive strength. The increase was observed as 9.8 % for 1:3 mortar, 17 % for 1:4

mix and decrease of 12.9% for 1:5 mix.

3.2. Compressive Strength of Brick Masonry

The compressive strength of brick masonry is influenced by both bricks and mortar, and it is estimated that

the strength and stiffness of masonry would be between that of bricks and mortar. The compression stress

of the bricks was found as 5.45N/mm2. Therefore, the bricks are categorized as soft bricks as presented by

Dayarathnam (1987) and Sarangapani (2002) that soft bricks (modulus of elasticity ~500

MPa)areresponsible for triaxial compression in bricks and axial compression with lateral tension in mortar

joints. Experimental results by Sarangapani (2002) has also shown that the compressive strength of

masonry increases with the increase in bond strength, which increases with the mortar strength. From the

results as shown intables 2 – 4, it can be observed that there is a marginal increase in the compressive

strength of mortar when the latex percentage was 20%. This has contributed to the increase in the bond

strength and subsequently the masonry strength as shown in Figure 2.



Figure 2 Comparison of Compressive stress of brick Masonry with various proportions of latex mortar

From figure 2, it can be observed that the increase in brick masonry strength for 1:3 mortar was

23.64%, for 1:4 it was 26.45% and for 1:5 concrete the increase was 2.7 % when 20% latex was added to

the mortar. However, the increase was not notable for 1:5 mortar.

3.3. Displacement Ductility Factor

Ductility factor of an elastoplastic system is defined as the ratio of peak deformation to the yield

deformation. µ= um/uy. Ductility is an important phenomenon that gives notice to the occupants and

provides sufficient time for taking preventive measures and hence reduce the loss of life. Ductility factor

was calculated for all the samples and the results are tabulated in tables 4. The yield deformation for the

masonry is taken as 0.33 f’m(33% ) as mentioned by Hemanth 2007 , where f’m is the prism strength, the

ultimate deflection is taken as 0.8 f’m on the descending curve as shown in figure 3. The values of ductility

ratio for various mixes are given in table 5. From table 5 it can be observed that the ductility factor was

maximum when the latex percentage was kept at 20%. Increase in latex beyond 20% shows a decrease in

ductility. The increase in ductility was observed as 78% for 1:3 mortar, 64% for 1:4 mortar and 64.8% for

1:5 mortar.

Figure 5 Ductility ratio from stress-strain curve

5.65

4.854.54

6.2

3.1 2.96

5.95.645

3.68

6.85

5.02

4.35

7.4

6.595

4.67

6.5

5.522

4.2

5.86

4.6

3.5

1;3 1;4 1;5

Co

mp

ress

ive

Str

ess

N/m

m2

0% 5% 10% 15% 20% 25% 30%

0

1

2

3

4

5

6

7

8

0 0.005 0.01 0.015 0.02 0.025

Str

ess

N/m

m2

Strain

f’m

0.8 f’m

0.33 f’m



Table 5 Ductility factor for various mixes

% Latex Ductility factor

1:3 1:4 1:5

0% 5.25 4.89 3.17

5% 3.54 7.7 3.03

10% 13.75 10 6.5

15% 20 12.43 8.08

20% 24 13.87 9.02

25% 18 9.2 5.98

30% 3.18 5.6 3.64

4. ANALYTICAL MODEL FOR ESTIMATION OF PRISM STRENGTH OF

MASONRY

The compressive strength of brick masonry, f'mis a required property. But conducting compressive test on

masonry may not be probable at all times. However, fb(brick strength) and f j (masonry test)are obtainable

from the codes or from simple tests. Eurocode6 (CEN 1996) has recommended the relation of the

compressive strengths as

��= �. ��

�.��. (1)

where, K, α, and β constants. fb and fj are brick and mortar strength respectively. Balasubramanian

(2015) in his paper has presented the comparative results suggested by various authors and presented that

the formula suggested by Dayaratnam (1987) shows deviations of test results of +1.73. The parameters

given are k= 0.275, α= 0.5 and β= 0.5. The error factor of the formula proposed by Dayaratnam is taken for

the present study. In the present study the mortar was mixed with latex to enhance the ductility, hence, the

value of the factor β was modified and obtained by regression analysis as 0.77. The equation (2) obtained

as given below, and this was for the optimum value of 20% latex.

��= �. ��

�.��.- (2)

5. CONCLUSION

Experiments were conducted on mortar cubes and on brick masonry to study the performance of mortar

incorporated with latex to enhance the ductility properties of the brick masonry. The latex percentage was

varied from 0% to 30% in increments of 5%. From the results obtained the following conclusions are

drawn

•••• For all the mix ratios of mortar ie., 1:3, 1:4 and 1:5 the latex of 20% gave the maximum compressive

strength. The maximum increase in percentage was observed for 1:4 as 17%.

•••• The results on brick masonry tests to determine the prism strength and ductility have shown a marginal

increase in compressive strength. However, the ductility was found to increase by more than 60% for all the

three mix ratios.

•••• Hence, it can be concluded that though the addition of latex to mortar has less improvement on the

compressive strength, the ductility can be enhanced to a considerable amount.

6. ACKNOWLEDGEMENTS

The authors thank Profs Andrey Zaytsev, AhmetYalciner, Anton Chernov, Efim Pelinovsky and Andrey

Kurkin for providing NAMI-DANCE software and for their valuable assistance in tsunami numerical

modelling of this study. Profs. Nobuo Shuto, Costas Synolakis, Emile Okal, Fumihiko Imamura are

acknowledged for invaluable endless collaboration. The VMP is grateful to Dr. B. K. Rastogi, Director



General, Institute of Seismological Research (ISR) for permission to use of ISR library and other resource

materials. APS is thankful to Director General, ISR, for permission and encouragement to conduct such

studies for the benefit of science and society.

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