Nano-Scale Binder Phase Identification in Asphalt Concrete

Author(s):  
Hasan M. Faisal ◽  
Zafrul Hakim Khan ◽  
Rafiqul Tarefder

Asphalt concrete (AC) consists of asphalt binder and aggregate. Aggregate consists of: coarse aggregate and fines. Asphalt binder creates a coating or film around the aggregate, which is defined as the binder phase of AC. Fines are believed to be trapped inside an asphalt film or mixed with asphalt binder, creating a composite material called mastic. Thus, AC has three phases: mastic, asphalt film binder, and coarse aggregate. All these phases play major roles in performance of AC. Researchers have performed various tests on asphalt binder at micro scale to understand the macro scale behavior of AC. However, test methods developed and performed on binders, to this day, are mostly rheological shear and bending beam tests. No studies have been conducted on the compression stiffness or modulus and hardness of and binder, rather than shear and binders stiffness. In addition, the existing tests used in the asphalt area cannot be performed on binder and mastic while they are an integral part of AC. Nanoindentation tests can be performed on aggregate and asphalt binder while they are integral parts of AC. Because, in nanoindentation test, a nanometer size tip, which is smaller than binder film thickness as well as other phases. In the study, Performance Grade (PG) 64–28 was used for the study, same binder had been used afterwards to characterize asphalt and AC. A loading rate of 0.005 mN/sec, a dwell time of 200 sec and a maximum load 0.055 mN were employed in the study. In the current study 20 indentations were done on the asphalt binder sample and 100 indentations were done on AC sample, due to heterogeneity of the sample. However, to identify a specific phase in AC sample, the current study adopts the depth range technique for as same loading protocol. The depth rage of binder phase was acquired by independent indentation on same asphalt binder sample. As, asphalt is known to be a viscoelastic material that exhibits creep behavior, the creep compliance of asphalt binder was used for validation of the depth range assumption. The validation of phase identification was done by comparing the asphalt binder phase creep response while they are integral part of AC with creep response of independent asphalt binder sample under nanoindenter. The comparison shows depth resolution technique can successfully identify the binder phase of AC.

Author(s):  
Hasan M. Faisal ◽  
Zafrul Hakim Khan ◽  
Rafiqul Tarefder

Traditionally, mechanical properties of asphalt concrete (AC) is evaluated through macro-scale testing. However, when aggregates are mixed with asphalt binder, it creates a thin film of 20μm to 40μm around the aggregate particles and the primary strength of AC is derived from the interaction between the binder and aggregates. Therefore, to understand the behavior of asphalt concrete it is necessary to study the binder properties in a nanoscale. Nanoindentation test has been adopted to examine the thin film material property. In a nanoindentation test, a loaded nanoindenter is used to indent the sample surface and measure the indenter displacement as a function of load. To this day, most researchers have used the Oliver-Pharr method to analyze the indentation test data and obtain Elastic modulus (E) and hardness (H) of the material. Generally, in a nanoindentation test, there is a loading and unloading phase. In an elasto-plastic material, loading phase has elastic and plastic response and unloading phase has only elastic response. In Oliver-Pharr method, elastic modulus is obtained through the slope of the unloading curve. Therefore, Oliver-Pharr method mostly applicable for the elasto-plastic metals because it does not incorporate any viscous effect. However, in case of visco-elastic material like asphalt, during the unloading phase, the slope of the unloading curve becomes negative due to the viscous flow. Therefore, using Oliver-Pharr (OP) method in this circumstances will yield an inaccurate value of modulus of elasticity. In the current study, the test data was modeled and analyzed using a well-established spring-dashpot-rigid (SDR) model for viscoelastic material to determine the elastic, plastic and viscous properties. The model assumes the indenter displacement is a function of a quadratic spring, a quadratic dashpot and a plastic rigid body. The loading phase of the nanoindentation test has three contributing parameters: elasticity (E), indentation viscosity (η) and hardness (H). During creep, only contributing parameter is indentation viscosity (η) and while unloading the contributing factors are found to be E and η. Nonlinear least square curve fitting technique was employed to model the nanoindentation test data to the SDR model to find out the contributing parameters E, η and H. In addition, the extended dwell time on the asphalt binder samples produced positive load displacement curves, which were further analyzed with Oliver-Pharr method. Comparison between two models results show traditional Oliver-Pharr model predicts the material properties 5 to 10 times lower than SDR model, as Oliver-Pharr does not consider the viscous behavior in the material.


2019 ◽  
Vol 2 (2) ◽  
pp. 214
Author(s):  
Faisal Abdul Yusuf ◽  
Ahmad Ridwan ◽  
Yosef Cahyo Setianto Poernomo

Asphalt Concrete (Hotmix) is a mixture of coarse aggregate, fine aggregate, and filler (filler) with asphalt binder in high-temperature conditions (heat) with a composition that is examined and regulated by technical specifications. In this research, concrete asphalt mixture was added with dolomite powder as a  mixture in filler to be an alternative material for portland cement filler mixture to minimize the price of portal and cement, which is increasingly expensive, and brantas sand as fine aggregate to study and determine the effect of dolomite powder and brantas sand in the mixture asphalt concrete with the addition of levels of 5%, 10%, and 15%. From the results of the study obtained the value of adding dolomite powder with levels of 5%, 10%, 15% at VIM values of 11.99%, 15.28%, 10.29 , VMA value of 26.30%, 29.05%,  24.88%,  VFB  value  of  54.49%,  48.33%,  58.81%,  stability  value  of  3402.503  kg, 3294.030 kg, 1958.946 kg, MQ value 733,8130 kg, 456,1891 kg, 471,9089 kg and from the testing chart the optimum content is at levels 5.5% to 8% and the maximum level is at 5% level.Aspal  Beton  (Hotmix)  adalah  campuran  agregat  kasar,  agregat  halus,  dan  bahan pengisi (Filler) dengan bahan pengikat aspal dalam kondisi suhu tinggi (panas) dengan komposisi yang diteliti dan diatur oleh spesifikasi teknis. Pada penelitian ini, campuran aspal beton diberi bahan tambahan serbuk dolomite sebagai campuran pada filler agar menjadi bahan alternativ campuran filler semen portaland untuk meminimalisir harga semen portaland yang  semakin  mahal  dan  pasir  brantas  sebagai  agregat  halus  untuk  mempelajari  dan mengetahui pengaruh serbuk dolomit dan pasir brantas pada campuran aspal beton dengan penambahan kadar 5%, 10%, dan 15%.dari hasil penelitian didapat nilai penambahan serbuk dolomite dengan kadar  5%, 10%, 15% pada nilai VIM sebesar 11,99%, 15,28%, 10,29, nilai VMA 26,30%, 29,05%, 24,88%, nilai VFB 54,49%, 48,33%, 58,81%, nilai stabilitas 3402,503 kg, 3294,030 kg, 1958,946 kg, nilai MQ 733,8130 kg, 456,1891 kg, 471,9089 kg dan dari grafik pengujian kadar optimum pada kadar 5,5% sampai 8% dan kadar maximum pada kadar 5%.


Author(s):  
Zafrul Khan ◽  
Hasan M. Faisal ◽  
Rafiqul Tarefder

Fracture toughness and fracture energy release rate are two important parameters to understand the crack propagation within any material. Fracture toughness of asphalt concrete (AC) is vital to explain the fatigue cracking and low temperature cracking of asphalt pavement. These two types of distresses are still unsolved issues for asphalt researchers. Measuring fracture toughness of AC is not a new phenomenon. Recently, researchers have used several techniques to measure the fracture toughness of AC. Tests like semi-circular bending (SCB) and disk-shaped compact specimen (DCT) testing have been used to measure the fracture toughness of the AC. From the SCB or DCT tests, past researchers have shown that crack in AC propagates through mainly binder and mastic phase. All these conventional tests are carried out in macro scale. It is important to understand that before propagation of these macro scale cracks, the cracks initiates at the nano/micro scale level. With the increment of the loads these nanoscale cracks become macro scale cracks and propagates through the sample. Therefore, it is important to understand the cracks at nanoscale. In this study, nanoindentation test was introduced to measure the fracture toughness of the asphalt concrete. In a nanoindentation test, the sample surface is indented with a loaded indenter. For this test, Berkovich indenter with load control method was used. A field cored asphalt concrete sample was used for this study. The sample was collected by coring at interstate 40 (I-40) near Albuquerque, New Mexico. The sample was field aged for four years. The maximum load applied in this study was 5-mn and the unloading was done at a faster rate than the loading rate. From the load-displacement curves of the nanoindentation tests, fracture toughness of the samples was measured. The unloading curve of the nanoindentation test was further used to obtain reduced modulus of the asphalt concrete using Oliver-Pharr method. In this study, fracture energy is thought of as a portion of irreversible energy. This irreversible energy is comprised of plastic energy and energy required for propagation of crack. By analyzing the load displacement curve along with the maximum indentation depth, energy release rate and mode I fracture toughness of asphalt concrete was measured.


2019 ◽  
Vol 2 (1) ◽  
pp. 154
Author(s):  
Supriadi Supriadi ◽  
Yosef Cahyo ◽  
Ahmad Ridwan ◽  
Agata Iwan Candra

Asphalt Concrete (Hotmix) is a mixture of coarse aggregate, fine aggregate and filler (Filler) with asphalt binder in high temperature conditions with the composition studied and regulated by technical specifications. In this study, asphalt concrete mixtures were given materials additional padas. This addition was carried out to study and determine the effect of padas on the asphalt concrete mixture with the addition of 5%, 10%, and 15%. Compressive strength specimens in the form of cylinders with a diameter of 10.09 cm and an average height of 7.8 cm. Testing is done after 2 days. Asphalt with the addition of 5% padas is better able to produce a better value of stability than others. The addition of padas rock produced a strong stability of 5% at 888.0747 kg, 10% at 598,199 kg, 15% at 441,6391 kg. To reach the optimum level, the mixture on concrete asphalt ranges < 5%Aspal Beton (Hotmix) adalah campuran agregat kasar, agregat halus, dan bahan pengisi (Filler) dengan bahan pengikat aspal dalam kondisi suhu tinggi (panas) dengan komposisi yang diteliti dan diatur oleh spesifikasi teknis.. Pada penelitian ini, campuran aspal beton diberi bahan tambahan batu padas. Penambahan ini dilakukan untuk mempelajari dan mengetahui pengaruh batu padas pada campuran aspal beton dengan penambahan 5%, 10%, dan 15%. Benda uji kuat tekan berupa silinder dengan diameter 10,09 cm dan  tinggi rata rata 7,8 cm. Pengujian dilakukan setelah 2 hari. Aspal dengan  penambahan batu padas 5% lebih mampu menghasilkan  nilai stabilitas yang lebih baik dari pada yang lainya. Penambahan batu padas menghasilakan  kuat stabilitas masing masing yaitu 5% sebesar 888.0747 kg, 10% sebesar 598.199 kg, 15% sebesar 441.6391 kg. Untuk mencapai kadar optimum maka campuran padas pada aspal beton berkisar antara < 5%


2019 ◽  
Vol 2 (2) ◽  
pp. 256
Author(s):  
Satria Arung Bangun Samodera ◽  
Yosef Cahyo Setianto Poernomo ◽  
Ahmad Ridwan ◽  
Agata Iwan Candra

Asphalt Concrete is a mixture of coarse aggregate, fine aggregate, and filler (Filler) with asphalt binder in high-temperature conditions with the composition regulated. This study uses three types of additions samples of red brick powder on concrete asphalt with a mixture of 5%,10%, and 20%. Each test results decreased with the addition of red brick powder among others 5% of 289,992 kg, 10% of 2248,822 kg, 20% of 1574,782,and produce volume of air cavity to mixture (VIM) with a level of 5%,10%,20% wich are among others 8,481%, 9,444%, 8,334%, and produce pore volume between aggregate (VMA) and levels of 5%,10%,20%,which are among others 22,575%, 23,390%, 22,450%, and produce pore volume between aggregate grains filled with asphalt (VFB) with levels of 5%,10%,20%, among others 62,575%, 59,903%, 62,897%, and produced a marshal question (MQ) with a 5% content of 942 kg/mm, 10% at 632 kg/mm, 20% at 378 kg/mm. To achieve optimum levels, the mixture of red brick powder on asphalt concrete ranges < 5%.Aspal Beton merupakan campuran agregat kasar, agregat halus, dan bahan pengisi (Filler) dengan bahan pengikat aspal dalam kondisi suhu tinggi (panas) dengan komposisi yang diatur. Penelitian ini mengunakan tiga jenis sampel penambahan serbuk batu bata merah pada aspal beton dengan campuran 5%,10%,dan 20%.Hasil pengujian masing masing mengalami penurunan dengan penambahan serbuk batu bata merah yaitu antara lain 5% sebesar 289,992 kg,10% sebesar 2248,822 kg,20% sebesar 1574,782,dan menghasilkan volume rongga udara terhadap campuran (VIM) dengan kadar 5%,10%,20% yaitu antara lain 8,481%,9,444%,8,334%,dan menghasilkan volume pori antara butir agregat (VMA) dengan kadar 5%,10%,20% yaitu antara lain 22,575%,23,390%,22,450%,dan menghasilkan volume pori agregat yang terisi aspal (VFB) dengan kadar 5%,10%,20% yaitu antara lain 62,575%,59,903%,62,897%,dan menghasilkan marshal quotient (QM) dengan kadar 5% sebesar 942 kg/mm,10% sebesar 632 kg/mm,dan 20% sebesar 378%. Untuk mencapai kadar optimum maka campuran serbuk batu bata merah pada aspal beton berkisar antara < 5%


Author(s):  
Tongyan Pan ◽  
Erol Tutumluer ◽  
Samuel H. Carpenter

The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Ning Tang ◽  
Kaikai Yang ◽  
Wenhao Pan ◽  
Limei Wu ◽  
Qing Wang ◽  
...  

Piezoelectric material has excellent characteristics of electromechanical coupling so that it could be widely applied in structural health monitoring field. Nondestructive testing of piezoelectric technique becomes a research focus on piezoelectric field. Asphalt concrete produces cumulative damage under the multiple repeated vehicle load and natural situation, so it is suited material and structure for nondestructive application. In this study, a test system was established by driving power of piezoceramic, laser displacement sensor, computer, and piezo-embedded asphalt concrete. Displacement, hysteresis, creeps, and dynamic behavior of KNN piezoceramic element embedded in asphalt concrete were tested. The results indicate that displacement output attained 0.4 μm to 0.7 μm when the loads were from 0 N to 150 N. The hysteresis was not obvious when the load was from 0 N to 100 N, aside from higher loads. The creep phenomenon can be divided into two parts: uptrend and balance. The more serious the asphalt binder ageing is, the larger the displacement is, when piezo-asphalt concrete has already been in serious ageing.


Author(s):  
Jhony Habbouche ◽  
Ilker Boz ◽  
Benjamin Shane Underwood ◽  
Cassie Castorena ◽  
Saqib Gulzar ◽  
...  

The objective of this paper is to provide information from multiple perspectives on the current state of the practice with regard to using recycled materials and recycling agents (RAs) in asphalt concrete mixtures. This information was collected through a survey of U.S. transportation agencies and RA suppliers combined with a search of RA-related specifications and pilot projects previously constructed. Moreover, a case study describing the Virginia Department of Transportation’s experience with RAs provides a tangible example of how at least one agency is approaching the potential implementation of these technologies. This practice review was achieved by documenting the experience, lessons learned, and best practices of multiple asphalt experienced contractors and asphalt binder suppliers in the Virginia area. This paper follows a similar survey conducted in 2014 as part of NCHRP 09-58 and provides a second look at the use of RAs across North America. Not all state departments of transportation have experience with using RAs. Factors preventing the use of RAs included specification limitations, lack of expertise in processing recycled materials, supporting data, and negative prior experiences. Developing a performance-based testing framework is mandatory for the successful use of RAs. In general, good and frequent communication with the RA supplier is critical and necessary during the planning stages, the production of mixtures, and the continuous quality control by the supplier to resolve issues when they arise. Finally, a strong quality control and quality assurance-testing program should be implemented to ensure that materials meet the properties needed to produce a good-performing mixture.


2014 ◽  
Vol 488-489 ◽  
pp. 550-553
Author(s):  
Xing Song Cao ◽  
Dong Wei Cao ◽  
Shi Xiong Liu ◽  
Xio Qiang Yang ◽  
Lin Lan

A novel high durability epoxy asphalt concrete for bridge deck pavements is introduced in this paper, including the manufacturing process of epoxy asphalt binder and laboratory evaluation for this material. Various laboratory tests were conducted to evaluate the pavement performance of the materials, such as fatigue test, wheel tracking test, moisture susceptibility test and thermal stress restrained specimen test. Test results show that epoxy asphalt concrete has 20137 cycles/mm dynamic stability at 70°C, and-28.4 °C fracture temperature. The fatigue equations of epoxy asphalt concrete at different temperatures were obtained. Findings from the research indicate that the epoxy asphalt concrete is a suitable material for the pavement of long-span steel bridges in China due to its profound performance.


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