ORIGINAL ARTICLE
Relative assessment of density and stability of foamproduced with four synthetic surfactants
Indu Siva Ranjani • K. Ramamurthy
Received: 12 March 2009 / Accepted: 5 January 2010 / Published online: 13 January 2010
� RILEM 2010
Abstract Selection of the surfactant has an impact
on many of the foam properties as it affects the
surface tension and gas–liquid interfacial properties.
The objective is to produce stable aqueous foam of
required density. These two characteristics are influ-
enced by the type of surfactant, its concentration and
foam generation pressure. This study compares the
density and stability of foam produced using four
synthetic surfactants namely sodium lauryl sulfate,
sodium lauryl ether sulfate, sulfanol and cocodie-
thanolamide through a systematic experiment design
based on response surface methodology. The relative
performance has also been assessed in terms of their
suitability for use in foamed concrete production
based on ASTM test method. The effect of surfactant
concentration has relatively lesser effect on foam
density for sodium lauryl sulfate and sulfanol
irrespective of foam generation pressure adopted.
The drainage is proportional to the initial foam
density for all the surfactant concentration for ionic
surfactants at different foam generation pressures.
For all the four surfactants under the optimum foam
generation pressure, a stable foam with drainage less
than 12% in 300 s (by considering economy as a
factor) is achieved. From the foam stability test based
on ASTM C 796-97, it is observed that all the four
surfactants are suitable for use in foamed concrete
production when optimized foam production param-
eters are adopted.
Keywords Density � Stability � Foam �Sodium lauryl sulfate � Sodium lauryl ether sulfate �Sulfanol � Cocodiethanolamide
1 Introduction
Foaming agents are surfactants which when present in
small amounts in solution facilitate the formation of
foam and ensures stability by preventing collapse.
These surfactants can be either natural or synthetic
based (origin), and ionic or non-ionic [1, 2]. Selection
of surfactant has an impact on the properties of foam as
it affects the surface tension and gas–liquid interfacial
properties. The nature of the surfactant also modifies
the properties of the thin liquid film which separates
the bubbles [3]. Stable aqueous foams are required in
many of the industrial applications. Several techniques
have been used in earlier studies to evaluate the
properties of foam produced with surfactants. Foam
density is an important property which determines its
volume to be added for achieving a desired density of
foam concrete. For this purpose the initial foam
density is presently being used as the basis. But the
I. S. Ranjani � K. Ramamurthy (&)
Building Technology and Construction Management
Division, Department of Civil Engineering, Indian
Institute of Technology Madras, Chennai 600036, India
e-mail: [email protected]
Materials and Structures (2010) 43:1317–1325
DOI 10.1617/s11527-010-9582-z
stability of the foam may be affected depending on the
surfactant, its concentration and foam generation
pressure. The fundamental physical mechanisms caus-
ing foam instability reported are; (i) coarsening caused
by inter-bubble gas transport, (ii) gravitational drain-
age from the films, and (iii) coalescence of adjacent
bubbles due to rupture of inter-bubble lamellae [4].
Drainage rate is often used to characterize the degree
of water retention ability of foam [5, 6].
Sodium lauryl sulfate is a commonly used surfac-
tant in detergent industry. This has also been used in
the concentration range of 0.1 to 0.4% for the
production of foamed gypsum of density less than
1,000 kg/m3 [7]. Studies were made on the effect of
additives namely sodium carboxyl methyl cellulose
and Galonol PBD, foam generation pressure and
bubble size distribution and temperature, on drainage
of aqueous foam produced with surfactant Sodium
lauryl sulfate [8–10]. Sarma et al. [10] observed that a
more uniform bubble size distribution and high initial
gas fraction resulted in stable foam. When sodium
lauryl sulfate is ethoxylated it forms sodium lauryl
ether sulfate with enhanced foaming properties [11].
Surfactant mixture of 2% sulfanol as foaming agent
and 0.3% bone glue hydro-solution as stabilizer in the
ratio 1:0.15 is reported to produce a stable foam for
which stability was assessed by the time taken for
surfactant breakdown [12].
In comparison to air aspiration method, compressed
air mode of foam generation is reported to result in
foam having uniform bubble size distribution [13]. At
low pressures (\30 kPa), the physical properties of
solutions, density, viscosity and dynamic surface
tension determine the size of bubble being formed.
However, as the pressure and hence the flow rate of the
air increases, solution effects are negated and the
bubble diameter is determined by the generation
pressure [14–17]. Aqueous foams used in fire fighting
applications are mainly classified by their expansion
ratio. For foam concrete applications, the expansion
ratio is defined in terms of foam density. Foam which
is over-expanded (say expansion ratio greater than
50:1) and thus of lower foam density may collapse and
increase the concrete density.
As a first step, the authors studied the effect of
foam generation parameters on foam characteristics
of one typical synthetic surfactant [18]. Based on
encouraging results of this study, it was decided to
undertake a systematic investigation on relative
performance of four commonly available and afford-
able synthetic surfactants on the foam characteristics.
The relative characteristics of foam produced with
four synthetic surfactants has been studied through a
systematic experiment design based on Response
surface methodology and to check their suitability
for use in foamed concrete production as per ASTM
C 796-97 [19]. The surfactant concentration and foam
generation pressure required to produce stable foam
was determined first. As a next step, the behaviour
of the foam in cement slurry was studied, which
established the stability of the foam in the mix.
2 Experimental investigations
2.1 Materials and equipment used
Foam was produced by aerating four commercially
available synthetic surfactants viz; sodium lauryl
sulfate, sodium lauryl ether sulfate, sulfanol (ionic
surfactants) and cocodiethanolamide (non-ionic sur-
factant). Table 1 shows an overview of their chemical
classification. A laboratory-scale foam generator
designed and developed at IIT Madras was used
wherein the foam was generated by mixing com-
pressed air and foaming solution in high density
restrictions.
2.2 Parameters and properties studied
For evaluating the relative characteristics of foam
produced with these surfactants, a range of surfactant
concentration (dilution ratio) from 0.5% (1:200) to 10%
(1:10) and foam generation pressure 98–294 kPa,
were adopted. The initial foam density was measured
immediately after its generation while the stability of
foam was assessed by free drainage test prescribed by
Def Standard 42–40 [20]. A drainage pan of 1612 ml
nominal volume with the centre of the conical base
rounded to accept externally a 12.7 mm bore by
25 mm long polymethyl methacrylate tube with a
1.6 mm bore brass cock at its lower end was used
(Fig. 1). The pan was filled with foam and the weight
of foam was measured at various time intervals after
foam generation. The small variations in the height of
foam with time were accounted for in the density
calculation. Response surface methodology (RSM)
using a two factor central composite design (CCD)
1318 Materials and Structures (2010) 43:1317–1325
with rotatability or equal precision was employed to
study the effect of surfactant concentration and foam
generation pressure on initial foam density (IFD)
[21, 22]. For each surfactant, 13 experimental treat-
ments were assigned based on the CCD with two
independent variables at five levels of each variable
using Statistical Analysis Software (SAS Release
8.02) [23]. The quadratic response surface model is
presented in Table 2, which were used to assess the
relative performance of foam produced with the four
surfactants.
3 Precision and reliability of models
The adequacy of response models were determined
using model analysis, coefficient of determination
(R2) analysis, and by comparing the experimental
data with values predicted by response surface
models [20]. Validation of the second order polyno-
mial regression models carried out through additional
experimental data were observed to be highly
adequate to interpret a reliable relationship between
the independent variables (surfactant concentration
and foam generation pressure) and response variables
(foam density at various time intervals) with a
satisfactory coefficient R2 ([0.9) for most of the
regression models (Table 3). As a next step, the
relative assessment of density and stability of foam
produced with four different surfactants are
discussed.
4 Initial foam density (IFD)
The effects of surfactant concentration and foam
generation pressure on the initial foam density are
plotted in Figs. 2, 3 and 4, respectively. For ionic
surfactants (i) the foam density is maximized when
the surfactant concentration and foam generation
pressures are at lower and higher levels, respectively,
and (ii) the initial foam density decreases with an
increase in surfactant concentration of up to 4% after
which there is only a marginal increase (Fig. 2a). For
non-ionic surfactant (cocodiethanolamide), (i) the
initial foam density increases with an increase in
surfactant concentration at lower foam generation
pressure (Fig. 2a), and (ii) this trend is reversed at
Table 1 An overview of foaming agents used for the present study
Name of foaming
agent
Chemical synonyms General group name Chemical
formula
Classification
based on charge
Sodium lauryl sulfate Sodium dodecyl sulfate Alkyl sulfates C12H25NaO4S Anionic
Sodium lauryl ether sulfate Sodium laureth sulfate Alkyl ether sulfate C16H33NaO6S Anionic
Sulfanol Sodium dodecyl benzene sulfonate Linear alkyl benzene sulfonate C18H29NaO3S Anionic
Cocodiethanolamide Coconut diethanolamide,
Cocamide DEA
Alkanolamides C16H33NO2 Non-ionic
200 mm
100 mm internal diameter
12.7 mm internal diameter x 25 mm long Polymethyl methacrylate tube
1.6 mm Bore brass cock
11°
Fig. 1 Experimental setup
for foam drainage study
(Def Standard 42-40
(2002))
Materials and Structures (2010) 43:1317–1325 1319
higher foam generation pressure (Fig. 2b). This is
attributed to the entry of more foaming solution into
foam due to turbulence at lower surfactant concen-
tration, which is not significant at lower foam
generation pressure unlike ionic surfactants.
For foam concrete, ASTM C 796 specifies the
foam unit weight range of 32 to 64 kg/m3 with a
remark that this range could be adjusted to manufac-
turer’s recommendation based on foam chemical and
generator used. For the surfactant concentrations and
Table 2 Response surface models for foam density at various time intervals for different surfactants
Foam property Surfactant Response surface models
IFD SLS IFD = 20.12124 - 2.05373 * SC ? 0.08349 * FGP - 0.0038 * SC * FGP
? 0.184089 * SC2 - 9.7 * 10-5 * FGP2
SLES IFD = 40.96705 - 9.17408 * SC ? 0.09647 * FGP ? 0.671866 * SC2
SULF IFD = 17.5775 - 0.91786 * SC ? 0.02379 * FGP - 0.00565 * SC * FGP
? 0.132912 * SC2 ? 0.0002 * FGP2
CDA IFD = 68.63874 ? 6.673567 * SC - 0.20224 * FGP - 0.03073 * SC
* FGP - 0.00825 * SC2 ? 0.000757 * FGP2
FD at 5th minute SLS FD = 18.39425 - 1.68899 * SC ? 0.066825 * FGP - 1.17893 * 10-3 * SC
* FGP ? 0.15216 * SC2 - 1.32224 * 10-4 * FGP2
SLES FD = 36.70574 - 5.80818 * SC ? 0.019059 * FGP ? 0.41971 * SC2
SULF FD = 20.66503 ? 0.65285 * SC - 0.086648 * FGP - 3.57686 * 10-3 * SC * FGP
? 7.9726 * 103 * SC2 ? 3.67456 * 10-4 * FGP2
CDA FD = 59.94294 ? 10.83776 * SC - 0.24160 * FGP - 0.027712 * SC * FGP
- 0.31490 * SC2 ? 7.29971 * 10-4 * FGP2
FD at 10th minute SLS FD = 7.51031 - 0.19505 * SC ? 1.00621 * 10-4 * FGP - 2.64309 * 10-3 * SC
* FGP ? 0.096673 * SC2 ? 3.67349 * 10-5 * FGP2
SLES FD = 16.60996 - 2.10015 * SC - 0.035515 * FGP ? 1.25622 * 10-3 * SC * FGP
? 0.14902 * SC2 ? 6.54138 * 10-5 * FGP2
SULF FD = 14.5659 ? 0.55116 * SC - 0.11302 * FGP ? 5.94545 * 10-4 * SC
* FGP - 0.036546 * SC2 ? 2.83675 * 10-4 * FGP2
CDA FD = 14.68048 ? 22.21186 * SC - 0.22063 * FGP - 0.026326 * SC
* FGP - 1.03357 * SC2 ? 6.25567 * 10-4 * FGP2
SLS sodium lauryl sulfate, SLES sodium laureth sulfate, SULF sulfanol, CDA cocodiethanolamide, IFD initial foam density, FD foam
density, SC surfactant concentration, FGP foam generation pressure
Table 3 R2, adjusted R2, probability values and F values for the response surface models
Foaming agent Variables R2 R2 adj Regression P value F value
SLS Initial foam density 0.9599 0.9312 \0.0001 33.48
SLES 0.9392 0.9189 \0.0001 46.34
SULFANOL 0.9247 0.8709 0.0008 17.19
CDA 0.9529 0.9192 0.0002 28.307
SLS Foam density at 5th minute 0.9633 0.9371 \0.0001 36.74
SLES 0.9512 0.935 \0.0001 58.52
SULFANOL 0.9397 0.8966 0.0004 21.80
CDA 0.9945 0.9907 \0.0001 255.64
SLS Foam density at 10th minute 0.916 0.86 0.0012 15.26
SLES 0.9327 0.8847 0.0006 19.41
SULFANOL 0.9109 0.8472 0.0015 14.31
CDA 0.9762 0.9592 \0.0001 57.50
1320 Materials and Structures (2010) 43:1317–1325
foam generation pressures adopted, the range of
initial foam density produced with sodium lauryl
sulfate, sodium lauryl ether sulfate, sulfanol and
cocodiethanolamide, respectively, are 20–35, 20–65,
20–40 and 40–100 kg/m3. For all the four surfactants,
the initial foam density obtained is satisfying the
ASTM requirements at lower surfactant concentra-
tion and higher foam generation pressure. But such
foam with higher initial foam density was observed to
contain foaming solution entrapped with the foam
due to turbulence resulting in foams with lower
stability. This aspect is confirmed by higher drop in
density with time as discussed in the next section.
The foam generation pressure controls the mixing
of air with foaming liquid and hence the foam density
varies with foam generation pressure. For a given
surfactant concentration the initial foam density
increases with an increase in foam generation
pressure for all surfactants except in the case of
cocodiethanolamide. It is observed from Fig. 3 that
the effect of foam generation pressure on the initial
foam density is lower for sodium lauryl sulfate and
sulfanol irrespective of the surfactant concentration.
Hence the densities of the foam produced using
sulfanol and sodium lauryl sulfate are the lowest. The
ASTM specified range of initial foam density was not
achieved when foam is produced at lower foam
generation pressure for surfactants sodium lauryl
sulfate and sulfanol. In the case of sodium lauryl
ether sulfate at higher surfactant concentration the
effect of foam generation pressure is significant.
Cocodiethanolamide produces foam with highest
10
20
30
40
50
60
70
80
90
Initi
al fo
am d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
Sodium lauryl sulfate Sodium lauryl ether sulfate Sulfanol Cocodiethanolamide
0 2 4 6 8 10
0 2 4 6 8 1010
20
30
40
50
60
70
80
90
Initi
al fo
am d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
Sodium lauryl sulfate Sodium lauryl ether sulfate Sulfanol Cocodiethanolamide
(a)
(b)
Fig. 2 Variation in initial foam density with surfactant
concentration. a FGP 110 kPa, b FGP 294 kPa
20
40
60
80
100
120
140
160
180
Initi
al fo
am d
ensi
ty (
kg/m
3)
Foam generation pressure (kPa)
Sodium lauryl sulfate Sodium lauryl ether sulfate Sulfanol Cocodiethanolamide
100 150 200 250 300
100 150 200 250 30010
20
30
40
50
60
70
80
90
Initi
al fo
am d
ensi
ty (
kg/m
3)
Foam generation pressure (kPa)
Sodium lauryl sulfate Sodium lauryl ether sulfate Sulfanol Cocodiethanolamide
(a)
(b)
Fig. 3 Variation in initial foam density with foam generation
pressure. a SC 0.5%, b SC 10%
Materials and Structures (2010) 43:1317–1325 1321
initial foam density irrespective of the foam gener-
ation pressure. For cocodiethanolamide, the foam
generation pressure has significant effect on initial
foam density, i.e., at higher surfactant concentration
an increase in foam generation pressure results in a
reduction in initial foam density and vice versa at
lower surfactant concentration.
5 Foam stability
The foam stability is assessed through the variation in
foam density with time which is caused predomi-
nantly by the drainage of diluted foaming agent
entrapped along the walls of the bubbles and to a
minor extent due to breakage of foam bubbles.
Figure 4 shows the variation in foam density with
time for the effect of surfactant concentration at
lower and higher foam generation pressures. For all
the four surfactants, the drainage increases with an
increase in foam generation pressure resulting in
unstable foam. For the three ionic surfactants within
the range of surfactant concentration studied, the
drainage is proportional to the initial foam density at
different foam generation pressures.
The reduction in foam density is significantly
higher after 5 min. For the three ionic surfactants,
within 10 min more than 40% of foam density is
reduced. In the case of cocodiethanolamide, a con-
centration of 4% and above results in retention of
stability. The foam produced with cocodiethanola-
mide is more stable when compared to that produced
0
10
20
30
40
50
60
70
Initial foam density (kg/m3) Foam density at 5th minute (kg/m3) Foam density at 10th minute(kg/m3)
Solid line - FGP 110 kPa Dashed line - FGP 294 kPa
Foa
m d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
0
10
20
30
40
50
60
70 Initial foam density (kg/m3) Foam density at 5th minute (kg/m3) Foam density at 10th minute(kg/m3)
Solid line - FGP 110 kPa Dashed line - FGP 294 kPa
Foa
m d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
0
10
20
30
40
50
60
70 Initial foam density (kg/m3) Foam density at 5th minute (kg/m3) Foam density at 10th minute(kg/m3)
Solid line - FGP 110 kPa Dashed line - FGP 294 kPa
Foa
m d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
0 2 4 6 8 10
0 2 4 6 8 10
0 2 4 6 8 10
0 2 4 6 8 100
10
20
30
40
50
60
70
80
90
Initial foam density (kg/m3) Foam density at 5th minute (kg/m3) Foam density at 10th minute(kg/m3)
Solid line - FGP 110 kPa Dashed line - FGP 294 kPa
Foa
m d
ensi
ty (
kg/m
3)
Surfactant concentration (%)
(a) (c)
(b) (d)
Fig. 4 Effect of SC and FGP on foam density with time for various surfactants. a Sodium lauryl sulfate, b sodium lauryl ether
sulfate, c sulfanol, d cocodiethanolamide
1322 Materials and Structures (2010) 43:1317–1325
with ionic surfactants, exhibiting substantially lower
drainage at high surfactant concentration. This retar-
dation in drainage is attributed to the high viscosity
enhancing and foam stabilizing property of cocodie-
thanolamide. Also the surfactant concentration has
opposite effect at lower and higher levels of foam
generation pressure for this non-ionic surfactant. This
is because at lower foam generation pressure, the
effect of lower surfactant concentration on foam
stability is not significant unlike ionic surfactants as
explained earlier. This is confirmed by lesser drop in
foam density with time up to 5 min at lower foam
generation pressure when compared to higher pres-
sure for the non-ionic surfactant. As the usage of
higher surfactant concentration is not economical, the
selection of lower concentration is preferable for use
in foam concrete production. But at very low
surfactant concentration and higher foam generation
pressure, though the foam produced has high initial
density, the stability is poor. Hence it appears that
there is an optimal surfactant concentration and foam
generation pressure which can produce stable foam.
6 Optimization of response surface models
Having identified that the foam stability is an
important factor, a multiple optimization was carried
out by numerical optimization method using SAS
Release 8.02 to predict the optimum levels surfactant
concentration and foam generation pressure for the
following criteria; minimize percentage solution
drained, maximize foam density ratio (ratio of foam
density to initial foam density) at various time
intervals (to increase foam stability), minimize sur-
factant concentration (to reduce cost), and to achieve
a target foam output rate of at least 0.09 m3/h which
was observed to be the minimum requirement to get
uninterrupted foam production for the laboratory
foam generator used. Each response has been
assigned an importance value (weightage) relative
to the other responses. Percentage solution drained
and foam density ratio was assigned an importance of
4 while the other responses were assigned of 3 out of
5 scale. Hence higher weightage was assigned to
foam stability.
From this study, the optimum surfactant concen-
tration value is 2 and 5% when economy is considered
as one of the factors for ionic and non-ionic surfactants
respectively (Table 4). The optimal surfactant con-
centration values for non-ionic surfactant cocodie-
thanolamide were 5 and 8%. However for all the four
surfactants the optimum foam generation pressure
ranges between 110 and 120 kPa under which a stable
foam with drainage less than 12% in 300 s (by
considering economy as a factor) is achieved. This
drainage value is very low when compared to the value
of 25% drainage obtained in time not less than 210 s as
prescribed by Def Standard 42-40 (2002) for synthetic
aqueous film forming foam for fire extinguishing.
However by assigning higher importance to foam
stability (without considering economy) the solution
drained can be reduced further for ionic surfactants
when higher surfactant concentration say 4% is used.
7 Stability of foam in the mix
With the establishment of optimal surfactant concen-
tration and foam generation pressure, as a next step,
the suitability of these four surfactants for the
production of foam concrete, i.e., whether the
requirements of ASTM C 869 [24] with respect to
fresh density, strength and water absorption of
foamed cement paste are fulfilled need to be verified.
This especially is essential as the initial foam
densities of foam produced by two ionic surfactants
are marginally lower than the ASTM specified range.
Table 4 Optimized parameters and corresponding response goals
Foaming agent Surfactant
concentration (%)
Foam generation
pressure (kPa)
Initial foam
density (kg/m3)
Foam output
rate (m3/h)
Solution drained
in 5 min (%)
Foam density
ratio in 5 min
Sodium lauryl sulfate 2 117 25 0.274 11 0.88
Sodium lauryl ether
sulfate
2 117 38 0.172 12 0.86
Sulfanol 2 117 21 0.24 12 0.87
Cocodiethanolamide 5 122 70 0.09 0 1
Materials and Structures (2010) 43:1317–1325 1323
ASTM C 796-97 furnished a way of measuring in the
laboratory, the performance of a foaming chemical to
be used in producing foam for making cellular
concrete through the following equations for arriving
at the foam volume required for achieving a cement
paste of known design density 641 kg/m3 and water-
cement ratio of 0.58:
Vf ¼ 1000 Va= 1000�Wufð Þ per m3 of cement paste� �
;
Va ¼ 0:359 �Wtw þ 0:7965 Wcð Þ=641 m3;
where Vf = volume of foam; Va = volume of air;
Wuf = unit weight of foam; Wtw = total weight of
water; and Wc = weight of cement.
Foam concrete was made by mixing the cement
slurry with a water-cement ratio 0.58 and preformed
foam produced from the surfactants at the optimized
economical surfactant concentration and foam gen-
eration pressure (Table 5). The stability of test mixes
was assessed by comparing the calculated and actual
quantity of foam required to achieve a plastic density
of foam concrete within ±50 kg/m3 of the design
value and is summarized in Table 5 along with
ASTM specifications. The foamed concrete made
with the foam produced with all the four surfactants,
at the optimized surfactant concentration and foam
generation pressure, meets the physical requirements
of ASTM, confirming the foam stability. If the foam
is unstable, slightly higher quantity of foam (to
compensate for the collapsed foam) than the volume
of foam calculated as per the equations listed above
would be required to attain the design density.
However, though the foam density of sodium lauryl
sulfate and sulfanol did not meet the minimum
criteria of 32 kg/m3 as specified by ASTM Standards,
the actual quantity of foam required to attain the
plastic density of 641 kg/m3 within ±50 kg/m3 of the
design value was the same as the calculated quantity
which again confirms the stability of the mix.
8 Conclusions
The conclusions drawn from this study and discussed
below are applicable to the characteristics of mate-
rials used and the range of parameters investigated.
• For all the synthetic ionic surfactants used, the
foam density increases with an increase in foamTa
ble
5C
om
par
iso
no
fte
stre
sult
sw
ith
AS
TM
spec
ifica
tio
ns
Su
rfac
tan
tF
oam
gen
erat
ion
pre
ssu
re(k
Pa)
Fo
amd
ensi
ty
(kg
/m3)
Fo
amco
ncr
ete
Act
ual
/cal
cula
ted
foam
req
uir
edto
pro
du
cefo
am
con
cret
ew
ith
in±
50
kg
/m3
of
the
des
ign
den
sity
Nam
eC
on
cen
trat
ion
Fre
shd
ensi
ty
(kg
/m3)
Dry
den
sity
(kg
/m3)
Co
mp
.
stre
ng
th,
MP
a
Wat
erab
sorp
tio
n
(%b
yv
olu
me)
So
diu
mla
ury
lsu
lfat
e2
11
72
56
42
51
62
.01
15
1
So
diu
mla
ury
let
her
sulf
ate
21
17
38
67
45
22
2.3
22
51
Su
lfan
ol
21
17
21
68
15
35
2.8
18
1
Co
cod
ieth
ano
lam
ide
51
22
70
67
65
27
1.4
22
1
AS
TM
C8
69
-91
Req
uir
emen
ts3
2–
70
64
1±
48
48
7±
40
1.4
0(m
in)
25
%(m
ax)
1
1324 Materials and Structures (2010) 43:1317–1325
generation pressure and decreases with an increase
in surfactant concentration up to a dosage of 4%.
• For the non-ionic surfactant cocodiethanolamide,
the initial foam density increases with an increase
in surfactant concentration at lower foam genera-
tion pressure with a reverse trend at higher foam
generation pressure. Also at higher surfactant
concentration, the foam density decreases with an
increase in foam generation pressure unlike ionic
surfactants.
• The effect of surfactant concentration has rela-
tively lesser effect on foam density for sodium
lauryl sulfate and sulfanol irrespective of foam
generation pressure adopted.
• The drainage is proportional to the initial foam
density for all the surfactant concentration for
ionic surfactants at different foam generation
pressures.
• For all the four surfactants under the optimum
foam generation pressure a stable foam with
drainage less than 12% in 300 s (by considering
economy as a factor) is achieved.
• From the foam stability test based on ASTM C
796-97, it is observed that all the four surfactants
are suitable for use in foamed concrete production
when optimized foam production parameters are
adopted.
References
1. Myers D (1998) Surfactant science and technology. VCH
Publishers, New York
2. Valore RC (1954) Cellular concrete, part 1. Composition
and methods of production. ACI J 50:773–796
3. Marze SPL, Jalmes AS, Langeven D (2005) Protein and
surfactant foams: linear rheology and dilatancy effect.
Colloids Surf A 263:121–128
4. Magrabi SA, Dlugogorski BZ, Jameson GJ (2001) Free
drainage in aqueous foams: model and experimental study.
AIChE J 47:314–327
5. Hutzler S, Cox SJ, Wang G (2005) Foam drainage in two
dimensions. Colloids Surf A 263:178–183
6. Jones MR (2001) Foamed concrete for structural use. In:
Proceedings of one day seminar on foamed concrete:
properties. Applications and latest technological develop-
ments, Loughborough University, July 3, pp 27–60
7. Colak A (2000) Density and strength characteristics of
foamed gypsum. Cem Concr Compos 22:193–200
8. Herzhaft B (1999) Rheology of aqueous foams: a literature
review of some experimental works. Oil Gas J 54:587–596
9. Pradhan MS, Sarma DSHS, Khilar KC (1990) Stability of
aqueous foams with polymer additives II. Effects of tem-
perature. J Colloid Interface Sci 139:519–526
10. Sarma DSHS, Pandit J, Khilar KC (1988) Enhancement of
stability of aqueous foams by addition of water soluble
polymers—measurement and analysis. J Colloid Interface
Sci 124:339–348
11. Salagar J (2002) Surfactants types and uses. FIRP Booklet,
E300-A, Version 2, Merida Venezuela
12. Laukaitis A, Zurauskas R, Keriene J (2005) The effect of
foam polystyrene granules on cement composite proper-
ties. Cem Concr Compos 27:41–47
13. Magrabi SA, Dlugogorski BZ, Jameson GJ (2002) A
comparative study of drainage characteristics in AFFF and
FFFP compressed-air fire-fighting foams. Fire Saf J 37:21–
52
14. Nambiar EKK, Ramamurthy K (2006) Air void charac-
terisation of foam concrete. Cem Concr Res 37:221–230
15. Kearsely EP, Visagie M (1999) Micro-properties of
foamed concrete. In: Dhir RK, Handerson NA (eds) Pro-
ceedings of international conference on specialist tech-
niques and materials for construction, Thomas Telford,
London, pp 173–184
16. Quebaud S, Sibai M, Henry JP (1998) Use of chemical
foam for improvements in drilling by earth–pressure bal-
anced shields in granular soils. Tunn Undergr Space
Technol 13:173–180
17. Wilde PJ (1996) Foam measurement by the micro-con-
ductivity technique: an assessment of its sensitivity to
interfacial and environmental factors. J Colloid Interface
Sci 178:733–739
18. Siva Ranjani GI, Ramamurthy K (2008) Analysis of the
foam generated using surfactant sodium lauryl sulfate. Int J
Con Str Mat (under review)
19. ASTM C 796 (2004) Standard test method for foaming
agents for use in producing cellular concrete using pre-
formed foam. American Society for testing and materials
20. Defence Standard 42-40 (2002) Foam liquids, fire extin-
guishing (concentrates, foam, fire extinguishing). Ministry
of Defence, UK, issue 2
21. Montgomery DC (2001) Design and analysis of experi-
ments, 5th edn. Wiley, New York
22. Myers R, Montgomery DC (2002) Response surface
methodology. Wiley, New York
23. SAS Release 8.02 (1999) SAS Institute Inc., Cary, NC,
USA
24. ASTM C 869-91 (2004) Specification for foaming agents
used in making preformed foam for cellular concrete.
American Society for testing and materials
Materials and Structures (2010) 43:1317–1325 1325
Top Related