Indirect Tension Test Research Articles

Geotechnical performance of isotropic and foliated quartzite waste as aggregate for road base and asphalt mixture

Quartzite mines produce a large amount of waste. Although the reuse of materials is essential for sustainable constructions, little is known about the geotechnical properties of isotropic (massive) and foliated (discontinuous) quartzite waste. In this paper, the potential use of these wastes as base layers and asphalt mixtures were examined by a series of laboratory tests and numerical simulations. This paper presents an analysis of the particle properties, durability, strength, and deformation response of quartzite waste in isotropic (IGM) and foliated granular (FGM) mixtures. Asphalt mixtures with isotropic (IAM) and foliated (FAM) quartzite waste as aggregates are evaluated using Brazilian tensile strength, moisture susceptibility, and repeated-load indirect tension tests, such as the resilient modulus and fatigue. To estimate the performance of these materials as pavement layers, numerical experiments are also carried out using the mechanistic-empirical design framework of the MeDiNa software package. As a base material, the mixtures showed plastic creep responses at the highest stress level (higher permanent strain of 1.2 % at σ3/σd = 360/120 kPa) and negligible expansion. The California bearing ratio (higher than 130 % for both IGM and FGM) and resilient modulus (average of 224 and 130 MPa for IGM and FGM, respectively) greatly exceeded the minimum requirement of Brazilian standards. As asphalt mixtures, both IAM and FAM met the minimum limit of tensile strength, but IAM showed greater stiffness. According to the stress–strain analysis of the MeDiNa software, granular and asphalt mixtures incorporating quartzite waste fulfilled the fatigue crack area and rut depth criteria, falling within the allowed thickness ranges for road pavements subjected to up to 5×106 repetitions (medium heavy traffic). This study provides support for the transformation of quartzite waste into a valuable byproduct.

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

Viscoelastic Characteristics and Mechanical Performances of Asphalt Mastic and Mixtures with Fly Ash from Municipal Solid Waste Incineration Residues

Effect of fiber addition on strength and toughness of rubberized concretes

In this paper, an experimental study was conducted to examine the static and dynamic behaviors of rubberized fiber-reinforced concrete (RFRC). Crumb rubber was partially replaced from sand at volume fractions of 0%, 5%, 10%, 15%, and 20%. Steel fibers (SFs) with fiber volume fractions (Vf%) of 0%, 0.5%, 1%, and 1.5% were used for the production of FRCs, while polypropylene fiber (PPF) with Vf% = 0.4% was adopted to produce others FRCs. A combination of 0.4% PPF and 1% SF was used for hybrid FRC. The static properties were evaluated through compression, indirect tension, and flexural tests. However, the drop weight impact test was conducted to assess the dynamic property by estimating the impact energy. It was observed that the replacement of sand with rubber reduced all mechanical properties of concrete. In the case of RFRC, a reduction in compressive strength, compared to samples without fibers, was noted, and this reduction increased with higher Vf%. Both toughness indices and fracture energy were affected slightly by increasing rubber percentages while markedly increased with higher Vf%. However, adding rubber and/or fibers enhanced the impact energy of concrete.

Understanding the evolution mechanism and classification criteria of tensile -shear cracks in rock failure process from acoustic emission (AE) characteristics

This study aimed to investigate the crack evolution and failure mechanism of rocks by conducting uniaxial compression tests (UCT) and Brazilian indirect tension tests (BITT) using four categories of rock specimens. Real-time acoustic emission (AE) signals were detected and recorded during rock failure processes by an AE monitoring system. The study focused on the accumulative AE hits curves, stress–strain curves, and other AE energy characteristics to divide the failure process into five stages, and determine the stress thresholds. Furthermore, the transition trend of rock crack types was analyzed based on RA-AF data. A novel classification criterion of crack types based on clustering and statistical theory was proposed, and the crack boundaries of the four rocks were determined. Additionally, the tension to shear ratios of the rocks in descending order were fine-grained granite, granite, yellow sandstone, and white sandstone. Finally, the crack development trend and failure characteristics of the rock were analyzed using the crack scale and crack dividing line. The study found that the failure mode of the rock could be predicted accurately by AE parameter analysis at Unstable Crack Growth (Stage-IV).

Low temperature failure behavior analysis of fiber reinforced asphalt concrete under indirect tension test using acoustic emission and digital image correlation

Failure behavior is the key property needed to be characterized in asphalt concrete at low temperature, which is one of the major influence factors for service life of asphalt pavement. In this study, the reinforcing effect of glass fiber on failure process of asphalt concrete under indirect tension (IDT) test at − 10 ℃ was investigated using acoustic emission (AE) and digital image correlation (DIC) techniques. Control asphalt concrete (CAC) with no fibers was also carried out for comparison. The evolutions of AE parameters including amplitude, count, duration, rise time and corresponding cumulative ones were obtained and analyzed to characterize the failure processes of fiber reinforced asphalt concretes (FRACs) and control one, which were compared with the results from static displacement and strain data obtained through DIC. The effect of fiber length was also investigated to better understand the reinforcing mechanism and determine the proper reinforcing fibers. The test results revealed that low temperature failure processes of CAC and FRAC could be effectively classified according to the variations of AE parameters and corresponding cumulative ones. Three and five failure stages were identified for CAC and FRACs, respectively, which could clearly reflect the reinforcing effect of glass fiber. Cumulative AE parameters presented better identification effect on fiber reinforcement than displacement or strain, while stain data exhibited favorable performance for microcrack initiation. As for the fiber length effect on damage failure process of FRAC, evolutions of cumulative AE parameters before final failure of specimen became more stable with the increase of fiber length within 6–20 mm. AE technique presented great potential for failure behavior analysis and explanation of fiber reinforcing mechanism in asphalt concrete, which also provided promising method for real-time monitoring of cracking in asphalt pavement.

Polyurethane-based composite binder for poroelastic road surface: composition, preparation and properties

To address the high cost and poor water stability of polyurethane (PU) binder used in poroelastic road surface (PERS), a type of PU-based composite binder prepared at room temperature was proposed by using PU as the main ingredient, emulsified asphalt (EA), cement, and defoamer as auxiliary agents. The stabilities of different types of polyurethane-emulsified asphalt (PU-EA) blend systems were investigated and the mix composition of the PU-EA blend system was determined through molecular dynamics (MD) simulations. The interaction mechanisms of all components of the PU-based composite binder were revealed by microscopic measurements through Fourier transform infrared (FTIR) spectroscopy and fluorescence microscopy (FM). The strength and water stability of the PERS mixture bound by the PU-based composite binder were evaluated by the indirect tension (IDT) test and the Cantabro abrasion test. The results showed that the stability of the polyether polyurethane (PEUR)-cationic emulsified asphalt (CEA) blend system was the best, and the potential energy of the PU-EA blend system was the lowest when the PU content was around 50 wt%. Both physical and chemical reactions occurred simultaneously in the polyurethane-emulsified asphalt-cement (PU-EA-C) blend system's components. The calcium silicate hydrate (C-S-H) enhanced the crosslinking gel properties of the PU-EA-C blend system. Cement improved the performance of the PERS mixture in a more efficient way than the PU. When the PU-based composite binder composed of 50 wt% PU, 41 wt% EA, 9 wt% cement, and 0.5 wt% defoamer was used, the water stability and strength performance of PERS mixture were the best. The material cost of the suggested PU-based composite binder was nearly half that of commonly used PU, while the material cost of the PERS mixture was reduced by 25%. These findings would serve as useful references for the promotion and application of PERS pavement.

Performance of fibre-reinforced landfill mined soil like fraction as an environment friendly fill material

Landfill mining is emerging as an effective strategy towards mitigation of the problems associated with legacy landfills. About 40–80% of the landfill mined waste is soil-like fraction (landfill mined soil like fraction, LMSF) that is obtained after removing the combustibles and recyclables. However, due to its lower calorific value and presence of organic content, LMSF has not found many applications except landfill cover material and filling of low-lying areas. In this context, the present study explores the strength properties of LMSF with and without fibres (coir and polypropylene fibres) through unconfined compression, direct shear, UU triaxial, cyclic UU triaxial, indirect tension and bending strength tests. Overall, the shear strength properties of LMSF are similar to sand with some cohesion. Further, the performance of LMSF with optimum fibre proportion (2% for coir fibres and 1.5% for polypropylene fibres) is quite superior under monotonic and cyclic compressive loading conditions, as well as indirect tension and flexural loading conditions. An assessment of 1 m replacement of soft soil with LMSF with/without fibre reinforcement infers substantial increase in the allowable bearing pressure of LMSF. Overall, though LMSF may need assessment/pre-treatment (as required) due to presence of organic content and any possible heavy metal concentration, utilization of LMSF would encourage the adoption of landfill mining process. The current research insights contribute in the direction of achieving sustainable infrastructure development by reduction in the landfill area that would reduce the depletion of conventionally utilized natural resources for fill applications such as sand and gravel, and contribute positively towards environment.

Quantification of inhomogeneity and anisotropy of bituminous mixtures using biaxial experimental data

Most of the existing mechanical characterization test methods and the analytical models for bituminous mixtures are developed based on the assumption of homogenous and isotropic material properties. However, the extent to which such assumptions hold good for bituminous mixtures is not very clear. A biaxial testing scheme in indirect tension mode can come in handy to collect the experimental data at different test temperature regimes. In this study, a bituminous mixture with a nominal maximum aggregate size (NMAS) of 13.2 mm is used to fabricate cylindrical test specimens with 150 mm diameter and 63.5 mm thickness for conducting the repeated load indirect tension (IDT) test. The input load level is selected as 5 to 13 % of the indirect tensile (ITS) failure load in the form of a haversine pulse of 0.1 s loading and 0.9 s rest period. Such loading is applied on zero-degree and ninety-degree orientations of the specimen. The resulting deformations in different directions are measured using linear variable differential transducers (LVDT) attached to both diametral faces of the specimen. The response of the bituminous mixture specimen is captured at three different temperatures of 20, 25, and 30 °C using two different gauge length (half and quarter gauge of the total diameter). A new framework is introduced in this study to evaluate the extent of inhomogeneity and anisotropy of bituminous mixtures. The deformation response of the test specimen captured in the same orientation at different diametral faces is compared to evaluate the extent of inhomogeneity. The extent of anisotropy is evaluated by comparing the deformation response of the test specimen captured at different orientations within the same diametral face. A 15 % variation in the average peak deformation is chosen as the demarcation for determining the extent of inhomogeneity and anisotropy. From this investigation, it is observed that half gauge length experimental data exhibits homogenous and isotropic behavior for all three test temperatures. The quarter gauge length data exhibit similar behavior at 30 °C, whereas it is observed as homogenous and anisotropic at the other two test temperatures.

Predicting crack growth of paving materials under indirect tensile fatigue loads

Cracking of paving materials affects the reliability and safety of pavement structures, and indirect tension (IDT) test is commonly used to investigate the cracking behavior of the paving materials. However, the existing studies usually adopted a reduced modulus or strength to indirectly quantify cracking damage under the IDT fatigue loads. A direct analysis method for the crack growth under the IDT fatigue loads is still missing. The objective of this study is to propose a crack growth prediction model under the IDT fatigue loads based on continuum damage mechanics (CDM), which can directly quantify and predict the crack growth of the paving materials. Two types of paving materials, cement-treated aggregates and asphalt mixtures, were investigated. A damage density model based on CDM was proposed to quantify the crack growth under the IDT fatigue loads. The model coefficients are obtained by the IDT horizontal tensile stress, material surface energy, resilient modulus, and the size of the IDT specimen. The surface crack length of the IDT specimen is obtained using the solved damage density with introducing a crack depth ratio. Results show that the cement-treated aggregates show relatively more brittle cracking where the cracks are penetrative and going through the whole thickness of the IDT specimen. In contrast, the asphalt mixtures exhibit more ductile cracking where multiple cracks present and are nonpenetrative. The cracks of the asphalt mixture penetrate only 48% and 46% of the specimen thickness when the IDT fatigue loads are 540 kPa (1 Hz) and 700 kPa (10 Hz), respectively. The damage density calculated by the CDM-based model can accurately predict the crack lengths for both the cement treated aggregates and the asphalt mixtures, which are found consistent with the measured crack lengths from the IDT tests. This study provides a mechanics model for determining the crack growth under the IDT fatigue loads that can serve as a tool for evaluating the fatigue crack resistance of the paving materials like the asphalt mixtures and cement treated aggregates.

Prediction of concrete anchor pull-out failure using cohesive zone modeling

Concrete anchor pull-out failure is predicted using the cohesive zone-based finite element analysis. For anchor pull-out tests, two sets of concrete specimens are prepared according to the curing temperatures. The displacement of an anchor steel bar is measured using the digital image correlation technique, and the cone failure surface is reconstructed using a 3D scanner. For each test set of concrete specimens, material properties such as the fracture energy, compressive strength, tensile strength, and elastic modulus are obtained from the three-point bending, cylindrical compression and indirect tension tests. Based on the measured material properties, the cohesive zone-based finite element analysis captures the load–displacement relationship of the anchor pull-out and three-point bending tests without the calibration of material properties. The experimental results demonstrate that the fracture energy is an essential material property to predict the concrete anchor pull-out failure, and thus the cohesive zone-based finite element analysis can provide accurate prediction of the anchor pull-out failure.

Comparative Study of The Asphalt Mix Stiffness Modulus Using Selected Test Methods – 2-Point Bending Test, 4-Point Bending Test and Indirect Tensile Test

The stiffness modulus of the asphalt mixture is a fundamental parameter in the understanding of the mixture strain behavior. It is also an essential design parameter of asphalt pavements. According to the European standards EN 12697-26, various test methods can be performed in order to determine this criterion. These tests are varying according to the loading type and the specimen dimensions and shape. The present paper deals with the study of three test methods: the 2-point bending test on trapezoidal specimens (2PB–TR), the 4-point bending test on prismatic specimens (4PB–PR), and the indirect tension test on cylindrical specimens (IT CY) used on three asphalt mixtures representing different structural pavement layers. The results show that the dual comparison of these tests, i.e., IT-CY and 4PB-PR, and 4PB-PR and 2PB-TR have indicated good correlation between each other. However, the comparison between the three tests did not substantiate to any general correlation.

Adhesion in Bitumen/Aggregate System: Adhesion Mechanism and Test Methods

A literature review of the five main theories describing the interaction mechanisms in the bitumen/aggregate system was conducted: theory of weak boundary layers, mechanical theory, electrostatic theory, chemical bonding theory, and thermodynamic theory (adsorption theory). The adhesion assessment methods in the bitumen/aggregate system are described, which can be divided into three main groups: determination of adhesion forces for bitumen with different materials, determination of bitumen resistance to the exfoliating action of water with different materials, and determination of adhesion as a fundamental value (contact angle measurements, interfacial fracture energy, adsorption capacity and others). It is proposed to evaluate the quality of adhesive interaction in the bitumen/aggregate system in two stages. The authors recommend using the adhesion determination methods for these two stages from the second group of methods the determination of bitumen resistance to the exfoliating action of water with different materials. In the first stage, the adhesion in the bitumen/aggregate system is determined by an accelerated technique in which the used bitumen binder and mineral material are considered as test materials. After the first stage, there are positive results in the second tests on compacted mixtures (indirect tensile strength test, Modified Lottman indirect tension test, immersion-compression test, and Hamburg wheel tracking test).

Acoustic emission characteristics and failure mode analysis of rock failure under complex stress state

To study the acoustic characteristics and failure mode of the rock failure process under a complex stress state, acoustic emission (AE) monitoring technology was employed to collect the AE signals in the Brazilian indirect tension test (BITT), uniaxial compression test (UCT), and triaxial compression test (TCT) of yellow sandstone. Moreover, the evolution of AE parameters as well as the characteristics of failure mode during the failure process were analyzed. The results reveal that the peak value of AE b decreases to its lowest point before the peak stress, and the decrease in b corresponds to the sudden increase in AE energy. The peak frequency is primarily distributed in the 0–100 kHz and 200–300 kHz frequency band in BITT. It is primarily distributed in 0–100 kHz and 200–300 kHz band for UCT. The 100–200 kHz band dominates in TCT. The parameter analysis of RA (rise time/amplitude) and AF (AE counts/duration) values for classifying different cracking modes during loading reveal that the highest proportion of tensile events in BITT occurs in the failure stage near the peak stress. Tensile events dominate before the peak stress of UCT, and the proportion of shear events will increase in peak and post-peak stress. The peak value of the proportion of shear events in TCT appears in the range near the peak stress. Moreover, the classification results of the cracking modes coincide with the macrocracks. The research results can provide some reference for the study of the failure process of complex stress rock.

Mechanical properties and enhancement mechanisms of cold recycled mixture using waterborne epoxy resin/styrene butadiene rubber latex modified emulsified asphalt

• CRM containing only fresh aggregate and WSEA has better mechanical properties; • WER/SBR modifier can provide the strengthening and toughening effects on CRM; • Dissipation energy ratio and relaxation time can better evaluate the CRM toughness; • The added fresh aggregates favor toughness rather than mechanical strength of CRM; • Asphalt syncretization occurs in the outermost three layers at RAP aggregate surface. To better understand the enhancement mechanisms of waterborne epoxy resin/styrene butadiene rubber latex modified emulsified asphalt (WSEA) on the mechanical properties of cold recycled mixture (CRM), four types of CRM specimens were prepared to systematically discuss the mechanical property changes based on nanoindentation tests. Then the syncretization state between aged asphalt and WSEA, as well as the microstructures of asphalt-aggregate interfaces were analyzed by Fourier transform infrared spectroscope and scanning electron microscope tests, revealing the performance enhancement mechanisms. Results indicated that the mechanical properties of CRM prepared by fresh aggregate and WSEA were better. Also, the toughness of CRM could be accurately characterized by the dissipation energy ratio and relaxation time rather than the creep compliance. Additionally, the syncretization occurred in the asphalt samples of the outermost three layers at RAP aggregate surface. The added fresh aggregate was beneficial to forming WSEA-fresh aggregate interface, improving the anti-cracking property and moisture stability. Finally, the result reliability of the nanoindentation test was verified by indirect tension tests and conventional tests of pavement performance.

Correlating damage and cracking with air (gas) permeability in concrete using the Brazilian tension test

• Using acoustic emission and digital image correlation in the indirect Brazilian tension test, damage and cracking can be correlated to gas permeability in concrete. • A microcrack size of 40 µm can distinguish between pre-cracking and post-peak behavior of concrete. • Gas permeability of concrete increases to almost half an order of magnitude in the pre-peak region. • Gas permeability of concrete increases to about six orders of magnitude during the progression of cracking in the post-peak region. This article investigates the relationship between stress, damage, crack propagation, and air (gas) permeability evolution in concrete using the Brazilian tension test. This investigation is important for situations where hazardous gases are in contact with concrete as it quantifies the effect that damage of concrete has on gas permeability. Cylindrical concrete disc specimen of diameter 101.6 mm and thickness 50.8 mm were used for this study. Acoustic emission sensors are used to observe damage occurrence and propagation in the concrete, while a digital image correlation set-up is used to precisely measure the crack opening displacement. A vacuum flow system is attached to the rear side of the concrete under loading to measure apparent air permeability through the concrete specimen before and after cracking. The collected data is synchronized and analyzed to correlate damage and crack propagation and air permeability evolution in concrete under tension stresses. It was found that the air (gas) permeability increased by over six orders of magnitude as the concrete cracking occurs and changes in air (gas) permeability directly correlate with changes in concrete damage and fracture.

Laboratory performance of dense graded asphalt mixtures prepared using highly polymer modified binders containing corn oil as softening agent

• High Polymer Modified Asphalt (HPMA) with corn oil can resist short term aging. • Crack Propagation slows with HPMA and corn oil combination compared to Control. • Life Cycle Analysis shows the cost-effectiveness of the optimized combination of HPMA and Corn Oil. This study evaluated the impact of aging on High Polymer Modified Asphalt (HPMA) mixtures containing a softening agent (SA). The aging susceptibility was evaluated in terms of rutting, cracking, and durability. Four asphalt mixtures were prepared, one with PG 52–34 binder as control, and three others using modified PG 52–34 with varying dosages of Styrene Butadiene Styrene (SBS) and corn oil (SA). The tests performed to evaluate the impact of aging (short, long, extended long term) were the Dynamic Complex Modulus, Hamburg Wheel Tracking, Flow Number, Indirect Tension and semi-Circular Bend tests. Based on these testing results, SBS and SA increased the durability and rutting resistance of asphalt mixtures. Modified asphalt mixtures also showed better cracking resistance than the control mix (i.e. lowering of crack propagation). However, with aging, fatigue cracking performance diminished while remaining comparable to the control mix. A balanced dosage of SBS (7.5%) and SA (7%) led to the best improvement in durability, rutting, and short-term cracking performance.

Durability improvement of poroelastic road surface with treated rubber: Molecular dynamics simulation and experimental observations

Poroelastic road surface (PERS) is usually composed of rubber particles, aggregates, and polyurethane. However, the poor bonding strength between rubber granules and polyurethane affects PERS’ durability. This study aimed to improve the durability of PERS with treated rubber using molecular simulation and experimental tests. The cohesive energy density (CED), interaction energy (IE) and shear bonding capacities between two kinds of rubber granules and one-component polyurethane were simulated using molecular dynamics (MD). The hydrophilicity test and Fourier transform infrared (FTIR) spectroscopy test were utilized to demonstrate the formation of oxygen-containing groups on rubber surfaces. The indirect tension (IDT) test and Cantabro test were employed to evaluate the durability of PERS mixtures with treated rubber. The MD simulation results showed that the oxygen-containing groups, including the hydroxyl group (-OH) and the carbonyl group (CO), could improve surface polarity of natural rubber (NR) and styrene-butadiene rubber (SBR) and thereby enhance rubber-polyurethane bonding performance. In particular, hydroxyl groups improved the bonding energy of NR-polyurethane by 59% while the carbonyl groups enhanced the bonding performance of SBR-polyurethane by 20%. The hydrophilicity of the treated rubber granules was effectively improved since new carbonyl groups were introduced on rubber surface. The treatment of rubber with NaOH solution improved the durability of PERS specimens by 8.4% in terms of tensile strength ratio (TSR) and 64.7% in terms of Cantabro abrasion loss. These findings prove the feasibility of designing durable PERS with good functional performance.

Preparation and Characterization of High Modulus Agent Modified Asphalt and Its High Modulus Mixture

Improving the high-temperature stability and water damage resistance of asphalt pavements has always been a priority. This study proposed a composite high modulus modifier with rock asphalt and nanopolymer as main materials (HRMA) to prepare the high modulus asphalt mixture for their excellent rutting resistance. Moreover, its modification effect and modification mechanism were studied. The effect of HRMA content on the rheological performance of asphalt was investigated using Brookfield rotational viscosity, dynamic shear rheometers (DSR), and bending beam rheometers (BBR). Their modification mechanisms were revealed by Fourier Transformation Infrared Spectroscopy (FTIR). Besides, the properties of the mixtures were studied in various laboratory tests and compared with the 90# asphalt mixture and SBS asphalt mixture. Some of these included the rutting test, the bending test, the Marshall immersion test, and the freeze-thaw indirect tension test. The results indicated that with the increase of HRMA content, the deformation resistance of the asphalt mixture under high-temperature conditions was significantly improved, and the temperature sensitivity was changed. However, the crack resistance of its asphalt mixtures under low temperature was reduced due to the lower ductility of HRMA-modified asphalt. The recommended HRMA content was 21.8% of the asphalt, combining performance and construction cost.

Investigation of dolomite’ rock brittle fracture using fully calibrated Karagozian Case Concrete model

This paper presents a procedure to compute the parameters of the Karagozian and Case Concrete (KCC) constitutive model for brittle materials based on dolomite rock. First, the fracture energy and fracture toughness of the dolomite rock were determined from two experimental tests: the semicircular bending test (SCBT) and Brazilian indirect tension test (BT). Next, the novel optimization-based strategy was developed for efficiently calibrating the brittle damage parameters, and a broad parametric study was performed based on dolomite rock. Finally, the optimal parameters were validated through three experimental tests: SCBT, BT and a drop-weight fragmentation test. The results were compared with those obtained using three different sets of parameters for dolomite rock that is the KCC model with automatically generated parameters, parameters that provides an instable softening behavior, and the KCC model with parameters calibrated by the authors in a previous study. A qualitative and quantitative comparison of the results confirmed that the approach presented here improves the efficiency of fracture reproduction.

Unified characterizing fatigue performance of high modulus asphalt concretes under diverse stress state

As a new material, high modulus asphalt concrete (HMAC) with good durability is widely used in the pavement engineering. One of the most critical performance indexes of HMAC is the fatigue cracking. However, in the experiment of evaluating the fatigue properties, different anti-fatigue effects are obtained only by adding different modifiers. In addition, using only one loading mode to determine the fatigue properties of HMAC neglects the fact that there is a difference among the fatigue test results in various loading modes, which artificially leads to the non-uniqueness and unscientific design of high modulus asphalt pavements for the fatigue resistance. Therefore, four internationally accepted mainstream strength tests at different loading rates, including direct tension, indirect tension, unconfined compression and four-point bending tests, were carried out to enhance the veracity of structural resistance design of high modulus asphalt pavements. It is revealed that the fitted curve for the variation of strength with loading rate is a power function with velocity dependence, and the models for direct tension, indirect tension, unconfined compression, and four-point bending strengths established as a function of loading rate are SD = 3.218v0.1425, ST = 3.833v0.1768, SC = 14.391v0.1130 and SF = 7.839v0.1489 respectively. Besides, it is shown that the conventional S-N fatigue equation does not take into account the velocity dependence of the strength of HMAC in the stress ratios determined by the tests, and the velocity-dependent stress ratios defined in this paper are determined by the strength model and therefore take into account the viscoelasticity of HMAC. In addition, it is found that extending the fatigue curve backwards, when the fatigue life of HMAC is also close to 1, the velocity-dependent stress ratio is 1. Meanwhile, the fatigue model Nf = tv-5.318 was developed by unifying the characterization of HMAC and considering the effect of loading rate in various loading modes. It eliminated the difference of fatigue test results caused by the specimen sizes and loading modes, and effectively improved the completeness of structural design of high modulus asphalt pavements, which provided a theoretical basis for designing the high modulus asphalt pavements.