Mahmut Ekenel and John J

Journal of ASTM International, July/August 2005, Vol. 2, No. 8 Paper ID JAI14019 Available online at www.astm.org

Mahmut Ekenel1 and John J. Myers2

Durability Performance of Bridge Concretes, Part II: HighStrength Concrete (HSC) ABSTRACT: A study was undertaken on the durability of high-strength concrete (HSC) produced using locally available materials in the State of Missouri. Thirty-six (36) different mixtures were produced as HSC. 30 % fly ash replacement by cement weight was utilized in the HSC mixtures, and ground granulated blast-furnace slag (GGBFS) was also substituted by 5 % of the cement weight for some mixtures. The mixtures included locally available limestone as coarse aggregate. The mixtures without cement replacement displayed higher strength development at the end of 56 days. All the air-entrained mixtures performed well under 300 freezing and thawing cycles warranting a minimal level of air entrainment requirement. However, the samples in which GGBFS was utilized performed poorly relative to the other samples. Similar poor performance was obtained from the same samples in chloride permeability tests. KEYWORDS: high-strength concrete, mix proportions, air-entrainment, concrete durability

Introduction According to a recent report released by the Federal Highway Administration (FHwA) in 1997 on the status of highway bridges in the United States, 31 % of the 581 862 bridges are substandard. 17 % are classified as “insufficient,” meaning they are either closed or require immediate rehabilitation to remain open [1]. One viable alternative to extend service life, or to repair or replace existing deteriorated bridges is the use of high-strength concrete (HSC), especially in bridge girder applications where strength and durability issues are main concerns [2,3]. ACI Committee 363 defines high-strength concrete as the concrete which has specified compressive strengths for designs of 55 MPa or greater [2]. HSC has been used more widely in recent years. Some examples for the primary applications of HSC in United States have been in high rise building column applications, as well as bridges, highways, and aircraft aprons, where the structural members are subject to high traffic loads and severe environmental conditions. The Federal Highway Administration (FHwA) has invested a significant amount of research funding into the use and application of HSC relative to highway applications. From the mechanical point of view, HSC provides significantly enhanced behavior that translates into structural benefits. For example, with high-strength properties, the number of beams per bent line can be significantly reduced in a bridge, or the span lengths between bridge piers can be longer than conventional ones. As a result of using fewer or longer spanning members, HSC can result in reduced construction costs. The utilization of HSC for pre-stressed concrete bridge girders also results in design flexibility for the bridge designer.

Manuscript received 22 September 2004; accepted for publication 20 April 2005; published July 2005. 1 Post-Doctoral Research Fellow - Civil, Environmental. & Architectural Engineering Department, University of Missouri-Rolla, Rolla, MO, 65409. 2 Assistant Professor - Civil, Environmental. & Architectural Engineering Department, University of MissouriRolla, Rolla, MO, 65409.

Copyright © 2005 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.

2

JOURNAL OF ASTM INTERNATIONAL

The basic concept of HSC is using a low water-to-cement ratio (w/c) with a moderately high to high cement content and in many cases one or more supplementary cementitious materials. Even though HSC can be produced without supplementary cementitious materials, it is usually preferred because the mineral admixtures typically reduce the concrete cost, improve concrete durability, reduce permeability and heat of hydration, and minimize CO2 production [4–6]. The research presented herein evaluates the durability of high-strength concrete produced by using locally available materials in the State of Missouri. ACI Committee 363R states that HSC has been produced using a wide range of quality materials based on the results of the trial mixtures. Consequently, durability of various mixture proportions is of keen interest because HSC applications are relatively new in the state of Missouri. One of the first applications was performed in the year 2000 by constructing a bridge in which HSC was utilized in girder construction [7]. The investigation herein addresses: i) physical and chemical properties of mixture constituents, ii) fresh characteristics including workability and air content, iii) strength properties, and iv) long-term durability in terms of chloride permeability and resistance to freezing and thawing (F-T). Research Objectives The main objective of this research is to investigate the durability of HSC by using the materials that are locally available in the state of Missouri. Investigation was focused on the examination of the long-term durability of HSC, as well as its mechanical properties, such as compressive strength and modulus of elasticity (MOE). Various mineral admixtures have been investigated to identify sources that are most appropriate for enhanced durability performance and for the production of HSC in Missouri. The aim of this research was also intended to advance the science of HSC and the current state-of-the-art. For this purpose, an investigation has been conducted on the impact of air entrainment on the durability performance of HSC, and the current suggestions that air entrainment may not be warranted for freezing and thawing resistance of high-strength concrete with low w/c ratio due to a discontinuous capillary network and lack of freezable internal water. Experimental Program Materials The raw material used in this research included a Type I portland cement, an ASTM Class F fly ash, Grade 100 ground granulated blast-furnace slag (GGBFS), natural fine aggregate, coarse aggregate, potable tap water, and chemical admixtures. All cementitious materials were commercially available in the state of Missouri. All materials were originated in the state of Missouri except the Class F fly ash, which was transported from an adjacent state. Class C fly ash was commercially unavailable in the State of Missouri when the research was in progress. Class F fly ash and low replacement levels of GGBFS were specifically used together in this mix design study because there were no studies available to the researchers on this combination. Another motivation was the cost of GGBFS, which was discussed in Part I of this study [8]. Moreover, their durability performance was of keen interest. The HSC mixtures exclusively used a locally available crushed limestone (dolomitic) coarse aggregate. This was selected because of its high level of compatibility with the paste matrix based on previous research studies [8,9]. This material was also Missouri Department of Transportation (MoDOT) approved and proven

EKENEL AND MYERS ON BRIDGE DURABILITY PART 2

3

to not cause alkali-aggregate reaction to any significance that would prohibit its use in concrete. The locally available coarse aggregate had a maximum aggregate size of 19 mm. The SSD specific gravity of coarse aggregate was 2.45, and absorption rate was 3.80 %. The locally available fine aggregate (sand) had a fineness modulus of 2.11 and absorption of 2.58 % with a SSD specific gravity of 2.54. All these values were obtained by laboratory tests. The physical properties of cement and cementitious materials are listed in Part I of this research [8]. These material properties were provided by the manufacturer. The chemical properties of cement and cementitious materials are also presented in Part I of this research [8]. These properties were obtained by the same manufacturer using the same test method. The chemical properties of Type I portland cement, fly ash, and GGBFS meet ASTM C 150, ASTM C 618, and ASTM C 989, respectively [10]. The natural fine aggregate (sand) and coarse aggregate were obtained from quarries in the State of Missouri and approved for use in bridge structures by the MoDOT. Dolomitic limestone is known locally as Jefferson City & Phelps County limestone. The general composition and physical and chemical properties can be found in Part I of this research paper [8]. Their particle sizes are within the aggregate grading recommended by ASTM 33 [10]. Potable water was used throughout the research, which conformed to ACI 301 [11]. In order to meet a slump target of 200 ± 50 mm, a high range water reducer (HRWR) was used for HSC mixtures with a dosage range of 0.7–1.1 kg/cwt. The HRWR used is a new generation of admixture based on polycarboxylate chemistry and was added after 75 % of the mixing water was added into the mixture during batching. This generation of HRWRs does not fundamentally alter the structure of the hydrated cement paste. Moreover, there have been no reports of retrogression of strength at later ages [12]. Furthermore, these HRWRs do not influence shrinkage, creep, modulus of elasticity, or resistance to freezing and thawing [12]. A variable range of air-entrainment admixture from 0–0.14 kg/cwt was used for HSC to produce concrete with four different air contents. This was intended to examine the level of air-entrainment needed for adequate F-T protection for low w/cm mixes with HRWR. Mixture Proportions Thirty-six (36) different mixes were utilized for HSC with cement contents of 412, 487, and 586 kg/m3. 25 % and 30 % Class F fly ash replacement by cement weight was utilized in HSC mixtures except control samples, which were produced by 100 % Type I portland cement. GGBFS also replaced 5 % of the cement by weight in the mixtures in which fly ash replaced 25 % of the cement weight. The mixture designs for the HSC series are presented in Table 1. The HSC mixtures were proportioned with three (3) w/cm ratios at 0.25, 0.30, and 0.35 primarily for bridge girder constructions, in which strength and durability are desirable performance issues. These w/cm ratios are often used in today’s pre-cast and pre-stressed concrete elements. Four different air-entrainments levels were used in the HSC mixtures to create four different total air contents. The mixtures prepared for HSC utilizations are compared with those of conventional concretes (without replacement materials) in which cement are used as the binder. The average unit weight measurements were 2273 kg/m3, 2271 kg/m3, and 2278 kg/m3 for control, fly ash, and fly ash-GGBFS mixtures, respectively.

4


No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 1 2

w/cm ratio 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35

TABLE 1—Mix design for HSC mixtures. % Replacement Cement Coarse Fine HRWR2 1 Aggr. Aggr. FA GGBFS (kg/m3) (kg/m3) (kg/m3) (kg/cwt) 0 0 586 1139 611 0.77 0 0 586 1139 611 0.71 0 0 586 1139 611 0.77 0 0 586 1139 611 0.85 30 0 410 1139 611 1.02 30 0 410 1139 611 1.36 30 0 410 1139 611 1.22 30 0 410 1139 611 1.22 25 5 410 1139 611 1.22 25 5 410 1139 611 1.22 25 5 410 1139 611 1.16 25 5 410 1139 611 1.16 0 0 487 1076 773 0.88 0 0 487 1076 773 1.11 0 0 487 1076 773 1.11 0 0 487 1076 773 0.68 30 0 341 1076 773 1.42 30 0 341 1076 773 1.39 30 0 341 1076 773 1.02 30 0 341 1076 773 1.02 25 5 341 1076 773 1.39 25 5 341 1076 773 1.11 25 5 341 1076 773 0.85 25 5 341 1076 773 0.91 0 0 412 1076 773 0.99 0 0 412 1076 773 1.30 0 0 412 1076 773 0.57 0 0 412 1076 773 0.88 30 0 290 1076 773 1.30 30 0 290 1076 773 1.08 30 0 290 1076 773 1.05 30 0 290 1076 773 1.22 25 5 290 1076 773 1.30 25 5 290 1076 773 1.08 25 5 290 1076 773 1.05 25 5 290 1076 773 1.05

AEA

Air

(g/cwt) 0.0 48.2 36.9 76.5 0.0 36.9 73.7 73.7 0.0 48.2 85.1 124.7 0.0 31.2 17.0 22.7 0.0 19.8 28.4 51.0 0.0 25.5 42.5 59.5 0.0 30.4 59.5 34.0 0.0 34.0 42.5 62.4 0.0 34.0 42.5 48.2

% 1.3 3.0 4.0 5.3 2.0 2.5 4.0 5.0 1.5 3.0 4.0 4.5 2.5 3.0 3.5 4.0 3.0 3.5 4.0 4.5 3.0 3.5 4.0 4.5 3.0 4.5 5.0 6.0 2.5 4.0 5.5 6.0 3.5 4.0 5.5 6.5

Limestone was utilized as coarse aggregate. Slump was kept constant as 200±50 mm.

Test Methods & Specimens Concrete was batched under laboratory conditions using a 0.25 m3 rotary drum mixer and moist cured at room temperature of 25 ± 2oC with a 100 % relative humidity until test date. The


5

unconfined-compression test followed the procedure of ASTM C 39 [10]. The modulus of Elasticity (MOE) was measured according to the ASTM C 469 using secant method. The resistance of concrete samples to external chloride attack was determined using AASHTO T 259-80I procedure with an increased calcium chloride solution of 7.5 % [13]. The rapid freezing and thawing test was conducted as per ASTM C 666, procedure A [10]. More details about test methods and specimens, such as specimen sizes, can be found in Part I of this research [8]. Test Results and Discussions Unconfined Compressive Strength of HSC Mixtures Figure 1 presents the compressive strength development of the HSC series with similar air contents. All mixtures represented in the figure have a total air content of 4 %, except the control sample with a 0.35 w/c ratio, which had a total air content value of less than 3 %. This is believed to be the reason of displaying higher compressive test results as compared to a control sample with 0.30 w/c ratio. All of the mixtures showed a similar strength development trend; as the w/cm ratio decreased, the compressive strength increased, as would be expected. It is noteworthy to mention that all the control samples displayed higher values at 7, 28, and 56-day curing periods, ranging from 55.8–61.3 MPa, as compared to the mineral admixture replacement samples. The average 56-day compressive strength of control mixtures was 25 % and 30 % higher than fly ash-GGBFS and fly ash replacement samples, respectively. This is attributed to decreased amount of cement content of cementitious material substituted mixtures, the slow reaction capability of GGBFS, and the low CaO content of Class F fly ash (4.77 %), which yielded a lesser amount of CSH gel production with respect to control samples.

FIG. 1—Strength development of HSC mixtures with similar air contents. It is also noted that even though the fly ash-GGBFS samples exhibited 2.5 % lower compressive strength values compared to fly ash samples at 28 days, they showed 4 % higher strength compared to fly ash replacement samples at the end of the 56-day curing period. The slow reaction of GGBFS at early ages was predicted because it depends upon the breakdown of the glass by the hydroxyl ions released during the hydration of the portland cement [12]. It requires the reaction of calcium hydroxide in a manner similar to pozzolans. Hence, the

6


progressive release of alkalis by the GGBFS, together with formation of calcium hydroxide by portland cement, results in a continuing reaction of GGBFS over a long period [12]. Long-term testing duration over 56 days is highly recommended to better understand GGBFS behavior. It is also noteworthy to mention that the total aggregate/cement ratio of mixtures was increased as the w/c increased. Although it is believed by some researchers that the total aggregate to cement ratio might affect the strength (leaner mix leads to more strength), it is also obvious that it is a secondary factor and not as important as ratio of cement to mixing water or shape, strength, and stiffness of aggregates [12]. Static Modulus of Elasticity of HSC Mixtures A pilot study was done on HSC mixtures to compare the relation between modulus of elasticity (MOE) and compressive strength test results by empirical equations given by ACI 318 and ACI 363 [2,14]. The secant modulus corresponding to 40 % of the ultimate strength was selected as the method for determining the MOE of the HSC mixtures and applied according to ASTM C 469. The minimum stress applied corresponded to a longitudinal strain level of 50 millionths. The method was selected because it is commonly used and recommended by ASTM C 469 for comparative purposes [10]. According to ACI 318-02, the static modulus of elasticity (E) of concrete with an average unit weight of 2340 kg/m3 is estimated by the empirical equation of: E = 57 * f c'

f’c

(1) 3

is compression strength in Psi, and E is in Ksi (10 Psi) (1 Psi = 0.0069 MPa). where According to ACI 363R, the static modulus of elasticity (E) of concrete with an average unit weight of 2340 kg/m3 and compressive strength between 21 MPa and 83 MPa is obtained by the empirical equation of: E = (40* f c' ) + 1000

f’c

(2)

3

where is compression strength in Psi, and E is in Ksi (10 Psi) (1 Psi = 0.0069 MPa). Figures 2–4 illustrate the results of the MOE as a function of compressive strength (f’c) in MPa. As seen in these graphs, the MOE empirical equations using ACI 318 yielded the closest results to actual test results, whereas the ACI 363 empirical equation for MOE values underestimated the test results. Freezing & Thawing (F-T) Resistance of HSC Mixtures Eighteen (18) test samples were selected for this test. The main criterion in selection of samples was to test two samples from each cementitious group, one with no air entrainment, and one with the highest air entrainment by percent. Previous studies have reported contradictory conclusions on freeze thaw resistance of HSC mixtures. While some researchers stated that airentrainment should be incorporated, other studies reported that lower than traditional airentrainment levels are required [2]. This study aimed to examine this requirement for the mix designs undertaken in this study. All of the mixtures analyzed herein completed 300 cycles with the highest mass loss of 4.15 %. Figures 5 and 6 present the scaling of fly ash used test samples after 300 F-T cycles. Figure 7 shows the percent mass loss versus freezing-thawing cycles. The highest mass losses at the end were 2.53 %, 4.15 %, and 3.15 % for the non air-entrained mixtures of control, fly ash replacement, and fly ash-GGBFS replacement samples, respectively.


7

FIG. 2—MOE vs. compressive strength of 100 % P. cement HSC mixtures.

FIG. 3—MOE vs. compressive strength of 70 % P. cement + 30 % fly ash HSC mixtures.

FIG. 4—MOE vs. compressive strength of 70 % P. Cement + 25 % fly ash + 5 % GGBFS HSC mixtures.

8


FIG. 5—30 % fly ash replaced concrete FIG. 6—30 % fly ash replaced concrete with 0.25 w/cm, no AE, 2 % total air. with 0.25 w/cm, 2.6g/cwt AE, 5 % total air.

FIG. 7—Freezing & thawing cycles of HSC mixtures. In addition to these three mixtures, two other mixtures with 0.35 w/cm and 0 % air entrainment, one with fly ash replacement and the other with fly ash-GGBFS replacement, presented mass loss of 1.3 % and 0.60 %, respectively. All other samples exhibited an increase in mass due to moisture absorption through the 100th cycle and stabilized after that. These samples did not show any mass loss throughout the 300 cycles exhibiting excellent freeze-thaw resistance, confirming that a minimal air-entrainment is required for improved F-T resistance. These samples, which did not exhibit any mass loss during cycling, were not included in Fig. 7 for clarity. The samples with different air-entrainment levels but with same measured air contents, i.e., mixtures Nos. 28 and 32 (see Table 1), both had 6.0 % air content with different amounts of air entrainment and exhibited no mass loss, which notes that the total air content should be the major consideration in freezing and thawing resistance. Many researchers have stated that the presence of class F fly ash and/or GGBFS in concrete improves the freeze-thawing resistance when compared with 100 % portland cement at equal strength and equal air contents [5,12]. However, it was also noted that the non air-entrained concrete incorporating fly ash and/or slag showed


9

poor freezing and thawing resistance compared to the portland cement concrete [15]. Consequently, it can be clearly interpreted from these results that the effect of air-entrainment is an important factor for improved freezing and thawing resistance of HSC. It is also noteworthy to mention that the fly ash and fly ash-slag incorporated samples exhibited less strength development throughout the entire curing period as compared to control samples, which may also contribute to the poor performance of such mixtures relative to control samples. Chloride Permeability of HSC Mixtures Figure 8 shows the percent chloride content by weight of HSC mixtures versus depth of concrete. The Building Research Establishment suggests that a total (acid-soluble) chloride content of less than 0.4 (% by weight) produces low risk of corrosion, between 0.4 % and 1.0 % produces a medium risk, and greater than 1.0 % produces a high risk [16,17]. As expected, there is a clear-cut difference between the mixtures with 0.25 w/cm and 0.35 w/cm ratios. This was expected because, as reported by many researches, there is a strong relation between chloride content and permeability coefficient of concrete. It was also proven that a reduction in water/cement ratio significantly lowers the coefficient of permeability, which provides more disconnected pore structure [5]. This could be the reason why mixtures with 0.25 w/cm ratio performed better than the 0.35 w/cm mixtures.

FIG. 8—Chloride content of HSC samples versus depth of concrete. It can also be noticed from Fig. 8 that the chloride content of all tested mixtures at the depth of 38.1 mm, often the minimum cover depth for reinforced concrete (RC) structures, were nearly zero. At the depth of 12.7 mm, the fly ash replacement mixtures with 0.25 w/cm ratio resulted in 38 % lower chloride content than control and 76 % lower chloride content than fly ash-GGBFS replacement mixtures. The reduction in chloride content for the 0.35 w/cm mixtures was 16 % lower chloride content than control and 18 % lower chloride content than fly ash-GGBFS replacement mixtures. As for comparison, the HPC samples produced by Myers, Touma, and Carrasquillo with 100 % portland cement, 25 % fly ash replacement, and 35 % fly ash replacement were ponded with 3 % (half of the amount used in this research study) sodium chloride for 90 days and tested according to AASHTO T 259. Test samples exhibited a chloride content (% by weight) ranging

10 JOURNAL OF ASTM INTERNATIONAL

between 0.08 (0.35 fly ash replacement) and 0.32 (no fly ash) at a depth of 12.7 mm [18]. The same phenomenon was also reported by Massazza [19]. He noted that the diffusion coefficient of chloride is reduced as the pozzolanic material content increased. For example, 30 % substitution of a portland cement for fly ash decreased the diffusion coefficient of chloride by one order of magnitude. It was explained that the volume of the precipitating mass of CSH gel produced by fly ash is unable to fill the larger pores; however, it was sufficient in amount to obstruct the thin connections existing between the larger pores or at least to reduce the span thereof which enhanced the chloride resistance [19]. The poor performance of slag-replacement mixtures can be explained by the slow reaction capacity and limited pozzolanic activity. Long-term testing can be conducted for better understanding of GGBFS utilized mixture behaviors under chloride permeability. Conclusions Based on the research study undertaken using the locally available materials obtained in Missouri, the following conclusions were drawn for the mix designs investigated: •

•

•

•

The control mixtures (100 % portland cement) for the high-strength concrete (HSC) series displayed higher strength development at the end of 56 days compared to the mixtures in which a Class F fly ash and fly ash-GGBFS blend were utilized as cement replacement material. This is attributed to the decreased amount of cement content due to cementitious material replacement: slow reaction capability of ground granulated blastfurnace slag, which started contributing to the strength development after 56 days; and the low CaO content of Class F fly ash (4.77 %), which yielded to lesser amount of CSH gel production with respect to control samples. Although the test date of 56 days for comparison was considered a more appropriate test age for the control and fly ash utilized mixtures, a longer term may also be suggested to understand the behavior of Grade 100 GGBFS utilized mixtures. The MOE test results exhibited a trend, which confirms ACI 318-02 recommended empirical equation for normal unit weight concrete and between a strength range of 34 and 70 MPa. The equation that is given by ACI 363-02 appeared to be underestimating the MOE for the compressive strengths within this range. Generally, this empirical equation serves as a good lower bound predictor for HSC. The effect of air-entrainment was clear on freezing and thawing resistance of concrete. The air-entrained HSC mixtures performed outstanding compared to mixtures without air-entrainment. This suggests that a minimal level of air entrainment (2–3 %) is warranted for HSC to ensure extremely high F-T resistance for mixes in the 0.25–0.35 w/cm ratio range. In terms of chloride permeability of HSC, the Class F fly ash replacement mixtures performed superior compared to control and fly ash-GGBFS replacement mixtures. The lower performance of fly ash-GGBFS replacement samples compared to the control mixes is explained by the relatively slower reaction speed of GGBFS and being a kind of hydraulic cement, not a pozzolan. All the HSC mixtures showed practically 0 % chloride concentration at the depth of 38.1 mm, which is often recommended as a minimum cover depth for reinforced concrete structures. The w/cm ratio was clearly the dominant factor to reduce the level of chloride content close to the surface of the concrete.

EKENEL AND MYERS ON BRIDGE DURABILITY PART 2 11

Acknowledgments The present research was funded by the University of Missouri Research Board and the University Transportation Center (UTC) at the University of Missouri-Rolla (UMR). The authors are thankful to several manufacturers in the State of Missouri, USA, who donated materials used in this research study. Their names are not mentioned herein to prevent any concern of commercialism. The authors would also like to acknowledge Mr. Brian Sides and Mr. Brian Sims for their effort on this project as undergraduate research assistants (URA). References [1] [2] [3] [4] [5] [6]

[7]

[8] [9] [10] [11] [12] [13] [14] [15]

Federal Highway Administration Report, “High Performance Concrete for Bridges,” 1997, www.ota.fhwa.dot.gov, accessed April 2002. ACI Committee 363, “State-of-the-Art Report on High Strength Concrete,” Farmington Hills, MI, 1998. Alampalli, S. and Owens F., “In Service Performance of High-Performance Concrete Bridge Decks,” Transportation Research Record – Journal of the Transportation Research Board, Washington, DC, No. 1696, Vol. 2, Publication 5B0121, 2000, pp. 193–196. Malhotra, V. M. and Mehta, P. K., “Pozzolanic and Cementitious Materials,” Overseas Publishers Association, 1996. Mehta, P. K., “Concrete: Structure, Properties, and Materials,” Prentice-Hall, Englewood Cliffs, NJ, 1986. Myers, J. J. and Carrasquillo, R. L., “Influence of Hydration Temperature on the Durability and Mechanical Property Performance of HPC Prestressed/Precast Beams,” National Research Council, Transportation Research Record – Journal of the Transportation Research Board, Washington, DC, No. 1696, Vol. 1, Publication 5B0038, April 2000, pp. 131–142. Yang, Y. and Myers, J. J., “Live Load Test Results of Missouri’s First High Performance Concrete Superstructure Bridge,” National Research Council, Transportation Research Record – Journal of the Transportation Research Board, No. 1845, Design of Structures 2003, Washington, DC, October 2003, pp. 96–103. Ekenel, M. and Myers, J. J., “Performance of Bridge Concretes, Part I: High Performance Concrete (HPC),” Journal of ASTM International, Vol. 2, No. 7, 2005 (in press). Myers, J. J. and Carrasquillo, R. L., “Mix Proportioning for High-Strength Bridge Beams,” American Concrete Institute Special Publication 189, American Concrete Institute, Detroit, MI, 1999, p. 37-6. Annual Book of ASTM Standards, Vol. 4.02, ASTM International, West Conshohocken, PA, 2002. ACI Committee 301, “Specifications for Structural Concrete for Buildings,” Farmington Hills, MI, 1999. Neville, A., “Properties of Concrete,” John Wiley & Sons, NY, 1996. AASHTO T 259, “Resistance of Concrete to Chloride Ion Penetration,” 1980. ACI Committee 318-02, “Building Code Requirements for Structural Concrete and Commentary,” Farmington Hills, MI, 2002. Virtanen J., “Freeze-Thaw Resistance of Concrete Containing Blast-Furnace Slag, Fly Ash and Condensed Silica Fume,” Proceedings, First International Conference in the Use of

12 JOURNAL OF ASTM INTERNATIONAL

[16] [17] [18]

[19]

Fly Ash, Silica Fume, Slag and Other Mineral By-Products in Concrete, Montebello, Quebec, Canada, Vol. 2, 1983, pp. 923–942. Arya, C., “Problem of Predicting Risk of Corrosion of Steel in Chloride Contaminated Concrete,” Proc. Instn Civ. Engrs, Part 1, 88, Oct., 889, 1990. Haque, M. N. and Kayyali, O. A., “Free and Water Soluble Chloride in Concrete,” Cement and Concrete Research, Vol. 25, No. 3, 1995, pp. 531–542. Myers, J. J., Touma, W., and Carrasquillo, R. L., “Permeability of High Performance Concrete: Rapid Chloride Ion Test vs. Chloride Ponding Test,” Proceedings for the PCI/FHWA International Symposium on High Performance Concrete, Advanced Concrete Solutions for Bridges and Transportation Structures, New Orleans, LA, October 1997, pp. 268–282. Massazza, F., “Pozzolanic Cements,” Cement & Concrete Composites, Vol. 15, 1993, pp. 185–214.