inspection of properties of expanded polystyrene (eps)

http://www.iaeme.com/IJCIET/index.asp 209 [email protected]

International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 1, January 2017, pp. 209–221, Article ID: IJCIET_08_01_022

Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1

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

© IAEME Publication

INSPECTION OF PROPERTIES OF EXPANDED

POLYSTYRENE (EPS), COMPRESSIVE BEHAVIOUR,

BOND AND ANALYTICAL EXAMINATION OF

INSULATED CONCRETE FORM (ICF) BLOCKS USING

DIFFERENT DENSITIES OF EPS

A. Arun Solomon

Assistant Professor, Department of Civil Engineering,

Karunya University, Coimbatore, Tamil Nadu, India

G. Hemalatha

Associate Professor, Department of Civil Engineering,

Karunya University, Coimbatore, Tamil Nadu, India

ABSTRACT

Insulated Concrete Form (ICF) is an emerging construction technology using the interlocking

of Expanded Polystyrene (EPS) sheet with poured in place concrete. Expanded Polystyrene has

many advantages like lighter in weight, good thermal insulation, moisture resistant, durable,

acoustic absorption, low thermal conductivity, etc., In this study, the properties of EPS were

determined by the standard procedure as per IS 4671:1984, compression behavior of ICF and

bondage between EPS and concrete were analyzed using ICF specimens casted using M25 grade

concrete. Two types of ICF specimens were casted with corrugated EPS and Plain EPS and using

different densities of 4,8,12 kg/m3and varying thickness of 50 mm and 100 mm EPS. The results

show that the compressive strength of ICF blocks casted with plain EPS was higher than the

samples casted with corrugated EPS as well as results show that good bondage exist between EPS

and concrete for plain and corrugated EPS without adding any bonding agent while casting and

when compared to plain concrete all the ICF blocks exhibit tremendous ductile nature of failure.

Key words: EPS sheet, Insulated Concrete Form, load-deflection curve, compressive strength.

Ductility ratio.

Cite this Article: A. Arun Solomon and G. Hemalatha. Inspection of Properties of Expanded

Polystyrene (EPS), Compressive Behaviour, Bond and Analytical Examination of Insulated

Concrete Form (ICF) Blocks Using Different Densities of EPS. International Journal of Civil

Engineering and Technology, 8(1), 2017, pp. 209–221.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=1

1. INTRODUCTION

The rapid growth of population in India has increased the demand for residential, commercial and

industrial structures. It is expected that the construction sector needs to build a structure with maximum

A. Arun Solomon and G. Hemalatha


benefit like cost, time of construction, disaster resistant, flexible to construct, etc., ICF systems of

construction is an emerging technology that provides light weight, faster construction and many more

advantages. Common applications for this method of construction are low-rise buildings, with property

uses ranging from residential to commercial and to industrial. Insulated Concrete Form (ICF) is made by

interlocking of Expanded Polystyrene (EPS) sheets and the cavity filled with concrete that holds EPS

together during the curing operation and remains in place permanently afterwards to serve as thermal

insulators. Figure 1 shows the typical ICF model made with interlocked EPS blocks. ICF are becoming

widely used today for a full range of building designs including residential theaters, schools and hospitals

[1, 2].

Figure 1 Typical Interlocked EPS for ICF blocks

1.1. Literature Survey

M. A. Mousa and N. Uddin [3] studied buckling behavior of Composite Structural Insulated wall panel

(CSIP). Here, the author used low cost thermoplastic orthotropic glass/polypropylene (glass-PP) laminate

as a face sheet and expanded polypropylene foam as a core. Investigations on the behavior of CSIPs under

concentric and eccentric load were carried out. Global buckling was observed when experimental

investigations were carried out with sample size of 101.6 x 76.2 x 34.48 mm. Analytical expressions for

concentric and eccentric loading to validate the experimental results were developed and found both results

were in good agreement. Design graphs for global buckling that can be used for preliminary design of the

composite structural insulated panel under concentric and eccentric loading were also developed.

In 2012, M. A. Mousa and N. Nuddin [4] developed smaller scale experiments into large scale

experiments. The size of the specimen was 1220 x 2440 x 147 mm and Pull off strength test was carried

out to determine the bonding nature between cores and face sheet of CSIP panel made with different

bonding agents. By the experimental results of Pull off strength test, it was concluded that spray adhesive

is the best solution for manufacturing CSIP panels because of its high strength and low cost benefits when

compared to other adhesives. CSIP panels designed to satisfy the design and deflection limits of ACI-318.

The failure of the panel was by debonding between face sheet and the inner core.

C. A. Yahia and T. Majidzadeh [5] experimentally investigated the identification of honeycomb in

between the contact surface of EPS sheet. Ground penetrating radar was used to locate the honeycomb or

voids in the Insulated concrete form structure. It was concluded that GPR was an effective method to

detect voids in between EPS sheet and concrete, though smaller voids less than 18.75 mm were difficult to

detect.

W. A. Friess et al. [6] carried out research on the increase in energy demand of Dubai and the

development of new technology of construction using EPS to reduce the energy consumption in terms of

electricity usage in Dubai. The energy demand was studied using past 10 years record of electricity

consumption in Dubai as well as model building of two storey semi detached single family villa was

constructed that mostly resembles at Dubai’s traditional construction. The building wall was constructed

using standard mid plane insulated precast concrete blocks (200 mm) typically utilized in Dubai in that 60

mm Expanded Polystyrene (EPS) as used as a mid plane and 70 mm aerated concrete on both sides of EPS.

As built villa is simulated with energy modeling software Design Builder (version 2.3.6) which uses the

well tested Energy Plus (version 6.0) hourly simulation engine by one year of billed electricity

Inspection of Properties of Expanded Polystyrene (EPS), Compressive Behaviour, Bond and Analytical

Examination of Insulated Concrete Form (ICF) Blocks Using Different Densities of EPS


consumption and infiltration data measured using a blower door tester. The extensive energy saving

analysis was carried out using simulated Energy Plus model and U value was determined for the wall and

RC frame with varying parameters and concluded that by Energy Utilization Index non-insulated block of

50 mm EPS can be preferred to decrease cost and increase thermal mass insulation over 30 % when

compared to other models and the yearly energy consumption saving up to 20000 kWh per villa as well as

reduction of CO2 emission up to 7.6 tons per household can be achieved.

L. Smakosz and J. Tejchman [7] examined experimentally the characteristics and behavior of

composite structural insulated panels (CSIP) developed by Glass Fibre Reinforced Magnesia Cement

Boards as face sheets and expanded polystyrene foam (EPS) as a core. The properties of used material in

terms of compression, tension, bending and shear were tabulated. Various properties were examined

through different test by using large and small scale specimens. It was found that CSIP panel has enormous

potential in terms of crushing debonding and load bearing, however, it was also mentioned that when

compared to traditional Structural Insulated Panel (SIP) CSIP panels were failed by brittle nature.

From the study, it is understood that EPS can be a prime material for construction and many research

are under progress with EPS, though ICF walls has limited research reports. ICF considered in this paper is

fabricated using M25 grade concrete with three different densities of EPS is 4, 8, 12 kg/m3 and two varying

thickness of 50 and 100 mm. The compression and flexure properties of different densities of EPS were

evaluated as per IS4671:1984 [10]. The compression behavior of ICF blocks made with different densities

and varying thickness of EPS was examined using computerized universal testing machine. Bonding nature

was analyzed using corrugated EPS and plain EPS. The results indicate that 12 kg density 100 mm thick

EPS exhibits good ductile nature when compared to other ICF blocks, but there was not much variation in

compression strength. EPS also displayed a high level of bonding with concrete without addition of any

admixture.

2. EXPERIMENTAL INVESTIGATION

Initially, to understand the compressive nature of ICF wall, ICF blocks were cast and tested for

compressive load. This paper examines the properties of EPS and investigates the compressive behavior of

ICF blocks with corrugated and plain EPS as well as to observe bonding nature between EPS and concrete

2.1. Description of the Materials

Expanded Polystyrene (EPS) is a rigid cellular plastic that is made from expandable polystyrene that

contains an expansion agent. Polystyrene is extracted from petroleum and gas industry. Styrene of 0.5 to

1.5 mm diameter called monomers expands 40 to 50 times its initial size through the process of

polymerization that is called as Expanded Polystyrene (EPS). The most common applications of EPS are

low thermal conductivity, ductility property, shock absorption, energy efficiency, etc., that makes the

material attain the demand for which it is used. EPS based construction provides reduction of scaffolding

and shuttering work and eliminates curing process and drastically decreases the construction time. The

densities of EPS taken for this study are 4, 8, 12 kg/m3

and thickness of 50 and 100 mm. Figure 2 shows

the typical 50 mm and 100 mm thick EPS sheets that would be cut by mechanical system to the required

size for compression and flexure test of EPS and to cast the ICF blocks. M25 grade concrete has been used

to prepare ICF blocks and the mix design was carried out using IS 10262:2009 [8] and IS 456:2000 [9] and

presented in Table 1.



Figure 1 Typical 50 mm and 100 mm thick EPS

Table 1 Mix ratio and quantities of M25 grade concrete

Materials Quantity Ratio

Cement 435.45 kg/m3 1

Fine Aggregate 676 kg/m3 1.55

Coarse Aggregate 1067.69kg/m3 2.45

Water 191.5 liters 0.44

2.2. Determination of Compressive Strength of EPS

The compressive strength of EPS was examined as per the standard procedure given in IS 4671: 1984 [10].

The sample size was taken as 200 x 200 mm and three different densities of EPS namely 4, 8 and 12 kg/m3

and two varying thickness of 50 and 100 mm was taken. As per the code, five samples have been prepared

(figure 3) for each category of EPS and compressive strength was determined by standard procedure using

a Universal Testing machine (Figure 4). Figure 4, shows the experimental setup for compression tests. It

was observed that, 100 mm thick EPS had the capacity to compress to its full length (figure 5) and regain

its one third of length after removal of load (figure 6), but the 50 mm thick EPS tend to buckle while

applying the compressive load (figure 7). Table 2 gives average of result of five specimen for maximum

load, compressive strength and maximum contraction of EPS. The compressive strength of EPS varies

between 0.15-0.21 MPa and 100 mm thick EPS shows more compression capacity (figure 9) when

compared to 50 mm thick EPS that fails by buckling during the compressive deformation of 33-41 mm

(figure 8).

Figure 3 Collected Samples for Figure 4 Typical testing arrangement for compression

Compression and Flexure test test of EPS




Figure 5 Fully Compressed 100 thick EPS Figure 6 Tested samples compared with fresh

while testing samples

Figure 7 Buckled 50 thick EPS Figure 8 Tested samples compared with

while testing fresh samples

Table 2 Compressive Strength of EPS

S.No EPS Specification

Maximum

Load

(kN)

Compressive

Strength

(MPa)

Maximum

Contraction

(mm)

1 4 kg Density 50 mm thick 1.5 0.15 36.9





6 12 kg Density 100 mm thick 3.7 0.185 132



Figure 9 Compressive Strength and Maximum Contraction comparison chart of EPS

2.3. Determination of Flexural Strength of EPS

The flexural strength of EPS was determined as per the standards given in IS 4671:1984 [10]. The flexural

strength was determined with sample size of 300 x 200 mm for three different densities of EPS, 4, 8 and 12

kg/m3 and two varying thickness of 50 and 100 mm. As per the code, five samples were prepared for each

category of EPS and flexural strength was determined by standard procedure using a universal testing

machine (Figure 10). Figure 10 gives an experimental set up of EPS for flexural tests. The expression to

determine flexural strength is1.5�� , where W is applied load in N, L is the length between the

supports, B is the width of the specimen and D is the thickness of the specimen in mm. It is observed that,

4 kg density 100 mm thick EPS exhibits its higher contraction and 12 kg density 100 mm thick EPS shows

higher flexural strength when compared to 50 mm thick EPS (Table 3 and Figure 11). Table 3 gives

average result five specimen for maximum load, maximum contraction and flexural strength of EPS, which

shows that the flexural strength of EPS varies between 0.10-0.45 MPa.

Figure 10 Typical experimental setup for flexure test of EPS

Figure 11 Typical failed samples of flexure test

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6

Com

pre

ssiv

e S

tren

gth

Mp

a

Sample ID

0

20

40

60

80

100

120

140

1 2 3 4 5 6

Ma

xim

um

Co

ntr

act

ion

mm

Sample ID




Table 3 Flexural Strength of EPS

S.No EPS Specification

Maximum

Load

(kN)

Flexural

Strength

(MPa)

Maximum

Contraction

(mm)







Figure 11 Flexural Strength and Maximum Contraction Comparison Chart of EPS

2.4. ICF Block Compressive Strength

ICF blocks were cast with a width of 200 mm and height of 150 mm, 12 blocks were prepared using

corrugated EPS and 12 blocks were cast with plain EPS to analyze the bonding nature between EPS and

concrete. All the 12 samples were cast usingM25 grade concrete with three different densities 4, 8,12

kg/m3 and two varying thickness of 50 and 100 mm EPS. Two plain concrete blocks were also cast of size

200 x 150 x 60 mm without EPS to compare the test results of ICF blocks (figure12-15). Membrane curing

(figure 16) was adapted to cure the ICF specimens. 6mm diameter MS rods were used to interlock EPS

sheets. The 6 mm diameter MS rod was penetrated into the EPS sheets to hold the EPS sheets in position to

maintain 60 mm spacing and for uniformly pouring of concrete in between the sheets.

Figure 12 Typical Interlocked corrugated EPS by 6mm MS rod ready for concreting

0

0.1

0.2

0.3

0.4

0.5

1 2 3 4 5 6

Fle

xu

ral

Str

eng

th M

Pa

Sample ID

0

10

20

30

40

50

60

1 2 3 4 5 6

Ma

xim

um

Co

ntr

act

ion

mm

Sample ID



Figure 13 Typical Casted ICF blocks with corrugated EPS Figure 14 Typical Casted ICF blocks with plain EPS

Figure 15 Plain concrete sample

Figure 16 Membrane curing

2.5. Experiments and Results

The compressive strength was found using 100 T capacity Computerized Universal Testing Machine.

Figure 17 shows the typical arrangement and position of test samples placed in UTM. The rate of loading

was controlled and monitored uniformly. Figure 18 shows the tested samples. It was observed that the

concrete failed by crushing, but no debonding or disintegration was observed in EPS sheet. Table 4 gives

test results of all samples. To understand the mode of failure and behavior of ICF blocks, load vs.

deflection graph was plotted. Figure 19 shows the load vs. deflection graph of ICF blocks with corrugated

EPS and Figure 20 shows load vs. deflection graph of ICF blocks with plain EPS. Figure 21 shows the

comparison of compressive strength between ICF blocks with corrugated EPS and plain EPS.

Figure 17 Typical Compressive testing arrangement of ICF in 100 T UTM




Figure 18 Typical tested sample exhibits zero disintegration in EPS

Table 4 Test Results of all samples

Sampl

e ID

Sample Specification (60 mm

thick concrete core with EPS

of)

With Corrugation With Plain EPS

Peak

load

kN

Def.

at

peak

load

mm

Maxi

mum

Defle

ction

mm

Compr

essive

Strengt

h

(MPa)

Peak

load

kN

Def.

at

peak

load

mm

Max.

Def.

mm

Comp.

Strengt

h

(MPa)

1 4 kg Density 50 mm thick 148.4 6.05 10.6 4.68 212.0 3.30 11.8 6.62






7 Plain Concrete 209.0 1.5 4.8 17.41

2.6. Analysis of Ductility Ratio

Ductility ratio or ductility factor is defined as the ratio of total deflection at ultimate load to the deflection

at elastic limit. It is a measure of ductile property of a material, the high ductility ratio indicates a higher

ductile property and vice versa. Ductile property is most desired property of a structure, especially for

seismic design. Table 5 and 6 give ductility ratio of ICF samples with corrugation and plain EPS and

Figure 21 shows the comparison of ductility ratio. It is understood from a table and chart that ICF

specimen of 12 kg density 100 mm thick plain EPS on both sides of the concrete has more ductility.

2.7. Discussion

The main objective of this paper was to find the basic properties of EPS as per code and to analyze

compression behavior of ICF specimens and to examine the bonding nature between EPS and concrete. It

is evaluated that, compressive strength of EPS varies from 0.15 to 0.21 MPa and flexural strength varies

from 0.1 to 0.41 MPa.



Figure 19 Load Vs Deflection graph of ICF blocks with corrugation

Figure 20 Load Vs Deflection graph of ICF blocks with plain EPS

Figure 21 Comparison chart of Compressive strength

Table 5 Ductility Ratio to the ICF samples with corrugation

0

50

100

150

200

250

300

350

0 5 10 15

Loa

d k

N

Deflection mm

4 Kg-50 mm With

Corrugation

8-Kg-50 mm With

Corrugation

12 Kg-50 mm

With Corrugation

4 kg-50 mm with

plain EPS

8 kg-50 mm with

plain EPS

12 kg-50 mm

With Plain EPS

Plain Concrete

0

50

100

150

200

250

300

0 5 10 15 20 25

Loa

d k

N

Deflection mm

4 Kg-100 mm

with

corrugation8 kg-100 mm

with

corrugation12 Kg-100 mm

with

corrugation4 kg 100 mm

with plain EPS

8 kg 100 mm

with plain EPS

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6

Co

mp

ress

ive

Str

eng

th M

Pa

Sample ID

With Corrugation

With plain EPS

Inspection of Properties of Expanded Polystyrene


http://www.iaeme.com/IJCIET

Sample ID Sample Specification

1 4 kg Density 50 mm thick






Table 6

Sample ID Sample Specifications







7 Plain Concrete

To evaluate the compression behavior, 24 ICF specimen was cast. 12 samples were casted with

corrugated EPS and 12 samples were casted with plain EPS, each category consists of two specimens and

membrane curing was adopted to

was carried out using 100 T universal testing machine. It was observed that, ICF blocks exhibits ductile

failue rather than brittle failure nature of concrete

After attaining peak load plain concrete failed suddenly mea

extended load carrying capacity with larger deformation that could be understood from the consolidated

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

1

Du

ctil

ity

Ra

tio



IJCIET/index.asp 219

Sample Specification

Peak

load

(kN)

Deflection

at peak

load(mm)

Maximum

Deflection

(mm)

4 kg Density 50 mm thick 148.4 6.1 10.6



g Density 100 mm thick 154.0 4.1 15.4



Table 6 Ductility Ratio to the ICF samples with plain EPS

Sample Specifications

Peak

load

(kN)

Deflection

at peak

load(mm)

Maximum

Deflection

(mm)







209.0 1.5 4.8

Figure 22 Ductility Ratio Graph

aluate the compression behavior, 24 ICF specimen was cast. 12 samples were casted with


cure all the specimens. After 28 days of curing period, compressive test


failue rather than brittle failure nature of concrete

After attaining peak load plain concrete failed suddenly meanwhile all the ICF specimens reveals


2 3 4 5 6

Sample ID

Without Corrugation

With Corrugation

(EPS), Compressive Behaviour, Bond and Analytical


[email protected]

Deflection

at Elastic

Limit(mm)

Ductility

Ratio

3.2 3.31

2.0 7.95

1.2 6.50

1.2 12.8

1.2 9.90

1.1 13.8

Ductility Ratio to the ICF samples with plain EPS

Deflection

at Elastic

Limit

(mm)

Ductility

Ratio

1.0 11.80

1.5 12.00

1.2 8.830

1.2 16.92

0.8 13.00

0.8 29.25

1.1 4.363

aluate the compression behavior, 24 ICF specimen was cast. 12 samples were casted with


s of curing period, compressive test


nwhile all the ICF specimens reveals


Without Corrugation

With Corrugation



load vs. deflection graph (figure 18 & 19). And it was noticed that, ICF blocks with plain EPShas higher

compressive strength (figure 20) when compared to the ICF blocks with corrugated EPS. The compressive

strength of corrugated EPS might have reduced due to decreased concrete quantity because of corrugation.

Simultaneously, zero disintegration was observed in the joint between EPS and concrete, though without

the addition of admixtures. Hence it could be concluded that, provision of the corrugation is not needed to

increase bonding property between EPS and concrete. From the analyses for ductility ratio, it could be

concluded that, ICF specimen with 12 kg density 100 mm thick plain EPS on both sides of the concrete

provides increased ductility to the structure.

3. CONCLUSIONS

From the experimental investigation the following conclusions are drawn.

• It was observed that, the compressive strength of EPS varies from 0.15 to 0.21 MPa and the flexural strength

of EPS varies from 0.1 to 0.41 MPa. The compressive and flexural strength of EPS is not directly related to

the density of that specimen. It is observed that there is a decrease in compressive and flexural strength even

though an increase in density.

• When compared to ICF blocks with corrugated EPS, plain EPS ICF blocks exhibited better compressive

strength due to the reason that more concrete is present. No debonding was observed after failure without

adding any bonding agent to concrete. This indicates that, there was no need to go for corrugated EPS to

make ICF block to increase bonding property.

• A total of 24 ICF specimens and 2 plain concrete specimens were casted for compression tests. 12 ICF

specimens were casted using plain EPS and 12 ICF specimens were casted using corrugated EPS with three

different densities of 4, 8 and 12 kg/m3 and two varying thickness of 50 mm and 100 mm EPS. Membrane

curing was adopted to cure all the samples and after 28 days, compression test was carried out on 100 T

capacity computerized universal testing machine. Load vs. deflection curve was plotted for all the tested

specimens. Brittle failure was observed in the plain concrete specimen and ductile failures were observed in

the ICF specimens.

• ICF specimens with 100 mm EPS exhibited larger deformation after attaining peak load. Among the tested

specimens, 12 kg density 100 mm thick EPS had maximum deflection of 23.4 mm when compared to other

ICF specimens.

• The ductility ratio was plotted and observed that 12 kg density 100 mm thick EPS provides more ductility of

29.25 when compared to other specimens.

• No disintegration was observed in any of the EPS sheets during failure.

REFERENCES

[1] Wensu Chen, Hong Hao, Dylan Hughes, Yanchao Shi, Jian Cui, Zhong-Xian Li, Static and dynamic

mechanical properties of expanded polystyrene, Materials and Science 69 (2015),170-180.

[2] CheirfAmer-Yahia, Todd Majidzadeh, Inspection of Insulated Concrete Form Walls with Ground

Penetrating Radar, Construction and Building Materials 26(2012), 448-458.

[3] Mohammed A. Mousa, Nasim Uddin, Global Buckling of Composite Structural Insulated Wall Panels,

Materials and Design 32 (2011), 766-772.

[4] Mohammed A. Mousa, Nasim Uddin, Structural Behavior and Modeling of Full-Scale Composite

Structural Insulated Wall Panels, Engineering Structures 41 (2012), 320-334.

[5] CherifAmer-Yahia, Todd Majidzadeh, Inspection of Insulated Concrete Form Walls with Ground

Penetrating Radar, Construction and Building Materials, 26 (2012), 448-458.

[6] Wilhelm Alexander Friess, Kambiz Rakhshanb, Tamer A. Hendawib, Sahand Tajerzadehb, Wall

insulation measures for residential villas in Dubai: A case study in energy Efficiency, Energy and

Buildings 44 (2012), 26–32.




[7] Smakosz.L, Tejchman.J, Evaluation of strength, deformability and failure mode of composite structural

insulated panels, Materials and Design, 54 (2014), 1068-1082.

[8] IS 10262:2009, Indian Standard, Concrete mix proportioning – Guidelines (fifth revision)

[9] IS456:2000, Indian Standard, Plain and reinforced concrete – code of practice (Fourth revision)

[10] IS 4671:1984, Indian Standard, specification for expanded polystyrene for thermal insulation purposes

(First Edition).

[11] Dr. B.Vidivelli and A. Jayaranjini . Prediction of Compressive Strength of High Performance Concrete

Containing Industrial by products Using Artificial Neural Networks, International Journal of Civil

Engineering and Technology, 7(2), 2016, pp. 302–314.

[12] V. Subbamma and Dr. K. Chandrasekhar Reddy, Experimental Study on Compressive Strength of Plain

Cement Concrete with Partial Replacement of Cement by Flyash & Metakaolin. International Journal of

Civil Engineering and Technology, 7(6), 2016, pp.82–89

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