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April 2009 The Arabian Journal for Science and Engineering, Volume 34, Number 1B 57

DURABILITY DESIGN AND APPLICATION OF STEEL

FIBER REINFORCED CONCRETE IN TAIWAN

Chih-Ta Tsai*

Assistant Research Fellow, Sustainable Environment Research Center

National Cheng Kung University, Tainan, Taiwan

Lung-Sheng Li

Associate Professor, Department of Assets and Property Management

Hwa-sha Institute of Technology, Taipei, Taiwan

Chien-Chih Chang

Research Assistant, Sustainable Environment Research Center

National Cheng Kung University, Tainan, Taiwan

Chao-Lung Hwang

Professor, Department of Construction Engineering

National Taiwan University of Science and Technology, Taipei, Taiwan

ة ـ صـالخلا:

ي ـ تلا اذه أنه إذا استخدمت أو أضيفت.قرير الطريقة التي استخدمت الديمومة للخرسانة باستخدام األلياف الحديدية في تايوانـ قدم ايملع موهفملا نمو لتعزيز الصالبة ،ومقاومة االحتكاك وقوة التحمل للصدماتاأللياف ال .حديدية في الخرسانة فذلك

لكن التصميم المحلي المطور لخلطة الخرسانة والحلول الحسابية لكثافة الخلطة قد استخدمت لحل التشابك أللياف الحديد في الخرسانة ،ولتكوين ) )SFRSCCمع تدفق سلس وزيادة للديمومة ،وذلك بتقليل آمية معجون اإلسمنتخرسانة باأللياف الحديدية تتميزباألندماج الذاتي

يمكننا الحصول على خرسانة تتدفق(super-plasticizer)وحين نزيد الكثافة للحجارة بمساعدة المواد البوزوالنية واستخدام اإلضافات الكيميائية الخلطة و.مثل العسل مع قليل من التشابك بين األلياف الحديدية هذه استخدمت في آثير من المشاريع مثل إنشاء حاوية أو صهريج)(SFRSCCقد

هذه الخلطة .للمخلفات التي تحتوي على قليل من اإلشعاعات ،و سطح الطرقات ،ومجسمين فنيين يمكن استخدامها))SFRSCCومن التوصيات فإن .النظر فيها ألنها تزيد من عمر المبانى الخرسانية لتحسين أداء األلياف الحديدية في الخرسانة ،والبد من

*Address for Correspondence:

Sustainable Environment Research Center, National Cheng Kung University

No. 500, Sec. 3, An-Ming Road, Tainan, Taiwan 70955

Email: [email protected]

Tel: +886-6-3840136 ext. 217

Fax: +886-6-3840960

Paper Received 27 March 2008; Accepted 9 February 2009



Chih-Ta Tsai, Lung-Sheng Li, Chien-Chih Chang, and Chao-Lung Hwang

58 The Arabian Journal for Science and Engineering, Volume 34, Number 1B April 2009

ABSTRACT

This paper presents the way durability has been introduced to steel fiber reinforced concrete in Taiwan. It is

generally acknowledged that steel fibers are added to improve the toughness, abrasion resistance, and impact

strength of concrete. However, a locally developed mixture design method, the densified mixture design algorithm

(DMDA), was applied to solve not only the entanglement or balling problem of steel fibers in concrete or to producesteel fiber reinforced self-consolidating concrete (SFRSCC) with excellent flow-ability, but also to increase the

durability by reduction in the cement paste content. By dense packing of the aggregates and with the aid of

pozzolanic material and superplasticizer (SP), concrete can flow honey-like with less entanglement of steel fibers.

Such SFRSCC has already been successfully applied in several projects, such as construction of a low radiation

waste container, bus station pavement, road deck panel, and two art statues. So it is recommended that the SFRSCC

can be used for improving the performance of ordinary steel fiber reinforced concrete in many ways and should be

considered for increasing the lifecycle of a concrete structure.

Key words: durability, steel fiber reinforced concrete, DMDA, dense packing, lifecycle





DURABILITY DESIGN AND APPLICATION OF STEEL FIBER REINFORCED

CONCRETE IN TAIWAN

1. INTRODUCTION

Although concrete is a widely used construction material, it has major disadvantages such as low tensile strength

and low strength to weight ratio, and it is liable to cracking [1]. The brittle nature of plain concrete cannot be

neglected and an approach to make concrete a ductile material is necessary. In this regard, steel is no doubt a useful

reinforcement material for concrete whether it is in the form of a steel fiber or a reinforcing bar. The addition of steel

fibers to concrete can improve the tensile strength and ductility, but it will also reduce the workability [2–7].

Research work is being conducted in Taiwan, since 1993, to improve the workability of steel fiber reinforcedconcrete (SFRC). A task force has been formed in Taiwan to develop High Performance Concrete (HPC) and self-

consolidating concrete (SCC) for solving the problems of honeycombing due to improper concrete practices. A local

mixture proportion method, Densified Mixture Design Algorithm (DMDA), has been developed to produce HPC and

SCC mixture proportions. This method combines the past volume method and the current weight method resulting in

a densely packed aggregate with the optimization of cement paste. The main objectives of the durability design using

DMDA were:

(1) To avoid any honeycombing, bleeding, segregation, and heterogeneous features by improving the workability

using less water and paste, with the aid of pozzolanic materials (PM) and super plasticizers (SP).

(2) To improve the volume stability by minimizing the water amount and cement content to reduce the possibility

of shrinkage and swelling, respectively.

(3) To determine the ability of concrete to resist harmful substances penetration by using electrical and

electrochemical techniques (e.g. concrete electrical resistivity and its ability to resist chloride ion penetration).

With the aid of the DMDA method, the steel fiber reinforced self-consolidating concrete (SFRSCC) can be

obtained from traditional steel fiber reinforced concrete, with improved durability aspects. SFRSCC has been

successfully used to construct:

(1) A high integrity concrete container (HIC) for storing radiation waste,

(2) Bus station pavement in Taipei city,

(3) High Performance Road Deck Panel (HPRDP), and

(4) Concrete art statues.

Regarding the concept of sustainable use of the material, SFRSCC has been identified as one of the future visions

[8] of the concrete industry in USA.

2. DENSIFIED MIXTURE DESIGN ALGORITHM (DMDA)

2.1. The Durability Design Logic of DMDA

The most important durability design logic of DMDA is the achievement of “least void” through the utilizationof fly ash (to fill the void between blended aggregates) and the cement paste (to fill the rest of the void) as shown in

Figure 1 and Figure 2. The utilization of fly ash (in addition to the cement paste) to fill the void between blended

aggregates will increase the density of concrete. And the addition of the SP (super plasticizers) is helpful to solve the

potential problem of tangling or balling of steel fibers. Thus the workability of the SFRSCC with the aid of SP is

ensured as a result.

2.2. The Durability Design Consideration of SFRSCC

In conventional mixture design, concrete workability is decided by the water amount and the compressive

strength, whereas the durability is decided by the water-to-cement ratio (w/c) [9]. The workability can be improved

by increasing the water amount and the strength can be increased by increasing the cement content. However, too

much cement paste will cause large slump loss and bleeding as well as segregation; moreover, the hydration of thecement will cause chemical shrinkage, and the shrinkage rate or expansion rate is in direct proportion to the water

and cement amounts [10]. Besides, ordinary concrete contains water at least twenty percent of the concrete volume,





and hence drying shrinkage cannot be avoided. Thus the durability of concrete is destroyed, due to disintegration and

crack formation. To avoid these problems, a concrete mixture designed with low water amount and low cement

content is suggested.

Durability design should be considered for improving both the fresh and hardened stages of the concrete and

should finally extend their service life. First and foremost the concrete mix design should have a very low water amount so as to minimize the shrinkage rate or the expansion rate of concrete [10]. Then, the concrete must be

(b)

(a) (c)

Figure 1. The procedure of aggregate packing; (a) The schematic drawing; (b) Variation of dry loose density as

coarse aggregate filled with sand; (c) variation of dry loose density as mixed aggregates filled with fly ash [11]

Figure 2. Cement paste acts as the role in DMDA [12]





designed to satisfy the construction needs such as low slump concrete (e.g. roller compacted concrete) or high slump

concrete (e.g. self-consolidating concrete, high performance concrete), type of construction work, and the required

final finished result. In the plastic stage, the fresh concrete is designed to prevent the occurrence of plastic shrinkage

cracks due to excess water evaporation from the concrete surface. A certain amount of steel fiber should be included

in the concrete mix to absorb energy and in the case of crack formation, to stop their propagating. The addition of

pozzolanic materials is necessary to help the self-healing of cracks if they are generated. A strict standard operation

procedure for mixture proportion, material selection, trial batch, quality control, and curing are required to lower the

possibility of crack formation.

2.3. The SFRSCC Design Procedure by DMDA

The following steps can be used to provide computational basis for design of the SFRSCC mixture employing

the DMDA procedure.

(1) Select proper material resource and gather material information.

This is an important step for the mix design of SFRSCC. The basic quality information of the ingredients of

concrete is necessary for the purpose of quality control.

(2) Obtain the maximum dry loose density by iteratively packing aggregates ( i.e. coarse aggregate, sand, fly ash)

shown in Figure 1 [11].

(2a) Fill coarse aggregate with sand and then obtain:

cs

cs ca

W

W W

′α =

′ ′+(1)

where α is the ratio at maximum dry loose density as coarse aggregate is filled with sand; csW ′ is the weight

of sand [kg]; caW ′ is the weight of coarse aggregate [kg].

(2b) Fill the rest void between coarse aggregate and sand with fly ash under fixed α, and obtain:

fly

fly cs ca( )

W

W W W

′β =

′ ′ ′+ +(2)

where β is the ratio at maximum dry loose density as blended aggregates filled with fly ash; flyW ′ is the weight

of fly ash [kg].

(3) Select the volume of steel fiber (η) added into concrete.

(4) Calculate the least void, V v shown in Figure 2 [12]:

1i

v

i

W V ′= − − ηγ∑ (3)

where iW ′ [kg/m3] and γi [kg/m

3] are the weight and density of i material in blended aggregates, respectively.

(5) Assign a lubricating paste thickness (t ) and calculate the volume of cement paste (See Figure 2):

p vV nV = (4)

where n is a multiplier for lubricating paste; V p is the volume of cement paste.

(6) Calculate the factor of volume variation (υ) [12]:

1

1

v

v

nV

V

− η −υ =

− η −(5)





(7) Calculate the weight of coarse aggregate, sand, fly ash, and steel fiber, respectively:

fiber fiber W = η× γ (6)

fly flyW W ′= υ× (7)

cs csW W ′= υ× (8)

ca caW W ′= υ× (9)

where fiber γ is the unit density of steel fiber [kg/m3]; W fiber , W fly , W cs , and W ca are weights of steel fiber, fly

ash, sand, and coarse aggregate, respectively [kg/m3].

(8) Calculate the amount of cement, slag, and mixing water:

w c sl

p

w c sl

W W W V = + +

γ γ γ(10)

If ξ is the ratio of replacing cement with slag by weight, then:

sl

sl c

W

W W ξ =

+(11)

where W w, W c , and W sl are weights of water, cement, and slag, respectively [kg/m3]; γw , γc , and γsl are

densities of water, cement, and slag, respectively [kg/m3].

Substitute Equation (11) into Equation (10) to obtain:

1

w

c ccc

p

w c sl

W W W

W W V

ξ⎛ ⎞ ⎛ ⎞⎜ ⎟ ⎜ ⎟− ξ⎝ ⎠ ⎝ ⎠= + +

γ γ γ(12)

If the water-to-cementitious material ratio (w/cm) is λ, then:

fly( )w c slW W W W = λ × + + (13)

Using Equation (11) and Equation (13), Equation (12) can be used to solve for W c :

fly

1 1

1

p

wc

w c w sl

W V

W

− λγ

=⎡ ⎤λ ξ λ⎛ ⎞

+ + +⎢ ⎥⎜ ⎟γ γ − ξ γ γ⎝ ⎠⎣ ⎦

(14)

The calculated W c can be substituted both into Equation (14) and Equation (11) to obtain W sl and W w ,

respectively.

(9) Determine the dosage of SP and amount of water.

The dosage of SP is determined by its quality and the total water content. Under fixed total amount of water and

w/cm ratio, the SP dosage can be estimated according to past experience (See Figure 3) [12].





(a)

(b)

Figure 3. The SP dosage based on past experience; (a) trial mixing in the laboratory; (b) mixing in the batching plant [12]

3. EXPERIMENTAL PROGRAM

3.1. Constituent Materials

The Type I Portland Cement produced by Taiwan Cement Company, blast-furnace slag (BF slag) provided by

China Steel Company, and class F fly ash supplied by Taiwan Power Station are used in this study for making the

concretes. Type G superplasticizer, a NF based lignin–sulfonate, was purchased from a local factory. Crushed

coarse aggregate and natural sand were provided from local quarries. The steel fibers made by HAREXE Companyin Germany were purchased from an agent in Taiwan. All materials conform to the related ASTM standards and

their physical properties as well as chemical compositions are shown in Tables 1–3.





Table 1. Physical and Chemical Analyses of Cement, BF Slag, Fly Ash, and SP

Item Cement BF slag Fly ash SP Specific gravity 3.15 2.86 2.20 1.18 Physical

propertiesSurface area (m

2

/g) 2970 4350 3110 -

SiO2 22.01 34.86 51.23 -

Al2O3 5.51 13.52 24.31 -

Fe2O3 3.44 0.52 6.14 -

MgO 2.59 7.18 1.61 -

SO3 2.03 1.74 0.61 -

P2O5 0.05 - - -

Na2O 0.40 - 0.31 -

K 2O 0.70 - 1.29 -

Solid content - - - 42.99

Chemical

compositions

(%)

Loss on ignition (%) 0.51 0.31 4.85 -

Table 2. Properties of Coarse Aggregate and Sand

Percentage of passing Sieve size

Coarse aggregate Sand 3/4 in 100 -

1/2 in 97.9 -

3/8 in 60.7 100

#4 5.3 99.1

#8 0 90.4

#16 - 65.3

#30 - 36.5

#50 - 11.4

#100 - 1.7

Specific gravity 2.64 2.64

Absorption (%) 0.8 2.0

Dry loose density (kg/m3) 1576 1649

Table 3. Types and Properties of Steel Fibers

Type ShapeDiameter

(mm)

Length

(mm)

Aspect ratio

(L/D)

Tensile strength

(MPa) A Double hook-edge 0.5 50 100 900

B Double hook-edge 0.5 30 60 850

C Straight 0.5 10 20 750





3.2. Mixture Proportioning

The mixture proportions of SFRSCC designed by DMDA in this study for investigating the effects (including

water to cementitious material ratio (w/cm), steel fiber content, and aspect ratio (L/D) of steel fiber) on the properties

of SFRSCC are shown in Table 4. Every SFRSCC mixture has its utility or construction requirement (e.g. C1–C4

mixture proportions are adopted to discuss properties of SFRSCC; C2 is the control mixture; A1, B1, C3, and D1mixes are respectively applied to the high performance road deck panel (HPRDP), the bus station pavement, the high

integrity concrete container (HIC), and concrete art statues).

Table 4. Mixture Proportions

Mix No. Proportion (kg/m3)

Binderw/cmFiber Content

(Vol. %)

Fiber

Length

(mm)Coarse

AggregateSand

Cement Pozzolan Water+SP

A1 0.25 0.5 30 964 819 300 204 127

B1 0.29 0.5 30 950 775 300 160 135

C1 0.32 0.5 50 734 924 300 235 171

C2 0.32 0.0 30 767 1014 274 202 152

C3 0.32 0.5 30 755 995 265 220 155

C4 0.32 1.0 30 745 982 255 235 157

D1 0.32 0.7 30 &10 427 878 235 233 150

Remark: Diameter of Steel Fiber is 0.5 mm

C2 is a control mixture

A1~C4 use normal weight aggregate and steel fiber

D1 uses lightweight aggregate and polypropylene (PP) fiber, and two types of steel fiber lengths

3.3. Testing Program

3.3.1. Workability Test

The slump and slump flow of SFRSCC were measured according to ASTM C143 [13] and CNS 14842 [14],

respectively. The flow time is different from ASTM C995 “Standard Test Method for Time of Flow of Fiber-reinforced Concrete through Inverted Slump Cone”. Herein the flow time of SFRSCC is defined as the passing time

from the slump cone lifted to concrete stops flowing in slump flow test.

3.3.2. Cylinder Compressive Strength Test

The preparations of SFRSCC specimens for cylinder compressive strength, cylinder splitting strength, concrete

electrical resistivity, and ability of concrete to resist chloride ion penetration tests follow ASTM C192 [15] and those

specimens are cured in saturated limewater at the temperature of 23 ± 2.0 °C. According to ASTM C39 [16], casting

of the SFRSCC cylinders with dimension of 150φ × 300H mm were conducted compressive strength test at the age

of 3, 7, 28, 56, and 90 days, respectively.

3.3.3. Cylinder Splitting Strength Test

According to ASTM C496 [17], casting of the SFRSCC cylinders with dimension of 150φ × 300H mm were

conducted for cylinder splitting strength test at the age of 28 days.





3.3.4. Flexural Strength Test

According to ASTM C293 [18], casting of the SFRSCC specimens with dimension of 75 × 75 × 280L mm were

conducted for flexural strength using simple beam with center point loading test at the age of 28 days.

3.3.5. Concrete Electrical Resistivity Test

A concrete electrical resistivity meter manufactured by the CNS Company in UK is used in this study for

conducting the concrete electrical resistivity test to measure the SFRSCC electrical resistivity under saturated

condition at the age of 3, 7, 28, 56, and 90 days, respectively.

3.3.6. Ability of Concrete to Resist Chloride Ion Penetration Test

According to ASTM C1202 [19], preparation of the SFRSCC specimens with dimension of 100φ × 50H mm

sliced from the cylinders of 100φ × 200H mm were conducted for chloride ion penetration test to assess the ability of

SFRSCC to resist chloride ion penetration at the age of 90 days.

4. EXPERIMENTAL RESULTS

4.1. Workability of SFRSCC

Figure 4 presents the workability including slump (see Figure 4(a)), slump flow (see Figure 4(b)), and flow time

(see Figure 4(c)) of each SFRSCC mixture type. As expected each mixture type had excellent workability except the

C4 mixture with 1.0% volume steel fiber. The addition of excessive amount of steel fiber will again result in tangling

of fibers and hence more lubrication paste is needed to improve the concrete workability. Although the slump of C4

mixture still is 220 mm, the slump flow significantly lowers down to 400 mm because of insufficient lubricating

paste on the fibers. D1 mixture with 0.7% volume steel fiber still had excellent workability close to C1 mixture.

Due to the light weight aggregate applied to D1 mixture, the spherical particles are helpful for workability of

concrete [2, 3, and 20]. Consequently Figure 4 also indicates that the dosage of steel fiber should not be greater than

0.5% for SFRSCC using normal weight as well as crushed coarse aggregate to achieve high flow-ability.

4.2. Compressive Strength of SFRSCC

Figure 5 shows the relationship between strength development and fiber content. Even if the result indicates that

the higher the fiber content, the higher will be compressive strength, flexural strength, abrasion resistance, and fiber

crack-control effect, the compressive strength of SFRSCC is not directly proportional to the fiber content. This is

because the compressive strength of SFRSCC is affected by a number of steel fiber factors including the shape,

casting direction, and distribution as well as the property of interface between steel fiber and cement paste among

others. Figure 6 shows that the compressive strength increases with increase in the aspect ratio (L/D) of fiber and

with decrease in the water-to-cementitious material ratio (w/cm).

4.3. Strength Efficiency of Cement of SFRSCC

The strength efficiency of cement implies the yielded strength per kilogram of cement and denoted as MPa/kg

cement. Figure 7 shows the higher amount of steel fiber the higher compressive strength and the higher strength

efficiency of cement. For the C4 mixture (with 1.0% volume fiber content), the strength efficiency of cement at

28-day and 90-day is in excess of 0.20 MPa/kg cement and 0.25 MPa/kg cement, respectively. The 90-day value is

3.6 times higher than that of traditional concrete (0.07 MPa/kg cement). Such result indicates that the cement

consumption is only about one quarter of the normal usage based on the same compressive strength. In such manner,

it not only saves cement usages, but also minimizes the detrimental effect of mechanisms causing crystallization,

sulfate attack and alkali aggregates reaction, and so forth [2, 3, and 20], and hence may increase the service life of

concrete. Consequently, the energy consumption and CO2 footprint during the production of cement can significantly

be reduced to environmental advantage.





(a)

(b)

(c)

Figure 4. Workability of SFRSCC; (a) slump; (b) slump flow; (c) flow time





4.4. Cylinder Splitting Strength of SFRSCC

ACI 363 [21] describes the relationship between the cylinder splitting strength and the compressive strength for

ordinary high strength concrete (i.e. compressive strength exceeding 21 MPa). Figure 8 shows that the curve for

SFRSCC mixtures is above one recommended by ACI 363. This implies that the SFRSCC mixtures designed by

DMDA method achieves not only increased cylinder splitting strength, but also improved crack resisting ability.The addition of pozzolanic material contributes to the increase in the cylinder splitting strength, which is greater than

the value obtained from Equation (15) recommended by ACI 363. This is because of the pozzolanic reaction and

densification of the interface, which improve the bonding strength within SFRSCC materials. A modified equation

for determining the cylinder splitting strength resulting from the compressive strength of SFRSCC mixes is given in

Equation (16).

0.59sp c f f ′= × (15)

0.738 0.737sp c f f ′= × − (16)

where f ' c is the compressive strength [MPa]; 21 MPa ≤ f ' c ≤ 85 MPa; f sp is the cylinder splitting strength [MPa].

4.5. Flexural Strength of SFRSCC

Figure 9 shows the load-deflection curves obtained for different fiber contents. The increase in the fiber content,

increases the sustained load and energy absorption capacity of SFRSCC, ( i.e., the area under P-∆ curve), as

expected. The fiber combined with pozzolanic material for SCC provides great improvement in the bonding force

surrounding fiber and withstands large deflection (i.e. crack arresting effect). Since the configuration of the fiber is

the double hook-edge type, it sustains more force to resist the deflection and also sustains an external load.

4.6. Concrete Electrical Resistivity of SFRSCC

The measurement of concrete electrical resistivity gives an indication of durability of the concrete [22, 23].

Figure 10 shows the relationship between concrete electrical resistivity and curing ages, and it indicates the

reduction of concrete electrical resistivity with increase in the steel fiber content due to conductivity of the steelfiber. The gel formation from cement hydration and pozzolanic reaction will, however, make the microstructure

dense as well as fill the conductive channel, and hence it decreases the effect of steel fiber conduction. In the long

run, the addition of 1.0% steel fiber will finally reach the desired concrete electrical resistivity of over 20 k Ω-cm

proposed by Taylor Woodrow [23].

Figure 5. Effect of fiber content on the compressive strength





(a)

(b)

Figure 6. Effect of fiber aspect ratio and w/cm ratio on the compressive strength; (a) Fiber aspect ratio; (b) w/cm ratio





Figure 7. Effect of fiber content on strength efficiency of cement of SFRSCC

Figure 8. Relationship of compressive strength and splitting strength of SFRSCC





4.7. Ability of SFRSCC to Resist Chloride Ion Penetration

The ASTM C1202 [19] method is adopted in this study for assessing the ability of concrete to resist chloride ion

penetration. Figure 11 shows that the charge passed by ASTM C1202 method increases with increase in the steel

fiber content, due to the conductivity of the steel fiber and the interface between steel fiber as well as cement paste in

SFRSCC. However the level of chloride ion penetration for all of SFRSCC remains in the “Low” range of the chargespectrum and thus indicating that the SFRSCC has a good ability to resist chloride ion penetration. This result also

illustrates the condition that fiber entanglement or balling within the SFRSCC does not necessarily occur and thus

the perceived accommodation of a conductive channel, which would otherwise increase the charge passed within the

SFRSCC, is not significantly generated.

Figure 9. Effect of fiber content on loading –deflection curves of SFRSCC

Figure 10. Effect of fiber content on concrete electrical resistivity of SFRSCC





Figure 11. Results of ASTM C1202 method on SFRSCC

5. SFRSCC PROJECTS

5.1. Bus Station Pavement in Taipei City

Due to the heavy traffic and exposure to severe environmental conditions, the top pavement layer of bus station

used the B1 SFRSCC mixture (See Table 4) with excellent flexural strength. But the bottom pavement layer wasmade with only SCC. The concrete selection was made to meet the requirement of JRCP [24] and to satisfy the

design requirements, as shown in Table 5. Figure 12 shows the quality control chart of both fresh SCC and SFRSCC,

and it indicates that the concrete has sustained stable quality throughout the concreting period. Figure 13 shows the

compressive strength development of hardened SCC and SFRSCC constructed in August 28, 1998. Furthermore,

Table 6 shows the flexural strength of SCC and SFRSCC at different ages. Due to the combined usefulness of steel

fiber and pozzolanic material, the flexural strength of the SFRSCC mix designs at 28 and 56 days are respectively

higher by 102% and 115% than the specified (required) value shown in Table 6. After 5 years of exposure to heavy

vehicular traffic, the road pavement in Taipei city is observed to be performing well without fracture, abrasion,

shrinkage crack, or any other defects with limits of normal maintenance routines.

Table 5. Requirement for Bus Station Pavement of Concrete in Taipei City

Property Time SCC SFRSCC Slump (mm) Up to 45 min. 250 ± 20 230 ± 20

Slump Flow (mm) Up to 45 min. 600 ± 50 500 ± 50

3 day 28 28

28 day 49 49 Compressive Strength

(MPa)

56 day 70 70

28 day 4.5 4.5 Flexural Strength

(MPa) 56 day 5.0 5.0




April 2009 The Arabian Journal for Science and Engineering, Volume 34, Number 1B 73 Figure 12. Quality control chart of SCC and SFRSCC in bus station pavement





Figure 13. Strength development of SCC and SFRSCC in bus station pavement

Table 6. Flexural Strength (MPa) of SCC and SFRSCC (Mixture B1)

in Bus Station Pavement

SCC Construction date Age 1998/8/27 1998/8/28 Ave. Req. Ave/Req.

28 7.6 7.7 7.65 4.5 1.70

56 8.3 8.3 8.3 5.0 1.66

SFRSCC Construction date Age 1998/8/27 1998/8/28 Ave. Req. Ave/Req.

28 8.3 9.9 9.1 4.5 2.02

56 10.0 11.5 10.75 5.0 2.15

5.2. Precast High Integrity Concrete (HIC) for Low Radiation Waste

Since 1996 research has been conducted in Taiwan for developing HIC for storing low radiation wastes.

The standard processes of mixture design, material inspection, and prototype test have been completed. Table 7

compares the performances of HIC between French and Taiwan specifications. The application of the SFRSCC to

HIC was successful and satisfied the prescribed strict specifications as shown in Table 7. Meeting these

specifications not only increases the safety, volume stability, durability of the storage structure, but also reduces the possibility of corrosion of steel rebar and the associated material cost. The C3 mixture (in Table 4) that has been

developed in the laboratory, as shown in Figure 14, was used for the HIC project.





Table 7. Specification of Low Radiation Waste HIC for France and Taiwan

French specification Taiwan specification C3 SFRSCC Cement type Cp 55 Portland Type I Portland Type I

Cement amount

(kg/m3) > 370 250~350 265

At 56-days

compressive strength

(MPa)

> 50 > 56 63

At 56-days

tensile strength

(MPa)

> 4.5 > 4.5 9.8

At 56-days

Shrinkage(µm/m)

< 300 < 300 245

(a) (b)

(c) (d )

Figure 14. Photographs of HIC; (a) Slump and slump flow measurement; (b) L-flow test;

(c) placing and casting; (d ) dropping test





5.3. High Performance Road Deck Panel (HPRDP)

Precast HPRDP elements of dimensions 1 m × 2 m × 150 mm and 1 m × 3 m × 150 mm with SFRSCC were

designed to replace the traditional steel road deck panel having 50 mm concrete topping. The A1 mixture as shown

in Table 4 was developed for this project. The initial crack load of HPRDP is four times more than the initialdesigned value 12 ton. Figure 15 compares the deflections of the HPRDP developed in Taiwan and the Metro-deck

panel developed in America [25], respectively. It was found that the HPRDP made with SFRSCC had higher energy

absorption capacity, higher flexural strength, and higher impact strength when compared to the Metro-deck panel.

Figure 16 shows the demonstration of the field abrasion test conducted by a 50-ton bulldozer. No abrasion or

scratches were observed after the test.

(a)

(b)

Figure 15. Comparison of the deflections: (a) Precast HPRDP; (b) Metro-deck panel





Figure 16. Field abrasion test, a 50-ton bulldozer on precast HPRDP element

5.4. Concrete Art Statues

There are two famous statues made by SFRSCC in Taiwan. One is “Xi Men” in Ying-Ger Ceramics Museum,Taipei County, as shown in Figure 17(a). The other is a statue of the badge of the department of Construction

Engineering in the National Taiwan University of Science and Technology, as shown in Figure 17(b). Filling

SFRSCC inside ceramic tiles without steel reinforced bars made the Xi Men statue. The SFRSCC used low water

and cement content, which not only reduces drying shrinkage, but also avoids the ceramic from stripping. The badge

statue was made with lightweight aggregates and hybrid fibers consisting of blended short and long steel fibers as

well as polypropylene (PP) ones. The D1 mixture SFRSCC (as shown in Table 4) was used to cast the badge.

(a) (b)

Figure 17. SFRSCC applied to statues in Taiwan; (a) Xi Men; (b) badge in NTUST





6. CONCLUSION

According to the results in this study, a number of conclusions such as the following can be drawn.

1. The SFRSCC designed by the DMDA method reduces the entanglement or balling problem of fibers.

To attain high flowing capability, the content of steel fiber should not be greater than 0.5% for normal weight

SFRSCC made with crushed coarse aggregate.

2. Test results reveal that higher fiber content has brought about increased compressive strength, flexural

strength, abrasion resistance, and fiber crack-control effect. Hence the addition of steel fiber within SFRSCC

is more helpful for the flexural strength than the compressive strength.

3. The usefulness of combined steel fiber and pozzolanic material improves the bonding strength as a result of

which a modified equation for determining the cylinder splitting strength from the compressive strength has

been derived for the SFRSCC.

4. Despite the use of highly conductive fiber, the range of concrete electrical resistivity as well as the level of

chloride ion permeability has remained in the passive range, by virtue of the dense microstructure gains

brought about by the DMDA.

5. The application of the SFRSCC designed on the basis of the DMDA has already been successful across a

number of projects in Taiwan, comprising road pavement, precast products, and art statues.

ACKNOWLEDGMENTS

The authors greatly appreciate Professor V. Ramakrishnan’s continuous support and technical assistance as well

as Dr. G.T.C. Kung’s assistance in English revision. The grant from National Science Council and Atomic Energy

Council as well as the financial support from RSEA Engineering Corporation, Kao Cheng Industrial and

Commercial Co. Ltd., Sun Tech Enterprise Co. Ltd., and Bayton Enterprise Co. Ltd. in Taiwan, are gratefully

acknowledged.

REFERENCES

[1] P. Balaguru and V. Ramakrishnan, “Properties of Fiber Reinforced Concrete: Workability, Behavior Under Long-

Term Loading, and Air-Void Characteristics”, ACI Materials Journal, 85(3)(1988), pp. 189–196.

[2] S. Mindess and J.F. Young, Concrete. Englewood Cliffs, NJ: Prentice-Hall Inc., 1981.

[3] P.K. Mehta, Concrete—Structure, Properties and Materials. Englewood Cliffs, NJ: Prentice-Hall Inc., 1986.

[4] P. Rossi, “Ultra High Performance Fiber Reinforced Concretes”, Concrete International, 23(12)(2001), pp. 46–52.

[5] P. Rossi, P. Acker, and Y. Malier, “Effect of Steel Fibers at Two Stages: The Material and the Structure”, Materials

and Structures Journal, 20(1987), pp. 436– 439.

[6] G. Orange, P. Acker, and C. Vernet, “A New Generation of UHP Concrete: Dual Damage Resistance and Micro

Mechanical Analysis, High Performance Fiber Reinforced Cement Composites”, in 3rd RILEM InternationalConference on High Performance Fiber Reinforced Cement Composites, Mainz, Germany, 1999, (ed. H.W.Reinhardt and A.E. Naaman), pp. 101–111.

[7] P. Rossi, “High-Performance Multi-Modal Fiber Reinforced Cement Composites (HPMFRCC): the LCPC

Experience”, ACI Materials Journal, 94(6)(1997), pp. 478– 483.

[8] W.H. Plenge, “Introducing Vision 2030: Our Industry’s 30-Year Map to the Future”, Concrete International,23(03)(2001), pp. 27–34.

[9] ACI Committee 211.1-91, Standard Practice for Selecting Proportions for Normal, Heavyweight and Mass

Concrete. Farmington Hills, Michigan: American Concrete Institute, 1991.

[10] C.L. Hwang and H.C. Lu, “The Effect of Paste Amount and Water Content on the Volume Stability of Concrete”,

Journal of the Chinese Civil and Hydraulic Engineering, 12(3)(2000), pp. 621–626. (In Chinese)

[11] C.T. Tsai, L.S. Li, and C.L. Hwang, “The Effect of Aggregate Gradation on Engineering Properties of HighPerformance Concrete”, Journal of ASTM International, 3(3)(2006), pp. 891–902.




[12] C.L. Hwang and C.T. Tsai, “The Application of Geometry Concept to Solve Algebraic Solution DMDA Method”,in Proceedings of Combining the 2nd North American Conference on the Design and Use of Self-Consolidating

Concrete and the 4th International RILEM Symposium on Self-Compacting Concrete, Chicago, USA, 2005, (ed. S.P.

Shah), pp. 1227–1233.

[13] ASTM C143-07, Standard Test Method for Slump of Hydraulic-Cement Concrete. Philadelphia, Pennsylvania:

American Society for Testing Materials, 2007.[14] CNS 1482, Method of Test for Slump Flow of High Flowing Concrete. Taipei, Taiwan: Bureau of Standards,

Metrology & Inspection, M.O.E.A., R.O.C., 2005. (In Chinese)

[15] ASTM C192/C192M-07, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory .

Philadelphia, Pennsylvania: American Society for Testing Materials, 2007.

[16] ASTM C39/C39M-05e1, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens.


[17] ASTM C496/C496M-04e1, Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens.


[18] ASTM C293-08, Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Center-Point

Loading). Philadelphia, Pennsylvania: American Society for Testing Materials, 2008.

[19] ASTM C1202-07, Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion

Penetration. Philadelphia, Pennsylvania: American Society for Testing Materials, 2007.

[20] C.L. Hwang, Property and Behavior of Concrete, 3rd edn. Taipei: Zan’s Publisher Inc., 2003. (In Chinese)

[21] ACI Committee 363.2R-98, Guide to Quality Control and Testing of High-Strength Concrete. Farmington Hills,Michigan: American Concrete Institute, 1998.

[22] Y.Y. Chen and C.L. Hwang, “Study on Electrical Resistivity and Chloride Ion Penetrability Behavior of ConcreteMaterials”, Journal of the Chinese Civil and Hydraulic Engineering, 13(2)(2001), pp. 293–302. (In Chinese)

[23] T. Woodrow, Marine Durability Survey of the Tongue Sands Tower . Concrete in the Oceans Technical Report No. 5,Taylor Woodrow Research Laboratories, Canada, 1980.

[24] AASHTOWare: DARWin 3.1, Guide for Design of Pavement Structures. Washington, D.C.: American Associationof State Highway and Transportation Officials, 1993.

[25] Introduction of Metor-deck . METRODECKs Inc., Ashburn, Virginia, USA, 1980, pp. 8–12.

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