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Salvador, Na, Nassif, and Corso 1

Effect of Accelerated Curing on Surface Resistivity and Rapid Chloride Permeability 1

of High Performance Concrete 2

3

Michael Salvador, Graduate Student 4

Rutgers Infrastructure Monitoring and Evaluation (RIME) Laboratory 5 Rutgers, The State University of New Jersey 6

96 Frelinghuysen Road, Piscataway, NJ 08854 7

Email: [email protected] 8

9 Chaekuk Na, Ph.D., Post-Doctoral Associate 10



Email: [email protected] 14 15

Hani Nassif*, Ph.D., P.E., Professor 16



Phone: (848) 445-4414, Fax: (732) 445-4775 20

Email: [email protected] 21

22

Frank Corso, P.E., Supervisor for Structures Construction 23 New Jersey Turnpike Authority 24

581 Main St # 1, Woodbridge, NJ 07095 25

Email: [email protected] 26 27

28 29

* Corresponding Author 30

Abstract 249 words < 250 words 31 Word Count 3002 words 32 Figure/Table 13@250 each = 3250 words 33

Total 6252 words < 7500 words 34 Re-Submission Date November 15, 2012 35

36

TRB 2013 Annual Meeting Paper revised from original submittal.


ABSTRACT 1

Recently, many bridges were built using High Performance Concrete (HPC) to increase their 2

durability. However, when subjected to cracking or exposed to aggressive environments, their 3 durability would gradually diminish, causing corrosion of reinforcement in the deck. This 4 phenomenon is one of the major factors causing delamination and structural deficiencies of 5 concrete decks. The corrosion risk is directly related to the chloride ion permeability of the 6 concrete, which can be determined using permeability testing at a minimum of 56 days. Since 7

the permeability testing is time consuming and labor–intensive, many of State Department of 8 Transportations (DOT’s) are exploring the use of more expedient and less variable testing 9 methods. To evaluate the long-term durability aspects of HPC at an earlier acceptance age but 10 with lower cost, accelerated curing and concrete resistivity measurement are proposed as a 11 potential replacement. There is a need to understand the effect of accelerated curing on concrete 12

resistivity and chloride ion permeability as a measure of durability. 13

This paper conducts an experimental program to evaluate the effects of accelerated curing 14

on durability performance of HPC. Both the Surface Resistivity (SR) and the Rapid Chloride 15 Permeability (RCP) tests were performed on concrete cylinders cured under accelerated as well 16

as normal wet curing conditions. Results show that RCP testing can be substituted by SR testing 17 as a measure of the durability of concrete. Moreover, accelerated curing can expedite the time 18 needed to test permeability. Additionally, SR testing combined with accelerated curing 19

correlated well with results from RCP testing. 20 21

Key Words: 22

Silica Fume 23

High Performance Concrete 24

Rapid Chloride Permeability 25

Surface Resistance 26

Accelerated Curing 27

28



INTRODUCTION 1

To increase durability and reduce maintenance costs, High-Performance Concrete (HPC) became 2

a standard construction material for bridge structures in the U.S. HPC is a low w/c composite 3 concrete mixture that is blended with Pozzolan such as silica fume, fly ash, and slag to enhance 4 its binding and durability properties. The porosity of HPC is lower due to the cementitious 5 compound created from the reaction of fine pozzolanic materials (i.e. silica fume and fly ash) 6 with both the calcium hydroxide released from Portland cement and water. As a result, the 7

number of capillary pores in HPC is reduced and the resistance to chloride ion penetration of 8 HPC is increased, but there are still issues with the durability of HPC structures. 9

The corrosion of reinforcement has become a predominant problem, reducing structural 10 durability under a harsh environment [1]. To determine the corrosion risk, the Rapid 11 Determination of the Chloride Permeability of Concrete, or Rapid Chloride Permeability (RCP) 12

test, was developed in 1981 by the Portland Cement Association (PCA). As opposed to the 13

ponding test which necessitated 90 day curing, the RCP test could be performed after only 56 14

days. However, RCP testing is not always consistent and results from different laboratories on 15 the same material can differ by up to 51% [2]. Therefore, a faster and more reliable testing 16

method is required to determine the corrosion risk of reinforcement. 17 In 2011, AASHTO announced that the Surface Resistivity (SR) testing could be used to 18

determine the electrical resistivity of concrete and provide an indication of its resistance to 19

chloride ion penetration as an alternate method to RCP testing [3]. As a result, the Florida DOT 20 has used the electrical resistivity of water-saturated field concrete specimens as an indication of 21

their permeability instead of RCP testing [4]. Many studies show that SR at 28 days have a 22 strong relationship with RCP at 28 days [5-7], and, in addition, research was performed on 23 accelerated curing for self-consolidating concrete to reduce the required time to test permeability 24

[8]. Since little is known about the effect of accelerated curing on RCP and SR, the relationship 25

between the RCP and SR results of HPC under an accelerated curing condition needs to be 26 investigated. 27

RCP testing requires a minimum of 56 days and the results do not always correlate with 28

those obtained from ponding testing. Therefore, the objective of this paper is to evaluate the 29 effect of accelerated wet curing on the electrical resistance and chloride ion permeability of HPC 30

and to determine the feasibility of the use of SR testing instead of RCP testing under accelerated 31 curing conditions. A prediction model is subsequently proposed relating the SR under 32

accelerated curing conditions and RCP under normal conditions. A total of six (6) different HPC 33 mixes were prepared, and the electrical resistance, chloride ion permeability and strength 34 properties for all concrete samples are presented. 35 36

EXPERIMENTAL PROGRAM 37

Concrete Mixtures 38

A total of six (6) concrete mixes with varying percentages of silica fume and fly ash were tested 39

to evaluate their compressive strength, electrical resistance and chloride ion permeability. The 40 amount of additives was determined based on the HPC specifications of the New Jersey 41 Turnpike Authority: silica fume and fly ash can replace a maximum of 5% and 20% of Portland 42 cement by weight, respectively. The first mix was control and the remaining five (5) mixes 43 included 3%, 5% and 8% of silica fume and 15%, 20% and 25% of fly ash. The total 44



cementitious material content was fixed at 386 kg/m3 and the ratio of coarse-to-fine aggregate 1

content was a minimum of 1.5 with a total coarse aggregate content not lower than 1068 kg/m3. 2

The mix proportions are presented in Table 1. 3 The cementitious materials used in this study are Portland cement, silica fume and fly ash. 4

The Portland cement was ASTM C150 Type I cement having a specific gravity of 3.15. The 5 silica fume was ASTM C1240 dried densified micro-silica powder with a specific gravity of 2.22, 6 and the low calcium fly ash (ASTM C618 Class F) had a specific gravity of 2.49. The coarse 7 aggregates were New Jersey crushed gravel with a nominal maximum size of 19 mm, a specific 8 gravity of 2.83 and 1.1% water absorption. The fine aggregates were concrete sand (silicone 9

dioxide) with a specific gravity of 2.62 and 0.4% water absorption. The air-entraining agent and 10 superplasticizer used in the mix proportions were both products of the same manufacturer. 11 12

TABLE 1 Mix Proportions 13

Mix ID

Material

CTRL S13F

220 S5F20 S8F20 S5F15 S5F25

Cement (kg/m3)

(lbs./cy.)

386

(650)

297

(501)

289

(488)

278

(468)

309

(520)

270

(455)

Silica Fume (kg/m3)

(lbs./cy.)

- 12

(20)

20

(33)

31

(52)

20

(33)

20

(33)

Fly Ash (kg/m3)

(lbs./cy.)

- 77

(130)

77

(130)

77

(130)

58

(98)

97

(163)

Total Cementitious (kg/m3)

(lbs./cy.)

386

(650)

386

(650)

386

(650)

386

(650)

386

(650)

386

(650)

Gravel (kg/m3)

(lbs./cy.)

1098

(1850)

1068

(1800)

1099

(1852)

1074

(1810)

1083

(1825)

1068

(1800)

Sand (kg/m3)

(lbs./cy.)

719

(1212)

703

(1185)

726

(1224)

700

(1180)

703

(1185)

707

(1192)

w/c ratio 0.4 0.4 0.44 0.4 0.4 0.4

AEA (ml/100kg)

(oz/cwt.)

130

(1.3)

130

(1.3)

130

(1.3)

130

(1.3)

130

(1.3)

130

(1.3)

Superplasticizer (ml/100kg)

(oz/cwt.)

326

(5)

326

(5)

326

(5)

326

(5)

326

(5)

326

(5)

Slump (mm)

(in.)

64

(2.5)

57

(2.25)

76

(3)

57

(2.25)

32

(1.25)

83

(3.25)

Air Content (%) 3.5 4.5 3.9 4.0 5.0 6.0

1 S=Silica Fume

2 F=Fly Ash, Class F

14



Specimen Preparation 1

The laboratory mixes modified the mixing procedure based on ASTM C 192; coarse and fine 2

aggregates as well as one third of the water and air-entraining agent were mixed for one minute. 3 Subsequently, all the cementitious materials were added as well as the final two thirds of water. 4 After mixing for three to four minutes, the concrete was left to rest for three minutes to hydrate. 5 Finally, the superplasticizer was added and the concrete was mixed for another two minutes. 6 The concrete batch was placed in plastic cylinders and then consolidated using a vibrating table. 7

After placement, all of the cylinders were cured in the environmental chamber as illustrated in 8 Figure 1(a). 9

A total of twenty 100 mm x 200 mm concrete cylinders were cased and cured in a curing 10 chamber as shown in Figure 1(b). After 14 days, they were moved to the environmental chamber 11 (a) until 91 days. Three cylinders were tested to measure the compressive strength at the ages of 12

1, 7, 14 and 28 day in accordance with ASTM C 39. An additional ten 100 mm x 200 mm 13

cylinders were prepared to test the electrical resistance and chloride ion penetrability for each 14

mix, half of which were cured under normal wet conditions and the other half of which were 15 cured in an accelerated curing water tank as shown in Figure 1(c). SR and RCP testing were 16

performed between the ages of 7 day and 91 day. For each test, two cylinders from each curing 17 condition were selected for SR and RCP testing. 18

19

Normal Wet Curing (NC) – The specimens were cured in the environmental chamber at 20 22

oC with 50% relative humidity (R.H.) after placement. After demolding at 24 hours, they were 21

stored in the curing room at 20oC with 100%. After 14 days, the cylinders were moved to the 22

environmental chamber again at 22oC with 50%. 23

Accelerated Curing (AC) – The accelerated cured specimens were left in the hot water 24 chamber at 38

oC after 1 day curing in the environmental chamber. 25

26

27

FIGURE 1 Curing Method; (a) Environmental Chamber (50% R.H., 22oC), (b) Mist-Cured 28

(100% R.H., 20oC), (c) Accelerated Curing (100% R.H., 38

oC). 29



Rapid Chloride Permeability Testing 1

RCP testing was performed in accordance with ASTM C1202. One accelerated cured cylinder 2

and one normal cured cylinder were selected to be tested at the ages of 7, 14, 28, 56 and 91 days. 3 For each test date and curing condition, one cylinder was cut into three 100 mm x 50 mm 4 samples and each sample was then epoxy coated and left to dry overnight. After the desiccation 5 and submersion process, the samples were inserted into the cells with a 3% NaCl solution on one 6 side and a 0.3 N (reagent grade) NaOH solution on the other. The number of coulombs that 7

passed through each specimen were determined after a 6 hour testing period. The environment 8 was maintained between 20°C and 25°C during RCP testing for consistency in the results. 9 Figure 2 illustrates the RCP testing setup. 10

11

12

FIGURE 2 RCP Testing Set-up; (a) PROOVE-it used in Rutgers University Laboratory, (b) 13 Epoxy Coated Sample, (c) RCP Testing Cell with Solution. 14

15

16

FIGURE 3 SR Testing Set-up; (a) RESIPOD used in Rutgers University Laboratory, (b) 17 Four-Points Wenner Array Probe [4]. 18



Surface Resistivity Testing 1

Two cylinders from each curing condition were marked at 0, 90, 180 and 270 degrees in 2

accordance with AASHTO TP 95-11 to determine their electrical resistance. One cylinder was 3 labeled specifically for SR measurements and the other cylinder was used for RCP testing to 4 ensure a good correlation between SR and RCP testing results. The surface of each cylinder was 5 dried before being tested for surface resistivity to maintain similar testing conditions. Readings 6 were taken by wetting and placing the four-point Wenner Array Probe on the dried concrete for a 7

total of eight times (twice at each angle). The cylinder used only for SR measurement was then 8 returned to its curing chamber for future measurements whereas the other cylinder was cut and 9 used for RCP testing. Figure 3 shows the SR test setup in this study. 10

Table 2 summarizes the comparison between RCP (ASTM C 1202) and SR (AASHTO 11 TP 95) values to determine chloride ion penetrability. 12

13

TABLE 2 Comparisons between RCP and SR Values to Determine Chloride Ion Penetrability 14

Chloride Ion

Penetrability

SR (KΩ-cm)

(AASHTO TP 95)

RCP (coulombs)

(ASTM C 1202)

High < 12 > 4000

Moderate 12 – 21 2,000 – 4,000

Low 21 – 37 1,000 – 2,000

Very Low 37 – 254 100 – 1,000

Negligible > 254 < 100

15

TABLE 3 Compressive Strength Results 16

Testing

Age

Compressive Strength (MPa) (psi)

CTRL F3A20 F5A20 F8A20 F5A15 F5A25

1 day 28.0

(4061)

14.9

(2166)

12.7

(1847)

17.0

(2468)

22.1

(3206)

15.9

(2305)

7 days 38.6

(5593)

31.2

(4526)

26.9

(3905)

27.6

(4009)

33.8

(4896)

40.6

(5892)

14 days 40.1

(5812)

38.8

(5621)

37.1

(5374)

35.4

(5135)

40.1

(5812)

45.3

(6568)

28 days 41.2

(5971)

48.7

(7066)

44.2

(6409)

47.8

(6927)

46.1

(6688)

51.3

(7444)

56 (MPa)

(psi)

42.0

6091

52.2

7564

46.9

6807

50.8

7365

55.3

8021

62.6

9076

17



RESULTS AND DISCUSSION 1

Effect of Silica Fume and Fly Ash on Strength and Durability 2

The compressive strength testing results at the ages of 1, 7, 14, 28 and 56 days are summarized 3 in Table 3. The mixes with pozzolanic materials have lower early age strength and higher 28-4 day strength than the control mix because cement is a more reactive material than pozzolan. As 5 can be seen in Table 3, the compressive strength of SF and FA HPC mixes were similar, because 6

HPC becomes denser with higher silica fume and fly ash content by lowering capillary pores, but 7 does not necessarily gain compressive strength. 8 RCP was measured at the ages between 7 and 91 days for both curing conditions. The 9 RCP results are plotted in Figure 4 and, as can been seen, the control mix attained the lowest 10 chloride permeability resistance because it did not have fine particles (pozzolan) to fill capillary 11

pores. F8A20 mix attained the highest permeability resistance because it had the highest 12 percentage of silica fume, which consisted of finer particles than fly ash. Therefore, a higher 13

percentage of silica fume yields higher permeability resistance. Contrarily to expectations, 14 F5A20 mix had the lowest early-age chloride ion permeability resistance, because it had higher 15 w/c ratio of 0.44. The permeability resistance of F5A20 at later age was, however, extremely 16 high and similar to the other mixes with pozzolanic materials. This suggests that the water-to-17

cement ratio played an important role considering the chloride ion permeability of concrete at 18 early age but became negligible at later ages. More testing relating the effects of w/c ratio to 19

RCP values of concrete needs to be examined to derive a relationship. 20 All accelerated cured mixes except for control mix had 7-day RCP values that were lower 21

than normal cured mixes. Two mixes with the higher pozzolan content (F8A20 and F5A25) had 22

higher chloride ion permeability resistance than control mix at early age, even though silica fume 23 and fly ash are less reactive than cement. This shows how important pozzolan are to the 24

durability of concrete because of their finer diameter. According to Figure 4, the lowest 25

resistance to chloride ion permeability at 56 days was attained by the control mix, followed by 26

F5A15, F3A20, F5A25 and F8A20 mixes. As proven by the results, silica fume is a more 27 effective material than fly ash in increasing chloride ion permeability because of its smaller 28 particle size. F5A20 mix was not discussed in comparison because of its higher w/c ratio. 29

Figure 5 shows the concrete electrical resistivity at each age. Similarly to the RCP results, 30 control mix attained the lowest SR measurements, followed by F5A15, F3A20, F5A25 and 31

F8A20. The order in which the SR and RCP mixes are ranked for durability proves the validity 32 of the relationship between SR and RCP testing. 33

As can be seen in Figure 4 and Figure 5, the accelerated curing induced higher 34

permeability resistance and higher resistivity than normal curing at each age, which can expedite 35 the required time for permeability testing. 36

RCP and SR results of mixes with pozzolan varied considerably at early ages but became 37 very low after 56 days. Figure 6 illustrates the linear relationship of permeability between 38

accelerated and normal cured samples. This relationship shows that chloride ion permeability can 39 be effectively predicted by the use of accelerated curing regardless of the testing ages. 40 Additionally, Figure 7 shows the relationship of SR measurements between accelerated and 41 normal curing. Similarly to the RCP relationship, the surface resistivity ratio between two curing 42 condition is linear. Therefore, concrete resistivity can be predicted using accelerated curing 43

regardless of the testing age. 44



1

FIGURE 4 Rapid Chloride Permeability Testing Results. 2

3

4

FIGURE 5 Surface Resistivity Testing Results. 5

0

1000

2000

3000

4000

5000

0 20 40 60 80 100

CTRL -NC

F3A20-NC

F5A20-NC

F8A20-NC

F5A15-NC

F5A25-NC

CTRL -AC

F3A20-AC

F5A20-AC

F8A20-AC

F5A15-AC

Pe

rme

ab

ilit

y (

Co

ulo

mb

s)

Age (days)

0

50

100

150

200

250

300

350

400

0 20 40 60 80 100

CTRL -NC

F3A20-NC

F5A20-NC

F8A20-NC

F5A15-NC

F5A25-NC

CTRL -AC

F3A20-AC

F5A20-AC

F8A20-AC

F5A15-AC

Su

rfa

ce

Re

sis

tivit

y (

Age (days)

-cm

)



0

1,000

2,000

3,000

4,000

5,000

0 1000 2000 3000 4000 5000

Pe

rme

ab

ilit

y (

Co

ulo

mb

s)

Acce

lera

ted

Cu

rin

g

Permeability (Coulombs)

Normal Curing

R2=0.923

1

FIGURE 6 Accelerated vs. Normal Cured RCP Testing Results. 2

3

0

50

100

150

200

250

300

0 50 100 150 200 250 300

Su

rfa

ce

Re

sis

tivit

y (

)

Acce

lera

ted

Cu

rin

g

Surface Resistivity ( )

Normal Curing

-cm

-cm

R2=0.923

4

FIGURE 7 Accelerated vs. Normal Cured SR Testing Results. 5

The relationships between RCP and SR under different curing conditions are plotted in 6 Figure 8 and Figure 9. As seen earlier in Table 2, the chloride ion penetrability can be estimated 7



by either resistivity or permeability. Since high electrical resistivity means lower permeability, 1

the relationship between RCP and SR is in inverse proportion. Both the RCP and SR boundaries 2 are plotted in grey in Figure 8 and Figure 9 to compare the testing results. 3

Since RCP testing is costly and requires a minimum of 56 days, the feasibility of the use 4

of SR testing in conjunction of accelerated curing should be verified. Figure 8 shows two 5 relationships between RCP and SR under normal and accelerated curing conditions. All results 6 are compared to the previous results reported by Kessler et al. [7] and Rupnow et al. [8]. As can 7 be seen in Figure 8, the testing results under normal curing conditions were more dispersed and 8 induced higher permeability than those under accelerated curing conditions, and therefore were 9

not within the boundary of ASTM C 1202 and AASHTO TP 95 in Table 2. Even if the testing 10 results are dispersed, the relationship between RCP and SR regardless of curing conditions can 11 be shown in Eq. (1). This correlation can be used as a prediction and as a cost-efficient way to 12 determine the chloride ion permeability. By measuring the electrical resistivity of concrete, the 13

durability of concrete can be estimated in a cost efficient way. 14 15

RCPAll = 3.76 E4 x (SRAll)

-0.915 (1) 16

17

Although SR measurements can predict RCP coulombs, 56 days are still necessary to 18 determine the chloride ion permeability. As mentioned previously, the accelerated curing was 19

applied to expedite the required time. Figure 9 depicts the relationship between normal cured 20 RCP and accelerated cured SR, and such correlation can be expressed by the following Eq. (2). 21 This means that the durability property (RCP measurement at 56 days) can be determined by 22

testing SR under accelerated curing condition. Contractors could use Eq. (2) as an approximated 23 estimation for concrete durability, but should not solely rely on Eq. (2), because this correlation 24

is not within the boundary of ASTM C 1202 and AASHTO TP 95. 25

26

RCPNC = 2.79 E4 x (SRAC)

-0.661 (2) 27

28 To verify Eq. (2) for field mixes, six concrete cylinders were collected from Patcong 29

Creek Bridge on Garden State Parkway in New Jersey. Three cylinders were cured in mist-30 curing room for normal curing condition, and the other three samples were accelerated cured in 31

the hot water tank. At the ages of 14 days and 56 days, SR testing followed by RCP testing of 32 each curing condition was performed. Table 4 represents the summary of the verification testing, 33 and the resting results are shown in Figure 9. The testing results show that the regressive 34 relationship of Eq. (2) can effectively estimate the chloride ion permeability by measuring 35 concrete resistivity under accelerated curing condition. 36

Regardless of the curing condition, w/c, or pozzolan content, results from this study show 37

a SR/RCP trend line that is higher than other studies [7, 8]. This may be due to the use of 38

materials from different sources than Rupnow and Kessler et al. These results are more 39 conservative and show that the Rupnow and Kessler et al. relationships may not be applicable for 40 concrete mixes with different aggregates, cement, or admixtures than those that were used in 41 their study. There is a need for more research work to understand this aspect of the study. 42

43



1

FIGURE 8 Comparisons between RCP and SR Measurement under Different Curing Condition. 2

3

4

FIGURE 9 Relationships between SR-AC and RCP-NC. 5

10

100

1,000

10,000

10 100 1,000

Surface Resistivity ( - AASHTO TP 95

Pe

rme

ab

ilit

y (

Co

ulo

mb

s)

- A

ST

M C

12

02

Kessler et al. (2008)

RCP=3.94e4x(SR)

-1.221

Accelerated Curing

RCPAC

=2.41e4x(SR

AC)

-0.881

[Negligible]

[MOD.]

[Very Low]

[LOW]

[HIGH] Normal Wet Curing

RCPNC

=3.53e4x(SR

NC)

-0.799

-cm)

Rupnow et al. (2011)

RCP=3.35e4x(SR)

-1.074

RCPALL

=3.76e4x(SR

ALL)

-0.915

Rupnow et al. (2011)

RCP=3.35e4x(SR)

-1.074

[HIGH]

[LOW]

[Very Low]

[MOD.]

[Negligible]

Kessler et al. (2008)

RCP=3.94e4x(SR)

-1.221

10

100

1,000

10,000

10 100 1,000

Field Testing Results

RCPNC

=2.79e4x(SR

AC)

-0.661

Surface Resistivity ( - AASHTO TP 95

Pe

rme

ab

ilit

y (

Co

ulo

mb

s)

- A

ST

M C

12

02

-cm)



TABLE 4 Comparisons between Measured and Estimated Permeability 1

SR (KΩ-cm2)

Accelerated Curing

Permeability (Coulombs)

Normal Curing

Measurement Estimation Error

Sample 1 at 14 days 78.7 1380 1557 +13%

Sample 2 at 56 days 243.7 1034 738 -29%

2

CONCLUSIONS 3

The following conclusions and recommendations could be deduced from this study: 4

1. The presence of pozzolanic materials considerably increases the chloride permeability 5

resistance of concrete at early ages. Since silica fume is much finer than cement particles, it is 6 recommended to add more than 3% silica fume so as to increase the chloride permeability 7

resistance of concrete. It is also recommended to add more than 20% fly ash since it is less 8 expensive than silica fume to further increase resistance to chloride permeability. 9

2. The correlations between surface resistivity and rapid chloride permeability are enough to 10 provide a rough estimation of RCP coulombs at 56 days. The accelerated cured surface 11

resistivity can estimate normal cured surface resistivity with adequate accuracy. Similarly, 12 accelerated cured RCP can predict normal cured RCP. To minimize cost and testing time, 13

accelerated cured SR can also predict normal cured RCP. 14

3. As of today, not enough data has been collected to predict normal cured samples using 15

accelerated curing. Future testing may be useful to refine current equations and make 16 predictions more certain. We cannot advocate hot curing to the NJTA solely based on these 17 results. We will incorporate slag mixes to increase the data set and make the prediction model 18

more reliable. 19

20

ACKNOWLEDGEMENTS 21

This study was funded by the New Jersey Turnpike Authority (NJTA). The views expressed in 22 this article are those of the authors and do not necessarily reflect the view of NJTA. Their 23 financial support and the technical assistance of NJTA staff as well as the assistance of 24 undergraduate students are gratefully acknowledged. 25

26

REFERENCES 27

1. Raupach, M. and Schießl, P. Macrocell sensor systems for monitoring of the corrosion risk of 28 the reinforcement in concrete structures, NDT & E International, Vol. 34, No. 6, pp.435-442, 29 2001. 30

2. ASTM Committee C09 “Standard Test Method for Electrical Indication of Concrete’s Ability 31 to Resist Chloride Ion Penetration”, ASTM Standard C 1202-10, 2010. 32



3. AASTHO Highway Subcommittee on Material “Surface Resistivity Indication of Concrete’s 1

Ability to Resist Chloride Ion Penetration”, AASHTO Designation TP 95-11, 2011. 2

4. Florida DOT “Testing Method for Concrete Resistivity as an Electrical Indicator of its 3 Permeability”, FM 5-578, 2004 4

5. Chini, A.R., Muszynski, L.C., and Hicks, J.K. “Determination of Acceptance Permeability 5 Characteristics for Performance-Related Specifications for Portland Cement Concrete.” Final 6

Report, 2003. 7

6. Kessler, R.J., Powers, R.G., Vivas, E., Paredes, M.A. and Virmami, Y.P. “Surface Resistivity 8 as an Indicator of Concrete Chloride Penetration Resistance”, Concrete Bridge Conference, St. 9

Louis, MO, May 4-7, 2008. 10

7. Rupnow, T.D. and Icenogle, P. “Evaluation of Surface Resistivity Measurements as an 11 Alternative to the Rapid Chloride Permeability Test for Quality Assurance and Acceptance”, 12

FHWA/LA.11/479, July, 2011 13

8. Ozyildirim, C., and Lane, D. S. “Final Report: Evaluation of Self-Consolidating Concrete”, 14

Virginia DOT, June, VTRC 03-R13, p.15, 2003. 15


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