Al-khwarizmi!! Engineering!!! Journal Al-Khwarizmi Engineering Journal, Vol.4 , No.1 , pp 68-79 (2008!) !! Evaluation of Hydrated Lime Filler in Asphalt Mixtures Dr. Mohammed Abbas Hasan Al-Jumaily Engineering College University of Kufa (Received 16 February 2007 ; accepted 26 November 2007) Abstract Mineral filler is one of important materials and affecting on properties and quality of asphalt mixtures .There are different types of mineral filler depended on cost and quality , the matter encourages us to achieve this study to evaluate hydrated lime filler effects on properties of asphalt mixes related with strength and durability. Conventional asphaltic concrete mixtures with Portland cement and soft sandstone fillers and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by Marshall properties , index of retained strength , indirect tensile strength , permanent deformation characteristics , and fatigue resistance .A typical dense graded mixture employed in construction of surface course pavement in Iraq in accordance with SCRB specifications was used .The materials used in this study included mineral aggregate materials (coarse and fine sizes) were originally obtained from Najaf Sea quarries and two grades of asphalt cements produced from Daurah refinery which are D47 and D66 . The physical properties , stiffness modulus and chemical composition are evaluated for the recovered asphalt cement from prepared asphalt mixes containing various filler types .The paper results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue life and the use of hydrated lime will decrease the moisture susceptibility of the asphalt mixtures. Key word: Hydrated Lime, Mineral Filler, Chemical Composition, Retained Strength Index, Indirect Tensile Strength, Indirect Tensile Creep, Indirect Tensile Fatigue, Rutting Distress, Absolute viscosity, Stiffness Modulus. Introduction Permanent deformation, fatigue and moisture damage are common distresses found in asphalt pavements today. In many cases , mineral fillers will increase the mixture stiffness. In Iraq , the performance of asphalt pavements has deteriorated over the last decade . Heavy axle loads coupled with the hot climate and poor drainage systems in middle part of Iraq are major contributing factors to the development of severe pavement distresses such as permanent deformation and loss of structure because of moisture damage. The use of lime to reduce moisture sensitivity has been promoted by FHWA for many years (Shah,1963). The structure of hydrated lime consists of different size fractions. The larger size fraction performs as a filler and increases the stiffness of the asphalt mixture. The smaller size fraction increases asphalt film thickness enhancing viscosity of the asphalt , and improving the asphalt cohesion and stiffness. Adhesion between the aggregate and asphalt increases (Dickinson ,1984) , resulting in decreased mixture segregation. The water sensitivity of asphalt mixes treated with hydrated lime and antistrip agents was evaluated previously (Kennedy et.al.,1982 and Kennedy et. al. , 1991). Results from these tests depended on the actual combinations of aggregate , asphalt and additives. However, Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 69 among the antistrip agents, hydrated lime was most effective in increasing the tensile strength and in improving the water sensitivity of the mixture. This paper presents the results of a comparative study conducted on various asphalt mixes with three different mineral filler types to determine if the use of hydrated lime as a mineral filler leads to any improvement in the fundamental engineering properties. In addition, effect of hydrated lime on physical properties and chemical composition of asphalt cement has been investigated in this study. Materials Asphalt cement The two grades of asphalt cement used in this work included: (40-50) and(60-70) penetration grade asphalt from Daurah refinery .The different physical properties of asphalt cement are evaluated according to ASTM standards including absolute viscosity (D2171) , standard penetration (D5),ductility (D113), specific gravity (D70) , solubility in trichloroethylene (D2042) and thin-film oven test (D1754). The chemical composition of the asphalt cement is determined by the modified precipitation method of Rostler (ASTM D 4124 ) , in which the asphalt is separated into four fractions (Rostler and Rostler ,1981) as shown in Table 1. The physical properties and chemical composition of the two asphalt types (D47 and D66) as well as State Commission of Roads and Bridges , SCRB (SCRB, 2003)specifications are presented in Table 2 . Aggregate and Mineral Filler Properties Mineral aggregate materials (coarse and fine sizes) were originally obtained from Najaf Sea quarries. The aggregate properties are listed in Table 3. Three different types of mineral filler were used as mineral filler in preparation of various asphalt mixes because these types were available in a large quantity during study period. The hydrated lime filler was obtained from Karbala’a factory. The Portland cement filler was brought from Kufa cement factory . The soft sandstone powder filler was obtained from Najaf Sea quarries. The physical properties of the mineral filler types are shown in Table 4. Asphalt Concrete Mixtures The asphalt concrete mixtures are prepared using crushed gravel and sand with three different mineral fillers and two asphalt cement types . The mid limits of the 12.5 mm nominal maximum size dense gradation in accordance with SCRB (SCRB, 2003) specification requirements are used in preparing six asphalt mixtures ( two asphalt cements and three mineral fillers) as reported in Table 5. The six asphalt mixture types included in this study are coded as shown in Table 6 . The optimum asphalt contents (O.A.C) of various asphalt mixtures which were determined from standard Marshall mix design in accordance with ASTM D1559 (ASTM,2003) are reported in Table 7 . Also, Marshall properties at (O.A.C) and SCRB (SCRB ,2003) specifications for asphalt mixes used in the construction of surface course are presented in Table 7. Fundamental Test Procedure Four fundamental tests were conducted to characterize the six mixtures and determining the effects of the hydrated lime mineral filler on the properties of asphalt mixes. Three specimens were prepared and the average results are reported for all tests .A brief description of each test is given below: Index of Retained Strength Test Index of retained strength test is used to evaluate moisture damage of asphalt pavement in accordance with method ASTM D1075 (ASTM ,2003). It is one of tests required by SCRB (SCRB , 2003) specifications to be performed on asphalt mixes used in surface course in addition to Marshall tests. This test is intended to measure the loss of cohesion resulting from the action of water on compacted bituminous mixtures containing penetration grade asphalt. A set of six cylindrical specimens 4 in (101.6mm) in diameter by 4 in (101.6mm) in height was prepared for each asphalt mixtures in according with the procedure described in the standard method of test for compressive strength of bituminous mixtures of ASTM D1074 (ASTM ,2003). Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 70 Indirect Tensile Strength Test The indirect tensile strength at 25oC is evaluated for cylindrical specimens (101.6mm diameter × 63.5 mm height ) in accordance with ASTM D4123 (ASTM,2003). Indirect Tensile Creep Test At testing temperature of 40 oC , a compressive stress of 0.138 Mpa (20 psi) was applied on the Marshall specimen (101.6mm diameter × 63.5 mm height ). The loading times include (3,5,10,100, and 1000 seconds) and rest periods are (2,2,2,4,and 8 minutes). The total permanent strains, εP (in/in) at the end of each rest period were measured. In last loading time (1000 seconds), the creep deformations were measured after 3, 6, 10, 30, 60,100, 300, 600, and 1000 seconds durations. The creep compliance, C (t), at each of these loading durations is calculated as follows: C(t)=є(t)/σo … (1) Where: C(t)= Creep compliance at (1/Mpa), є(t)=Vertical strain at loading duration t (mm/mm), and σo = Applied stress (Mpa) . Indirect Tensile Fatigue Test To determine the fatigue resistance of the asphalt concrete samples, this test was conducted at 25oC temperature by using the machine manufactured by the researcher in the highway laboratory in College of Engineering in Kufa University . The (10 %) of the test failure load obtained from indirect tensile test was used as the peak value of the cyclic load with loading duration of 0.10 second followed by a rest period of 0.90 second was applied to the test specimen (Loulizi et.al.,2002) .The number of cycles were monitored through the duration of test and the test was terminated when the specimen reached to failure. 4. Discussion of Test Results The test results obtained from experimental work will be discussed in the following sections Effect of Mineral Filler Type on Asphalt Cement Properties and Chemical Composition To evaluate the effect of mineral filler type on the physical properties and chemical composition of asphalt cement , there is need to recovery the asphalt from asphalt mixture specimens .Extraction test was achieved by using a solvent in accordance with the method standardized in ASTM D 2172 (ASTM , 2003) to quantitative separation of the aggregate and asphalt cement . The asphalt was then recovered from asphalt-solvent solution (extract) in accordance with the method described in ASTM D1856 (ASTM ,2003). The stiffness modulus values of recovered asphalt cement types at temperature of 60 oC and a loading time of 0.02 second were determined by using Shell nomographs (Bonnaure et. al. ,1977) .Three properties of the recovered asphalt cement are evaluated : absolute viscosity , ductility and stiffness modulus .The effect of mineral filler type on these properties are shown in Fig.1. (a) Absolute viscosity (b) Ductility 1000 3000 5000 7000 9000 D47 D66 A b so lu te v is co si ty at 6 0 (p o is es ) Recovered asphalt cement type Hydrated lime filler Portland cement filler Soft sandstone filler o C 60 70 80 90 100 D47 D66 Recovered asphalt cement type D u ct il it y (c m ) Hydrated lime filler Portland cement filler Soft sandstone filler Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 71 (c) Stiffness modulus Fig. (1) Effect of mineral filler type on asphalt cement properties It can be noticed that recovered asphalt cement from mixes containing hydrated lime as a filler exhibits high absolute viscosity and stiffness values and has low tensile properties represented by low ductility values when compared with other asphalt types. The chemical composition parameter, Gaestel Index (IG) defined as the ratio of (Asphaltenes and saturates ) fractions to (Naphthene Aromatics and Polar Aromatics) fractions which is related with asphalt durability (Ishai I. ,1995). High values of (IG) refers to reduction in the asphalt durability and asphalt exhibits brittle and hardening behavior. The Chemical fractions and Gaestel index values of original and recovered asphalt cement types are reported in Table 8. The asphalt cement considers durable if the range of (IG) values lie within a range of about (0.4-1.2) (Ishai I. ,1995). It may be seen from Table 8 that all asphalt cement types fall within this range and have good durability. Effect of Mineral Filler Type on Marshall Stiffness and Air Voids Marshall stiffness (KN/mm) , which is calculated as the ratio between Marshall stability and corresponding Marshall flow at optimum asphalt content, represents the combination of stability and flow in single value .Marshall stiffness gives the indication about the resistance of asphalt mixture to plastic flow resulted from loading. High values of Marshall stiffness means the asphalt mixtures have considerable resistance to permanent deformation in case these mixes will be used in construction of pavement. It is well known that percentage of air voids is related to durability of asphalt mixture. The role of mineral filler type in increasing or decreasing of air voids is necessary to be investigation. The effect of mineral filler type on Marshall stiffness and air voids is shown in Fig. 2. (a) Marshall stiffness (b) Air voids Fig.(2) Effect of mineral filler type on Marshall stiffness and air voids of asphalt mixes It can be seen from figure that using hydrated lime as a mineral filler increases the mixture stiffness and improving the it durability represented by low air voids percent 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 M a rs h a ll s ti ff n e s s (K N /m m ) Asphalt mixture type 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type A ir v o id s ( % ) 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 D47 D66 Recovered asphalt cement type S ti ff ne ss m od ul us a t 6 0 ( P a) Hydrated lime filler Portland cement filler Soft sandstone filler o C × 10 5 Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 72 in comparison with using other mineral filler types. Effect of Mineral Filler Type on Index of Retained Strength The moisture damage of asphalt concrete mixtures had produced serious distress , reduced performance and increased maintenance for asphalt pavements. SCRB (SCRB ,2003) specifications require this distress to be checked by performing the index of retained strength percent test . Fig. 3 indicates effect of mineral filler type on index of retained strength percent of asphalt mixes Fig. (3) Effect of mineral filler type on index of retained strength percent of asphalt mixes SCRB (SCRB, 2003) specifications require the minimum percentage of index of retained strength as 70 % for asphalt mixtures used in a construction of surface course pavement . It can be noticed from Fig. 3 that all asphalt mixtures have index of retained strength percent above minimum percentage From test results illustrated in Figure , it can be seen that asphalt mixtures prepared from hydrated lime filler has high resistance to moisture damage because they exhibit high percentages of index of retained strength in comparison with other asphalt mixtures. Effect of Mineral Filler Type on Indirect Tensile Strength (ITS) Fig. 4 presents the indirect tensile strength (ITS) test results. In this test , high tensile strength at failure is desirable property for stiff mixtures. For the ITS test performed at 25oC , the addition of hydrated lime increases the strength for D47HL and D66HL asphalt mixtures. This may be due to the fact that at intermediate temperatures the combined viscosity of the asphalt and minus 0.075 material decreases more in mixtures with other mineral filler types , causing the mixture to lose more of its strength. In other words , the using of the lime filler improved the indirect tensile strength for two asphalt mixtures. Fig. (4) Effect of mineral filler type on indirect tensile strength of asphalt mixes Effect of Mineral Filler Type on Rutting Distress One of the main types of structural distress which may affect the performance of asphalt concrete pavements is permanent deformation , also known as rutting . Rutting develops with an increasing number of axle load applications. Rutting is caused by a combination of densification and shear related deformation and may occur in any course of a pavement structure. VESYS 5W software program is short for Visco - Elastic Pavement System Analysis Program (Kenis et. al. ,1982) and (FHWA , 2003) . It is necessary to mention that the rut depth computed by the 70 75 80 85 90 95 100 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type In d e x o f re ta in e d s tr e n g th ( % ) 1000 1250 1500 1750 2000 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type In d ir e c t te n s il e s tr e n g th ( K p a ) Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 73 VESYS 5W program is the summation of the permanent deformation values of all courses .Therefore , the VESYS 5W software program requires the input of material properties of the courses ,the course thicknesses ,traffic data ,and environmental conditions. These input data will be described in the following articles: Material Properties To obtain input parameters required for the VESYS 5W software , an average curve of creep compliance C (t) versus time is constructed on a log-log graph and extrapolated backward to obtain values of C (t) at 0.1 and 0.30 seconds . The total permanent strain versus incremental time of loading is plotted on a log-log graph and the best-fit line is obtained .The intersection of the line with the vertical axis is denoted by i and the slope by s . The permanent deformation properties μ and α are determined as follows: μ=is/ε … ( 2 ) α=1-s … ( 3 ) Where ε is the recovered strain which was obtained from resilient modulus test The parameters (α and μ) obtained from the incremental static creep test performed on asphalt mixture are used as input into the VESYS 5W software to estimate the rut depth of a specific pavement structure using properties of different asphalt mixtures. Resilient modulus values, Alpha (α) and Gnu (µ) parameters for binder, base, subbase and subgrade courses are taken as a default values [Fujie and Tom (2002)] and [Mohammed and Michael (1999)] while corresponding values for the surface course were determined from laboratory tests. Average resilient modulus values (Mpa) of various asphalt mixtures which were obtained by conducting the resilient modulus test on three Marshall specimens for different asphalt mixes. The specimens were tested at 25, 40 and 60 oC temperatures according to a modified ASTM D4123 (ASTM,2003). The conventional flexible pavement structures are layered systems , and consist of a surface course , binder course , base course ,subbase course and subgrade . The selected pavement structure consists of five courses with material properties and thicknesses are reported in Table 9. The variability coefficients of the course properties were taken as 10, 10, 15, 15 and 20 % for the surface, binder, base, subbase and subgrade courses respectively. Traffic Loading Initially an equivalent 80 KN (18 Kip) single axle load (ESAL) with dual tires was adopted . Traffic loading is assumed to be one million ESAL at end of first year of pavement service life . The dual tires are spaced 13.57 inch (34.5 cm) apart with tire pressure of 80 psi (552 KPa) and radius contact area of 4.25 inch (10.8 cm).Tire contact area depends on contact pressure .Thus , the contact pressure was assumed equal to the tire pressure (no effect of tire wall ) . The use of ESAL is based on the results of experiments that have been shown that the effect of any load on the performance of a pavement can be represented in terms of the number of single applications of (ESAL). Annual growth rate is assumed to be 10 percent. Environmental Conditions Many environmental conditions influence the performance of the flexible pavement. The only environmental effect that is included in the developed model is the temperature of the asphalt course. Changes in the temperature of the asphalt course affect the elastic and viscous properties of the asphalt. Three temperatures (25 ,40 and 60 oC) were used in estimation of rut depth within selected pavement structure. Rut Depth Values The system rutting formulation treats the pavement system as a whole and first calculates an equivalent set of pavement system permanent deformation parameters (α sys and μ sys) which are determined as functions of load repetitions by least square regression analysis .VESYS 5W software program is applied to estimate rut depth in selected pavement structure by using resilient modulus values , three testing temperatures . Fig. 5 below presents the rut depth values of various asphalt mixtures at end of 10 years of analysis time. Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 74 10 15 20 25 30 35 40 D47HLD47PCD47SSD66HLD66PCD66SS R u t d e p th (m m ) Asphalt mixture type Fig. (5) Effect of mineral filler type on rut depth values of asphalt mixes When comparing the rut depth results showed in Fig. 5 , it is noted that the addition of hydrated lime improved the performance indicators with low rut depth values . Effect of Mineral Filler Type on Indirect Tensile Fatigue Test Results Fatigue cracks are caused by repeated traffic loading and it occurs in asphalt pavements when repeated stress or strain having a maximum value generally less than the ultimate strength of the material (Yoder and Witczak ,1975) . The results of the indirect tensile fatigue test are presented in Fig. 6 . While evaluating the fatigue resistance of asphalt concrete mixes , the number of cycles to failure are used as performance indicators.A high number of cycles to failure are the desired properties. Fig. 6: Effect of mineral filler type on number of cycle to failure of asphalt mixes The results of the fatigue test indicate that the addition of hydrated lime as a filler increased the fatigue resistance of the mixes. The D66HL mixture was the mix that showed the highest endurance to the repeated cyclic loading of the fatigue test. 5. Conclusions Within the limitations of materials and test procedures used in this work, the following are concluded: 1. The smaller size fractions of hydrated lime enhancing the absolute viscosity , and improving the asphalt durability and stiffness of the recovered asphalt from asphalt concrete mixture containing hydrated lime as a filler. 2. The hydrated lime is effective in increasing the moisture damage resistance of the mixture, thereby providing pavements that are highly strip resistance. 3. The asphalt mixes with hydrated lime showed improved stiffening and durability properties when incorporated into the mixture. 4. The tensile strength are highest for the asphalt concrete mixes containing hydrated lime fillers than mixes designed with other mineral filler types. 5. The research results revealed that the hydrated lime fillers can have an effect on the rutting susceptibility and fatigue life of flexible pavements , and the use of hydrated lime can improve resistance of the mixes to rutting and fatigue cracking distresses. Table 1: Chemical composition of asphalt cement Fraction Chemical Reactivity Asphaltenes – A Low Polar Aromatics –PA High Napthene Aromatics -NA High Saturates -S Low 100000 400000 700000 1000000 1300000 1600000 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type N u m b e r o f c y c le t o f a il u re Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 75 Table 2 : The physical properties chemical composition of asphalt cement types Property Daurah (40-50) Daurah (60-70) SCRB specifications (40-50) (60-70) Standard Penetration ,1/10 mm 47 66 40-50 60-70 Absolute viscosity at 60 oC, poises 2033 1340 ------ -------- Ductility ( 25 oC , 5 cm/min ),cm >100 >100 =>100 =>100 Specific gravity at 25oC 1.035 1.03 ------- -------- Solubility in trichloroethylene ,% 99.72 99.9 >99 >99 Mass loss , % 0.35 0.58 <0.75 <0.80 Residue from Thin film oven test -Retained penetration,% of original -Ductility ( 25 oC,5 cm /min.), cm 65 75 61 92 >55 >25 >52 >50 Chemical Composition , % Asphaltenes – A 20.03 18.31 Polar Aromatics –PA 35.42 37.08 Napthene Aromatics -NA 24.20 25.37 Saturates -S 20.35 19.24 Table 3 : Coarse and fine aggregate properties Property Value Test method Specification source Specification requirements Coarse aggregate Sieve size (mm) 12.5 to 2.36 SCRB ------------- Bulk specific gravity 2.632 ASTM C127 --------- -------------- Percent wear, Los Angeles (%) 19.2 ASTM C535 SCRB Not more than 30 % % Crushed pieces (One face) 96 ---------- SCRB At least 90% by weight of material Soundness, total weight loss percent 3 ASTM C88 SCRB Not more than 12 % Fine aggregate Sieve size (mm) 2.36 to 0.075 SCRB --------- Bulk specific gravity 2.676 ASTM C128 ------- -------- Soundness , total weight loss percent 4.6 ASTM C88 SCRB Not more than 12 % Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 76 Table 4: Physical properties of mineral filler types Property Test method Result Hydrated lime Passing sieve No. 200, % --------------- 100 Specific gravity ASTM C128 2.785 Plasticity index AASHTO T90 1.5 Portland cement Passing sieve No. 200, % --------------- 96 Specific gravity ASTM C128 3.15 Surface area (m2/Kg) 357.82 Soft sandstone Specific gravity ASTM C128 2.653 Plasticity index AASHTO T90 3.2 Table 5: Selected gradation of aggregate Sieve size (mm) 19 12.5 9.5 4.75 2.36 0.30 0.075 % Passing 100 95 83 59 43 13 7 Table 6: The code for the six asphalt mixture types Asphalt mixture code Description D47HL Daurah 47 pen.asphalt with hydrated lime filler D47PC Daurah 47 pen.asphalt with Portland cement filler D47SS Daurah 47 pen.asphalt with soft sandstone filler D66HL Daurah 66 pen.asphalt with hydrated lime filler D66PC Daurah 66 pen.asphalt with Portland cement filler D66SS Daurah 66 pen.asphalt with soft sandstone filler Table 7 : Marshall properties of different asphalt mixture types at optimum asphalt content SCRB specifications Asphalt mixture type Property D66SSD66PCD66HLD47SSD47PCD47HL Min. 8 KN 9.58.610.712.911.314.4Marshall stability (KN) 2-4 mm3.43.73.13.23.62.8Marshall flow(mm) 3-5 %4.24.03.54.64.33.8Voids in total mix (%) Min. 1415.915.114.816.916.615.7 Voids in mineral aggregate (%) 65-85 %73.673.576.472.874.175.8 Voids filled with asphalt (%) 4-6 %5.484.75.205.034.95.36 Optimum asphalt content (%) Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 77 Table 8: Chemical fractions and Gaestel index values of original and recovered asphalt cement types Asphalt cement Original D47 Original D66 Recovered asphalt cement types D47HL D47PC D47SS D66HL D66PC D66SS % A 20.03 18.31 26.29 23.77 22.61 23.24 21.48 20.07 % P.A. 35.42 37.08 22.45 33.65 22.92 20.19 38.56 36.41 % N.A. 24.20 25.37 31.80 22.61 34.44 38.35 21.59 24.83 % S 20.35 19.24 19.46 19.97 20.03 18.22 18.37 18.69 IG 0.68 0.60 0.84 0.78 0.74 0.71 0.66 0.63 Table 9: Material properties of pavement structure courses Material properties Surface Binder Base Subbase Subgrade Resilient modulus (psi) Variable 143000 66000 10000 5000 Poisson’s ratio 0.35 0.35 0.35 0.40 0.45 Thickness (cm) 5 8 15 25 infinity Permanent deformation properties Alpha (α) Variable 0.66 0.65 0.88 0.77 Gnu (µ) Variable 0.12 0.15 0.03 0.04 References 1.AASHTO,(1989),"Standard Specification for Transportation Materials and Methods of Sampling and Testing ", American Association of State Highway and Transportation Officials, 14th Edition, Part I, Part II,Washington, D.C., U.S.A 2. ASTM Standards, (2003), "Roads and Paving Materials" , Annual Book of the American Society for Testing and Materials Standards , Section 4 ,Vol. 04-03. 3. Bonnaure , F., G. Gest , A. Gravots , and P. Uge , (1977), " A New Method of Predicting the Stiffness of Asphalt Paving Mixtures ", Proceeding of Association of Asphalt Paving Technologists , Vol.46 , pp.64 – 100. 4. FHWA , (2003) ,"VESYS 5W ’s User Manual ", Federal Highway Administration Office (FHWA)of Infrastructure Research and Development ,Truck Pavement Interaction Program, June 26, Washington, D.C. 5. Fujie ,Z. and Tom, S.,(2002)," VESYS 5 Rutting Model Calibrations with Local Accelerated Pavement Test Data and Associated Implementation " , Texas Department of Transportation in Cooperation with the U.S. Department of Transportation Federal Highway Administration , September, Report 9-1502-01-2 , Project Number 9-1502. 6. Ishai I. ,(1995), "Long Term Laboratory and Field Behavior of PPA Asphalt Cement Blends ", Proceedings of the Association of Asphalt Paving Technologists, Vol. 64, pp.306-337. 7.Kenis, W.J., J.A. Sherwood, and T.F. McMahon,(1982), "Verification and Application of the VESYS Structural Subsystem", Proceedings of the Fifth International Conference on the Structural Design of Asphalt Pavements, The Netherlands, 1982 , Vol.1, pp. 333-346. 8. Kennedy , Thomas W., Roberts, Freddy L., and Lee , Kang W., (1982), " Evaluation of Moisture Susceptibility of Asphalt Mixtures Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 78 Using the Texas Freeze-Thaw Pedestal Test" ,Proceeding of Association of Asphalt Paving Technologists , Vol.51 , pp.327 – 341. 9. Kennedy , Thomas W. , and Ping , W. Virgil , (1991), " An Evaluation of Effectiveness of Antistripping Additives in Protecting Asphalt Mixtures from Moisture Damage " , Annual Meeting of the Association of Asphalt Paving Technologists , March 4-6 . 10. Loulizi, A., Al-Qadi, I.L., Lahour, S., and Freeman, T.E., (2002), "Measurement of Vertical Compressive Stress Pulse in Flexible Pavements and Its Representation for Dynamic Loading", Transportation Research Board, Paper No.02-2376. 11. Mohammed , M. E. and Michael , S.M.,(1999), " Effect of Aggregate Gradation on the Rutting Potential of Superpave Mixes " , Transportation Research Board , 78th Annual Meeting , January 10-14 , Washington , D.C. 12. Rostler and Rostler , K.,(1981), "Basic Considerations in Asphalt Research Pertaining to Durability ", Proceeding of Association of Asphalt Paving Technologists , Vol.50. 13. Shah ,S.C., (1963) , " Asphaltic Concrete Pavement Survey " , Louisiana Transportation Research Center Report No.9 , Baton Rouge , Louisiana , 1963. 14. State Commission of Roads and Bridges (SCRB), (2003), "General Specification for Roads and Bridges", Republic of Iraq, Ministry of Housing and Construction, Department of Planning and Studies, Baghdad, Revised Edition ,Addendum No.3. 15. Yoder , E . J. and Witczak , M. W. , (1975) , " Principles of Pavement Design " , Second Edition , John Wiley and Sons , New York. !! Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) 79 تقییم الجیر المطفأ كمادة مالئة في الخلطات االسفلتیة محمد عباس حسن الجمیلي .د قسم الھندسة المدنیة جامعة الكوفة -كلیة الھندسة :الخـــالصــة ا ال ةعلى خواص ونوعی ةالمؤثرو ةالمھم دالمادة المالئة المعدنیة ھي احد الموا فلتیة تخلط اك , اإلس د ھن ة وتوج واع مختلف ن أن م ذه الدراس إجراء على االمر الذي شجع ، ةوالنوعی ةالكلف فیما بینھا من ناحیة المالئة متباینةالمواد أثیرا تل ةھ یم ت أ تقی ر المطف ى الجی عل ال اإلسفلتیة من حیث مقاومة تخواص الخلطا ة األحم م تح .و متان فلتیة ت ات اإلس یر الخلط ة ض تخدام التقلیدی منت باس د اس و بورتالن رى مطحون كمادة المالئة و يحجر رمل ة أخ ھا معدل یم خواص أ لتق ر المطف ل یةھندس ال الجی ن قب ة م ي ُمَعرَّف ا ھ یِة كم واص األساس خ ترجعة المقاومة مارشال، دلیل ة ، المس ّد ا مقاوم ائص اللش ر، خص ر مباش و الغی ة ، ويدائم ه تش ل مقاوم م .الكل تخدام ت درج اس ف ال الت كثی راق لتحضیر الخلطة و المستخدم في انشاء مثاليال ي الع طحیة ف فات الطبقة الس ب مواص ذه . (SCRB)بموج ي ھ تعملة ف واد ألمس الم الع بح ) مقاسات خشنة وناعمة( ةركام معدنی ادتضمنت مو ةالدراس ف رتم الحصول علیھا من مق ن ونج ان م فلت نوع ن اإلس تج م المن فى دورة مص ا ال یم .D66, D47 وھم م تقی ة ت واص الفیزیائی ن الخ تعادة م فلت المس اوي لإلس ب الكیمی الدة و التركی ل الص ومعام ة .المالئة المختلفة المحضرة و التي تحتوي على المواد اإلسفلتیةالخلطات ادة مالئ أ كم ر المطف افَة الجی أّن إض أظھرت نتائج البحث ب .للخلطات اإلسفلتیةالجیر المطفأ یقلل من حساسیة الرطوبة استعمال كذلك الدائمي وعمر الكلل و ِهالتشو صَن خصائَحّس 2 . 0 2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 5 . 5 M a r s h a l l s t i f f n e s s ( K N / m m ) Asphalt mixture type 70 75 80 85 90 95 100 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Index of retained strength (%) 1000 1250 1500 1750 2000 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Indirect tensile strength (Kpa) 1000 3000 5000 7000 9000 D 47 D 66 A b s o l u t e v i s c o s i t y a t 6 0 ( p o i s e s ) Recovered asphalt cement type Hydrated lime filler Portland cement filler Soft sandstone filler 100000 400000 700000 1000000 1300000 1600000 D47HLD47PCD47SSD66HLD66PCD66SS Asphalt mixture type Number of cycle to failure 70 75 80 85 90 95 100 D47HLD47PCD47SSD66HLD66PCD66SS Asphalt mixture type Index of retained strength (%) 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 D47HLD47PCD47SSD66HLD66PCD66SS Asphalt mixture type Air voids (%) 60 70 80 90 100 D47D66 Recovered asphalt cement type Ductility(cm) Hydrated lime filler Portland cement filler Soft sandstone filler 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 D47D66 Recovered asphalt cement type Stiffness modulus at 60 ( Pa ) Hydrated lime fillerPortland cement filler Soft sandstone filler 1000 1250 1500 1750 2000 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Indirect tensile strength (Kpa) 1000 3000 5000 7000 9000 D 47 D 66 A b s o l u t e v i s c o s i t y a t 6 0 ( p o i s e s ) Recovered asphalt cement type Hydrated lime filler Portland cement filler Soft sandstone filler 70 75 80 85 90 95 100 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Index of retained strength (%) 2 . 0 2 . 5 3 . 0 3 . 5 4 . 0 4 . 5 5 . 0 5 . 5 M a r s h a l l s t i f f n e s s ( K N / m m ) Asphalt mixture type 1000 1250 1500 1750 2000 D47HLD47PCD47SSD66HLD66PCD66SS Asphalt mixture type Indirect tensile strength (Kpa) 10 15 20 25 30 35 40 D 47 HL D 47 PC D 47 SS D 66 HL D 66 PC D 66 SS R u t d e p t h ( m m ) Asphalt mixture type تخطيط1 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Marshall stiffness (KN/mm) 5.14 3.14 4.03 3.45 2.32 2.79 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler D47 7230 5100 4618 D66 4492 3851 2663 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 C (poises) ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler D47 4.27 2.93 3.51 D66 2.66 1.85 2.09 ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Stiffness modulus at 60 C (Pa) ورقة4 D47HL 3.8 D47PC 4.3 D47SS 4.6 D66HL 3.5 D66PC 4 D66SS 4.2 ورقة4 Asphalt mixture type Air voids (%) ورقة3 D47HL 5.14 D47PC 3.14 D47SS 4.03 D66HL 3.45 D66PC 2.32 D66SS 2.79 ورقة3 Asphalt mixture type Marshall stiffness (KN/mm) تخطيط2 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Rut depth (mm) 11.3 20.8 17.6 27.8 36.5 32.4 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler D47 7230 5100 4618 D66 4492 3851 2663 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 C (poises) ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler D47 4.27 2.93 3.51 D66 2.66 1.85 2.09 ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Stiffness modulus at 60 C (Pa) ورقة4 D47HL 11.3 D47PC 20.8 D47SS 17.6 D66HL 27.8 D66PC 36.5 D66SS 32.4 ورقة4 Asphalt mixture type Rut depth (mm) ورقة5 D47HL 21.3 D47PC D47SS D66HL D66PC D66SS ورقة3 D47HL 1951 D47PC 1643 D47SS 1486 D66HL 1334 D66PC 1202 D66SS 1111 ورقة3 Asphalt mixture type Marshall stiffness (KN/mm) تخطيط3 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Index of retained strength (%) 85 80 71 94 87 76 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler D47 7230 5100 4618 D66 4492 3851 2663 ورقة1 0 0 0 0 0 0 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 C (poises) ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler D47 4.27 2.93 3.51 D66 2.66 1.85 2.09 ورقة2 0 0 0 0 0 0 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Stiffness modulus at 60 C (Pa) ورقة4 D47HL 3.8 D47PC 4.3 D47SS 4.6 D66HL 3.5 D66PC 4 D66SS 4.2 ورقة4 0 0 0 0 0 0 Asphalt mixture type Air voids (%) ورقة3 D47HL 85 D47PC 80 D47SS 71 D66HL 94 D66PC 87 D66SS 76 ورقة3 0 0 0 0 0 0 Asphalt mixture type Marshall stiffness (KN/mm) تخطيط3 D47 D47 D47 D66 D66 D66 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 (poises) 7230 5100 4618 4492 3851 2663 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler D47 7230 5100 4618 D66 4492 3851 2663 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 (poises) ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler D47 4.27 2.93 3.51 D66 2.66 1.85 2.09 ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Stiffness modulus at 60 (Pa) ورقة4 D47HL 928077 D47PC 327185 D47SS 204863 D66HL 1522986 D66PC 710485 D66SS 476114 ورقة4 Asphalt mixture type Number of cycle to failure ورقة5 3 5 10 30 50 100 300 500 750 1000 ورقة3 D47HL 1951 D47PC 1643 D47SS 1486 D66HL 1334 D66PC 1202 D66SS 1111 ورقة3 Asphalt mixture type Marshall stiffness (KN/mm) تخطيط1 D47HL D47PC D47SS D66HL D66PC D66SS Asphalt mixture type Indirect tensile strength (Kpa) 1951 1643 1486 1334 1202 1111 ورقة1 Hydrated lime filler Portland cement filler Soft sandstone filler D47 7230 5100 4618 D66 4492 3851 2663 ورقة1 0 0 0 0 0 0 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Absolute viscosity at 60 C (poises) ورقة2 Hydrated lime filler Portland cement filler Soft sandstone filler D47 4.27 2.93 3.51 D66 2.66 1.85 2.09 ورقة2 0 0 0 0 0 0 Hydrated lime filler Portland cement filler Soft sandstone filler Recovered asphalt cement type Stiffness modulus at 60 C (Pa) ورقة4 D47HL 3.8 D47PC 4.3 D47SS 4.6 D66HL 3.5 D66PC 4 D66SS 4.2 ورقة4 0 0 0 0 0 0 Asphalt mixture type Air voids (%) ورقة3 D47HL 1951 D47PC 1643 D47SS 1486 D66HL 1334 D66PC 1202 D66SS 1111 ورقة3 0 0 0 0 0 0 Asphalt mixture type Marshall stiffness (KN/mm) Al-Hikama Intermediate School Mohammed Abbas Al-khwarizmi Engineering Journal, Vol.4 , No. 1 PP 68- 79 (2008) Al-khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal, Vol.4 , No.1 , pp 68-79 (2008 ) Evaluation of Hydrated Lime Filler in Asphalt Mixtures Dr. Mohammed Abbas Hasan Al-Jumaily Engineering College University of Kufa (Received 16 February 2007 ; accepted 26 November 2007) Abstract Mineral filler is one of important materials and affecting on properties and quality of asphalt mixtures .There are different types of mineral filler depended on cost and quality , the matter encourages us to achieve this study to evaluate hydrated lime filler effects on properties of asphalt mixes related with strength and durability. Conventional asphaltic concrete mixtures with Portland cement and soft sandstone fillers and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by Marshall properties , index of retained strength , indirect tensile strength , permanent deformation characteristics , and fatigue resistance .A typical dense graded mixture employed in construction of surface course pavement in Iraq in accordance with SCRB specifications was used .The materials used in this study included mineral aggregate materials (coarse and fine sizes) were originally obtained from Najaf Sea quarries and two grades of asphalt cements produced from Daurah refinery which are D47 and D66 . The physical properties , stiffness modulus and chemical composition are evaluated for the recovered asphalt cement from prepared asphalt mixes containing various filler types .The paper results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue life and the use of hydrated lime will decrease the moisture susceptibility of the asphalt mixtures. Key word: Hydrated Lime, Mineral Filler, Chemical Composition, Retained Strength Index, Indirect Tensile Strength, Indirect Tensile Creep, Indirect Tensile Fatigue, Rutting Distress, Absolute viscosity, Stiffness Modulus. Introduction Permanent deformation, fatigue and moisture damage are common distresses found in asphalt pavements today. In many cases , mineral fillers will increase the mixture stiffness. In Iraq , the performance of asphalt pavements has deteriorated over the last decade . Heavy axle loads coupled with the hot climate and poor drainage systems in middle part of Iraq are major contributing factors to the development of severe pavement distresses such as permanent deformation and loss of structure because of moisture damage. The use of lime to reduce moisture sensitivity has been promoted by FHWA for many years (Shah,1963). The structure of hydrated lime consists of different size fractions. The larger size fraction performs as a filler and increases the stiffness of the asphalt mixture. The smaller size fraction increases asphalt film thickness enhancing viscosity of the asphalt , and improving the asphalt cohesion and stiffness. Adhesion between the aggregate and asphalt increases (Dickinson ,1984) , resulting in decreased mixture segregation. The water sensitivity of asphalt mixes treated with hydrated lime and antistrip agents was evaluated previously (Kennedy et.al.,1982 and Kennedy et. al. , 1991). Results from these tests depended on the actual combinations of aggregate , asphalt and additives. However, among the antistrip agents, hydrated lime was most effective in increasing the tensile strength and in improving the water sensitivity of the mixture. This paper presents the results of a comparative study conducted on various asphalt mixes with three different mineral filler types to determine if the use of hydrated lime as a mineral filler leads to any improvement in the fundamental engineering properties. In addition, effect of hydrated lime on physical properties and chemical composition of asphalt cement has been investigated in this study. Materials Asphalt cement The two grades of asphalt cement used in this work included: (40-50) and(60-70) penetration grade asphalt from Daurah refinery .The different physical properties of asphalt cement are evaluated according to ASTM standards including absolute viscosity (D2171) , standard penetration (D5),ductility (D113), specific gravity (D70) , solubility in trichloroethylene (D2042) and thin-film oven test (D1754). The chemical composition of the asphalt cement is determined by the modified precipitation method of Rostler (ASTM D 4124 ) , in which the asphalt is separated into four fractions (Rostler and Rostler ,1981) as shown in Table 1. The physical properties and chemical composition of the two asphalt types (D47 and D66) as well as State Commission of Roads and Bridges , SCRB (SCRB, 2003)specifications are presented in Table 2 . Aggregate and Mineral Filler Properties Mineral aggregate materials (coarse and fine sizes) were originally obtained from Najaf Sea quarries. The aggregate properties are listed in Table 3. Three different types of mineral filler were used as mineral filler in preparation of various asphalt mixes because these types were available in a large quantity during study period. The hydrated lime filler was obtained from Karbala’a factory. The Portland cement filler was brought from Kufa cement factory . The soft sandstone powder filler was obtained from Najaf Sea quarries. The physical properties of the mineral filler types are shown in Table 4. Asphalt Concrete Mixtures The asphalt concrete mixtures are prepared using crushed gravel and sand with three different mineral fillers and two asphalt cement types . The mid limits of the 12.5 mm nominal maximum size dense gradation in accordance with SCRB (SCRB, 2003) specification requirements are used in preparing six asphalt mixtures ( two asphalt cements and three mineral fillers) as reported in Table 5. The six asphalt mixture types included in this study are coded as shown in Table 6 . The optimum asphalt contents (O.A.C) of various asphalt mixtures which were determined from standard Marshall mix design in accordance with ASTM D1559 (ASTM,2003) are reported in Table 7 . Also, Marshall properties at (O.A.C) and SCRB (SCRB ,2003) specifications for asphalt mixes used in the construction of surface course are presented in Table 7. Fundamental Test Procedure Four fundamental tests were conducted to characterize the six mixtures and determining the effects of the hydrated lime mineral filler on the properties of asphalt mixes. Three specimens were prepared and the average results are reported for all tests .A brief description of each test is given below: Index of Retained Strength Test Index of retained strength test is used to evaluate moisture damage of asphalt pavement in accordance with method ASTM D1075 (ASTM ,2003). It is one of tests required by SCRB (SCRB , 2003) specifications to be performed on asphalt mixes used in surface course in addition to Marshall tests. This test is intended to measure the loss of cohesion resulting from the action of water on compacted bituminous mixtures containing penetration grade asphalt. A set of six cylindrical specimens 4 in (101.6mm) in diameter by 4 in (101.6mm) in height was prepared for each asphalt mixtures in according with the procedure described in the standard method of test for compressive strength of bituminous mixtures of ASTM D1074 (ASTM ,2003). Indirect Tensile Strength Test The indirect tensile strength at 25oC is evaluated for cylindrical specimens (101.6mm diameter × 63.5 mm height ) in accordance with ASTM D4123 (ASTM,2003). Indirect Tensile Creep Test At testing temperature of 40 oC , a compressive stress of 0.138 Mpa (20 psi) was applied on the Marshall specimen (101.6mm diameter × 63.5 mm height ). The loading times include (3,5,10,100, and 1000 seconds) and rest periods are (2,2,2,4,and 8 minutes). The total permanent strains, εP (in/in) at the end of each rest period were measured. In last loading time (1000 seconds), the creep deformations were measured after 3, 6, 10, 30, 60,100, 300, 600, and 1000 seconds durations. The creep compliance, C (t), at each of these loading durations is calculated as follows: C(t)=є(t)/σo … (1) Where: C(t)= Creep compliance at (1/Mpa), є(t)=Vertical strain at loading duration t (mm/mm), and σo = Applied stress (Mpa) . Indirect Tensile Fatigue Test To determine the fatigue resistance of the asphalt concrete samples, this test was conducted at 25oC temperature by using the machine manufactured by the researcher in the highway laboratory in College of Engineering in Kufa University . The (10 %) of the test failure load obtained from indirect tensile test was used as the peak value of the cyclic load with loading duration of 0.10 second followed by a rest period of 0.90 second was applied to the test specimen (Loulizi et.al.,2002) .The number of cycles were monitored through the duration of test and the test was terminated when the specimen reached to failure. 4. Discussion of Test Results The test results obtained from experimental work will be discussed in the following sections Effect of Mineral Filler Type on Asphalt Cement Properties and Chemical Composition To evaluate the effect of mineral filler type on the physical properties and chemical composition of asphalt cement , there is need to recovery the asphalt from asphalt mixture specimens .Extraction test was achieved by using a solvent in accordance with the method standardized in ASTM D 2172 (ASTM , 2003) to quantitative separation of the aggregate and asphalt cement . The asphalt was then recovered from asphalt-solvent solution (extract) in accordance with the method described in ASTM D1856 (ASTM ,2003). The stiffness modulus values of recovered asphalt cement types at temperature of 60 oC and a loading time of 0.02 second were determined by using Shell nomographs (Bonnaure et. al. ,1977) .Three properties of the recovered asphalt cement are evaluated : absolute viscosity , ductility and stiffness modulus .The effect of mineral filler type on these properties are shown in Fig.1. (a) Absolute viscosity (b) Ductility (c) Stiffness modulus Fig. (1) Effect of mineral filler type on asphalt cement properties It can be noticed that recovered asphalt cement from mixes containing hydrated lime as a filler exhibits high absolute viscosity and stiffness values and has low tensile properties represented by low ductility values when compared with other asphalt types. The chemical composition parameter, Gaestel Index (IG) defined as the ratio of (Asphaltenes and saturates ) fractions to (Naphthene Aromatics and Polar Aromatics) fractions which is related with asphalt durability (Ishai I. ,1995). High values of (IG) refers to reduction in the asphalt durability and asphalt exhibits brittle and hardening behavior. The Chemical fractions and Gaestel index values of original and recovered asphalt cement types are reported in Table 8. The asphalt cement considers durable if the range of (IG) values lie within a range of about (0.4-1.2) (Ishai I. ,1995). It may be seen from Table 8 that all asphalt cement types fall within this range and have good durability. Effect of Mineral Filler Type on Marshall Stiffness and Air Voids Marshall stiffness (KN/mm) , which is calculated as the ratio between Marshall stability and corresponding Marshall flow at optimum asphalt content, represents the combination of stability and flow in single value .Marshall stiffness gives the indication about the resistance of asphalt mixture to plastic flow resulted from loading. High values of Marshall stiffness means the asphalt mixtures have considerable resistance to permanent deformation in case these mixes will be used in construction of pavement. It is well known that percentage of air voids is related to durability of asphalt mixture. The role of mineral filler type in increasing or decreasing of air voids is necessary to be investigation. The effect of mineral filler type on Marshall stiffness and air voids is shown in Fig. 2. (a) Marshall stiffness (b) Air voids Fig.(2) Effect of mineral filler type on Marshall stiffness and air voids of asphalt mixes It can be seen from figure that using hydrated lime as a mineral filler increases the mixture stiffness and improving the it durability represented by low air voids percent in comparison with using other mineral filler types. Effect of Mineral Filler Type on Index of Retained Strength The moisture damage of asphalt concrete mixtures had produced serious distress , reduced performance and increased maintenance for asphalt pavements. SCRB (SCRB ,2003) specifications require this distress to be checked by performing the index of retained strength percent test . Fig. 3 indicates effect of mineral filler type on index of retained strength percent of asphalt mixes Fig. (3) Effect of mineral filler type on index of retained strength percent of asphalt mixes SCRB (SCRB, 2003) specifications require the minimum percentage of index of retained strength as 70 % for asphalt mixtures used in a construction of surface course pavement . It can be noticed from Fig. 3 that all asphalt mixtures have index of retained strength percent above minimum percentage From test results illustrated in Figure , it can be seen that asphalt mixtures prepared from hydrated lime filler has high resistance to moisture damage because they exhibit high percentages of index of retained strength in comparison with other asphalt mixtures. Effect of Mineral Filler Type on Indirect Tensile Strength (ITS) Fig. 4 presents the indirect tensile strength (ITS) test results. In this test , high tensile strength at failure is desirable property for stiff mixtures. For the ITS test performed at 25oC , the addition of hydrated lime increases the strength for D47HL and D66HL asphalt mixtures. This may be due to the fact that at intermediate temperatures the combined viscosity of the asphalt and minus 0.075 material decreases more in mixtures with other mineral filler types , causing the mixture to lose more of its strength. In other words , the using of the lime filler improved the indirect tensile strength for two asphalt mixtures. Fig. (4) Effect of mineral filler type on indirect tensile strength of asphalt mixes Effect of Mineral Filler Type on Rutting Distress One of the main types of structural distress which may affect the performance of asphalt concrete pavements is permanent deformation , also known as rutting . Rutting develops with an increasing number of axle load applications. Rutting is caused by a combination of densification and shear related deformation and may occur in any course of a pavement structure. VESYS 5W software program is short for Visco - Elastic Pavement System Analysis Program (Kenis et. al. ,1982) and (FHWA , 2003) . It is necessary to mention that the rut depth computed by the VESYS 5W program is the summation of the permanent deformation values of all courses .Therefore , the VESYS 5W software program requires the input of material properties of the courses ,the course thicknesses ,traffic data ,and environmental conditions. These input data will be described in the following articles: Material Properties To obtain input parameters required for the VESYS 5W software , an average curve of creep compliance C (t) versus time is constructed on a log-log graph and extrapolated backward to obtain values of C (t) at 0.1 and 0.30 seconds . The total permanent strain versus incremental time of loading is plotted on a log-log graph and the best-fit line is obtained .The intersection of the line with the vertical axis is denoted by i and the slope by s . The permanent deformation properties μ and α are determined as follows: μ=is/ε … ( 2 ) α=1-s … ( 3 ) Where ε is the recovered strain which was obtained from resilient modulus test The parameters (α and μ) obtained from the incremental static creep test performed on asphalt mixture are used as input into the VESYS 5W software to estimate the rut depth of a specific pavement structure using properties of different asphalt mixtures. Resilient modulus values, Alpha (α) and Gnu (µ) parameters for binder, base, subbase and subgrade courses are taken as a default values [Fujie and Tom (2002)] and [Mohammed and Michael (1999)] while corresponding values for the surface course were determined from laboratory tests. Average resilient modulus values (Mpa) of various asphalt mixtures which were obtained by conducting the resilient modulus test on three Marshall specimens for different asphalt mixes. The specimens were tested at 25, 40 and 60 oC temperatures according to a modified ASTM D4123 (ASTM,2003). The conventional flexible pavement structures are layered systems , and consist of a surface course , binder course , base course ,subbase course and subgrade . The selected pavement structure consists of five courses with material properties and thicknesses are reported in Table 9. The variability coefficients of the course properties were taken as 10, 10, 15, 15 and 20 % for the surface, binder, base, subbase and subgrade courses respectively. Traffic Loading Initially an equivalent 80 KN (18 Kip) single axle load (ESAL) with dual tires was adopted . Traffic loading is assumed to be one million ESAL at end of first year of pavement service life . The dual tires are spaced 13.57 inch (34.5 cm) apart with tire pressure of 80 psi (552 KPa) and radius contact area of 4.25 inch (10.8 cm).Tire contact area depends on contact pressure .Thus , the contact pressure was assumed equal to the tire pressure (no effect of tire wall ) . The use of ESAL is based on the results of experiments that have been shown that the effect of any load on the performance of a pavement can be represented in terms of the number of single applications of (ESAL). Annual growth rate is assumed to be 10 percent. Environmental Conditions Many environmental conditions influence the performance of the flexible pavement. The only environmental effect that is included in the developed model is the temperature of the asphalt course. Changes in the temperature of the asphalt course affect the elastic and viscous properties of the asphalt. Three temperatures (25 ,40 and 60 oC) were used in estimation of rut depth within selected pavement structure. Rut Depth Values The system rutting formulation treats the pavement system as a whole and first calculates an equivalent set of pavement system permanent deformation parameters (α sys and μ sys) which are determined as functions of load repetitions by least square regression analysis .VESYS 5W software program is applied to estimate rut depth in selected pavement structure by using resilient modulus values , three testing temperatures . Fig. 5 below presents the rut depth values of various asphalt mixtures at end of 10 years of analysis time. Fig. (5) Effect of mineral filler type on rut depth values of asphalt mixes When comparing the rut depth results showed in Fig. 5 , it is noted that the addition of hydrated lime improved the performance indicators with low rut depth values . Effect of Mineral Filler Type on Indirect Tensile Fatigue Test Results Fatigue cracks are caused by repeated traffic loading and it occurs in asphalt pavements when repeated stress or strain having a maximum value generally less than the ultimate strength of the material (Yoder and Witczak ,1975) . The results of the indirect tensile fatigue test are presented in Fig. 6 . While evaluating the fatigue resistance of asphalt concrete mixes , the number of cycles to failure are used as performance indicators.A high number of cycles to failure are the desired properties. Fig. 6: Effect of mineral filler type on number of cycle to failure of asphalt mixes The results of the fatigue test indicate that the addition of hydrated lime as a filler increased the fatigue resistance of the mixes. The D66HL mixture was the mix that showed the highest endurance to the repeated cyclic loading of the fatigue test. 5. Conclusions Within the limitations of materials and test procedures used in this work, the following are concluded: 1. The smaller size fractions of hydrated lime enhancing the absolute viscosity , and improving the asphalt durability and stiffness of the recovered asphalt from asphalt concrete mixture containing hydrated lime as a filler. 2. The hydrated lime is effective in increasing the moisture damage resistance of the mixture, thereby providing pavements that are highly strip resistance. 3. The asphalt mixes with hydrated lime showed improved stiffening and durability properties when incorporated into the mixture. 4. The tensile strength are highest for the asphalt concrete mixes containing hydrated lime fillers than mixes designed with other mineral filler types. 5. The research results revealed that the hydrated lime fillers can have an effect on the rutting susceptibility and fatigue life of flexible pavements , and the use of hydrated lime can improve resistance of the mixes to rutting and fatigue cracking distresses. Table 1: Chemical composition of asphalt cement Fraction Chemical Reactivity Asphaltenes – A Low Polar Aromatics –PA High Napthene Aromatics -NA High Saturates -S Low Table 2 : The physical properties chemical composition of asphalt cement types Property Daurah (40-50) Daurah (60-70) SCRB specifications (40-50) (60-70) Standard Penetration ,1/10 mm 47 66 40-50 60-70 Absolute viscosity at 60 oC, poises 2033 1340 ------ -------- Ductility ( 25 oC , 5 cm/min ),cm >100 >100 =>100 =>100 Specific gravity at 25oC 1.035 1.03 ------- -------- Solubility in trichloroethylene ,% 99.72 99.9 >99 >99 Mass loss , % 0.35 0.58 <0.75 <0.80 Residue from Thin film oven test -Retained penetration,% of original -Ductility ( 25 oC,5 cm /min.), cm 65 75 61 92 >55 >25 >52 >50 Chemical Composition , % Asphaltenes – A 20.03 18.31 Polar Aromatics –PA 35.42 37.08 Napthene Aromatics -NA 24.20 25.37 Saturates -S 20.35 19.24 Table 3 : Coarse and fine aggregate properties Property Value Test method Specification source Specification requirements Coarse aggregate Sieve size (mm) 12.5 to 2.36 SCRB ------------- Bulk specific gravity 2.632 ASTM C127 --------- -------------- Percent wear, Los Angeles (%) 19.2 ASTM C535 SCRB Not more than 30 % % Crushed pieces (One face) 96 ---------- SCRB At least 90% by weight of material Soundness, total weight loss percent 3 ASTM C88 SCRB Not more than 12 % Fine aggregate Sieve size (mm) 2.36 to 0.075 SCRB --------- Bulk specific gravity 2.676 ASTM C128 ------- -------- Soundness , total weight loss percent 4.6 ASTM C88 SCRB Not more than 12 % Table 4: Physical properties of mineral filler types Property Test method Result Hydrated lime Passing sieve No. 200, % --------------- 100 Specific gravity ASTM C128 2.785 Plasticity index AASHTO T90 1.5 Portland cement Passing sieve No. 200, % --------------- 96 Specific gravity ASTM C128 3.15 Surface area (m2/Kg) 357.82 Soft sandstone Specific gravity ASTM C128 2.653 Plasticity index AASHTO T90 3.2 Table 5: Selected gradation of aggregate Sieve size (mm) 19 12.5 9.5 4.75 2.36 0.30 0.075 % Passing 100 95 83 59 43 13 7 Table 6: The code for the six asphalt mixture types Asphalt mixture code Description D47HL Daurah 47 pen.asphalt with hydrated lime filler D47PC Daurah 47 pen.asphalt with Portland cement filler D47SS Daurah 47 pen.asphalt with soft sandstone filler D66HL Daurah 66 pen.asphalt with hydrated lime filler D66PC Daurah 66 pen.asphalt with Portland cement filler D66SS Daurah 66 pen.asphalt with soft sandstone filler Table 7 : Marshall properties of different asphalt mixture types at optimum asphalt content SCRB specifications Asphalt mixture type Property D66SS D66PC D66HL D47SS D47PC D47HL Min. 8 KN 9.5 8.6 10.7 12.9 11.3 14.4 Marshall stability (KN) 2-4 mm 3.4 3.7 3.1 3.2 3.6 2.8 Marshall flow(mm) 3-5 % 4.2 4.0 3.5 4.6 4.3 3.8 Voids in total mix (%) Min. 14 15.9 15.1 14.8 16.9 16.6 15.7 Voids in mineral aggregate (%) 65-85 % 73.6 73.5 76.4 72.8 74.1 75.8 Voids filled with asphalt (%) 4-6 % 5.48 4.7 5.20 5.03 4.9 5.36 Optimum asphalt content (%) Table 8: Chemical fractions and Gaestel index values of original and recovered asphalt cement types Asphalt cement Original D47 Original D66 Recovered asphalt cement types D47HL D47PC D47SS D66HL D66PC D66SS % A 20.03 18.31 26.29 23.77 22.61 23.24 21.48 20.07 % P.A. 35.42 37.08 22.45 33.65 22.92 20.19 38.56 36.41 % N.A. 24.20 25.37 31.80 22.61 34.44 38.35 21.59 24.83 % S 20.35 19.24 19.46 19.97 20.03 18.22 18.37 18.69 IG 0.68 0.60 0.84 0.78 0.74 0.71 0.66 0.63 Table 9: Material properties of pavement structure courses Material properties Surface Binder Base Subbase Subgrade Resilient modulus (psi) Variable 143000 66000 10000 5000 Poisson’s ratio 0.35 0.35 0.35 0.40 0.45 Thickness (cm) 5 8 15 25 infinity Permanent deformation properties Alpha (α) Variable 0.66 0.65 0.88 0.77 Gnu (µ) Variable 0.12 0.15 0.03 0.04 References 1. AASHTO,(1989),"Standard Specification for Transportation Materials and Methods of Sampling and Testing ", American Association of State Highway and Transportation Officials, 14th Edition, Part I, Part II,Washington, D.C., U.S.A 2. ASTM Standards, (2003), "Roads and Paving Materials" , Annual Book of the American Society for Testing and Materials Standards , Section 4 ,Vol. 04-03. 3. Bonnaure , F., G. Gest , A. Gravots , and P. Uge , (1977), " A New Method of Predicting the Stiffness of Asphalt Paving Mixtures ", Proceeding of Association of Asphalt Paving Technologists , Vol.46 , pp.64 – 100. 4. FHWA , (2003) ,"VESYS 5W ’s User Manual ", Federal Highway Administration Office (FHWA)of Infrastructure Research and Development ,Truck Pavement Interaction Program, June 26, Washington, D.C. 5. Fujie ,Z. and Tom, S.,(2002)," VESYS 5 Rutting Model Calibrations with Local Accelerated Pavement Test Data and Associated Implementation " , Texas Department of Transportation in Cooperation with the U.S. Department of Transportation Federal Highway Administration , September, Report 9-1502-01-2 , Project Number 9-1502. 6. Ishai I. ,(1995), "Long Term Laboratory and Field Behavior of PPA Asphalt Cement Blends ", Proceedings of the Association of Asphalt Paving Technologists, Vol. 64, pp.306-337. 7. Kenis, W.J., J.A. Sherwood, and T.F. McMahon,(1982), "Verification and Application of the VESYS Structural Subsystem", Proceedings of the Fifth International Conference on the Structural Design of Asphalt Pavements, The Netherlands, 1982 , Vol.1, pp. 333-346. 8. Kennedy , Thomas W., Roberts, Freddy L., and Lee , Kang W., (1982), " Evaluation of Moisture Susceptibility of Asphalt Mixtures Using the Texas Freeze-Thaw Pedestal Test" ,Proceeding of Association of Asphalt Paving Technologists , Vol.51 , pp.327 – 341. 9. Kennedy , Thomas W. , and Ping , W. Virgil , (1991), " An Evaluation of Effectiveness of Antistripping Additives in Protecting Asphalt Mixtures from Moisture Damage " , Annual Meeting of the Association of Asphalt Paving Technologists , March 4-6 . 10. Loulizi, A., Al-Qadi, I.L., Lahour, S., and Freeman, T.E., (2002), "Measurement of Vertical Compressive Stress Pulse in Flexible Pavements and Its Representation for Dynamic Loading", Transportation Research Board, Paper No.02-2376. 11. Mohammed , M. E. and Michael , S.M.,(1999), " Effect of Aggregate Gradation on the Rutting Potential of Superpave Mixes " , Transportation Research Board , 78th Annual Meeting , January 10-14 , Washington , D.C. 12. Rostler and Rostler , K.,(1981), "Basic Considerations in Asphalt Research Pertaining to Durability ", Proceeding of Association of Asphalt Paving Technologists , Vol.50. 13. Shah ,S.C., (1963) , " Asphaltic Concrete Pavement Survey " , Louisiana Transportation Research Center Report No.9 , Baton Rouge , Louisiana , 1963. 14. State Commission of Roads and Bridges (SCRB), (2003), "General Specification for Roads and Bridges", Republic of Iraq, Ministry of Housing and Construction, Department of Planning and Studies, Baghdad, Revised Edition ,Addendum No.3. 15. Yoder , E . J. and Witczak , M. W. , (1975) , " Principles of Pavement Design " , Second Edition , John Wiley and Sons , New York. تقييم الجير المطفأ كمادة مالئة في الخلطات الاسفلتية د. محمد عباس حسن الجميلي قسم الهندسة المدنية كلية الهندسة- جامعة الكوفة الخـــلاصــة: المادة المالئة المعدنية هي احد المواد المهمة والمؤثرة على خواص ونوعية الخلطات الإسفلتية, وتوجد هناك أنواع مختلفة من المواد المالئة متباينة فيما بينها من ناحية الكلفة والنوعية، الامر الذي شجع على إجراء هذه الدراسة لتقييم تأثيرات الجير المطفأ على خواص الخلطات الإسفلتية من حيث مقاومة الأحمال و متانة . تم تحضير الخلطات الإسفلتية التقليدية باستخدام اسمنت بورتلاند و حجر رملي مطحون كمادة المالئة و أخرى معدلة الجير المطفأ لتقيم خواصها الهندسية الأساسيةِ كما هي مُعَرَّفة من قبل خواص مارشال، دليل المقاومة المسترجعة، مقاومة الشدّ الغير مباشر، خصائص التشوه دائمي، ومقاومة الكلل.تم استخدام التدرج الكثيف المثالي لتحضير الخلطة و المستخدم في انشاء الطبقة السطحية في العراق بموجب مواصفات(SCRB) . المواد ألمستعملة في هذه الدراسة تضمنت مواد ركام معدنية (مقاسات خشنة وناعمة) تم الحصول عليها من مقالع بحر نجف و نوعان من الإسفلت المنتج من مصفى الدورة وهما D66, D47. تم تقييم الخواص الفيزيائية ومعامل الصلادة و التركيب الكيمياوي للإسفلت المستعادة من الخلطات الإسفلتية المحضرة و التي تحتوي على المواد المالئة المختلفة . أظهرت نتائج البحث بأنّ إضافةَ الجير المطفأ كمادة مالئة حَسّنَ خصائص التشوهِ الدائمي وعمر الكلل وكذلك استعمال الجير المطفأ يقلل من حساسية الرطوبة للخلطات الإسفلتية. � EMBED Excel.Chart.8 \s ��� � EMBED Excel.Chart.8 \s ��� � EMBED Excel.Chart.8 \s ��� oC � EMBED Excel.Chart.8 \s ��� oC X105 oC×10 5 � EMBED PBrush ��� PAGE 77 _1258123747.xls _1300184780.xls _1039819024.xls _1258123537.xls _1039817889.xls