Mastic Test Research Articles

Dysarthria and dysphagia in patients with mitochondrial diseases

BackgroundInformation about dysarthria and dysphagia in mitochondrial diseases (MD) is scarce. However, this knowledge is needed to identify speech and swallowing problems early, to monitor the disease course, and to develop and offer optimal treatment and support. This study therefore aims to examine the prevalence and severity of dysarthria and dysphagia in patients with MD and its relation to clinical phenotype and disease severity. Secondary aim is to determine clinically relevant outcome measures for natural history studies and clinical trials. MethodsThis retrospective cross-sectional medical record study includes adults (age ≥ 18 years) diagnosed with genetically confirmed MD who participated in a multidisciplinary admission within the Radboud center for mitochondrial medicine between January 2015 and April 2023. Dysarthria and dysphagia were examined by administering the Radboud dysarthria assessment, swallowing speed, dysphagia limit, test of mastication and swallowing solids (TOMASS), and 6-min mastication test (6MMT). The disease severity was assessed using the Newcastle mitochondrial disease scale for adults (NMDAS). ResultsThe study included 224 patients with MD with a median age of 42 years of whom 37.5% were male. The pooled prevalence of dysarthria was 33.8% and of dysphagia 35%. Patients with MD showed a negative deviation from the norm on swallowing speed, TOMASS (total time) and the 6MMT. Furthermore, a significant moderate relation was found between the presence of dysarthria and the clinical phenotypes. There was a statistically significant difference in total time on the TOMASS between the clinical phenotypes. Finally, disease severity showed a significant moderate relation with the severity of dysarthria and a significant weak relation with the severity of dysphagia. ConclusionDysarthria and dysphagia occur in about one-third of patients with MD. It is important for treating physicians to pay attention to this subject because of the influence of both disorders on social participation and wellbeing. Referral to a speech and language therapist should therefore be considered, especially in patients with a more severe clinical phenotype. The swallowing speed, TOMASS and 6MMT are the most clinically relevant tests to administer.

Evaluating and quantifying the variations and sensitivity in asphalt-filler interaction indices

The interaction within an asphalt-filler blend is usually defined by its volume filling and interfacial reciprocation tendencies. This interplay between a reinforcing solid filler within liquid asphalt thus ends up dictating the blend's transition point from a “diluted region” to a “concentrated region”, and the glass transitioning state of the asphalt itself. While prior studies focused on distinguishing asphalt-filler interactions based on composite reinforcement models, describing the definitive behaviour of its suffusing phase reciprocation has proved elusive. Hence, this study aims at redefining asphalt-filler interaction by evaluating and quantifying the varying distinctions in each established mastic composite model. Asphalt mastics composed of three distinct fillers of dolomite powder (DP), lime kiln dust (LKD), and ordinary Portland cement (OPC), along with a conventional PEN 60/70 binder, were blended together at 0.4, 0.8, and 1.2 filler to binder ratios (F/B) based on the Superpave mix dust to binder specification. The OPC mastic was regarded as the control mastic sample for all tests performed. A temperature sweep test was conducted on all prepared mastic test samples using dynamic shear rheometer equipment at varying temperatures of 46 °C, 52 °C, 58 °C, 64 °C, 70 °C, 76 °C, and 82 °C, for a controlled strain value of 5%, and an angular velocity of 10 rad/s. Asphalt-filler interaction was further analysed using evaluation index coefficients based on rheological performances, i.e., ΔG*, L-A-δ, K-B-δ, K-B-G*, and KE respectively. Variations in the evaluation coefficients obtained were also determined via statistical normality tests of skewness and kurtosis. Results obtained indicated a strong asphalt-filler interaction response for coefficients ΔG*, L-A-δ, K-B-G*, and KE, while K-B-δ exhibited inconsistent interaction responses. Similarly, the normality test results also inferred that ΔG*, L-A-δ, K-B-G*, and KE portrayed better skewness values compared to K-B-δ.

Feasibility of using a protein gel for masticatory assessment of older people

Masticatory function plays a crucial role in the breakdown of food for bolus formation and safe swallowing. Chewable silicone gel particles (Optosil) were used for assessing masticatory performance by dentists but such particles were found not suitable for older people due to its hard and dry texture and unfavored flavor. Therefore, with fast growing number of older people who have eating and swallowing difficulties, seeking a suitable model food for masticatory performance assessment becomes an important issue. This study was to develop a glucose-containing model food system for reliable evaluation of the masticatory performance. Three formulas with different amount of gelatin were used to prepare the gels and their textural properties were analyzed. A glucometer was used to measure glucose concentration in saliva. Both young adults (23.5 ± 1.1 years) and older subjects (72.9 ± 5.4 years) were asked to perform mastication tests to verify the reliability of the method. Results showed that the Gel-15% sample gave the best performance and was selected as the test food. Reliability of the current method was proved by the classical standard of Optosil method. Moreover, our findings indicated that masticatory performance was significantly positively correlated with bite force in both young and older adults (young subjects: r = 0.874, p < 0.01; older subjects: r = 0.638, p < 0.01). In conclusions, this study suggested that the newly method could accurately and efficiently measure the masticatory performance of older people.

Comparing different fatigue test methods at asphalt mastic level

Latest research is focused on predicting the fatigue behavior of asphalt mixtures through cost-effective and simple test methods on asphalt mastic level (asphalt binder + mineral fines). There are numerous fatigue test methods for asphalt binders and mastic using the dynamic shear rheometer (DSR). However, up to now, the results of the different fatigue tests on DSR have not been directly compared. Therefore, four different asphalt mastic mixes were prepared, and each was tested with the two most popular fatigue tests [linear amplitude sweep (LAS) test and time sweep (TS) test] and then compared to each other. The TS tests were performed as stress-controlled and as strain-controlled tests. All LAS and TS tests were performed with cylindrical and hyperbolic specimen shapes to identify impact of specimen shape. Different fatigue criteria were applied for evaluation to investigate the comparability of the results. Stress-controlled TS tests, strain-controlled TS tests, and LAS tests reveal different rankings of fatigue performance. However, a dissipated energy approach can combine stress-controlled and strain-controlled TS tests into one fatigue curve. The hyperbolic specimen shape can be used for TS tests and results in the same rankings. The hyperbolic specimen shape is not applicable for LAS tests. A calculation model could be derived to establish a relationship between the measured and actual stresses and strains in the necking of a hyperbolic specimen. TS tests using the dissipated energy approach appear to be the most promising mastic fatigue tests.

Assessing creep properties of asphalt binder, asphalt mastic and asphalt mixture

In this article, creep properties of asphalt binders and asphalt mastics (binder filler composite) are tested in the Dynamic Shear Rheometer using a single shear creep test and considering steady-state flow conditions. These tests are performed for a set of 10 different asphalt binders and 18 corresponding asphalt mastics. The same material combinations are used to produce asphalt mixtures in the laboratory, which are then subjected to cyclic compression tests to assess the creep properties of the asphalt mixture. Finally, the creep properties resulting from asphalt binder tests, asphalt mastic tests and asphalt mixture tests are comparatively analysed in terms of the material-specific creep rates. The results show reasonable and sound correlations across the different material scales. The authors concluded that the asphalt binder has a significant impact on the creep behaviour of the corresponding asphalt mixture.

Effect of structure on the mechanical and physical properties of chocolate considering time scale phenomena occurring during oral processing

Micro-aeration has been employed by the chocolate industry as a texture and flavour modifier. However, the impact of micro-aeration on oral processing is still not well understood. This study quantifies the mechanical, thermal and tribological behaviour of chocolate materials of different porosity levels. These material properties were then linked to sensory data considering the temporal phenomena of the oral process. In-vivo mastication tests were utilised to define the level of fragmentation of chocolate and coupled with heat transfer numerical models to simulate the melting during oral processing. Micro-aeration affects all material properties resulting in lower fracture stresses, rapid melting and a lower friction coefficient. The sensory results showed that micro-aeration creates a perception of a softer, less sticky chocolate which melts fast inside the mouth, without compromising the sweetness perception. This research adopts an innovative multidisciplinary approach to the physics of chocolates, bringing together the fields of solid mechanics, heat transfer, tribology, and sensory analysis and employing engineering experimental and numerical approaches to provide a link between chocolate structure, material properties and sensory perception. The outcome can contribute a powerful design tool for controlling the perception of sensory attributes for specific chocolate composition.

DETERMINATION OF CHEWING EFFICIENCY IN PATIENTS WITH RESTORED TOOTH CROWN PART

Supporting teeth preservation at the restoration of dentition defects with the help of fixed porcelain fused metal dentures is considered one of the most important issues of prosthodontics.&#x0D; Margin line preparation strategies are still disputable nowadays. In most cases preparation is confined to the ledge creation. Its function is to provide a smooth transition of orthopedic restoration to a tooth root and prevent the traumatization of marginal paradontium.&#x0D; These issues are gaining a momentum when the possibility of manufacturing fixed prosthesis with the use of partially or completely ruined teeth with the preserved root as a support appears.&#x0D; Since the opportunities of thermal method for gingiva retraction and marginal line formation around the supporting teeth are not studied enough in modern scientific sources, our research aims to define the mastication efficiency state in patients of sample groups after the fixation of dentures on the supporting teeth prepared for prosthesis with the help of diathermocoagulation and mechanical retraction.&#x0D; The authors of the article have determined the mastication efficiency in the patients with the restored tooth crown. Altogether 54 patients of two sample groups aged from 20 to 60 years and above with completely ruined tooth crowns were examined. Their soft tissues around the supporting teeth were prepared for the fixed prosthesis manufacturing.&#x0D; The first sample group involved 29 patients that made up 53.7% of general studied population. Their supporting teeth gingiva margins were retracted with the help of diathermocoagulation while preparing them for the fixed dentures. While the gingiva margins of the patients of the second sample group, consisting of 25 people (46.3% of general studied population), were retracted with the help of cotton Ultrapak cord, produced by Ultradent (the USA). It is offered in several size options.&#x0D; Mastication efficiency state after prosthesis was determined with the help of mastication test (Ukrainian Utility Patent # 94841). In this case, mastication index was the main diagnostic tool. It was received with the help of computer analysis of digital samples in software “Adobe Photoshop Extended”.&#x0D; The analysis of the dynamics of mastication test indices of the patients of sample group 1 delivered typical results. In a week after the fixation of fixed porcelain fused metal dentures, the reduction of the mean value of mastication test index by 0.2 was fixed. The verification of these changes according to the statistical significance showed positive result (at p = 0.0004). At the same time, the verification of the changes, occurred during the period from the 7th to the 30th day after the fixation of dentures in patients of sample group 1, with the help of Wilcoxon test showed that at p = 0.9 the reduction of the mean value to 5.148 had no statistical significance.&#x0D; While the dynamics of mastication test changes in sample group 2 looked as follows. The reduction of the mean values of mastication test index from 5.184 to 5.112 was observed. So, the spread between the values received before the retraction and in seven days after crown fixation made up 0.072. The conducted statistical verification of these changes (at p = 0.01) proved their statistical significance. In contrast, the collation of the indices received after seven days of denture fixation and in 30-days period after it (from 5.112 to 5.132) at p = 0.961 demonstrated changes at the level of statistical error.&#x0D; According to the received research results, prosthesis with the fixed porcelain fused metal dentures promotes patients’ mastication efficiency restoration. That is traced in the reduction of the mastication test index values received after the 7th day of crown fixation in both sample groups. It should be noted here, that statistically significant difference between the indices of the patients of sample group 1 and 2 was not found. On the 30th day of denture fixation, mastication efficiency indices remained almost the same.

Effect of micro-aeration on the mechanical behaviour of chocolates and implications for oral processing.

Aeration in foods has been widely utilised in the food industry to develop novel foods with enhanced sensorial characteristics. Specifically, aeration at the micron-sized scale has a significant impact on the microstructure where micro-bubbles interact with the other microstructural features in chocolates. This study aims to determine the effect of micro-aeration on the mechanical properties of chocolate products, which are directly correlated with textural attributes such as hardness and crumbliness. Uniaxial compression tests were performed to determine the mechanical properties such as Poisson's ratio, Young's modulus and macroscopic yield strength together with fracture tests to estimate the fracture toughness. In vivo mastication tests were also conducted to investigate the link between the fracture properties and fragmentation during the first two chewing cycles. The uniaxial stress-strain data were used to calibrate a viscoplastic constitutive law. The results showed that micro-aeration significantly affects mechanical properties such as Young's modulus, yield and fracture stresses, as well as fracture toughness. In addition, it enhances the brittle nature of the chocolate, as evidenced by lower fracture stress but also lower fracture toughness leading to higher fragmentation, in agreement with observations in the in vivo mastication tests. As evidenced by the XRT images and the stress-strain measurements micro-aeration hinders the re-arrangement of the microscopic features inside the chocolate during the material's deformation. The work provides a new insight of the role of bubbles on the bulk behaviour of complex multiphase materials, such as chocolates, and defines the mechanical properties which are important input parameters for the development of oral processing simulations.

Association of Body Composition, Physical Functioning, and Protein Intake in Adult Patients With Mitochondrial Diseases.

BackgroundWhether decreased physical functioning of patients with mitochondrial disease (MD) is related to altered body composition or low protein intake needs clarification at the background of the nutrition state.MethodsIn this 2‐site cross‐sectional study, MD patients were age‐, body mass index (BMI)–, and gender‐matched to controls. Body composition was assessed by dual‐energy x‐ray absorptiometry. Physical functioning was measured by handgrip strength, 6‐minute walking test, 30‐second sit‐to‐stand test (30SCT), and 6‐minute mastication test. Total daily protein intake was calculated by 3‐day food records. Malnutrition was assessed by Patient‐Generated Subjective Global Assessment and the Global Leadership Initiative on Malnutrition (GLIM) criteria and sarcopenia by the 2018 consensus. Data were analyzed using independent samples t‐tests, Fisher exact test, and Spearman and Pearson correlation coefficients.ResultsThirty‐seven MD patients (42 ± 12 years, BMI: 23 ± 4 kg/m2, 59% females) and 37 matched controls were included. Handgrip strength was moderate, inversely related to fat mass index in both MD patients and controls, whereas it correlated with fat‐free mass index in controls solely. Protein intake was associated with muscle strength (handgrip strength and 30SCT) in MD patients but not in controls. Twenty‐seven MD patients (73%) were malnourished, and 5 (14%) were classified as sarcopenic.ConclusionsMuscle strength is related to body composition and protein intake in MD patients. This, in combination with the high incidence of both malnutrition and sarcopenia, warrants individual nutrition assessment in MD patients.

Two mastication tests used in children with down syndrome: A feasibility study.

Children with Down syndrome can have problems with chewing and swallowing. However, no objective tests are available that give information about the efficiency and endurance of mastication. In this study, the feasibility of two mastication tests is studied by answering two research questions: are the Test of Mastication and Swallowing of Solids and the 6-min mastication test feasible to use in children with Down syndrome? Do these tests give information about the mastication efficiency and endurance in these children? A total of 24 (4-18years) children with Down syndrome participated. The collected variables in the Test of Mastication and Swallowing of Solids were masticatory time, discrete bites, masticatory cycles and number of swallows per cracker. The inter-rater reliability of these variables was tested. Collected variables in the 6-min mastication test were total masticatory cycles and percentage difference between minutes 1 and 6. Qualitative ratings of masticatory movements were made. In both tests, a comparison with a typically developing group was made. In both tests, a total of 87.5% of the children completed the test. Both tests are feasible for children with Down syndrome with language comprehension skills of 3years and over. The tests give information about the function and endurance during mastication in children with Down syndrome. The results showed that children with Down syndrome do not have endurance problems during mastication, but there is a lack of efficiency in mastication.

Experimental study on usability of various construction wastes as fine aggregate in asphalt mixture

In this study, some properties of asphalt mixture containing ceramic, marble and redbrick as recycled waste materials were investigated. Because of the low strength, recycled waste materials were used only as fine aggregate and filler. Various tests including moisture susceptibility, Marshall stability, Cantabro, mechanical composition, mineral composition and physical properties test were conducted. In addition, softening point and penetration properties of asphalt mastic containing the above-recycled waste materials as powder were researched. The results indicated marble mixture exhibited better performance than other mixtures, especially in 25% content. In addition, from asphalt mastic test results, ceramic asphalt mastic showed the superiority of high and low-temperature properties.

Efficiency of Using Mastication Test with Food Stimuli While Performing Electromyographic Studies in Dental Patients

The relevance of the topic is related to the necessity for a more detailed study of the effectiveness of surface electromyography as a method for diagnosis of pathological conditions of the teeth-and-jaws system and estimation of the orthopaedic treatment results. The objective of the study was to investigate the effectiveness of using a mastication test while performing surface electromyography in dental patients. We studied and analysed the output of surface electromyograms of m.masseter and m.temporalis obtained from a functional test of the maximum jaw clenching and a mastication test with a food stimulus in 54 persons. The results of the study showed a slight difference in the absolute values between the data of the functional test of the maximum jaw clenching and the mastication test. However, the comparative data of the tests after editing (removal of fragments representing the maximal mouth opening during the mastication from electromyograms in the "Neuro-MSP" program) showed no significant difference in data ($&gt;$0.05) and the maximum approximation of the absolute values of the functional and mastication tests in all cases. Thus, it has been established that in practice the mastication test while performing electromyography in dental patients should be determined and carried out as an additional one in order to clarify the results of treatment. Further studying and establishment of the most effective methods for electromyography is considered to be promising in dentistry.

Evaluation of waste materials as alternative sources of filler in asphalt mixtures

There are many different ways to reduce the construction industry’s impact on environment. The incorporation of waste in the fabrication of construction materials may be beneficial for both the waste management sector and the construction industry. The aim of this research was to investigate the use of three different waste materials (construction and demolition waste, brick powder and fly ash) as filler in asphalt mixtures. Limestone filler was used as reference material. The materials were characterized in terms of their geometrical, physical and chemical properties, and the interaction with bitumen was assessed with two mastic test methods using four different bitumens. The specific surface of waste materials shows a wide-ranging variation due to material specific shape and texture of particles. However, the Rigden voids and bitumen number tests adequately measure the stiffening effect of these materials. The delta ring and ball test results showed there is a good relation with the filler content when the results are affected by the bitumen type. The f/b ratio for a specific bitumen–filler combination can be determined from the maximum filler-to-bitumen ratio and the recommended stiffening increase. The mastics with these waste materials showed strong resistance to water damage.

The 6-min mastication test: a unique test to assess endurance of continuous chewing, normal values, reliability, reproducibility and usability in patients with mitochondrial disease.

In patients with mitochondrial disease, fatigue and muscle problems are the most common complaints. They also experience these complaints during mastication. To measure endurance of continuous mastication in patients with mitochondrial diseases, the 6-min mastication test (6MMT) was developed. This study included the collection of normal data for the 6MMT in a healthy population (children and adults). During 6 min of continuous mastication on a chew tube chewing cycles per minute, total amount of chewing cycles and the difference between minute 1 (M1 ) and minute 6 (M2 ) were collected in 271 healthy participants (5-80 years old). These results were compared with those of nine paediatric and 25 adult patients with a mitochondrial disease. Visual analogue scale (VAS) scores were collected directly after the test and after 5 min. A qualitative rating was made on masticatory movements. The reproducibility of the 6MMT in the healthy population with an interval of approximately 2 weeks was good. The inter-rater reliability for the observations was excellent. The patient group demonstrated lower total amount of chewing cycles or had greater differences between M1 and M6 . The 6MMT is a reliable and objective test to assess endurance of continuous chewing. It demonstrates the ability of healthy children and adults to chew during 6 min with a highly stable frequency of mastication movements. The test may give an explanation for the masticatory problems in patient groups, who are complaining of pain and fatigue during mastication.

Electrical and mechanical properties of asphaltic composites containing carbon based fillers

Electrically conductive asphalt concrete has strong potential for diverse multifunctional applications including heated pavements to remove snow and ice, self-sensing, self-healing, and energy harvesting. In this study, the effects of powder type carbon based additives including eight graphite and carbon black on asphaltic composites are investigated. The physical, electrical, and mechanical properties of the raw materials, asphalt mastic, and asphalt concrete are experimentally evaluated focusing on electrical conductivity. The mastic test results indicate that electrical conductivity of the asphalt mastics substantially influenced by the particle shape, and flake type graphite is efficient in imparting conductivity. Based on the mastic test results, two flake type graphite were selected, and added into asphalt concrete specimens. The results showed that a sufficiently high electrical conductivity can be achieved by adding 2–3% of filler size flake graphite by volume of asphalt concrete. In addition, adding the flake graphite improves the indirect tensile strength of asphalt concrete up to 40%. The findings of the study will provide fundamental backgrounds in using carbon based powder type conductive additives for multifunctional applications of asphaltic composites.

Only severe malocclusion correlates with mastication deficiency

ObjectivesThe relation between level of dentofacial deformity and extent of masticatory deficiency was studied. DesignThree groups of human young adults were formed: (i) subjects needing orthodontics plus orthognathic surgery (SevDFD, n=18), (ii) subjects needing orthodontic treatment only (ModDFD, n=12), and (iii) subjects needing no treatment (NoDFD, n=12). For mastication tests, carrot boluses were collected at the deglutition time. Bolus particle size range was expressed as d50 value, which was compared with the Masticatory Normative Indicator (MNI). Index of treatment need (IOTN), global oral health assessment index (GOHAI) and chewing kinematic characteristics were also recorded. We used a general linear model univariate procedure followed by a Student-Newman-Keuls test. ResultsAll the SevDFD subjects showed impaired mastication with MNI above the normal limit (d50 mean=7.23mm). All the ModDFD subjects but one were below this limit (d50 mean=2.54mm), and so could adapt to a low level of masticatory impairment as also indicated by kinematics. IOTN indicated a treatment need for ModDFD (3.7±0.5) and SevDFD (4.3±0.6) groups, while GOHAI values were unsatisfactory only for SevDFD (42.6±9.2 vs. 55.3±1.9). ConclusionsOur findings emphasize the need for an objective evaluation of masticatory function to discern truly deficient mastication from mild impairment allowing satisfactory adaptation of the function. However, malocclusions are known to worsen with time justifying thus their corrections as early as possible.

The reinforcement and healing of asphalt mastic mixtures by rejuvenator encapsulation in alginate compartmented fibres

This paper explores the potential use of compartmented alginate fibres as a new method of incorporating rejuvenators into asphalt pavement mixtures. The compartmented fibres are employed to locally distribute the rejuvenator and to overcome the problems associated with spherical capsules and hollow fibres. The work presents proof of concept of the encapsulation process which involved embedding the fibres into the asphalt mastic mixture and the survival rate of fibres in the asphalt mixture. To prove the effectiveness of the alginate as a rejuvenator encapsulating material and to demonstrate its ability survive asphalt production process, the fibres containing the rejuvenator were prepared and subjected to thermogravimetric analysis and uniaxial tensile test. The test results demonstrated that fibres have suitable thermal and mechanical strength to survive the asphalt mixing and compaction process. The CT scan of an asphalt mortar mix containing fibres demonstrated that fibres are present in the mix in their full length, undamaged, providing confirmation that the fibres survived the asphalt production process. In order to investigate the fibres physiological properties and ability to release the rejuvenator into cracks in the asphalt mastic, the environmental scanning electron microscope and optical microscope analysis were employed. To prove its success as an asphalt healing system, compartmented alginate fibres containing rejuvenator were embedded in asphalt mastic mix. The three point bend tests were performed on the asphalt mastic test samples and the degree to which the samples began to self-heal in response was measured and quantified. The research findings indicate that alginate fibres present a promising new approach for the development of self-healing asphalt pavement systems.

Influence of the geometrical and physical properties of filler in the filler–bitumen interaction

The objective of this laboratory study is to investigate the relationship between the geometrical and physical properties of filler and the consistency of filler–bitumen mixtures and the stripping resistance. Five fillers (3 manufactured and 2 natural) were geometrically and physically characterized with various test methods, including SEM imaging. The filler–bitumen interaction was assessed with two consistency-related mastic tests and a water susceptibility test.SEM images show significant differences in size, shape and surface texture between tested fillers, and a strong correlation with the stiffening effect. It is proposed the inclusion of the f/bmax ratio, obtained from the absorbing capacity test, in the filler specifications to serve as an indicative threshold value of the filler content added.

Three-dimensional micromechanical finite element analysis on gauge length dependency of the dynamic modulus of asphalt mixtures

The dynamic modulus of asphalt mixture is one of the major parameters for pavement design. It is generally measured by gauge-point-mounted (GPM) measurement system based on indirect tensile test (IDT), which is very costly and time-consuming. Furthermore, the gauge length in the GPM system has a significant effect on the dynamic modulus but has not been taken into account. This paper focuses on the numerical simulation of the dynamic modulus of asphalt mixture and its dependency on gauge length. The microstructure of asphalt mixture was captured using the non-destructive X-ray computed tomography technique. The series of images were transformed into a three-dimensional (3D) data array that can be mapped into finite element method elements to build a 3D model. Meanwhile, the general Maxwell model was applied for viscoelastic mastic and calibrated from Prony series analysis of the mastic test data. The IDT numerical simulations by incorporating specimen microstructure and ingredient properties were conducted within linear viscoelastic range. The simulation results of the dynamic modulus have good correlations with the testing results. Moreover, the simulation shows the relationship between the dynamic modulus and gauge length. These results indicate that different gauge lengths affect the dynamic modulus significantly. Additionally, this study simulated the gauge length dependency of the dynamic modulus when considering viscoelasticity and heterogeneity.

Prediction of Dynamic Modulus and Phase Angle of Stone-Based Composites Using a Micromechanical Finite-Element Approach

This paper presents a micromechanical finite-element (FE) model for predicting the viscoelastic properties (dynamic modulus and phase angle) of asphalt mixtures, typical stone-based composites. The two-dimensional (2D) microstructure of asphalt mixtures was captured by optically scanning the surface image of sectioned specimens. FE mesh of image samples was generated within each aggregate and asphalt mastic. Along the aggregate boundary, the FEs share the nodes to connect the deformation. The micromechanical FE model was accomplished by incorporating specimen microstructure and ingredient properties (viscoelastic asphalt mastic and elastic aggregates). The generalized Maxwell model was applied for viscoelastic asphalt mastic with calibrated parameters from nonlinear regression analysis of the mastic test data on dynamic modulus and phase angle. The displacement-based FE simulations were conducted on the numerical samples under sinusoidal cyclic loading. The predicted dynamic modulus and phase angle were compared favorably with the mixture test data over a frequency range. The simulation results of the asphalt mixture samples have good correlations with the numerical calibration of asphalt mastic specimens. These results indicate that the developed micromechanical FE model can provide a computational tool for predicting the global viscoelastic properties of asphalt mixtures with captured microstructure and ingredient properties. Additionally, this study can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking their microstructure.