For the purpose of researching on the applicability of BTNE in the field of transport Works, the thesis focuses on the component, mechanical properties, technical standards and the workability of BTNE.
MINISTRY OF EDUCATION AND TRAINING UNIVERSITY OF TRANSPORT AND COMMUNICATIONS TRAN THI CAM HA RESEARCH ON COMPONENTS, MECHANICAL PROPERTIES AND THE APPLICABILITY OF EPOXYBITUMEN BINDER FOR ASPHALT MIXTURES IN VIETNAM Field of study: Transport engineering Code : 9580205 Speciality: Highway and urban road engineering SUMMARY OF DOCTORAL THESIS HANOI – 2020 This research is completed at: University of transport and communications Supervisors: AssocProf.Dr Tran Thi Kim Dang University of Transport and Communications Prof.Dr Bui Xuan Cay University of Transport and Communications Reviewer 1: Prof.Dr Nguyen Xuan Truc Reviewer 2: Prof.Dr Nguyen Thuc Tuyen Reviewer 3: Prof.Dr Pham Cao Thang The thesis will be defended before Doctoral-Level Evaluation Council at University of Transport and Communications at …… on …….th …… 2020 The thesis can be read at: National Library of Vietnam Library of University of Transport and Communications AUTHOR’S PUBLICATION LIST Tran Thi Cam Ha, Tran Thi Kim Dang (2017), “A study on several mechanical properties of epoxy bitumen”, Transport Journal No 5/2017 Tran Thi Cam Ha, Bui Xuan Cay (2018), “Experimental research on static elastic modulus and flexural strength of epoxy asphalt concrete”, Transport Journal No 5/2018 Tran Thi Cam Ha (2018), “Experimental research ondynamic shear modulus of bitumen- epoxy”, Transport Journal No 11/2018 Tran Thi Cam Ha, Nguyen Quang Tuan, Tran Anh Tuan, Hoang Viet Hai (2018), “Shear behavior of epoxy asphalt concrete coating and epoxy adhesive on steel deck”, Transport and Communication Science Journal No 66 INTRODUCTION I Research background In fact, the use of asphalt pavements on main national road in Vietnam showed that there was a lot of premature deterioration of asphalt pavements such as rutting in National road No.5, National road No.1, East – West boulevard, the access road to Thanh Tri bridge, Ring road No.3; the deterioration of the overlay on Thanglong bridge; deep rutting on the road linked to Cat Lai port This deterioration greatly affected the socio-economic development, so the government had to spend a lot of money to repair these deterioration Moreover, this also affects the physical and mental well -being of road users In many countries in the world such as UK, USA, Japan, Ukraine , the research and the use of modified asphalt mixtures with epoxy-bitumen binder as the surface layer for heavy roads and steel bridges have achieved good results These modified asphalt surface significantly reduced the deterioration compared with asphalt pavements using conventional bituminous binders Vietnam has also had a project using epoxy asphalt concrete (BTNE) as the surface of Thuan Phuoc bridge – Danang city Unfortunately this first application was not successful This epoxy asphalt concrete surface on Thuan Phuoc bridge has therefore been replaced almost entirely by the modified asphalt mixture (BTNP) using polymer modified bitumen The researches about this material before applying for Thuan Phuoc bridge were also quite limited Currently, in Vietnam, epoxy can be supplied by domestic and foreign suppliers, but there has not been any study about the applicability of epoxy bitumen binder for modified asphalt mixtures Therefore, the thesis "Research on components, mechenical properties and the applicability of epoxy-bitumen binder for asphalt mixtures in Vietnam” is scientific and practical II Research objective For the purpose of researching on the applicability of BTNE in the field of transport Works, the thesis focuses on the component, mechanical properties, technical standards and the workability of BTNE III Reseach contents The thesis contents include: Overview study of BE and BTNE; Empirical research to determine the properties of BE materials, evaluate the applicability of BE binders for BTNE mixtures using in road pavement structures; analysis and selection of epoxy content for BE binder for BTNE mixtures; Empirical research in the laboratory to determine the physical and mechanical properties of BTNE as a basis for assessing the applicability and scope of use of BTNE materials; Proposing some typical pavement structures using BTNE material as surface layers IV Scientific and practical contribution Scientific contribution: The thesis studies mechanical properties of BE binder and BTNE mixture, analyzes the advantages and disadvantages and the scope of application of this new material in Vietnam conditions Systematizing testing standards for quality assessment of BE binder and BTNE mixture Practical contribution: Based on experimental research results of BTNE mixture compared with other types of asphalt mixtures, thereby proposing the method of designing mixed components, proposing experiment al standards for quality assessment of BTNE mixture; From mechanical properties of BTNE, the thesis proposes some road pavement structures using BTNE surface course in Vietnam CHAPTER LITERATURE REVIEW Chapter provides an overview of the use of BE and BTNE as the basis for the selection of epoxy for empirical studies in the following chapters 1.1 Epoxy bitumen and epoxy asphalt mixture 1.1.1 Overview of additives to improve the performance of bitumen Main components of modified bitumen are bitumen and additives The additives using for bitumen includes basic groups: non-polymer, polymer and the chemical additive (create chemical reactions when blending) The types of polymer additives is shown in Table 1-1 1.1.2 Epoxy resin Epoxy resins are a class of thermoset materials – transformed into solid form under the action of heat or a chemical reaction that is then not melted or dissolved again Epoxy offer high strength, low shrinkage, excellent adhesion to various substrates, chemical and solvent resistance and low toxicity Epoxy resins are used as glues, coatings, packaging, molding materials and adhesives, etc An epoxy resin are made by mixing three basic components: basic resin (main resin), curatives, and the modifiers For a simple mixing formula, an epoxy resin only includes a single epoxy resin and curative Other formulas can include various epoxy resins, modifiers and a combination of curatives 1.1.2.1 Basic resin (main resin) The term “epoxy resin” describes a broad class of thermosetting polymers in which the primary cross linking occurs through the reaction of an epoxy group In general, an epoxy resin can be thought of as a molecule containing a three-membered ring, Fig 1-1 Basic chemical consisting of one oxygen atom and two carbon structure of epoxy group atoms (Fig 1-1) Two branches connected to two carbon atoms of the ring can be very diverse, thereby creating different types of epoxy resins 1.1.2.2 Epoxy Resin Curatives Epoxy resins will react with a large number of chemical species called curatives or hardeners The most commonly used chemical classes of curatives are amines, amine derivatives, and anhydrides Cure times can range from seconds to days, even months to years at room temperature The materials have been separated into the general categories of room temperature cure, room - or elevated-temperature cure, elevated temperature cure, and miscellaneous curatives 1.1.3 Epoxy bitumen Epoxy bitumen (BE) is a two-component (two-phase) chemical system in which a part is thermoset epoxy (continuous phase) mixed with ordinary bitumen (dispersed phase) Bitumen is a heat sensitive adhesive, which becomes flexible when heated and hardens when cooled Epox y is a thermoset material that becomes permanently hard after curing Epoxy bitumen is a thermosetting material that has both the rigidity of epoxy and the flexibility of bitumen The percentage of epoxy in BE usually ranges from 15% to 50% by weight 1.2 Studies of epoxy-bitumen (BE) and epoxy asphalt mixture in the world A lot of studies about BE and BTNE have been done around the world For example, the BE pilot project with the participation of countries including Denmark, France, Germany, New Zealand, Ukraine, United Kingdom and USA was implemented from 2006 to 2008; the research project of BTNR using local materials in China in 2002; Studies about BE and BTNE in Japan in the late 70s of the 20th century These studies have shown that BTNE material has high fatigue resistance (10 times higher than conventional asphalt concrete BTN), high rutting resistance (almost no rutting in wheel track tests), good tensile strength and good anti-skid resistance 1.3 Some applications of BTNE all over the world BTNE mixture can be used as an overlay on the bridge deck, surface layer of long life pavements, airport runway pavements, roads on port area, asphalt surface layer for inproving pavement texture 1.4 Some researches and applications in Vietnam Until now, Vietnam also has the project “Thuan Phuoc Bridge - Da Nang city” which used BE and BTNE The overlay on the steel plate deck is a 41mm thick BTNE layer The water-proof layer use a type of BE binder which is also an adhesive layer between the steel plate surface and the above BTNE layer BE used in the project is Epoxy Asphalt Id of Chemco System (USA) Thuan Phuoc Bridge was opened to traffic on July 14, 2009 By the hot season of 2013, the asphalt overlay on the bridge deck was seriously damaged on a large scale It greatly affected traffic on the bridge The observation results during the years showed that the worst status of the asphalt surface layer occured after each hot period in June and July every year, so it can be confirmed that high temperature was a main factor causing damage to the overlay The asphalt layer on Thuan Phuoc steel deck surface suffered from disadvantages relating to working temperature due to heat accumulation effect in the 655m long closed steel box beam without ventilation system In summer, temperature inside the steel box beam can be up to 7080 C This makes the overlay and the adhesive layer always worked at a disadvantage Damages on Thuan Phuoc HìnhFig 1-21.1-21 Các hư hỏng tượng xô dồn bề mặt, In 2013, Thuan Phuoc bridge bridge surface after was conducted to repair the liên kết với thép sau 44 years năm khai thác overlay: Digging away the old BTNE layer After that a new overlay included asphalt layers of BTNP PMB3 The thickness of total layers is 800 mm Adhesive layer between BTNP layer and steel plate with two-component epoxy resin of Chemco System (USA) was still used Adhesion strength was enhanced by welding steel ribs 80cm apart on steel deck Between layers of BTNP was reinforced by fiberglass mesh layer with tensile strength of 100 kN After repaired, the overlay was still damaged after years of the operation and is being continued to be repaired 1.5 Problem statement The thesis focuses on solving the following issues: - Researching on componets of epoxy-bitumen and modified asphalt mixtures using epoxy-bitumen in order to suit with climatic conditions and construction technology level in Vietnam; - Initially proposing technical properties of epoxy-bitumen (with particular components) and BTNE mixture using BE binder for road pavement’s surface layers in Vietnam condition; - Proposing and evaluating some pavement structures using BTNE surface layer; Recommending suitable pavement structures for highway and bridge deck; - Making some initial recommendations on production technology and construction technology of BTNE in Vietnam The thesis carefully studies about components, mechanical properties, technical standards, applicability of BTNE without researching on construction technology of it in field 1.6 Research methodology Combining between of research methods: theoretical method, experimental method, statistical probability method, experimental method and modeling method CHAPTER RESEARCH ON COMPONENTS AND BASIC PROPERTIES OF EPOXY- BITUM Chapter carries out empirical research in laboratories for purpose of selecting the type of epoxy, the rate and the method of mixing bitumen and epoxy; Experiments were conducted to determine technical characteristics of BE binder compared with some bitumens used commonly in Vietnam 2.1 Determining components and method of manufacturing BE binder 2.1.1 Selection of epoxy resin Epoxy resin used in this research is provided by TAIYU KENSETSU, JAPAN This type of epoxy is widely used in Japan, China and even in Korea Epoxy resin includes two main components: basic resin and curatives (hardener) The technical characteristics of each component and mixing ratios shown in Table 2-3 2.1.2 Selecting type of bitumen used in research Bitumen 60/70 of Shell, Singapore was used to manufacture BE binder 2.1.2.1 Content of epoxy in epoxy - bitumen The technical properties of BE binder vary with different contents of epoxy in binders In this study, the properties of BE binders were be tested with epoxy contents of 15%, 20%, 30%, 35%, 40%, 50% by weight They were abbreviated respectively: BE15, BE20, BE30, BE35, BE40, BE50 2.1.2.1 Steps of mixing epoxy-bitumen - - Step 1: Producing epoxy resin: Blending main resin with curatives in proportion of 56:44 during one minute in order to produce epoxy resin for the research Step 2: Producing BE binder: Mixing bitumen 60/70 with epoxy resin made from step in a paricular proportion during minutes BE binder obtained from this process will be poured into a mold and dried at 150 C for hour Step 3: Maintaining BE sample (As shown in section 2.1.4) 2.1.3 Setting out a time interval and temperature level of epoxy-bitumen sample curing before testing In this study, BE binder was cured at two different temperature levels: 60 C (corresponding to the temperature of pavement surfaces in very hot summer areas and on steel plate bridges); 25 C (corresponding to average temperature in Vietnam) For the cured samples at room temperature of 25 C, tests for them were carried out at different curing time intervals: 2h, 4h, 24h, 48h, 72h, 96h and 168h., tests for them was conducted after curing during 96h for cured sample at 60 C 2.2 Selecting technical specifications and testing methods for BE binders In Vietnam, TCVN 7493: 2005 "Bitumen-technical requirements" are used to assess the quality of bitumens All technical characteristics to evaluate bitumens according to this specification were applied to BE binders In addition, viscosity and dynamic shear modulus (DSR) of BE binders were al so performed in this study Testing methods comply with current standards Using Minitab software to design general experiments The number of common repetitions is ANOVA analysis and post-editing analysis used to detect differences according to Tuckey standard Carrying out the evaluation to remove outliers according to ASTM E178; evaluating the precision according to ASTM C670 with the acceptable limits specified by the respective standard tests 2.3 Penetration of BE binder with diffirent percentages of epoxy Penetration tested in accordance with TCVN 7495: 2005 The total number of experimental sample groups was 49 By precision analysis in accordance with ASTM D5 -2013, it could be confirmed that penetration test results me t the precision requirements Fig 2-1 Relationship between penetration and epoxy content and different curing conditions Fig 2-2 Penetration values of epoxy bitumen - Penetration (Pe) decreases with increasing epoxy content In the case of epoxy content less than 30%, the reduction rate of Pe is about 6,5 ÷ 15 (1/10mm) corresponding to increasing by 15% epox The average decrease is 3,64 (1/10mm)/5% increase of epoxy content) The rate of reduction in Pe is significant (average reduction of 6.7 (1/10mm)/5%) if the epoxy content increases from 30% to 35% In the case of epoxy content greater than 35%, the rate of reduction returned to the original level with an average of 3,64 (1/10mm)/5% [see fig 2-5 and fig 2-6] - PE of BE binders in all types of content decreases with increasing curing time, but for the epoxy content below 35% this reduction is negligible and almost stable at 96h; At 35%, 40% and 50%, this reduction is obvious with increasing curing time (see fig 2-6) - PE of samples cured at 60 C for 96h were lower than those of samples cured at 25 C for 168h For samples with 50% epoxy content and curing at 60 C for 96h, Pe was lower than 20 (1/10mm) (see fig 2-5) The reduction of PE or the increased hardness of the BE binder compared with conventional bitumen is due to epoxy resin as a thermoset component In BE binders, epoxy is a three-dimensional continuous phase that is hard and becomes harder when heated As epoxy content increases, the mixtures with more hard components reduce their Pe, while BE binder cured at higher temperature makes it harden faster Long curing time makes BE continue to complete dispersion phase of epoxy and increase the hardness of BE binder Setting up the second regression equation showing the relationship between Pe and variables (BE and T) in research limit as follows : Pe = 79,62 – 1,0153 BE – 0,06700 T + 0,00990 BE*BE + 0,000283 T*T – 0,003223 BE*T The equation ensures reliability with the adjustment coefficient R p-value of all parameters is less than 0,05 (2-1) đc = 97,68%, 2.4 Softening point (ring-and-ball apparatus) This test was carried out according to TCVN 7497:2005 - ring-and-ball apparatus Total number of sample groups was 49 10 2.7 Dynamic shear modulus of BE binder - DSR test results of original BE15, BE35 and BE50 binders are equivalent to PG70, PG76 and PG82 - PG of BE35 and of BE50 after RTFO remain the same as the original BE resin, respectively PG76 and PG82 - PG of BE15 after the RTFO decreases by one level compared to PG of corresponding original BE, from PG70 to PG64, which is equivalent to PG of ordinary bitumen 60/70 (BE0) 2.8 Conclusion for chapter BE binders using epoxy supplied by TAIYU, Japan meet the requirements for bitumen used in construction according to TCVN 7493:2005 With an epoxy content of 35% or more, SP of BE binder is significantly higher than that of conventional bitumen With epoxy content up to 50%, this property is also superior to that of PMB III It is recommended to use BE type with a minimum epoxy content of 35% by weight of BE SP and Pe of BE binders are affected by curing time and temperature The higher the epoxy content is, the greater the influence of these factors on SP and Pe At an air temperature of 25 C, after mixing for hours, there is any significant difference between properties of BE binder and of bitumen 60/70, so the use of BE as a binder for asphalt mixtures will not meet difficulties in the process of blending in asphalt mixing plant and in construction The decline of Pe to approximately 20-25 (1/10mm) during the use of pavements is a risk for cracking by hardening of bitumen Therefore, it is necessary to study the effect of increasing hardness of bitumen on crack resistance by fatigue testing for asphalt concrete using BE binder PG of BE15, BE35 and BE50 are based on |G*|/sin of original BE and after RTFO are PG64, PG76 and PG82 respectively CHAPTER EXPERIMENTAL RESEARCH ON MECHANICAL AND PHYSICAL PROPERTIES OF BTNE USING BE BINDER Chapter focuses on the study of technical properties of BTNE to assess the quality of them, analyze pavement structure s with BTNE surface layers in Vietnam In addition to common mechanical properties (Marshall stability and flow, static elastic modulus, ), other properties (fatigue life, dynamic modulus ) of BTNE were also analyzed and evaluated 3.1 Mix design of BTNE mixtures and reference mixtures 11 From the conclusions of Chapter 2, this chapter only conducted experiments in BTNE (BTNE35 and BTNE50) respectively using BE35 binder and BE50 binder The reference mixture is BTNP using PMB III binder The study only focused on only one aggregate gradation with a nominal maximum size of 12,5mm (BTNC12,5) with all types of binders: BE35, BE50 and PMB III (see Fig 1) Optimum asphalt content range is determined by Marshall method (see Table 3-6) Choosing optimal asphalt content value corresponding to Va equal to 4,5% ÷ 5,0% (recommended range arcording to Decision 858/QĐ BGTVT) Selecting optimum asphalt content for BTNP mixture was 5,2% by mixed weight, for both BTNE35 and BTNE50 mixtures were 6,0% by mixed weight 3.2 Preparation of experimental samples of BTNE Step 1: Mixing BE binder according to the steps in section Error! Reference source not found Step 2: Mixing BTNE mixtures - After mixing, BE binder as mentioned in Step will be immediately put into the oven to dry at 140 C - Coarse and fine aggregates are dried at approximate 170 C, mineral powders not need drying - Mixing BE binder, coarse and fine aggregates and mineral powders similar to conventional asphalt mixture Step 3: Preparing of experimental asphalt samples by gyration or roller compactor After that, BTNE samples was cured at 25 C for 168 hours (7 days) before tesing In summary, it can be seen that the process of preparing BTNE samples for testing to determine properties of BTNE mixtures is similar to that of conventional AC mixture, except for the production of BE binder 3.3 Marshall stability, flow and residual stability 3.3.1 Result of Marshall test and analysis An assessment of precision of Marshall stability and flow arcording to ASTM D6927-15 showed that these results were satisfactory 12 Marshall stability of BTNE50 when immersed in water at 60 C for 1h is 51,72 kN, 3,328 times as much as that of BTNP (15,56 kN) and approximately 1,53 times as much as that of BTNE35 (33,86 kN) Marshall stability of BTNE50 when immersed in water at 60 C for 24 h is 46,33 kN, 3,319 times as much as that of BTNP (13,96 kN) and approximately 1,59 times as much as that of BTNE35 (29,08 kN) Average value of Marshall stability of BTNE35 is 2,18 times and 2,08 times as much as these of BTNP when immersed in water at 60 C for 1h and for 24h respectively From ANOVA analysis results of Marshall flow, following conclusions can be drawn: - Influence of sample immersion time on Marshall flow is statistically significant; - The type of BTN does not affect Marshall flow It means Marshall flow of BTNE is similar to that of BTNP This is an advantage of BTNE, Marshall stability is much higher than that of BTNP but Marshall flow is still in the required range Marshall flow of the mixes ranges from 3mm - 6mm, meets the requirements of BTNP mixture (see Fig 3-5) BE binder with epoxy - thermosetting component has played an important role in forming hardness and improve Marshall stability of BTNE Asphalt component maintains plasticity of BTNE mixtures which is shown by Marshall flow not much different from that of BTNP 3.4 Static elastic modulus of BTNE Static elastic modulus tested for different temperatures (15 C, 30 C and 60 C) complies with Annex C, 22TCN211-06 13 3.4.1 Test result and analysis At test temperatures of 15 C, 30 C, 60 C, average static elastic modulus (E đh ) are 64,98%, 35,60% and 24,37% higher than those of BTNP, respectively At 15 C, the difference of E đh between types of BTN is significant, the degree of difference between them decreases at 30 C, and is no longer significant at 60 C, especially between BTNE35 and BTNP 3.4.2 Representative static elastic modulus of BTN At 15 C, 30 C, 60 C, E đh đt is higher than that of BTNP respectively by 61,56%, 32,43% and 20,04%; E đh đt of BTNE35 is 30,81%, 9,90% and 4,35% higher than that of BTNP (see Table 3-12) The results of static elastic modulus test show that BTNE has higher deformation resistance than conventional asphalt concrete (BTN) and also higher than BTNP using PMB III which are commonly used in Vietnam Epoxy with the ability to improve hardness and maintain elasticity of BE is a factor that enhances the deformation resistance of BTNE 3.5 Flexural strength of BTNE Flexural strength of asphalt concrete is determined in accordance with annex C of standard 22 TCN 211-06 The test was performed on beam samples with dimensions of 240x60x60 mm 3.5.1 Result of flexural strength test and analysis At 15 C, R ku of BTNE35 and that of BTNE50 respectively 1,07%, 87,44% higher than that of BTNP Experimental results are statistically significant at the 95% confidence level Analysis of fracture cross-section of the sample after the test (see Fig 3-16) showed that: fracture of BTNE35 and BTNP samples only occurred at position of BE binder Fractures of the BTNE50 samples were very flat and cut through aggregate particles It shows that BE50 has very high hardness due to epoxy component in BE binder 14 a BTNE50 b BTNE35 c BTNP Fig 3-1 Photos of fractures after bending test 3.5.2 Representative flexural strength of BTN At 15 C, R kuđt of BTNE35 and BTNE50 are respectively 21,95%, 93,96% higher than that of BTNP R kuđt of BTNE50 is 59.05% higher than that of BTNE35 Thus, it can be seen that bending resistance of BTNE50 is superior to that of BTNE35 and BTNP High tensile flexural strength at 15 C is quite consistent with the results of a pilot project in Europe These results indicate that the role of main resin component in epoxy resin ensures flexibility and plasticity of BE binder at low temperature, when conventional asphalt binder is hard-brittle This feature was further verified by fatigue test for BTNE 3.6 Wheel rutting depth of BTNE After 40.000 cycles of loading, wheel rutting depth of BTNE50 and of BTNE35 are only approximately 1/3 and 1/2 of that of BTNP respectively Rutting depth of BTNE50 sample after 40.000 cycles is equivalent to that of BTNP sample after 1.400 cycles and that of BTNE35 sample after 13.000 cycles Rutting depth of BTNE35 sample after 40.000 cycles of loading is equivalent to the depth of BTNP sample after 3.600 cycles From the above analysis, it can be seen that Rutting deep of BTNE (especially BTNE50) is very good Outstanding advantage of BTNE rutting resistance compared to that of BTNP is due to thermoset propertie of epoxy resin, with its hardness and ability to maintain its elasticity at high temperature This result is completely consistent with many studies in the world 3.7 Fatigue life of BTNE 15 Principles and parameters of test: 4-point beam bending test, deformation control, sinusoidal continuous load, 10Hz load frequency, test temperature 10 C Initial stiffness module (S ) of BTNE50 is much higher than that of BTNE35 and of BTNP Phase angle of BTNE50 is the lowest and thag of BTNP is the highest This shows that BTNE50 exhibits the lowest viscosity properties and BTNP has the highest viscosity properties of three tested types of BTN N f50 of BTNE50 is significantly better than that of BTNE35 and of BTNP N f50 of BTNE35 is not significantly higher than that of BTNP at levels of deformation 200 300, but much lower than that of BTNP at deformation level of 400 Higher stiffness module and smaller phase angle of BTNE50 show more clearly a role of epoxy resin to ensure higher elasticity of BE in BTNE mixture Higher fatigue life of BTNE, especially BTNE50 verifies the ability to maintain the toughness of BE binder in the mixture Establishing fatigue life equation Fatigue curve of three types of asphalt concrete has been built and shown in Fig 3-32 Results of establishing fatigue life equation (relationship between fatigue life (N f50 ) and deformation ( )) of three types of asphalt at 10 C, 10Hz are shown in equations (3-8), (3-9) and (3-10) 16 The slope of fatigue curves of BTNP, BTNE35 and BTNE50 are 3,615; 4,256 and 3,770 These results are consistent with published results of fatigue research in the world (usually from ÷ 6) Fig 3-32 shows: fatigue sensitivity of BTNE35 is the greatest, respectively 17,73% and 12,89% higher than that of BTNP and of BTNE50; Fatigue curve of BTNE35 is very close and cuts through fatigue curve of BTNP 3.8 Dynamic modulus of BTNE 3.8.1 Analyze experimental results on dynamic module of BTN Experimental results ensure the precision and shown in Figure -37, Figure 338 and Figure 3-39 From the results of these experiments, the following conclusions can be drawn: Temperature and load frequency have a great influence on |E*|, as follows: At the same frequency, when experimental temperature increases, |E*| decrease very fast; At the same temperature, when the frequency decreases then |E*| also drops This explains viscoelasticity of BTNP and BTNE materials At all experimental test temperatures (between 10 – 60 C) and experimental frequencies, |E * | of BTNE50 are greater than that of BTNE35 and |E * | of BTNE35 is greater than that of BTNP At higher temperatures, the greater the gap between |E * | of BTNE and of BTNP is 3.8.2 Establishing master curve of dynamic modulus 17 Master curve of dynamic modulus (|E * |) is constructed from timetemperature correlation Master curves of |E * | characterize viscoelastic property of asphalt materials in a wide range of frequencies and temperatures It is used to predict |E * | at different load frequencies and temperatures 3.8.3 Modelling master curve of dynamic modulus using 2S2P1D model 2S2P1D model was studied and proposed by Olard, F., & Di Benedetto (2003) This model consists of input parameters (E 00 , E , δ, β, τ, k and h) to model master curves of dynamic modulus of both asphalt binder and asphalt concrete Parameters of 2S2P1D model are determined by Trial and error to minimize the errors between results from experiment and model Assessing the fit between 2S2P1D model and experimental results Using statistical model "Goodness of Fit" to assess the fit of 2S2P1D model with experimental results The results in table 3-25 show that R > 0,90 and Se/Sy < 0,35 for all BTNE35, BTNE50 and BTNP This proves that this is a suitable model 3.9 Conclusion for chapter Marshall stability of BTNE50 and BTNE35 are times and times as much as that of BTNP respectively Static elastic modulus (E đh ) of BTNE50 is significantly higher (from 64% to 24%) than that of BTNP Tensile strength (R ku ) of BTNE50 is superior to that of BTNE35 and BTNP R ku is approximately times as much as that of BTNP, and R ku of BTNE35 is only 1,2 times as much as that of BTNP Wheel rutting resistance of both BTNE50 and BTNE35 is very good ... penetration and softening point of BE binders, the following conclusions are drawn: - Epoxy content ≤ 30%: The rate of reduction of Pe and increase of SP is not significant; PE of BE binders with... phase, thereby increasing SP of BE binder The longer curing time is, the more dispersed thermoset phase develops, thereby increasing SP of BE binder 9 Setting up the second regression equation showing... mechenical properties and the applicability of epoxy-bitumen binder for asphalt mixtures in Vietnam? ?? is scientific and practical II Research objective For the purpose of researching on the applicability