International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 04 29

Chloride-Ion Impermeability of
Self-Compacting High-Volume Fly Ash Concrete
Mixes
Amrutha*, Gopinatha Nayak*, Mattur C. Narasimhan* and S.V.Rajeeva**
*National Institute of Technology Karnataka, Surathkal, Mangalore
**Mahendra Engineering college ,Mahendhirapuri, Tamilnadu


Abstract-- This paper presents the results of an experimental and the general safety of the public amenity is severely
study on the durability properties of self compacting, high- degraded. It is thus apparent that for many reinforced concrete
volume fly ash concrete mixes (SCC-HVFC) mixes. Five self- members, the ability of the concrete to resist chloride
compacting concrete mixes with a higher cement replacement at penetration is an essential factor in determining its successful
60% of cement with fly-ash, are designed and their performance performance over an extended period.
is compared with two normally-vibrated concrete mixes (NCs) of
equivalent M30 strength grade. The durability properties are At micro-level, the chloride permeability of a concrete mix is
evaluated in terms of chloride-ion penetrability as measured by related to the pore structure of the cement-paste matrix. As
RCPT tests . The results indicate that the SCC-HVFC mixes pore volume increases, the apparent chloride diffusion
would have lesser permeable voids than the normally-vibrated coefficients increases [3-[5]. Pore-structure of concrete varies
concrete mixes of comparable strengths. The experimental results
with age and depth from the exposed surface[6]-[9]. The
also show that large improvements against chloride penetration
can be realized with self- compacting high-volume fly-ash water-cement ratio has a profound effect on several
concrete mixes additionally admixed with GGBFS, silics fume, characteristics of concrete; Mixes with low water/ cement
metakaolin and rice husk ash. ratios, though less workable, are of high strength, low
Index Term-- Self compacting concrete; large-volume fly ash permeability and high durability [10],[11]. The resistance to
replacement; chloride permeability, chloride penetration of concrete is significantly increased with
the incorporation of finer fly ash particles [12],[13] Such an
I. INTRODUCTION increase in chloride-ion penetration results from the reduced
One major challenge facing the civil engineering community water-to-binder ratio, the reduced average pore-size of the
is to execute projects in harmony with nature using the paste and the improved interfacial zone. The incorporation of
concept of sustainable development. This calls for use of high fly ash may also enhance the workability of the mixes due to
performance, environment-friendly and economical the smooth spherical surfaces of the fine fly ash particles.
construction materials. In the context of concrete, which is the Hence the use of higher volumes of fly ash in concrete is
most predominant building material, it is necessary to identify advantageous in reducing the permeability of concrete due to
less expensive cement-substitutes. In recent years, many their filler as well as pozzolanic effects[14]. In the present
researchers have established that the use of supplementary study, an attempt is made to investigate the chloride
cementitious materials (SCMs) like fly ash, blast furnace slag, permeability resistance characteristics of a few candidate self-
silica fume, metakaolin and rice husk ash etc. can, not only compacting, high-volume fly ash concrete mixes. Further,
improve the various properties of concrete - both in its fresh effect of blending other mineral admixtures like GGBFS silics
and hardened states, but also can contribute to economy in fume, metakaolin and rice husk ash concrete mixes are also
construction costs. However the strength and durability examined.
characteristics of concrete mixes with such SCMs have to be
ascertained before using them in large infrastructural projects. II. EXPERIMENTAL INVESTIGATIONS
Permeability of concrete is believed to be the most important Materials
characteristic of concrete that affects its durability[1],[2]. Poor Ordinary Portland cement conforming to the requirements of
impermeability of concrete may lead to the ingress of Chloride 43 grade OPC [15] [16]was used. Fly ash meeting the
ions into concrete resulting in the corrosion of the steel requirements of ASTM C 618 (Class F) was used. The
rebars embedded in it. Once this occurs, the structure will no characteristics of cement, fly ash and other pozzolanic
longer maintain its structural integrity; the lifespan is reduced, materials used herein are evaluated and are presented in Table
I. Two fractions of crushed granite metal, with MAS of 12.5
and 20 mm, and good quality well graded river sand were used
Hary Christady Hardiyatmo, Dr., Ir., M.Eng., DEA. Lecturer of The
as coarse and fine aggregates, respectively. The coarse and
Department of Civil and Environmental Engineering Faculty of Engineering,
Gadjah Mada University, Yogyakarta, Indonesia. e-mail: fine aggregates had specific gravities of 2.68 and 2.61,
harychristady@yahoo.com. Phone +62-274-545675, Fax: +62-274-545676. respectively. A commercially available poly-carboxylic-based

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 International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 04 30

high-range water reducing admixture has been used as a II. Thorough mixing and adequate curing are most essential
hyper-plasticizer in the present investigation. for achieving a good self compacting concrete. In the
laboratory, the concrete was mixed in a special horizontal
Mix design shaft ribbon mixer of 125L capacity. The total mixing time
In the present investigation two conventional normally- was kept at about 3–4 min for normal concretes. It was
vibrated concrete mixes were initially designed. These base increased to about 5–6 min for self compacting concretes
designs were later modified, based on a series of trials, to made with hyper-plasticizers for realizing the complete
develop five different self compacting fly ash concrete mixes, potential of the hyper-plasticizer. All the mixes were tested for
all with a constant, high-volume fly ash dosage of 60% and their flow properties satisfying the EFNARC guidelines .
again admixed with other superpozzolanas. EFNARC- Generally, the demoulding was done between 12 and 24 h of
guidelines were used to design the SCC mixes. The details of casting.
the mix proportions for the various mixes are given in Table
Table I
Properties and Chemical Composition of Cementitious Materials
Cement FA SF MK GGBFS RHA
Specific gravity 3.05 2.06 2.20 2.60 2.81 2.43
LimeReactivity,
---- 4.73 4.10 4.82 5.16 4.48
N/mm2
0.28 0.76 -- 0.72 0.19 ----
LOI
Oxides Percentage contents
CaO 60.84 1.79 0.68 0.08 23.28 0.51
SiO2 16.34 58.87 94.89 52.20 43.63 95.96
Al2O3 6.95 32.17 2.20 44.50 14.82 0.27
Fe2O3 5.38 2.93 0.18 1.11 5.14 0.57
K2O 2.73 1.14 0.92 -- 1.92 1.06
Na2O 1.5 0.37 0.19 0.41 2.06 0.01
Na2Oeq --- 1.12 0.80 0.41 --- ---
MgO 2.32 0.92 0.46 -- 3.40 0.21
Mn2O3 ---- -- 0.48 -- ---- ----
P 2O 5 1.67 0.56 -- 0.65 1.60 0.62
SO3 1.99 0.49 -- 0.32 3.97 0.33

Table II
Mix Proportions for various fly ash admixed SCC mixes - M30 Grade
Mix no CC1 CC2 SCFA SCSF SCMK SCGGBS SCRHA
3
Cement ( Kg/m ) 410 405 240 222 168 120 198
3
Fly Ash ( Kg/m ) --- ---- 360 360 360 360 360
3
Silica Fume ( Kg/m ) --- --- --- 18 --- --- ---
3
Metakaolin ( Kg/m ) --- --- --- --- 72 --- ---
3
GGBFS ( Kg/m ) --- --- --- --- --- 120 ---
3
Rice Husk Ash ( Kg/m ) --- --- --- --- --- --- 42
3
Water ( Kg/m ) 175 172 168 168 168 168 168
3
Coarse Aggregate( Kg/m ) 1134 1130 720 720 720 720 720
3
Fine Aggregate( Kg/m ) 612 612 765 731 735 754 727
w/p 0.43 0.41 0.28 0.28 0.28 0.28 0.28
3
HP (kg/ m ) 3.0 3.0 3.0 3.0 3.0 3.0
Slump/Slump flow in mm 90 110 760 700 785 730 735
V funnel in sec -- --- 9 11 9 10.5 10.5
Compressive Strength 7days 33.65 36 34.2 21.5 27 34 18
2
(N/mm ) 28days 43.65 45 55.33 38 45 42 37.5

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 International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 04 31

III. RESULTS AND DISCUSSIONS ions are free and may lead to the initiation of the corrosion
process. The increased % of fly ash along with Metakaolin
Cube Compressive Strengths may lead to an increase in the amount of alumina present in
Five cubes of size 100mm were tested for each mix in a 2000 the mix and to an increase in the content of calcium silicate
kN-capacity compression testing machine as per IS: 516-1975 hydrate that is formed in the pozzolanic reactions. Thus, the
for determining compressive strengths at 7- and 28-days of chloride-binding capacity of concrete tends to increase with
curing. All the results obtained for cube compressive strengths fly ash addition and consequently less free-chloride is
for the various SCC mixes at the two ages are tabulated in available to initiate the corrosion process. This view is well
Table 2. All the mixes have achieved their target mean supported by the data in Fig. 3 where it appears that the
strength at the age of 28 days of curing. Among all the mixes, alumina content has a significant influence on the chloride ion
SCSF and SCRHA recorded lowest strength at 28 days , penetrability into the concrete. As the alumina (Al2O3) content
whereas SCFA mix has achieved the maximum strength of increases, the total charge passed decreases indicating
55.33 MPa which may be attributed to higher cement content increased resistance against chloride ion penetration and hence
in this mix. When the cement content in SCFA mix are further corrosion. Thus, in aggressive chloride environment, such as
replaced by 20 % of GGBS and 12% of metakaolin, the drop sea coast or structures where deicing salts are used, the
in strength is marginal as compared to the binary blends. This increased addition of fly ash in SCC mixes will prove
may be to the presence of appreciable amount of Calcium beneficial.
oxide in GGBS and to the presence of larger amounts of
amorphous, reactive silica in metakaolin. The implications of such substantial decreases in chloride
ion penetrability should be seriously considered in the
Rapid chloride penetration test design of offshore structures, bridge decks, parking
Accelerated chloride permeability tests were conducted on garages and other structures that are vulnerable to
standard cylindrical specimens (100 mm dia, 50mm thick) of corrosion of reinforcing steel under chloride ion attack.
all the candidate large volume fly-ash admixed self- Not only would SCC made with high-volume replacement
compacting concrete mixes, after different periods of curing, composite cements provide excellent workability at a
as per ASTM C1202- 1994. The RCPT test set-up used for competitive cost, but the repair, maintenance and overall life
these tests is shown in Fig.1. All the results of total charge cycle costs would make such a material more appealing. The
passed through standard specimens in 6 hours (the RCPT results show that at an early age, chloride permeability is most
values), taken as a measure of the chloride permeability, are influenced by the water/binder ratio. However, at later ages
presented in Fig.2. It can also be observed that the total the beneficial effects of fly ash is apparent and is the
charge passed decreases with the increase in the curing period, governing parameter in reducing permeability.
measured herein up to 90 days, in specimens of all the mix
compositions. It is seen that, while the RCPT values (total IV. CONCLUSIONS
charge passed in 6 hours) are quite large during the initial The following conclusions drawn based on the results of the
periods (3- and 7-days), all self-compacting `fly ash based present study. Increased of wet curing decreases the chloride
SCC mixes evaluated herein have RCPT values less than 1000 penetrability of SCC-HVFA concrete mixes.The high volume
Coulombs beyond 28-days of curing and can be classified fly ash SCC mixes showed significantly lower chloride ion
under very low chloride permeability concrete mixes as per permeability than normal concretes mixes. All the SCC-
ASTM C 1202–94 assessment criteria. The corresponding HVFA mixes were assessed to have ‗‗very low‖ chloride
normally-compacted concretes, however, have shown very permeability as per ASTM C 1202–94 assessment criteria,
high values of charge passed, in the range of 1800-2000 with RCPT values< 1000 coulombs after 28-days of wet
Coulombs, even when tested after 90 days of curing, which curing. Among the mixes tested herein, metakaolin-blended
fall in the range of low to moderate. self compacting high volume fly ash concrete mix, SCRHA
has exhibited the best performance under chloride attack.As a
It can be concluded that all the SCC mixes have performed future scope same mixes can be analysed for corrosion under
extremely well in an aggressive chloride-rich environment. accelerated curing conditions and life of the structure can be
Comparatively speaking, it is observed that SCMK mix has predicted
the lowest RCPT values compared to the other SCC mixes. REFERENCES
[1] Aitcin,P.C., ―High Performance Concrete.” E&FN SPON, New
This could be due to the fact that the chloride ion penetration
York. 1998.
depends on the chloride binding capacity of the constituent [2] Baykel,M.(2000) ―Implementation of Durability Models for
materials. Usually chlorides penetrate into concrete by Portland Cement Concrete into a Performance Based Specification
diffusion along water-conveyance paths or open pores. The ‖, Austin, Texas, The University of Texas at Austin, College of
Engineering.
resistance to such diffusion can be increased by refining the
[3] Savas,B.J. (1999) ―Effects of Micro Structure on Durability of
pore-structure of the concrete. Again from the point of view of Concrete‖ Raleigh N.C.: North California State
chemical reactions, some of these chlorides can react with the University.Department of Civil Engineering
cement compounds, mainly tricalcium-aluminates (C3A), [4] ASTM C1202-97, ―Standard Test Method for Electrical Indication
of Concrete‘s Ability to Resist Chloride Ion Penetration‖, Annual
forming stable chloro-complexes while the excess of chloride

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 International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 04 32

Book of ASTM Standards, vol. 04.02, American Society for Testing Ed.) Water-Cement Ratio and other Durability Parameters-
and Materials, Philadelphia, 2003. Techniques for Determination (pp.57-6868).Farmington Hills, MI:
[5] ACI 211-1-91, (1993), ―Standard practice for selecting proportions American Concrete Institute.
for normal, heavy weight and mass concrete‖ ACI Manual of [11] V.Sivasundaram,G.G.Carette and V.M. Malhotra (1991),
Concrete Practice, Part 1. ‖Mechanical Properties, Creep,and Resistance to Diffusion of
[6] Saricimen,H.,Maslehuddin,M.,Shameem,M Al Gamdhi, A.J. and Chloride Ions of Concrete Incorporating High Volumes of ASTM
Barry, M.S.(2000) ―Effect of Curing and Drying on Strength Class F Fly Ashes from Seven Different Sources‖, ACI Materials
Absoption of Concretes Containing Fly Ash and Silica Fume‖.In Journal 88(4), 407-416.
V.M.Malhotra(Ed), Durability Of Concrete, 103-118, Farmington [12] P. Chindaprasirt , C. Chotithanorm , H.T. Cao, V. Sirivivatnanon
Hills,MI: ACI. (2007) ―Influence of fly ash fineness on the chloride penetration of
[7] Basheer, P.A.M, ―Permeation Analysis‖, in Handbook of analytical concrete‖,Construction and Building Materials pp 356–361
techniques in concrete science and technology, Principles, [13] Kalifa P, Menneteau DF, Quenard D. Cem Concr Res
techniques and applications, Ed., V.S.Ramachandran and James J. 2000;30:1915–27.Chloride Ion Diffusivity in Hardened and Plastic
Beaudoin, Noyes publications, USA., 2001. 658-737. Concrete by Resistivity Measurement‖ in M.S Khan (Ed.) Water-
[8] Yuzer N, Akoz F, Ozturk LD. Compressive strength—colour Cement Ratio and other Durability Parameters-Techniques for
change relation in mortars at high temperature. Cem Concr Res Determination (pp.57-68).Farmington Hills, MI: American
2004;34:1803–7. Concrete Institute.and Building Materials pp 356–361.
[9] Stanish, P.E. Hooten,R.D. and Thomas, M.D.A.(1997) ―Testing of [14] Sherman, M.R., McDonald D.B., Pfeifer, D.W. (1996) ―Durability
chloride penetration of concrete: A Literature Review(FHWA Aspects of Prestressed concrete Part 2: Chloride Permeability
Contract DTFH61-97R-00022: Pridiction of chloride penetration in Study‖ PCI Journal, 41, #4, pp 75-96.
concrete‖, Toronto ON Canada: University of Toronto, [15] IS 8112 –1989, Specifications for 43 Grade ordinary Portland
Department of Civil Engg Engineering. cement, BIS, New Delhi.
[10] MacDonald,K.A.and Northwood,D.O(2000) ― Rapid Estimation of [16] IS 383-1970, Specifications for coarse and fine aggregates from
Water-Cementitious Ratio and Chloride Ion Diffusivity in natural sources for concrete, BIS, New Delhi.
Hardened and Plastic Concrete by Resistivity Measurement‖ in
M.S Khan ()

Fig. 5. RCPT Test Apparatus

5000
total charge passed in coulumbs

CC1 CC2 SCFA SCSF

4000 SCMK SCGGBS SCRHA

3000

2000

1000

0
3 7 28 56 90
age in days
Fig. 2. RCPT-Test Results for Various SCC Mixes

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 International Journal of Civil & Environmental Engineering IJCEE-IJENS Vol: 11 No: 04 33

2500 25
RCPT at 90 days

Total charge passed in coulumbs

Al2O3 in %
2000 20

Al2O3 in %
1500 15

1000 10

500 5

0 0
CC1 CC2 SCFA SCRHA SCSF SCGGBS SCMK

Fig. 3. Graph of Chloride Ion Penetration with Al2O3

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