This study investigated the effect of water-cement ratio, cement type, and seawater exposure on the electrical resistivity of concrete. Specimens were made with Type I and Type IP cement and water-cement ratios of 0.50, 0.55, 0.60 and 0.65. Some specimens were submerged in seawater for 60 days while others were submerged in a 3% NaCl solution to simulate seawater exposure conditions. Testing found that electrical resistivity decreased as the water-cement ratio increased and that Type IP cement concrete had higher resistivity than Type I cement concrete. It was concluded that lower water-cement ratios and Type IP cement yielded the highest electrical resistivity when

1. EFFECT OF WATER-CEMENT RATIO ON THE ELECTRICAL
RESISTIVITY OF TYPE I AND TYPE IP CEMENT
CONCRETE SUBJECTED TO SEAWATER EXPOSURES
Student No: 2008-22674 Name: Edangal, Ma. Filipina L. Adviser: Engr. Dan Michael A. Sadia
In the Philippines, studies concerning the effect of actual seawater exposure, as well as cement type and
water-to-cement (w/c) ratios on the electrical resistivity of concrete structures were limited. This study aimed
to investigate the effect of these parameters on concrete’s resistivity. To determine the concrete electrical
resistivity with different cement types and w/c ratios, DC Electrical Resistivity Test was conducted. The test
used Type I and IP cement, and w/c ratios of 0.50, 0.55, 0.60 and 0.65. The specimens were submerged in the
coastal area of Balayan in Batangas, Philippines for 60 days. To simulate this chloride exposure condition,
another batch was submerged in 3% NaCl Solution located in the laboratory. The study showed that as the
w/c ratio increases the electrical resistivity of the concrete decreases. Moreover, Type IP cement concrete had
higher electrical resistivity when compared to Type I cement concrete Colorimetric test was also conducted to
check the validity of the data observed. It was then concluded that lower w/c ratio with Type IP cement yields
the highest electrical resistivity of concrete.
Keywords: concrete, electrical resistivity, chloride penetration depth, seawater, salinity, colorimetric test
1. INTRODUCTION
According to Aguilar (2002), due to the growing
population, 62 percent of the Filipinos live in seaport
and coastal area. To relieve land from pressures of
urban congestion and pollution, floating offshore
platforms made of concrete are being considered for
location of new airports, power plants, and waste
disposal facilities. (Sandvik, 1993) Concrete exposed
to marine environment may deteriorate as a result of
combined effects of chemical action of seawater
constituents on cement hydration products, alkali-
aggregate expansion when reactive aggregates are
present, crystallization pressure of salts within
concrete if one face of the structure is subject to
wetting and others to drying conditions, frost action
in cold climates, corrosion of embedded steel in
reinforced or pre-stressed members, and physical
erosion due to wave action and floating objects
(Mehta & Monteiro, n.d.).
Since the studies that center on the electrical
resistivity of concrete in actual seawater is very
limited in the Philippines, this study focused on the
effect of varying water-cement ratio and cement
types on the electrical resistivity of concrete
immersed in actual marine environment. Laboratory
simulation will also be conducted.
This study which used cement types I and IP and
w/c ratios of 0.50, 0.55, 0.60 and 0.65 could help
assess the most desirable concrete mix that would be
durable in environments where chloride attacks are
very strong.
2. REVIEW OF LITERATURE
2.1 Electrical Resistivity
Electrical resistivity is simply defined as the
resistance of a certain unit volume of a material with
constant cross section to the applied current that is
uniformly distributed to it. The high electrical
resistivity of concrete is a measure of its high
durability especially to chlorides.
The factors affecting the electrical resistivity of
concrete are:
(a) Material Characteristics and Proportions.
The study of Monfore in 1968 showed that as
w/c increases the resistivity of concrete
decreases. He concluded that varying
chemical components have effect on concrete
resistivity.
(b) Moisture Content. On 1977, Gjørv et al.
showed that the increase in amount of
moisture in the concrete which is expressed
in terms of the degree of saturation increases
its electrical resistivity.
(c) Time of Curing. McCarter et al. (1981) cured
specimens with w/c ratio from 0.6 to 0.8 for
up to 120 days. And, Hope et al. (1985)
cured specimens with w/c ranging from 0.37
to 0.57 for up to about 60 days. These two
studies yielded the same results that as the
time of curing increases the resistivity also
increases.
(d) Temperature. Temperature changes have
effects on the fluid filling the pores inside the
concrete (McNeil, 1980). The viscosity of the
fluid decreases with the decrease in density
as the temperature increases. Decrease in

2. I - 0.50- A
electrical resistivity of porous materials such
as the concrete is due to the increase in
temperature, thereby increasing the mobility
of ions which carry current.
2.2 Relationship between Electrical
Resistivity and Chloride Penetration
The chloride resistance is dependent on the
concrete permeability and thickness of the concrete
cover. Through capillary action and absorption, the
chlorides penetrate the pores in the concrete
(Jezierski & Kazberuk, 2005).
To determine the amount reach of the chlorides
that had penetrated in the concrete without further
destruction, electrical resistivity measurement is used
which is non-invasive and non-destructive (Ghods et
al., n.d.). The resistivity of the concrete depends on
the amount of chloride that consumed the pores. The
ions in the pore fluid are the carriers of the current
that is applied in the concrete. However, resistivity is
very susceptible to chloride penetration since the
more permeable zones experience lower resistivity
and higher chloride penetration. Therefore, the
electrical resistivity decreases as chloride penetration
depth increases.
2.3 Seawater
The salinity of seawater around the globe is
approximately 3.5 % on the average but the salinity
of seawater at different depths is varying. This
knowledge is an important factor to consider in
constructing concrete structures at a certain depth
from seawater surface since the salinity declares the
susceptibility of concrete to the chloride attacks.
Some of the factors that affect salinity are
temperature and density. The high temperature in low
and mid-latitude such as tropic regions results to
excessive evaporation on the surface of the seawater.
This results to higher salinity on sea surface. On the
other hand, the ice formation on sea surface of high
latitude such as polar region results to very cold
water. Since cold water is denser than warm water, it
sinks and spreads down the sea floor resulting to
higher salinity below sea surface.
3. METHODOLOGY
The materials used in the study were Type I and
Type IP cement and fine and coarse aggregates and
the apparatus were concrete molds, power supply,
multimeter and some miscellaneous tools.
Material properties such as the specific gravity
and fineness modulus were taken to be used in the
computation of the concrete mixes. The fine
aggregates have FM = 3.90 while Table 3-2 shows
the summary of specific gravity of the materials.
Table 3-2. Materials and their specific gravity
MATERIAL SPECIFIC GRAVITY
Coarse Aggregate 2.73
Fine Aggregate 2.59
Type I Cement 3.16
Type IP Cement 2.98
3.1 Materials Preparation
Five specimens were casted for each w/c ratio
and for two types of cement, producing a total of 40
parent specimens where 80 disc specimens were
taken. Half were submerged in seawater and the other
was used in the simulation in the laboratory. After
being stored in room temperature for approximately
24 hours the parent specimens were demolded and
properly labelled. To achieve 100% relative humidity,
the parent specimens were immersed in distilled
water bath. After 28 days, each parent specimen was
cut according to the schematic diagram of the cutting
plane shown in Figure 1. They were obtained from
the middle of the parent specimens since it is the part
wherein the concrete is properly compacted and the
aggregates are most likely to be uniformly
concentrated. Each test specimen has a diameter of
100 ±3 mm and cut to thickness of 50±3 mm.
Figure 1. Schematic diagram of the cutting plane
of the specimen
3.4 Chloride Exposure Set-Up
Laboratory Set-Up. The test specimens were
immersed in 3% sodium chloride (NaCl) solution.
The purpose of this is to simulate the feature of the
seawater wherein the salinity is around 3% (based on
the laboratory test result of the seawater sample taken
from Balayan Bay). The 3% NaCl solution by mass
was prepared by adding 30 grams of salt to 970
Legend:
Specimen
(50 ±3 mm)
Trimming
I - 0.50- A
I - 0.50- A

3. grams of water. After 60 days of immersion the
specimens were blotted dry and were subjected to the
electrical resistivity test. The Figure 2 shows the
image of specimens in chloride exposure set-up in the
laboratory.
Figure 2. Specimens immersed in 3% NaCl Solution
in the laboratory
Actual Seawater Exposure. After curing and cutting
of the desired specimens prepared in the laboratory,
the specimens were brought to Balayan Bay, San
Luis, Batangas wherein it was submerged. The
salinity of the water taken from the site and tested in
the laboratory was around 3.1% which is relatively
close to the salinity of the NaCl solution in the
laboratory. To ensure that the specimens were
submerged for 24 hours for 60 days the specimens
were placed in the location wherein it is still
submerged in seawater whether the condition of the
sea was high tide or low tide. The distance of the
specimens below the water level wherein the water
level was the lowest and the highest in the entire day
was around 3 ft and 6 ft, respectively. Figure 3 shows
the image of specimens submerged in sea water.
After 60 days the specimens were brought back to the
laboratory for the electrical resistivity and
colorimetric tests.
Figure 3. Specimens submerged in seawater
3.5 Laboratory Tests
Electrical Resistivity Test. The direct current
(DC) electrical resistivity test was performed on the
test specimens. Each specimen was place in between
two steel plates which served as electrodes, as shown
in Figure 4. The moist tissue papers were placed in
between the steel plates and the two surfaces of the
specimen to ensure that the current could pass
through this area. The tissue should not be too wet to
prevent the water from dripping along the sides of the
specimen which could affect the current reading of
the multimeter.
The multimeter was set in DC mode and the
voltages were adjusted using the adaptor itself.
Voltage readings were done before, during and after
the current measurements to monitor the consistency
of the measurements.
Colorimetric Test. To verify whether or not the
data obtained from the electrical resistivity test is
valid, the colorimetric test was conducted. The
specimens had undergone colorimetric test to visually
assess the amount of chloride ions that had penetrated
in the pore connections during the 60-day period. The
specimens were fractured using the UTM. After
fracturing, 0.1N AgNO2 solution was sprayed on the
fractured faces of the specimens. When the solution
dried up the color change was visible, bordering the
parts of the specimens that had been and not been
penetrated with chloride ions. Using the digital
caliper, the depth of the lighter part which represents
the chloride penetration depth was measured and
recorded. Since the variation in the depths was very
visible, 10 measurements were taken for each
fractured specimen.
Figure 4. Electrical Resistivity Test Set-Up
(a) Multimeter (d) Steel Plates
(b) Power Supply (e) Moist Tissue
(c) Concrete Specimen

4. 4. RESULTS AND DISCUSSION
4.1 Effect of Water-Cement Ratio on Electrical
Resistivity
The results of the test conducted in the laboratory
were graphically represented as shown in Figures 5
and 6.
In Figure 5 where specimens where still
unexposed to marine environment he electrical
resistivities yielded by Type I cement concrete
specimens that were to be submerged in the coast of
Batangas had very small difference with the
specimens to be used as control specimens for the
simulation in the laboratory. For example, the
electrical resistivity of Type I cement concrete on site
and in the laboratory with water-cement ratio (w/c) of
0.65 were 161.07 ohm-m and 161.52 ohm-m,
respectively. The closeness of the values was
expected since the specimens have not yet been
exposed to two different environments of concern of
the study. The measured electrical resistivity of
concrete before immersion was summarized in Table
4-1. Additionally, it was also observed that as the w/c
decreases the electrical resistivity increases. The
same trend was also seen on the Type IP cement
concrete specimens.
Table 4-1. Summary of the electrical resistivity of the
concrete specimens before exposure to chloride
environment
W/C
ratio
Electrical Resistivity (ohm-m)
3% NaCl Solution Seawater
Type I Type IP Type I Type IP
0.50 227.09 301.97 224.38 304.04
0.55 193.22 262.10 193.38 261.11
0.60 182.81 233.24 181.91 231.60
0.65 161.52 217.38 161.07 219.40
However, when the specimens were immersed in
their respective environments for 60 days the
electrical resistivities decreased to up to 60 percent of
their initial resistivities. Table 4-2 summarizes the
electrical resistivity of concrete after 60 days. Figure
6 shows the electrical resistivities of the specimens
after 60 days of exposure to marine environment.
Similar to the trend yielded by the specimens before
they were subjected to the two environments the
electrical resistivity increases as the w/c decreases.
The observed values in the specimens with the same
w/c and cement type were also close to one another.
The highest value of the resistivity of the specimens
used in the simulation in the laboratory was 80.59
ohm-m (with w/c of 0.50) while the lowest was 63.28
ohm-m (with w/c of 0.65). The highest and lowest
values for the specimens on site were 75.83 ohm-m
and 58.00 ohm-m, respectively. For the Type IP
concrete specimens the highest and lowest values for
specimens on site and in the laboratory were 126.50
and 70.86 ohm-m, and 155.86 and 74.07 ohm-m,
respectively.
Table 4-2. Summary of the electrical resistivity of the
concrete specimens after exposure to chloride environment
W/C
ratio
Electrical Resistivity (ohm-m)
3% NaCl Solution Seawater
Type I Type IP Type I Type IP
0.50 80.59 155.86 75.83 126.50
0.55 72.40 123.23 72.31 117.04
0.60 66.40 104.51 64.95 98.74
0.65 63.28 74.07 58.00 70.86
This relationship between the electrical resistivity
and w/c is accounted to the series of complex
processes taking place in the network of pores
present in the concrete. One of these processes that
greatly affect the properties of the concrete is the
hydration process. When water is mixed with cement,
the exothermic chemical reaction takes place
resulting to the rise of the temperature that is
dissipated in the air. As the cement dissolves in water
it releases ions into the water forming an aqueous
solution that contains variety of ions. This process
continues until the water present would be
supersaturated with cement minerals that the ions
present start to form and combine into new solid
phases called precipitation. However, not all the
water used in mixing was used in the hydration
process. The water was kept inside the network of
void spaces in the concrete. The appropriate amount
of mixing water results to less porous concrete. When
the void spaces are less the amount of water kept in
these spaces will also be less thereby hindering the
electrical conductivity of the concrete.
As the w/c increases the amount of water in the
concrete mix also increases and the amount of
cement decreases. Since the cement is lesser in
amount the water to be used in the hydration process
is also lesser. This results to the increase in the
amount of water present in the void spaces of the
concrete. If there is more water in the network of
voids the current will have the higher potential to
pass through which results to the decrease in the
resistivity. Therefore, the w/c has a direct effect on
the electrical resistivity of the concrete.

5. Figure 4-1. Electrical resistivity of Type I and Type IP cement concrete cured for 28 days (before immersion to
chloride environments)
Figure 4-2. Electrical resistivity of Type I and Type IP cement concrete cured for 28 days (after immersion to
chloride environments)
4.2 Effect of Cement Type on Electrical Resistivity
Before and after the immersion of the specimens
to their respective environments it is observed that
the electrical resistivity of the Type I concrete is
lower than that of the Type IP concrete regardless of
the water-cement ratio or the environment they were
exposed in.
The flow of charges in the concrete is accounted
to the interfacial transition zone (ITZ) which is the
region wherein different types and amount of pores
and microcracks are present. It also contains the

6. highly soluble calcium hydroxide (CH) and ettingrite
(C-A-S-H). ITZ is located between the cement paste
and the aggregates which provide pathways for the
chloride ions. Figure 4-3 shows how the
microstructure of the cement pastes in the concrete
changes as the hydration progresses.
As the hydration process continues the spaces
which are originally occupied by the mixing water is
replaced with hydration products which are primarily
C-S-H gel and CH. This then decreases the amount of
pore and water replacing it with the less porous
tricalcium silicate and C-S-H gels. This transition is
seen in items b and c of Figure 4-3 wherein more C-
S-H gels are present.
Figure 4-3. Cement hydration. Phases are color
coded: Black = water and pores, Red = tricalcium
silicate, Blue = dicalcium silicate, Yellow = C-S-H
(a) Cement particles dispersed after mixing. b) 30 %
hydration, 1 day. c) 70 % hydration, 28 days
Courtesy: NIST
The Type IP cement concrete exhibits a higher
electrical resistivity because of the presence of
pozzolan in Type IP Portland cement. The pozzolanic
reaction that takes place consumes the CH. As a
result more C-S-H gels were produced. The increase
in C-S-H content hinders the transport of electricity
in the network that holds the fluid since C-S-H has
very minimal void content. This explains why the
Type IP cement concrete has a higher electrical
resistivity when compared to the Type I cement
concrete.
4.3 Chloride Penetration Depth and Corrosion
Potential of Concrete
In the study, the colorimetric test was used to
measure the chloride penetration depth on the
concrete specimens on the laboratory and on site.
This is to support the reliability of the electrical
resistivity test done in this study since the higher the
amount of chloride ions that penetrated the lower the
electrical resistivity that will be yielded. The chloride
permeability or the transport of chloride ions on
concrete is an important feature on the concrete
durability since amount of the chloride ions in the
concrete qualitatively determines the amount of
charges that could pass through the concrete.
Table 4-3 summarizes the chloride penetration
depth of the specimens after 60 days and Figures 4-4
and 4-5 show the chloride penetration depths of the
concrete specimens of different w/c, environments
and cement type. Figure 4-4 shows the chloride
penetration depth of Type I concrete specimens on
site and on the laboratory. The specimens with w/c of
0.50 yielded the highest resistivity to electricity while
the specimens with the highest w/c of 0.65 yielded
the lowest values. However, the concrete specimens
on the laboratory have lower chloride penetration
depths when compared to the concrete specimens
immersed on the actual environment even though
they have the same w/c ratios.
Table 4-3. Chloride Penetration Depths of Concrete on the
Laboratory and On Site
W/C
Ratio
Chloride Penetration Depth (mm)
3% NaCl Solution Seawater
Type I Type IP Type I Type IP
0.50 13.49 11.53 16.92 16.64
0.55 14.98 12.84 17.58 17.37
0.60 15.84 14.75 19.50 18.61
0.65 16.22 15.58 20.02 19.66
Based on the water sample taken from the coast
of Balayan in Batangas, it is found out that the
salinity of the water sample is approximately 3.1 %.
To simulate this, half of the number of specimens
was immersed in 3% NaCl solution. Figure 9 shows
that the Type IP concretes show the same trend as
that of the Type I concrete in Figure 8. Nevertheless,
the Type IP concretes have lower chloride
penetration depth, thereby having higher electrical
resistivity.
The electrochemical process of corrosion of the
reinforced concrete is one of the major concerns in
the construction industry since it could lead to the
premature deterioration of concrete structures before
they reach their service. The chlorides that penetrate
through salt or seawater sprays together with the
carbonation which occurs due the penetration of the
carbon dioxide in the concrete leads to the cracking
of the concrete by reducing the cross-sectional area
of the concrete. When the alkalinity of the concrete
which protects the reinforcements from corrosion has
overcome by a sufficient amount of chlorides the
concrete would have reduction of electrical resistivity.
This may also lead to the corrosion of the
reinforcements present in the concrete life.

7. Figure 4-4. Chloride penetration depths of Type I cement concrete on the laboratory and on site
Figure 4-5. Chloride penetration depths of Type IP cement concrete on the laboratory and on site
Since the plots of chloride penetration depth vs.
electrical resistivity of both Type I and Type IP
cement concrete on both environments show the
same trend, the values of the electrical resistivity
given the chloride penetration depth could be
approximated using Equation 4-1:
Where:
ρ is the electrical resistivity of concrete (in ohm-m)
CPD is the chloride penetration depth in concrete (in mm)
C1, C2 is constant (See Table 4-4)
Table 4-4. Values of C1 and C2
Cement
Type
Exposure
Condition
C1 C2
I
laboratory -6.249 165.20
seawater -5.204 164.05
IP
laboratory -18.054 429.50
seawater -18.217 363.55
(Equation 4-1)

8. The Portland cement reacts with the sodium
chloride present in seawater to form chloroaluminates,
also known as Friedel’s salt. This immobilizes the
chlorides and reducing the free chloride ions which in
return depassivates the steel reinforcements. The
amount of the external chlorides that penetrate into
the network of pores in the concrete is highly
dependent on the porosity of the concrete (CCAA,
2009).
In Type I cement concrete the amount of C-S-H
in the ITZ increases as the hydration process
continues. However, the presence of pozzolans in the
Type IP cement generates the pozzolanic reaction
which produces more C-S-H gels when compared to
the Type I cement. Therefore, as the C-S-H which
has very little concentration of voids increases the
chloride ions that could penetrate decreases.
Moreover, as the w/c increases, less cement content
undergoes the hydration process. Thus, the chloride
penetration depth, together with the electrical
conductivity, increases.
4.4 Statistical Analysis
Statistical analysis was conducted to determine
whether or not the factors considered in the study
have significance in the electrical resistivity. This
includes the varying w/c ratio, cement type and the
type of environment wherein the concrete specimens
were immersed for 60 days.
It is found out that the combined effect of the
cement type and water-cement ratio has a significant
effect to the electrical resistivity of the concrete. It is
also concluded that both the cement type and w/c
have significant effect and there is no need to conduct
a test if parameter independently affects the electrical
resistivity.
It is also found out in the statistical analysis that
the type of environment wherein the concrete
specimens were immersed had significance to the
electrical resistivity. The specimens immersed at the
coast of Batangas have higher penetration depth and
lower electrical resistivity when compared to the
control specimens in the laboratory that were used for
the simulation. Since more chlorides have penetrated
in the system of the concrete specimens, the electrical
resistivity has increased and the difference was
significant.
5. CONCLUSION
The following conclusions were drawn from the
study:
(a) The increase in w/c ratio results in the decrease
in concrete resistivity. This is due to the denser
packing of structure of concrete when w/c ratio is
lower;
(b) Concrete were Type IP cement is used have
higher electrical resistivity when compared to the
other. This is accounted on the pozzolanic
reactions in Type IP concrete;
(c) The specimens submerged in the seawater
yielded a relatively low value of electrical
resistivity that those of the specimens immersed
in 3% NaCl solution in the laboratory; and
(d) The chloride penetration depth is higher on Type
I than Type IP cement concrete and is increasing
as w/c ratio increases.
Knowing the effects of water-cement ratio and
cement type, it could be concluded that durable
concrete could be obtained with the right
combination of low water-cement ratio and type IP
cement. This combination could be best on structures
near or in the salt environment, such as bridges, dams,
piles, infrastructures and foundations.
6. RECOMMENDATIONS
The author recommends to:
(a) Use AC Electrical Resistivity Test to minimize
the effects of polarity on resistivity measurement;
(b) Submerge the specimens in seawater for varying
number of days (15, 30, 60 days) and different
depths to observe the behavior of concrete
resistivity at these different conditions;
(c) Use the percentage of salinity of the seawater
wherein the specimens are submerged in making
the NaCl solution in the laboratory. Also, replace
the NaCl solution in the laboratory every week;
and
(d) Expose the concrete specimens in seawater
exposure conditions aside from permanent
immersion.

9. REFERENCES
ACI Committee (2001). Guide to the selection and use of
hydraulic cements. AC225R-85. Detroit:
American Concrete Institute
ASTM C470 Standard Specification for Molds for
Forming Concrete Test Cylinders Vertically
ASTM C595 Standard Specification for Blended
Hydraulic Cements
Aguilar, G. (2002). Present and future role of the college
of fisheries and ocean sciences in fisheries and
coastal resource management. University of the
Philippines Visayas.
Ahmad, S. and Shabir, Z. (2005). Effect of water-cement
rato on the corrosion of reinforced concrete. 30th
Conference on OUR WORLD IN CONCRETE &
STRUCTURES., Singapore Institute. AOI:
100030013
Allizadeh, R. (2011). Cement and art. Retrieved February
5, 2013 from http://cementlab.com/cement-
art.htm
Anderson, G. (2008). Seawater compositon. Retrieved
December 27, 2012 from
http://www.marinebio.net/marinescience/index.ht
m
Anthoni, J. F. (2006). The chemical composition of
seawater. Retrieved December 27, 2012 from
http://www.seafriends.org.nz/linkadv3.htm
CEMENT CONCRETE & AGGREGATES AUSTRALIA.
(2009). Chloride resistance of
concrete. Retrieved December 27, 2012 from
http://www.concrete.net.au/
publications/pdf/ChlorideResistance.pdf
CEMENT CONCRETE & AGGREGATES AUSTRALIA.
(2007). Moisture in concrete and moisture-
sensitive finishes and coatings. Retrieved
December 27, 2012 from
http://www.concrete.net.au/publications/pdf/Chlo
rideResistance.pdf
Day, R. W., and Quinn, G. P. (1989). Comparisons of
treatments after an analysis of
variance in ecology. Ecological Monographs Vol. 59, pp.
433-463.
Ghods, P., Hoseimi, M. Chini, M. and Alizadeh, R.
Evaluating the chloride diffusion of concrete by
measuring electrical resistivity. University of
Tehran. Chloride Diffusion, pp. 193-199
Gjorv, O.E., Vennesland, Ø , & El-Busiady, A.H.S.(1977).
Electrical Resistivity of Concrete in the Oceans.
Proceedings – 9th Annual Offshore Technology
Conference, Houston, Texas,pages 581 to 588.
Gordon, A. L. (2004). Ocean stratification. Retrieved
March 30, 2013 from
http://eesc.columbia.edu/courses/ees/climate/lectu
res/gordon_strat_04.ppt
Hydration process. Retrieved February 5, 2013 from
http://iti.northwestern.edu/cement/monograph/Mo
nograph5_1.html
Kazberuk, M. K. (2007). Evaluation of the concrete
resistance to chloride penetration by means of
electrical resistivity monitoring. Bialystok
Technical Univesity, Poland.
Larsen, C. K., Sellevold, E.J, Askeland, F., Østvik, J.M, &
Vennesland, O. (2007). Electrical resistivity of
concrete. Part II: Influence of moisture content
and temperature. Statens vegvesen, Norwegian
Public Roads Administration, pp. 16- 24.
Lentz, J. (2010). Salinity. Retrieved March 30, 2013 from
http://science.nasa.gov/earth-
science/oceanography/oceans-interactive/
Mehta, P. K., & Monteiro, P. J. M. (2006). Concrete:
Microstructure, properties, and materials. 3rd ed.
New York: McGraw-Hill.
Neville, A. M. (1995). Properties of concrete. 4th ed.
Essex: Addison Wesley Longman Limited.
Parsad, R. (2007). Multiple Comparison Procedure, pp.
184-194. New Delhi: IASRI, Library Avenue.
Polder, R. & de Rooij, M. (2005). Durability of marine
concrete structures – field investigations and
modelling. HERON Vol. 50, No. 3, 133-153
Preseul-Moreno, F. (2005). An introduction to the
parameters measured by ECI-1 and their use in
determining concrete resistivity. Note by Virginia
Technologies, Inc.
Scheel, D. (2008). Properties of seawater – Temperature,
salinity, density & oxygen solubility. Alaska
Pacific University.
Scrivener, K., Crumbie, A. and Laugese, P. (2004). The
interfacial transition zone (ITZ) between cement
paste and aggregate in concrete. Interface Science
Vol. 12, pp. 411-421. The Netherlands: Kluwer
Academics Publisher.
Simon, T. and Vass. V. (2012). The electrical resistivity of
concrete. Concrete Structures, pp. 61-64
Variation of seawater properties with depth. (2010) NACE
Resource Center, Nace International. Retrieved
March 30, 2013 from
http://www.nace.org/content.cfm?parentID=1001
&contentID=1001
Whiting, D.A. and Nagi, M.A. (2003). Electrical resistivity
of concrete – A literature review. Portland
Cement Association, R&D Serial No. 2457.
Retrieved May 5, 2012 from
http://www.cement.org/bookstore/download.asp?
mediatypeid=1&id=6822&ite
mid=SN2457