Australian Journal of Basic and Applied Sciences

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1 AENSI Journals Australian Journal of Basic and Applied Sciences ISSN: Journal home page: Effect of steel Fiber on the Performance of Hot Mix Asphalt with Different Temperaturesand Compaction 1 Dr. Ahmed S. D. AL-Ridha, 2 Mr. Atheer Naji Hameed, 3 Mr. Sinan Khaleel Ibrahim 1 Al-Mustansiriya University, Highway and Transportation Department, College of Engineering, Baghdad, Iraq. 2 Al-Mustansiriya University, Highway and Transportation Department, College of Engineering, Baghdad, Iraq. 3 Al-Mustansiriya University, Highway and Transportation Department, College of Engineering, Baghdad, Iraq. A R T I C L E I N F O Article history: Received25January1 Received in revised form 12 March 1 Accepted 1 April1 Available online 2 April 1 Keywords: Steel Fiber, Additives, Temperature, Compaction, Hot Mix Asphalt. A B S T R A C T Theprincipalfunctionofthefiberistoprovideadditionaltensilestrengthintheresulting composite.thiscouldincreasetheamountofstrainabsorbedduringthefatigueandfracture processofthemixture.fibersaresometimesaddedtostabilizethebinderduringmixingand placement. An additional benefit of using fibers is that fibers have been shown to allow increased asphalt binder contents and thus increase film thicknesses thereby increasing durability. The main objectiveofthepresentstudyistoevaluate the effect of steel fiber percentage (0.1%,,,and 0.%) by volume of the total mix within selected grade on mechanical and volumetric properties and vertical strain.all the specimens have been tested by Marshall Method at different temperatures (50, 0, 70) C o and different compaction blows (50, 75,125), and also tests by ultrasonic device. As a result of the present study,when increasing the steel fiber content, the voids among asphalt mixture wereincreased and the percentage of this increment was decreased when the compaction is increased. Another result was When adding the steel fiber to hot mix asphalt, the stability was increased and then decreasing in crest manner which means that the use of steel fiber as a modifier additive has improved Marshall Stability in comparison with the conventional mixture without fiber.asphalt mixture that contains (0.1) % and (0.2) % steel fibers by volume of total mix were found to have higher stability at all testing temperatures.the results of ultrasonic test show that when adding the steel fiber, the steel fibers increase the conductivity of asphalt mixture and that made the ultrasonic time decrease, and when steel fiber increased the voids in mixture increased which lead to increase the ultrasonic time.threedeveloped models from laboratory test results obtained in this work can be used to evaluate the effect of different variables on the performance related to stability and Bulk specific gravity of modified mixture. The stability models showed that when the steel fiber less than or equal to the effect of the steel fiber positive on stability and when the steel fiber more than, the effect of steel fiber negative on the stability.adding of steel fibers to surface layer of flexible pavement may cause discomfort for drivers and reduces safety on the road, which may be caused by a tire puncture, therefore, it is recommended to use it in the layers that under the surface layer such as the binder course or use it in leveling course if the wearing course is exist. 1 AENSI Publisher All rights reserved. ToCite ThisArticle: Dr. Ahmed S.D. AL-Ridha, Mr. AtheerNajiHameed, Mr. SinanKhaleel Ibrahim, Effect of steel Fiber on the Performance of Hot Mix Asphalt with Different Temperatures and Compaction. Aust. J. Basic & Appl. Sci., (): , 1 INTRODUCTION Asphalt cement modifiers have been used in pavement technology to enhance pavement performance and reduce different types of pavement distress, of which, rutting, low temperature cracking, fatigue cracking, stripping, and hardening are the most common failure. Fiber is one of the additives used for this purpose (Thomas and Haiming, 1999). Using fibers to improve the behavior of materials is not a new concept. The use of fibers to reinforce a brittle material can be traced back to Egyptian times when asbestos fiber was used to reinforce clay pots about 5000 years ago (Mehta, 0). Fibers are widely used as reinforcing agent in concrete, however, the modern ways of fiber reinforcement started in the early 1950s (Saeed and Ali, 00). The principal function of the fiber is to provide additional tensile strength in the resulting composite.thiscouldincreasetheamountofstrainabsorbedduringthefatigueandfracture processofthemixture.fibersaresometimesaddedtostabilizethebinderduringmixingand placement. An additional benefit of using fibers is that fibers have been shown to allow increased asphalt binder contents and thus increase film thicknesses thereby increasing durability (Thomas and Haiming, 1999). Corresponding Author: Ahmed S.D. AL-Ridha, Al-Mustansiriya University, Highway and Transportation Department, College of Engineering, Baghdad, Iraq. Ahmedsahibdiab@Yahoo.com

2 12 Ahmed S.D. AL-Ridha et al, 1 Flexible pavements are designed so as to have at least years project life. The current researches include studies that focusing on increasing the performance and lifetime off-road pavements. It is aimed to increase the performance and lifetime of roads by using different additive materials. (Serin et al., 12) Steel fibers have been used in concrete since the early 1900s. The early fibers shape were round and smooth and the wire was cut or chopped to the required lengths. The use of straight, smooth fibers has largely disappeared and modern fibers have either rough surfaces, hooked ends or are crimped or undulated through their length. Modern commercially available steel fibers are manufactured from drawn steel wire, from slit sheet steel or by the melt-extraction process which produces fibers that have a crescent-shaped cross section (Ravindra et al.11). Objective of Study The objective of the this study is to evaluate the effect of steel fiber percentage (0.1, 0.2,0.3, 0.) % by volume of total mix within selected grade on mechanical and volumetric properties and vertical strain by testing the specimens bymarshall method at different temperature (50, 0, 70) C o and different compaction blows (50, 75,125) and also testing by ultrasonic device and compare the performance characteristics of the fiber modified mixtures with that of control mix without fiber. Materials: The materials used in this study are locally available and currently used in road construction in Iraq except the steel fibers that are available in local market in Baghdad but they are not used in the asphalt constructions at this time. Asphalt Cement: The asphalt cement of grade (0-50) was used in this work from Daurah refinery.the optimum asphalt content is founded by ( Ahmed I. Ahmed, 12) was used the same gradation and materials source of aggregate and asphalt that use in this research. The optimum asphalt content is equal to(5.0) % by weight of total mix, and this value is used in this research. The physical properties of this grade of asphalt cement are presented in table (1). Table 1: Physical Properties of Asphalt Cement Property ASTM Designation Asphalt Cement Number Daurah (0-50) Penetration (25 C, 0 Gm, 5sec), (1/ Mm) D-5 3 Kinematic Viscosity At 135 C, Cst D Softening Point (Ring And Ball), C D Ductility, Cm D-113 > 0 Flash Point (Cleaveland Open-Cup) D Specific Gravity, 25 C D Loss On Heat (5 Hrs, 13 C, 1/"), % D Aggregate: The source of aggregate is from Al-Nibaay quarry. Onegradation with a top size of (12.5mm) was used according to State Corporation of Roads and Bridges (SCRB, 03).The table(2) and figure(1) represent the upper and lower limits of the Iraqi specification and the selected gradation of aggregate. Table 2:Specification Limits and Selected Gradation of HMA Mixtures (SCRB,03) Sieve No. Sieve Opening (Mm) Gradation Type B Specification Limits Selected Gradation ½ /

3 Percent Passing % 125 Ahmed S.D. AL-Ridha et al, specification upper limit selected grade specification lower limit seive size (mm) Fig. 1: Specification limits and selected gradation of HMA mixtures Mineral Filler: Portland cement was used as mineral filler which is obtained from Tasluga cement factory. The physical properties and chemical composition of Portland cement are presented in the following tables (3 and ). Table 3: Physical Properties of Portland cement* Property Cement Specific Surface * (cm 2 /gm) 3372 Bulk sp. gr. (gm/cm 3 ) 3. % Passing No. 0 9 Table : Chemical Composition of Portland Cement.* Chemical Composition* (%) Cement L.O.I. 3.5 SiO2.25 CaO 2. MgO 2.19 SO 3 1. Fe 2O 3.32 Al 2O 3.73 * Tested by National Center for Construction Laboratories, according to IQS Steel Fiber: The steel fibers used in this research were straight steel fibers manufactured by Bekaert Corporation. Each steel fiber has a diameter of about 175 μm and length of approximately 13 mm (Roux, 199). The fibers have the properties described in Table (5) which is brought from China. A thin brass coating is applied to the fibers during the drawing process; therefore, virgin fibers may be gold/-colored. Figure (2) shows the ultra-fine steel fibers used throughout this research. Table 5: Properties of the Steel Fibers* Description Length (mm) Diameter (mm) Density (Kg/m 3 ) Tensile Strength Fu(Mpa) Aspect Ratio Straight *Manufacturer Properties

4 12 Ahmed S.D. AL-Ridha et al, 1 Fig.2:Steel Fiber Work Plan: The work plan of this study is to prepare an asphalt specimens from selected grade of aggregate, asphalt content, mineral filler and different rate of steel fiber (0,0.1,0.2,0.3,0.) % of total mix and then tested by ultrasonic device, bulk specific gravity device, maximum theoretical specific gravity device and then tested by Marshall stability and flow testing device at three temperature(50,0,70) and three compaction blows(50,75,125)(suham,0). Figure (3) represents the work plan of study and figure () represents the specimens that had been tested in laboratory divided into groups. Ac 0-50, selection aggregate grade Compaction 50 blows 75 blows 125 blows Temperature Temperature Temperature 50 C o 0 C o 70 C o 50 C o 0 C o 70 C o 50 C o 0 C o 70 C o Fig.3:Work Plan of the Study

5 127 Ahmed S.D. AL-Ridha et al, 1 Vf=0.% Vf= Vf= Tested at Temperature 70 Tested at Tested at Temperature 0 Temperature blow Fig. : Groups of Tested Specimens Test Methods: The following tests were performed on the prepared laboratory samples to evaluate the performance ofhot mixture of asphalt with different rates of steel fiber: 1.Resistance to Plastic Flow (Marshal Method, ASTM D 1559). 2.Standard Test Method for Percent of Air Voids (ASTM D 1). 3. Ultrasonic test (BS 11 part 3).. Bulk specific gravity test (ASTM D 272). Presentation of Testing Results: Resistance to Plastic Flow (Marshal Method) Marshall Methodology for mix design is used in this work as an indicator to plastic flow. Stability and flow were tested for each specimen using ASTM D The test results are presented in figure (5) and (). Figure (5) represent that when adding the steel fiber to hot mix asphalt, the stability was increased and then decreasing in crest manner which means that the use of steel fiber as a modifier additive has improved Marshall Stability in comparison with the conventional mixture without fiber; this improvement may be because the steel fiber prevent the micro-cracks in asphalt mixture from growth. The higher percentage of steel fiber in asphalt mixture increase the probability of steel fiber balling, this lead to increase of present the internal voids within the mixture which cause a week point in specimen and lead to decreasing the stability, also may be the steel fiber increased the surface area of mixture that lead to reduce the asphalt content which decreased the stability. In order to evaluate the variation of properties for hot mix asphalt at different content of steel fiber, figures (7, ) is drawn, which represent the effect of steel fiber rates on the Marshall stability at different temperature and compaction.

6 Stability (kn) Flow (mm) Stability (kn) Stability (kn) Stability (kn) 12 Ahmed S.D. AL-Ridha et al, blow 70 C 50 blow 0 C 50 blow 50 C 75 blow 50 C 75 blow 70 C 75 blow 0 C 125 blow 70 C 125 blow 0 C 125 blow 50 C Fig.5:Effect of Steel Fiber Percentage, Temperature and Number of Blows on Stability Flow values for different fiber content by volume (Vf)% and for certain Number of blows with Temperature 0 C blow 75 blow 125 blow Fig.:Flow Values for Different Volume Fraction (Vf ) of Steel Fiber and Compaction at Temperature 0 C o Temperature = 0 C Vf= Vf= Vf=0.% Temperature = 50 C Temperature = 70 C Vf= Vf= Vf= Vf= Vf= Vf=0.% Number of blows Number of blows Number of blows Fig.7:Effect of Compaction on the Marshall Stability with Variable Volume Fraction of Steel Fiber (V f )

7 % Air voids Stability (kn) 129 Ahmed S.D. AL-Ridha et al, blow Vf= Vf= Vf=0.% Temperature, C 75 blow Vf= Vf= Vf=0.% 125 blow Vf= Vf= Vf=0.% Temperature, C Temperature, C Fig.:Effect of Temperature on Marshall Stability with Variable Volume Fraction of Steel Fiber (V f ) Calculation of Percentage of Air Voids: The air voids of each specimen were calculated depend on the maximum theoretical specific gravity and bulk specific gravity and this test achieved in laboratory as shown in figure (9). The figure () represents the relationship between steel fiber and air voids in asphalt mixture. The results showed that the air voids are increased when the steel fiber increased, this increment is increase when the compaction was decreased. Fig. 9:Vacuum of Air Voids from Asphalt Mixture Blow 75 Blow 50 Blow Fig.:Effect of Steel Fiber and Compaction on Air Voids

8 Ultrasound (µs) 130 Ahmed S.D. AL-Ridha et al, 1 Ultrasonic Testing Results: The main advantage of this test is that it is nondestructive. In addition, the test can be performed on both laboratory-prepared specimen and field core (rajas and yaun, 1999). The prepared specimens can be used to perform ultrasonic tests at 25C o as shown in figure (11), and the testing result of ultrasonic is represented in figure (12). This figure shows that, first the ultrasonic time decreased and then in creased with increasing the steel fiber sin a sag manner, this behavior may be due to when the steel fiber increased, the conductivity of asphalt mixture increased, and that made the ultrasonic time decreased, and when steel fibers increase the voids in the mixture increased which lead to increment the ultrasonic time. Fig. 11:Ultrasonic Test 25 Ultrasound values for different fiber content by volume (Vf)% and for certain Number of blows blow 75 blow 125 blow Fig.12:Ultrasound Values for Different Steel Fiber Content and Compaction Bulk Specific Gravity Testing Results: After preparation of asphalt mixture specimens, the bulk specific gravity values are calculated for each specimen. Figure (13) show the testing device for bulk specific gravity. Figure (1) represents the bulk specific gravity values. The testing result represents that the bulk specific gravity decreases when the percentage of steel fiber increases and this decrementisdecreased when compaction was increased.

9 Density (gm/cm3) 131 Ahmed S.D. AL-Ridha et al, 1 Fig. 13:Bulk Specific Gravity Test Blow Blow 75 Blow 2. Fig.1:Bulk Specific Gravity Values with Variable Volume Fraction of Steel Fiber (V f ) and Compaction Blows Statistical Model For Stability And Bulk Specific Gravity: The effect of temperature, steel fiber content and compaction on stability and bulk specific gravity of hot mix asphalt mixture is examined by descriptive statistical analysis. The relationship between dependent and in dependentvariables was examined using SPSS statistical package. The package was used to perform the required statistical analysis. Two models were achieved to represent the stability behavior and one model for bulk specific gravity. The first model for stability was represent, the values of stability when the steel fiber percentage less than or equal to and the other stability model represents stability values when the steel fiber great than or equal to.the results of the statistical analysis are represented in table () and the (R 2 ) values are high. These models show that the steel fiber effect positively when the obtained steel fiber less than or equal to (0.2) % and negatively when steel fiber more thanor equal (0.2) %, and the effect of temperature are negative and the compaction is positive on stability. Table :Statistical Models Case Model R 2 Model Limitation Stability S= V f+0.01c-0.211t For ( 0 V f 0.2)% S= V f+0.07c-0.21t 0.95 For ( 0.2 V f 0.)% Density D= Vf+0.001C 0.19 For (0 V f 0.)% where: S: Stability. D: Bulk specific gravity. V f: Volume fraction of steel fiber C: Number of blow. T: Temperature. Conclusion: On the basis of the materials used and laboratory testing performed in this study withasphalt content is equal to(5.0) % by weight of total mix, the following conclusion could be made:

10 132 Ahmed S.D. AL-Ridha et al, 1 1. When adding the steel fiber to hot mix asphalt, the stability was increased and then decreasing in crest manner. Asphalt mixture that contain (0.1) % and (0.2) % steel fiber by volume of total mix were found to have higher stability at all testing temperatures and compaction. 2. When increasing the steel fiber content, the voids among asphalt mixture were increased. The percentage of this increment was decreased when the compaction is increased. 3. When the steel fiber increased in the asphalt mixture, the density of asphalt mixture was decreased. The percentage of decrement was increased with decreasing of compaction.. The results of ultrasonic test show that when adding the steel fiber, the steel fibers increase the conductivity of asphalt mixture and that made the ultrasonic time decrease, and when steel fiber increased the voids in mixture increased which lead to increase the ultrasonic time. 5. The development of three models from laboratory test results obtained in this work can be used to evaluate the effect of different variables on the performance related to stability and Bulk specific gravity of modified mixture. The stability models showed that when the steel fiber less than or equal to the effect of the steel fiber positive on stability and when the steel fiber more than, the effect of steel fiber negative on the stability.. Adding of steel fibers to surface layer of flexible pavement may cause discomfort for drivers and reduces safety on the road, which may be caused by a tire puncture, therefore, it is recommended to use it in the layers that under the surface layer such as the binder course or use it in leveling course if the wearing course is exist. ACKNOWLEDGMENT We thank the colleagues listed below for their achievement search: 1. Dr. Mohammad B. Abduljabar. Lecturer at Highway and Transportation Department College of Engineering Al-Mustansiriya University Baghdad Iraq. 2. Dr. Nagham T. H. Al-Shafi'I and Lecturer. Abbas F. Jassim [PhD student in USA].Staff members of Highway and Transportation Department College of Engineering Al-Mustansiriya University Baghdad Iraq. 3. Lecturer. Awadh E. Ajeel. Tutor of Highway and Transportation Department College of Engineering Al-Mustansiriya University Baghdad Iraq.. Staff members of asphalt laboratory of Highway and Transportation Department College of Engineering Al-Mustansiriya University Baghdad Iraq, essentially engineer Ahmed Sh. Qusad and Assist engineer Teba T. Khaleed. REFERENCES ASTM Annual Book of ASTM Standard.,199. Section, Volume 0.03, Road and Paving Materials; Pavement Management Technology. American Society for Testing and Materials, Philadelphia, Pa. British Standard.,19. BS 11: part 3. Mehta, P.K. and P.J.M.Monteiro,0. Concrete; Microstructure, Properties, and Materials. 3rd ed., New York: McGraw-Hill. Rajas,J., S.nazarian, V. Tendon and d.yaun,1999.quality Management of Asphalt-Concrete Layer Using Wave Propagation Techniques. Journal of association of asphalt paving technologists,. Roux, N., C. Anreadeand M.A.Sanjuan, 199. Experimental Study of Durability of Reactive Powder Concretes. Journal of Materials in Civil Engineering, February, pp: 1-. Serin.,S., N. Morova, M. Saltan and S. Terzi, 12. Investigation of Usability of Steel Fibers in Asphalt Concrete Mixtures. Construction and Building Materials,3: Saeed, G.J. and K.Ali,00.Carbon Fiber Reinforced Asphalt Concrete.the Arabian Journal for Science and Engineering, 33(2B): SCRB., 03. General Specification for Roads and Bridges.Section R9, Hot Mix Asphalt Concrete Pavement, Revised Edition. Suham, E.S. Al-maliky., 0.Prediction Model of Permanent Deformation Paving Materials. A special edition for engineering and development refereed scientific engineering journal. comprehensive scientific engineering conference, no.3, part I. Thomas, D.W. and H.Haiming,1999. Effect of Fibers on HMA Performance. TRB, National Research Council, Washington, D.C. Ravindra, V.S., C.B. Mishra, F.S. Umrigar and D.A. Sinha, 11.Use of Steel Fiber in Concrete Pavement: A Review. National Conference on Recent Trends in Engineering & Technology.