Properties Of Asphalt Concrete Mixtures Research Articles

Development of technology for obtaining asphalt concrete mixture using oil sludge as an additive

Oil sludge is similar in composition to the composition of bitumen, which is one of the important components of asphalt concrete mixture. Therefore, oil waste can be used in the production of asphalt concrete, both as an organic binder to strengthen local soils and as a binder to produce organomineral mixtures. The use of oil sludge in road construction helps preserve natural resources, improve the environmental situation, and reduce the cost of building materials. In this work, physical and mechanical properties of asphalt concrete mixture of grade I type B were researched. To improve the performance characteristics of asphalt concrete oil sludge from oil company Zhaik Munay LLP (Uralsk) was used as an additive. Oil sludge was added to the asphalt concrete mixture in amounts of 5, 10 and 15%. When using 5% oil sludge, no significant changes in the properties of asphalt concrete are observed. An addition of 15% of oil went to the reduction of maximum efficiency during compression (0.03% by volume) and shear resistance by the efficiency of internal friction coefficient (0.01% by volume). The optimal amount is to use 10% oil sludge, at the same time, the compressive strength increases by 0.07% by volume, water resistance increases (0.02% by volume), water saturation decreases by 0.28% by volume, which has a positive effect on the quality of asphalt concrete. The properties of asphalt concrete before and after adding oil sludge were studied: compressive strength, water resistance, water saturation, shear resistance. It was concluded that it is advisable to use oil sludge as an additive. A technology for producing asphalt concrete mixture using oil sludge has been developed, which allows reducing its cost.

Evaluation of Properties of Asphalt Concrete Mixture Using Basalt Aggregate from Jeju Island

In this study, the engineering properties of basalt aggregate used for asphalt road pavement on Jeju Island were evaluated, and the characteristics of the asphalt mixtures used were evaluated to assess the suitability of Jeju Island basalt as road construction material. Chemical composition and surface morphology analysis of the basalt and granite aggregate, engineering characteristics analysis, and filler property evaluation were performed. Mix design was performed, and the basic properties of three asphalt mixtures for the surface, intermediate, and base layers were evaluated. Permanent deformation resistance was evaluated through a wheel tracking test, and moisture resistance was evaluated through a dynamic immersion test and a tensile strength ratio test. The optimum asphalt contents of the asphalt mixture using low-porosity basalt aggregate and high-porosity basalt aggregate were determined to be 5.7% and 5.9% in the surface layer, 5.3% and 5.4% in the intermediate layer, and 4.7% and 5.1% in the base layer, respectively. It was found that the basic properties of the asphalt mixtures satisfied Korean quality standards. The dynamic immersion test results of low-porosity basalt aggregate and high-porosity basalt aggregate were 20% and 10%, respectively, which fall far below the quality standard of 50%. The tensile strength ratios of the basalt asphalt mixtures for the intermediate layer were 0.69 and 0.40, and they were found to increase significantly to 0.87 and 0.80 after the application of a suitable anti-stripping agent. Therefore, it was concluded that in order to apply Jeju Island basalt to asphalt pavement, an appropriate anti-stripping material must be applied.

Effect of Waste Iron Powder on Properties of Asphalt Concrete Mixtures: State of the Art

Effect of Waste Iron Powder on Properties of Asphalt Concrete Mixtures: State of the Art

Second Life for Plastic Fibre Waste Difficult to Recover: Partial Replacement of the Binder in Asphalt Concrete Mixtures by Dry Incorporation.

In previous studies, different additives and modifiers have been studied to improve the properties of asphalt concrete mixtures, whose main failures are plastic deformation and cracking. In this research, the improvement of the properties of asphalt concrete mixtures were investigated by introducing residual plastics as a substitute for virgin bitumen, which improves the sustainability of the mixtures. Furthermore, the results obtained from these new mixtures were compared with a mixture designed with polymer-modified bitumen (PMB). Ten experimental designs were tested with three types of waste fibre plastics from a municipal solid waste treatment plant and two percentages of bitumen replacement (15% and 25%). The experimental testing plan included air void characterization, moisture sensitivity, stiffness and fatigue resistance, among others. An increase of approximately 5% in voids could be observed when introducing the plastic material and therefore some tests were carried out to over-compact the specimens. The results showed an improvement in the mechanical performance of the experimental mixtures, highlighting the resistance against plastic deformations, which even reached similar values to the mixtures made with PMB.

ОСОБЛИВОСТІ ТЕРМОНАПРУЖЕНОГО СТАНУ АСФАЛЬТОБЕТОННОГО ДОРОЖНЬОГО ПОКРИТТЯ З ГУМОВИМИ ВКЛЮЧЕННЯМИ

Introduction. According to international estimates [18], 1.5 billion worn tires go to waste every year in the world. A significant part of them is stored in landfills, buried in the ground or burned, thus polluting the air, wastewater and soil with harmful and poisonous gases, as well as liquid and solid fractions. At the same time, rubber has a number of useful and valuable substances for the industry, the recycling of which will allow to significantly reduce environmental pollution and obtain material benefits. In addition, worn tire material has a number of unique thermomechanical properties attractive for industrial applications, including low density, good thermal and electrical insulating properties, mechanical elasticity and strength, etc. One of the promising directions of recycling worn tires is their use as admixtures in asphalt concrete materials for road surfaces. However, as field tests have shown, the mechanical properties of such materials largely depend on impurities in the material and modification of their properties by the bitumen fraction. Since these issues have not been sufficiently analyzed in the scientific environment, the problem of their study is urgent. Problems. The problem of recycling the material of worn car tires in road construction is largely limited by the instability of the thermomechanical properties of asphalt concrete mixtures with rubber crumb admixtures depending on its grain size, the percentage of its volume inclusions and the level of bitumen modification. Establishing rational parameters that characterize these factors can be implemented by mathematically solving the problem of the thermally deformed state of the road surface using methods of the theory of thermoelasticity. Purpose. The purpose of the article is to determine the reasons leading to a violation of the strength of asphalt concrete materials with admixtures of rubber crumb. For this purpose, the influence of the incompatibility of thermomechanical characteristics (moduli of elasticity, Poisson’s ratios and coefficients of thermal expansion) of bitumen and rubber on the concentration of additional internal thermal stresses in the system caused by seasonal and daily temperature changes is analyzed. Materials and methods. Mathematical modeling methods are used to conduct research using the main provisions of the theory of thermoelasticity. It is believed that bitumen is an elastic medium, which includes a rubber crumb modeled by an elastic ball. Equations of thermoelastic equilibrium of the system when its temperature changes are formulated, boundary equations and conditions of elastic interaction of the bituminous medium and rubber inclusion on their contact surface are formulated. Using the methods of analytical transformations, the solutions of these equations were built in a closed form, which allow determining the thermal stress in both fractions of the system and their dependence on the values ​​of the parameters of thermoelasticity. The principle of correspondence of the solutions of problems of the theory of elasticity and viscoelasticity is formulated, which allows to use the obtained solutions for the analysis of the thermal strength of real asphalt concrete road surfaces. The results. In the work, the reasons for the low thermal strength of bituminous materials with inclusions in the form of rubber crumbs were revealed using mathematical modeling methods. It is shown that it is related to the thermoelastic incompatibility of bitumen and rubber, which is due to the practical volumetric incompressibility of rubber and the difference in the values ​​of the thermal linear expansion coefficients of these materials. The positive role of modifying rubber with bitumen is noted, which allows to reduce the thermoelastic incompressibility of these materials and the resulting concentration of thermal stresses on the contact surface of bitumen and rubber grain. Conclusions. With the help of a theoretical analysis of the thermoelastic state of bituminous material with rubber inclusions, the reason for the concentration of thermal stresses on the contact surface of these fractions, which is caused by the incompatibility of their thermoelasticity parameters, has been established. The obtained results allow establishing ways of rational modification of rubber with bitumen, which make it possible to increase the thermal strength of road surfaces in conditions of seasonal and daily temperature changes and thereby increase their durability.

EVALUATION OF MARSHAL STABILITY AND FLOW OF HYBRID MODIFIED ASPHALT CONCRETE

Highway engineers and researchers are constantly trying to enhance the performance of asphalt concrete pavement, in order to keep up with the global adequate and sustainable highway infrastructure drive. Modification of asphalt concrete could improve certain properties of the mixture and reduce cost of road construction materials. In this research, evaluation of Marshal Stability and flow of hybrid asphalt modified concrete was studied, the wastes from various industries such steel industry, plastic industry and coal-fired power plant industries were combined together to form hybrid composite. Steel slag, fly ash, waste plastic, aggregate and bitumen were used to produce the asphalt concrete in a hybrid manner to evaluate effect of stability and flow properties of asphalt concrete mixture. The physical properties of steel slag, fly ash aggregate, bitumen and waste plastic based polypropylene were determined by carrying out tests such as sieve analysis, moisture content, flakiness and elongation, aggregate impact, aggregate crushing, specific gravity, hygrometer, penetration, softening point, flash and fire point, viscosity, ductility and water-in-bitumen test. Bitumen with penetration grade 60/70 was used and the content varied from 5.0 to 7.0 % at 0.5% interval. A cylindrical sample with the composite mixture of asphalt concrete was produced using varying proportions of hybrid composite which comprises of steel slag (SS) and fly ash (FA) at 2%, 4%, 6% and 8% by weight of the asphalt concrete to partially replace the conventional materials (aggregate and filler) and bitumen which was partially replaced with polypropylene (PP) at 5%, 10%, 15% and 20% respectively. The Marshal Stability test conducted on the hybrid composite asphaltic concrete gives optimum stability values of 10.50 kN, 12.50 kN, 12.30 kN and 13.50 kN and optimum flow values of 3.30 mm, 2.80 mm, 2.80 mm, and 2.70 mm at 2%, 4%, 6% and 8% respectively. Comparing with Asphalt Institute specification, the non-conventional material used as fillers, coarse and fine aggregate can be conveniently used in light, medium and heavy traffic. Based on the findings, the application of these wastes material which constitute higher stability and flow will improve the properties of asphalt concrete, reduce the cost of constituent material and decrease environmental problem that arise from various industries.

Spherical indentation test for quasi-non-destructive characterisation of asphalt concrete

The indentation test is a promising technique for the viscoelastic characterisation of asphalt concrete (AC). Indentation measurements are primarily influenced by the material properties in the direct vicinity of the indenter-specimen contact point. Accordingly, it may become a useful alternative for the characterisation of thin asphalt layers as well as for a quasi-non-destructive AC characterisation in the field. In this study, the spherical indentation test is used to measure the linear viscoelastic properties of AC mixtures extracted from a road test section. The measured complex moduli are compared to those obtained by the shear box test and are found to exhibit a linear correlation. The measurements are further analysed using the Gaussian mixture model to assign each indentation test to either aggregate-dominated or mastic-dominated response. The measurements attributed to mastic-dominated response are found to be more sensitive to the temperature and AC’s binder properties as compared to the average measurements. Accordingly, the proposed test method may provide a promising tool to measure AC viscoelastic properties and monitor the changes in AC binder phase in a non-destructive manner. A finite element micromechanical model is used to identify a representative scale for the response measured in mastic-dominated tests as well as to quantify the effect of measured properties on the AC damage propensity.

Evaluation on Mechanical Deterioration of the Asphalt Mixtures Containing Waste Materials When Exposed to Corrosion Solutions

This research investigates the effect of corrosion solutions on the mechanical properties of asphalt concrete mixtures. A control asphalt mixture (CM) and five polymer-modified (PM) or filler-modified (FM) mixtures containing waste materials are prepared, namely PM high-density polyethylene plastic (PM-PL), PM crumb rubber (PM-CR), FM Para wood ash (FM-PA), FM palm empty fruit bunch ash (FM-EA), and FM rice husk ash (FM-RA). The experiment is conducted by immersing the mixture specimens in four types of water solutions (i.e., distilled water, alkaline solution, sulfate solution, and acid solution), followed by the splitting tests. Finally, the corrosion resistance factor (fc) is computed to assess the corrosive effect of the corrosion solutions. The results show that the degree of reduction in tensile strength mainly depends on the type of corrosion solutions, type of mixtures, and immersion time. FM-EA provides better resistance under the alkaline and acid solutions, while PM-PL exhibits the greatest fc under the sulfate solution. Among all the mixtures, PM-PL shows the greatest ability in withstanding the corrosion solutions.

Microstructural integrity characterization of cement-based construction materials

In this paper, a new micromechanical framework to characterize the microstructural integrity and predict the effective properties of multi-phase particulate composites is presented. Within the framework, a new scalar micromechanical parameter is identified and used to derive new expressions for the effective elastic properties of particulate composites using the mean-field homogenization technique. The derived equations are then generalized for composites with multiple phase constituents. The generality of the proposed framework is demonstrated by combining the derived equations with the existing homogenization techniques such as the Mori–Tanaka method and the Generalized Maxwell’s Approach (GMA). The results show that the theory delivers consistent estimates of the effective properties of two-phase elastic composite materials. The new scalar micromechanical parameter is also used to characterize the microstructural integrity of both asphalt mixtures and Portland cement concrete. The results show that the new scalar micromechanical parameter correlates well with multiple key fundamental properties of asphalt concrete mixture, including the creep rate, the fracture energy density, the endurance limit, and the damage rate parameters. The results also show that the new micromechanical framework can be used to accurately predict the effective modulus properties of Portland cement concrete mixtures.

Influence of Temperature on Mechanical Properties of Asphalt Concrete Mixture

Asphalt binder is a thermoplastic material that conducts as an elastic solid at lower service temperatures or throughout fast loading rate. At a high temperature or slow rate of loading, asphalt binder conducts as a different liquid. The classical duplication generates a required to assess the mechanical properties of asphalt concrete at the anticipated service temperature to reduce the stress cracking, which happens at lower temperatures, fatigue, and the plastic deformation at higher temperatures (rutting). In this study, an achievement was made to assess the effect of temperature on the mechanical characteristics of asphalt concrete mixes. A total of 132 asphalt concrete samples were attended utilizing two asphalt cement grades (40-50) and (60-70), and one aggregate gradation (type III A for wearing course) SCRB (R/9, 2003). The specimens were then tested at five different temperatures represented by 5, 15, 25, 40, and 60 °C to estimate their mechanical characteristics, including resilient modulus (Mr), permanent deformation, and fatigue features as Marshall features. The average resilient modulus (Mr), which belongs to a temperature of 5°C, was 328036 psi revealing an approximate loss of 88% of its strength in resilient modulus when there is an increase in temperature over 60°C. Meanwhile, there is an increase in the permanent deformation accumulation rate (slope value) of about three folds as the temperature changes from (5-60) °C whereas the fatigue life reduces 32 % with the rise in temperature from (5-25) °C.

Investigating the Effect of Olive Husk Ash on the Properties of Asphalt Concrete Mixture

Technology in transportation used available resources to make it safe, fast, suitable, easy, economic, and environmental to transport people and goods. Olive Husk became an environmental problem as waste materials especially in the Middle East where huge quantities are found. The objective of this research is to investigate the effect of addition of Olive Husk Ash (OHA) on the properties of asphalt concrete mixtures. Marshall Test was used to perform the asphalt concrete mixture by the addition of OHA to the binder of asphalt; different percentages of OHA (0, 5, 10, 15, and 20%) by volume were added to the binder. Five percent of asphalt cements (5, 5.5, 6, 6.5 and 7%) by weight and limestone aggregate were used for preparing asphalt mixture specimens to find the optimum content of asphalt that could be used in the binder. Tests on flow, stability, air void percentage and void in mineral aggregate, retained stability, stiffness, and retained stiffness were made. The principle results on OHA as filler in Asphalt binder improves the Marshall Stability, and void in mineral aggregate and decrease in flow, retained stability, stiffness, and retained stiffness with a 10%-15% of olive husk ash replacement of asphalt binder. The contribution that OHA could be used as a pavement construction material in field.

ПОВЫШЕНИЕ УСТОЙЧИВОСТИ ЩЕБЕНОЧНО-МАСТИЧНОГО АСФАЛЬТОБЕТОНА К КОЛЕЕОБРАЗОВАНИЮ ЗА СЧЕТ ИСПОЛЬЗОВАНИЯ ПОЛИМЕРНЫХ МОДИФИКАТОРОВ

Rutting is an important problem in Russia today. One of the ways to improve the properties of asphalt concrete mixtures and reduce wear on road surfaces is to modify the binder with polymer additives. The aim of the work was to test the selected compositions of MMAC mixtures containing bitumen modified with the addition of sevilene and rubber for rutting resistance, which make it possible to predict the formation of plastic rut. It was revealed that when using sevilen in its composition, with an increase in the concentration of vinyl acetate, the depth of the track increases in comparison with the industrial polymer-bitumen binder. It is shown that with the introduction of a complex additive based on sevilen and rubber into the binder composition, its rutting decreases and the service life of the road surface increases, which indicates a high elasticity of the complex-modified binder. In this work, the calculation of the service life of the coating before the formation of a critical rut requiring repair of the coating is carried out. It was found that in terms of the slope of the rutting curve and the proportional depth of the rut, the compositions with sevilene and rubber are not inferior to traditional industrial PBB.

Role of Aggregate Gradation in Balancing the Performance of Asphalt Concrete Mixtures

Improving the durability and long-term performance of asphalt concrete (AC) has become a major concern, especially with the increase in the use of recycled materials, warm mix asphalt additives and modified binders. This paper presents an evaluation of different mix design approaches to balance the mechanical properties of AC mixtures. The current volumetric-based design method was enhanced with a performance-based analysis methodology that specifies the parameters from the overlay tester, Hamburg wheel tracking device and indirect tension tests. Two typical Superpave mixes from different plants that exhibited a poor performance, especially in cracking, were selected for this evaluation. The mixtures were first designed following the current volumetric-based design process and characterized under the proposed performance-based analysis. Two alternative approaches that consider the influence of the asphalt content and the aggregate gradation were explored to improve the engineering behavior of the mixtures. From this evaluation, two mixtures that could potentially yield optimal volumetric and balanced mechanical properties were developed. The optimization of the aggregate gradation is a promising approach to formulate a mixture with a balanced stability and durability, as judged by its rutting and cracking potentials.

Extending the service life of asphalt concrete pavements through the addition of conductive metallic waste particles for induced crack healing

ABSTRACT This paper investigates the potential application of a metallic waste addition obtained from the cutlery industry to improve the electrical conductivity and allow crack healing of asphalt concrete mixtures through electromagnetic induction heating. The effects of three different metallic waste content on the physical and mechanical properties of asphalt concrete mixtures have investigated. The crack healing potential by electromagnetic induction heating has been assessed in fully and partially cracked asphalt concrete specimens to simulate preventive and corrective maintenance. The crack healing potential has been evaluated through the results of load versus displacement curves obtained through SCB tests, based on a fracture-based approach by the ratio of fracture strength recovery after electromagnetic induction heating. Potential benefits such as simple mixing process and the possibility of using habitual design methods with satisfactory physical and mechanical properties can be achieved by using 10% of metallic waste by volume of bitumen added to asphalt concrete mixtures. The addition of metallic waste modified the fracture behaviour of the asphalt concrete mixtures, which indicates that after crack healing, samples may present a loss of ability to resist crack propagation. Healing indexes of 0.77 and 0.83 obtained for fully and partially cracked specimens produced with 10% of metallic waste by volume of bitumen.

Influence of short term oven aging on volumetric properties of asphalt concrete mixture containing modified Buton asphalt and limestone powder filler

In an effort to develop the use of modified Buton asphalt (MBA), this study designed a concrete asphalt mixture using the MBA as the main binding material and modified it with limestone powder fillers to produce concrete asphalt that has good resistance to aging. Short-term aging test was simulated in the laboratory on a loose mixture. The volumetric void in mixture (VIM), void in mineral aggregate (VMA) and void filled asphalt (VFB) values were evaluated on compacted specimens and had experienced STOA. Based on VIM, VMA and VFB values, it can be noted that mixture that only used MBA or mixture that combined MBA and limestone powder can provide resistance to bleeding or cracking, sufficient durability and stable interface adhesion between asphalt films and aggregate surfaces.

The Effect of Using Sustainable Materials on the Performance-Related Properties of Asphalt Concrete Mixture

Sustainability is very important in this world at this time. One of the best materials used for sustainability in asphalt concrete pavements is the warm mix asphalt (WMA) as well as the reclaimed asphalt pavement (RAP). WMA technology has the ability to reduce production temperature to reduce the fuel usage and emissions. RAP is the old concrete asphalt mixture that is out of service and using it again leads to preservation of the virgin material. This search studied the viability of using WMA with different percentages of RAP (10%, 30%, and 50%) and compared them with control hot mix asphalt (HMA) and WMA. The Marshall properties, Tensile strength ratio (TSR), rut depth and fatigue life were determined in this work. The results showed that the tensile strength ratio (TSR) for HMA was better than that for WMA by 6%, rut depth for HMA was (4.37 mm) lower than that for WMA was (6.5mm), better fatigue life was obtained for WMA was (700 cycle) as compared to HMA was (500 cycle). In case of WMA with RAP (WMA-RAP), when the percentage of RAP increased with WMA, the moisture damage resistance improved by 2.5%, 13.3% and 15.4% for G1, G3 and G5 respectively, also the rutting resistance improved by 34.6%, 48% and 62.3% for G1, G3 and G5 respectively, but deteriorated of fatigue life by 45.8%, 74% and 88.5% for G1, G3 and G5 respectively.

Laboratory investigation on the properties of asphalt concrete mixture with GGBFS as filler

Consuming of by product materials in build manufacture such as making of hot asphalt mixtures introduces worthy interest on the way of ecological, economic standpoint. Accordingly, in this experimenter research, it was scrupulous for using Ground Granulated Blast Furnace Slag (GGBFS) in state traditional metal filler in hot asphalt mixtures. The mechanical characteristic was rating by lineal Marshall Stability & Indirect Tensile Strength tests. However, moisture harm and long-range aging were investigated by locate Index of retained Strength (IRS) & Mean Marshall Stability Ratio (MMSR), respectively. The empirical outcomes have presented a considerable refinement in the mechanical properties and a fundamental promotion in durability of the generated mixtures i.e. Asphalt Concrete Mixtures with GGBFS as a mineral filler (GGBFSAC) in rapprochement with the control mixtures that were infectious by ordinary Portland cement (OPC) as a mineral filler (OPCAC). As an outcome of this research, GGBFS can be united in state classical mineral filler in asphalt concrete mixtures especially in region where there is large GGBFS waste.

Poisson’s Ratio of Asphalt Concrete Mixes Using Indirect Tensile Test

Abstract Increased interest in mechanistic evaluation of flexible pavement structures has brought a demand for accurate and practical methods, models, or both to estimate the mechanical properties of asphalt concrete mixtures. One of these properties is the Poisson’s ratio (ν) of asphalt concrete mixtures, which is often assumed to have a constant value of 0.35 in asphalt concrete evaluations. However, investigations have reported that mixture type, air void content, and temperature produce considerable variation in measured ν-values that could have a significant effect on evaluations of asphalt concrete mixes. The objective of this study was to evaluate the effect of air voids, binder type, and testing conditions on the measured ν-values. Indirect tensile (IDT) tests were conducted to measure ν-values. The study indicated that the Poisson’s ratio of the asphalt concrete mixes, on average, attained a maximum value at a particular level of air void content. Furthermore, when comparing the Poisson’s ratio values in relation to the dynamic modulus, calculated using the Mechanistic Empirical Pavement Design Guide (MEPDG) equation, higher ν-values were attained. This demonstrates the importance of measuring the Poisson’s ratio of a mix type.

Experimental Study of using Waste Glass as additives in Asphalt Concrete Mixtures

In road engineering, it is important to develop paving technology and improving asphalt pavement efficiency in terms of increasing their service life and reducing the damage caused by rutting, fatigue and thermal cracks. Waste glass can be used as asphalt modifiers, which can be add in certain properties to the asphalt mixture in ordered to modify some of the properties of the mechanical properties of asphalt concrete mixtures. The waste glass that is crushed can be used as a portion of fine aggregate in asphalt concrete mixtures. The aim of this research is to study the effect of using waste glass as asphalt concrete mixtures additives. From the review different portion of waste, glass can be used as asphalt concrete mixtures additives up to 15%. In this research fine natural aggregate replaced with crushed Waste glass in deferent percentage namely 6%, 9%, 12%, 15% and 18%. The mechanical properties of the glass-asphalt were evaluated using Marshall Stiffness, compressive strength and indirect tensile strength. Based on the results, it was found that 15% of crushed Waste glass improves the mechanical properties of asphalt concrete mixtures in the terms of Marshall Stiffness and compressive strength. On the other hand, no improvement in the tensile strength was noticed.

Experimental-Statistical Investigation of Testing Variables of a Semicircular Bending (SCB) Fracture Test Repeatability for Bituminous Mixtures

Abstract Given the fact that fracture is a primary distress causing pavement failure, it is important to identify and characterize the fracture/cracking properties of asphalt concrete mixtures and to include them in pavement design processes. This study examined the testing variables for a reliable and practical semicircular bending (SCB) fracture test to evaluate the fracture characteristics of asphalt concrete mixtures at intermediate service temperatures. An integrated experimental-statistical approach was employed to identify testing variables by which repeatable SCB test results can be achieved. Using a typical Nebraska asphalt mixture, five critical testing variables (i.e., the number of testing specimens, specimen thickness, notch length, loading rate, and testing temperature) of the SCB test were investigated due to their significant effects on mixture fracture characteristics. Statistical analysis of test results indicated that approximately six specimens/replicates were a reasonable sample size that could properly represent asphalt concrete fracture behavior of a typical dense-graded mixture. Then, the coefficient of variation (COV) of the mixture fracture energy for six specimens was used to evaluate the effects of other remaining test variables. A range of a specimen thickness of 40 to 60 mm, a notch length from 5 to 40 mm, and a testing temperature between 15 and 40°C showed the reasonably low COV value of fracture energy at around or less than 10 %. The loading rates (0.1 to 10 mm/min.) attempted in this study did not show any significant differences in the testing repeatability.