Dynamic Modulus Ratio Research Articles

Engineering properties-based parameters used for moisture damage evaluation of asphalt mixtures: a review

Moisture-induced damage has been known as a major premature distresses in asphalt pavement. Numerous review papers have been made to provide the progression in study on moisture damage of asphalt pavement. However, mechanical properties of asphalt mixtures used as a parameter for moisture susceptibility evaluation were not reviewed in detail. To make the review of moisture-induced damage in asphalt pavement more comprehensive, this paper reviews research studies on moisture damage of asphalt pavement in view of mechanical properties as a parameter during the past 50 years. These parameters include tensile strength ratio (TSR), cohesion ratio (CR), dynamic modulus ratio (DMR), resilient modulus ratio (RMR), and shear strength ratio (SSR). TSR and CR are only relevant at bottom of asphalt concrete (AC), while SSR can be used to describe moisture damage at different AC depths. DMR and RMR are concentrated on the impact of moisture damage via performance characteristics of asphalt mixtures.

Analysis of Modulus Properties of High-Modulus Asphalt Mixture and Its New Evaluation Index of Rutting Resistance

High-modulus asphalt mixture (HMAM) is one of the most effective materials to enhance the rutting resistance of asphalt pavement and upgrade pavement sustainability. The objectives of this study are to investigate the modulus properties of different HMAMs and their correlation with the rutting resistance, to propose reasonable modulus evaluation indicators, and to analyze the rutting resistance mechanisms of different materials (hard asphalt, polyethylene, dissolved polyolefin). The effect of three HMAMs and two styrene-butadiene-styrene (SBS) modifiers on asphalt mixtures’ rutting resistance were evaluated by dynamic modulus test and wheel track test, and the results were simulated and further analyzed via ABAQUS. The results indicate that the dynamic modulus of the mixtures showed a gradual increase and decrease with the increase of loading frequency and testing temperature, respectively. The ratio of dynamic modulus in low frequency to that in high frequency correlates well with dynamic stability under high-temperature conditions, and the wider the frequency coverage, the higher the correlation between this ratio and dynamic stability. The rutting resistance of asphalt pavements can be improved by reducing the frequency sensitivity of HMAMs under high temperatures or by increasing the modulus’ absolute value of the pavement structural layer. Therefore, two indicators, the absolute value of the modulus and the ratio of 0.1 Hz dynamic modulus to 25 Hz dynamic modulus at 55 °C, are recommended for the evaluation of rutting resistance of HMAMs. Based on the evaluation indexes proposed in this paper, a comparative analysis of the rutting resistance mechanism of HMAMs prepared with different materials was carried out, and it was concluded that the mixture with high-modulus agents had the best rutting resistance, which is consistent with the test road observations, thus verifying the feasibility of the modulus evaluation indexes recommended in this paper for the evaluation of the rutting resistance of different types of HMAMs.

Evaluation of Moisture Susceptibility of Asphalt Mixtures: Influence of Aggregates, Visual Analysis, and Mechanical Tests

Asphalt pavement failure is directly related to the traffic and climate effects. Temperature and moisture severely impact pavement service life. It is known that moisture changes the stiffness and stress–strain distribution and all the mechanical behaviors of the mixture/structure. There is a huge interest in studying the impact of water on the behavior of flexible pavements, mainly on freeze–thaw regions under tropical climates with high rainfall levels. The scope of the present paper was to check the susceptibility to moisture-induced damage of dense asphalt mixes produced and applied on highways in Brazil’s southernmost region using different laboratory tests: visual adhesion of coarse aggregate; tensile strength ratio (TSR), and dynamic modulus ratio (DMR). Thus, this study evaluated the morphological, chemical, and mineralogical properties of aggregates from 11 quarries, as well as the interaction between aggregates and the respective bituminous binders. Rocks with high Si contents performed worse in visual adhesiveness tests; chemical ratios such as Fe/Si above 1 and Ca/K above 5, as well as the rougher texture of aggregates, considerably improved the coating, reducing the failures in adhesion. Results of TSR and DMR, after applying the induced moisture damage cycle, indicated greater susceptibility to conventional binders than mixtures containing modified binders in their composition. The action of moisture damage for most mixtures caused a reduction in strength and stiffness, warning of a decrease in the binder’s ability within the mixture, completely changing the distribution of efforts within the structure. Therefore, from this study, it is possible to suggest using DMR instead of TSR to assess susceptibility to moisture damage.

Presentation of thermodynamic and dynamic modules methods to investigate the effect of nano hydrated lime on moisture damage of stone matrix asphalt

ABSTRACT Stone matrix asphalt (SMA) mixtures are the most resistant type of asphalt mixtures today in which the aggregate skeleton bears the bulk load. In this study, the effect of nano hydrated lime (NHL) on the moisture sensitivity of SMA mixtures was investigated. To examine the effect of NHL, the surface free energy (SFE) method and the dynamic modulus (DM) test were applied under wet and dry conditions on mixtures constructed with limestone and granite aggregates. The SFE results indicated that the granite aggregates had a greater polar component and limestone aggregates had a higher non-polar component which shows their higher moisture resistance. The adhesion free energy (AFE) results showed that the adhesion of base bitumen and limestone aggregate was higher, and using NHL improved the AFE values. The results of DM tests indicated that as the load cycles raised, the wet to dry DM ratio reduced and using NHL increased this ratio. The reduction slope of the DM ratio in samples constructed with granite aggregates showed a faster trend compared to limestone aggregates, and using NHL improved the resistance of SMA mixtures constructed with granite aggregates to moisture more than limestone aggregates.

Moisture susceptibility of asphalt mixtures: 2S2P1D rheological model approach and new index based on dynamic modulus master curve changes

A methodology is proposed for evaluating the induced moisture damage in asphalt mixtures via a new index called the dynamic modulus area ratio (DMAR), which is used to calculate the difference under the areas of the dynamic modulus master curves fitted by the 2S2P1D model before and after conditioning. Were evaluated 21 mixtures applied in the field by comparing data obtained via empirical tests, e.g., the tensile strength ratio and dynamic modulus ratio, using AASHTO T283. The behavior that moisture damage analysis based on stiffness loss measurements in modulus tests can lead to different conclusions than those based on damage resistance tests like TSR. The 2S2P1D model proved to be adequate to evaluate the changes promoted by the deleterious effect of water on the stiffness of the mixtures after the induced moisture damage cycle. For the DMAR, the results clearly differed according to the type of binder, indicating that the impact of water damage on the linear viscoelastic behavior depends on the type of binder used in the mixture. The estimation of susceptibility to moisture using the DMAR, which assesses broader temperature and frequency ranges, enables a stiffness evaluation that is closely related to the field impact on this property, making it possible to evaluate variations in the entire stiffness spectra of the mixtures; thus, it can be used in methods based on the performance for the selection of asphalt mixtures.

Study on dynamic modulus of asphalt mixture in cold regionunder rotary accelerated loading

In order to study the evolution law of mechanical properties of asphalt pavement mixture in cold regions under long-term load, the rotary accelerated loading equipment was used to carry out a total of 500,000 accelerated loading tests on the full-scale pavement, and the dynamic modulus test of the mixture before and after wheel load was carried out respectively. The master curve of dynamic modulus and dynamic modulus ratio (dynamic modulus value after wheel load / dynamic modulus value before wheel load) of the mixture at -20ºC were established to predict the long-term mechanical response of the mixture at low temperature. The results show that: low-frequency (or high temperature) has a more significant effect on the viscoelastic properties of the asphalt mixture. In the conversion frequency range of 1.6×10–3~1.6×102 Hz, the dynamic modulus ratio decreases with the increase of frequency, and the maximum ratio is 0.62 when the frequency is 1.6×10–3 Hz, which indicates that the high frequency (low temperature) has little effect on the performance of asphalt mixture. This study can be used as a theoretical reference for the structural design and performance optimization of asphalt pavement in cold regions.

Investigation of the Impact of Deicer Materials on Thermodynamic Parameters and Its Relationship with Moisture Susceptibility in Modified Asphalt Mixtures by Carbon Nanotube

Road maintenance in winter is one of the road engineers’ concerns, especially asphalt specialists. As pavement frosts lead to road closures and accidents, one of the ways to prevent these events is spraying deicer materials on the pavement surface. Therefore, investigation of the impact of the deicer materials on asphalt is essential. So in this study, the effect of deicer materials on the moisture susceptibility of base asphalt mixtures and modified ones by carbon nanotube (CNT) was investigated utilizing penetration and softening point tests and surface free energy (SFE) concept and dynamic modulus (DM) test. Two common deicers CaCl2 and MgCl2 along with distilled water (DW) were used. Results indicated that using CNT increased the softening point and reduced the penetration degree of modified bitumens, which increased the penetration index amounts and improved the sensitivity of the samples against temperature variations. The SFE results showed that modifying bitumen with CNT led to an increase in adhesion free energy (AFE). The samples saturated in CaCl2 and modified with 1% CNT had the highest CFE values. The MgCl2 solution had less detachment energy, which reduced the energy of the system and stripping occurred sooner. Results of the DM test showed that CNT increased the wet-to-dry DM ratio in saturated conditions with deicer materials and DW, improving the resistance of the saturated mixtures to moisture. The GMDH model compared to the MVR method had higher accuracy and less error in prediction of stripping percentage with the R2 value of 99.46%.

Effect of laboratory long-term oven aging on the stiffness of asphalt mixtures

This study evaluates the effect of laboratory long-term oven aging (LTOA) on the stiffness of asphalt mixture using laboratory dynamic modulus test. A large variety of materials was subjected to diverse LTOA conditions including different aging temperatures and durations with loose mixture and compacted samples. Dynamic modulus master curve and dynamic modulus ratio (DMR) data shows that the aging of loose mixture at 95 °C could be an ideal LTOA procedure with the efficiency and capability to characterize the long-term aging in the field. The variety of materials including the use of recycled asphalt pavement, warm mix asphalt technologies and asphalt binder performance grade was also found to have appreciable effect on the LTOA properties.

Establishment of Complex Modulus Master Curves Based on Generalized Sigmoidal Model for Freeze-Thaw Resistance Evaluation of Basalt Fiber-Modified Asphalt Mixtures.

This study aims to study the freeze–thaw (F–T) resistance of asphalt mixture incorporating styrene–butadiene–styrene (SBS) polymer and basalt fiber by using the established complex master curves of the generalized Sigmoidal model. Asphalt mixture samples incorporating styrene–butadiene–styrene (SBS) polymer and basalt fiber were manufactured following the Superpave gyratory compaction (SGC) method and coring as well as sawing. After 0–21 F–T cycles processing, a complex modulus test asphalt mixture specimen was performed to evaluate the influence of the F–T cycle. Besides, according to the time–temperature superposition principle, the master curves of a complex modulus were constructed to reflect the dynamic mechanical response in an extended range of reduced frequency at an arbitrary temperature. The results indicated that the elastic and viscous portions of asphalt mixture incorporating SBS and basalt fiber have decreased overall. It could be observed from the dynamic modulus ratio that the dynamic modulus ratios of specimens were more affected by the F–T cycle at low frequency or high temperature. Thus, in the process of asphalt pavement design and maintenance, attention should be paid to seasonal frozen asphalt pavement under low frequency and high temperature.

Pulse velocity–strength and elasticity relationship of high volume fly ash induced self-compacting concrete

ABSTRACTSelf-compacting concrete (SCC) represents one of the most outstanding advances in concrete technology during the last decade. The amount of SCC used for the structural purpose has strongly increased worldwide, and consequently, there is a need to assess the applicability of non-destructive testing techniques to survey SCC’s transient in situ mechanical properties. Information of the elastic behaviour of SCC is alluring if the behaviour of concrete structures is to be translated legitimately. Ultrasonic Pulse Velocity (UPV) method is a standout among the most prominent non-destructive techniques utilized in the appraisal of concrete properties. This paper deals with the investigation of the velocity–strength and elasticity relationship of high volume fly ash (HVFA) induced SCC. The relationship between UPV, static and dynamic Young’s modulus is analyzed. A new general simplified expression that allows estimation of compressive strength from UPV has been defined and is based on the ratio of dynamic modulus of elasticity to the static modulus of elasticity. The mathematical model has been validated by comparing predicted versus measured compressive strength.

Relationship between Asphalt Binder Parameters and Asphalt Mixture Rutting

The selection and specification of asphalt binder is one of the factors that ultimately affect the long-term performance of asphalt pavements. Many agencies currently follow AASHTO M320 for their binder specifications, where the ratio of dynamic modulus to the sine of the phase angle, | G*|/sin δ, is the binder rutting parameter. However, an alternative now exists, AASHTO M332, which uses the non-recovered creep compliance, J nr , for this purpose. In this paper, the relative merits of these two parameters are compared using experimental results from 21 different asphalt mixtures from Arizona. The rutting parameters according to AASHTO M332 and M320 were determined for each of the binders in these mixtures and, for each mixture, two rutting performance tests were conducted: Hamburg wheel tracking test and repeated load permanent deformation test. The two binder rutting parameters demonstrated very high correlation to one another for non-polymer modified asphalts, but inconsistent correlation for polymer modified asphalts. Both Hamburg wheel tracking tests and repeated load permanent deformation tests showed positive correlations to both | G*|/sin δ and Jnr. It was concluded that, while both parameters showed good correlation, the Jnr of the binder relates better to mixture rutting than does | G*|/sin δ. Considering the results in this study, it is believed that Jnr is a slightly better rutting parameter for binder specifications.

Comparative Study on the Effect of Organic and Inorganic Fiber on the Anti-wheel Impact Performance of Airport Pavement Concrete under Freeze-thaw Environment

Abstract In this paper, the poly-acrylonitrile synthetic fiber concrete (PSC) (the representative of organic fiber concrete) and alkali resistant glass fiber concrete (ARGC) (the representative of inorganic fiber concrete) were studied and compared. The test were carried out by the IMYD-X single side freeze-thaw machine of concrete and the modified wheel impact test machine which was pressurized and accelerated. The dynamic deformation and toughness performance of fiber concrete have been comparatively analyzed, and the effect of fiber on the performance of concrete has been investigated. Three concrete performance indexes were selected to evaluate the anti-wheel impact performance of the airport pavement concrete in freeze-thaw environment, namely relative mass ratio, relative compressive strength ratio, and relative dynamic modulus ratio. The results showed that adding fiber in the concrete can significantly improve these indexes. Four indexes of concretes decreased when the test durations increased, and the relationship between various indexes and test durations can be described as an exponential function. Moreover, all the indexes of fiber concrete increase with the increasing fiber volume content. The optimal content of both organic fiber concrete and inorganic fiber concrete were 1.6 kg/m3. From the overall trend, the relationship among fiber concretes by the anti-wheel impact performance in freeze-thaw environment can be listed as follow: ordinary concrete

Evaluation of Moisture Susceptibility of Asphalt Mixtures Using Dynamic Modulus

Abstract A pothole is one of the distresses in asphalt pavement caused by the presence of water in the asphalt pavement and the presence of traffic passing over the affected area. Recently, lots of potholes were observed due to heavy rain in Korea. Thus, the indirect tensile strength ratio (TSR) is commonly used based on the AASHTO T 283 procedure to evaluate the moisture susceptibility of an asphalt mixture; however, TSR cannot be used as a representative index for the mechanical behavior of the moisture-conditioned asphalt mixture. In this study, the dynamic modulus │E*│ laboratory test is applied as a replacement test for the TSR in order to assess the moisture susceptibility of four different asphalt mixtures. The dynamic modulus test is used to determine the % of retained stiffness, a term that was referred to as the dynamic modulus ratio (DMR). The results of both TSR and DMR conducted on the same mixtures are compared and statistically analyzed. The logistic regression model was used to evaluate the correlation between TSR and DMR. The correlation between TSR and DMR at 20°C is significant. However, there was no relation between TSR and DMR at other temperature ranges (5°C, 40°C, 54.4°C) because there was different viscoelastic behavior at different temperature.

Assessment of the Effect of Pore Pressure Cycles on Moisture Sensitivity of Hot Mix Asphalt Using MIST Conditioning and Dynamic Modulus

Abstract In this study, a recently developed Moisture Induced Sensitivity Tester (MIST) is used for moisture conditioning of asphalt concrete samples, and then dynamic modulus testing is used to assess whether MIST is sensitive to moisture-induced damage in asphalt. MIST applies a pumping action by generating repeated pore pressure in a compacted asphalt sample; however, it is not known yet whether MIST affects the dynamic modulus of asphalt concrete. In essence, the dynamic moduli (E*) of a Superpave mix were determined with and without MIST conditioning. Dynamic moduli at different temperatures and frequencies as well as dynamic modulus mastercurves were compared for with and without MIST conditioning cases using a dynamic modulus ratio (DMR). Computed DMR results consistently show that dynamic modulus decreases due to MIST conditioning, which indicates that MIST conditioning causes moisture damage in asphalt samples. Considering the consistency of DMR results and the added benefit provided by MIST to simulate cyclic pore water pressure due to traffic on wet pavement, MIST conditioning with a dynamic modulus test is found to be a good option to study moisture sensitivity of asphalt mixes.

Towards a Mechanistic Understanding of Moisture Damage in Asphalt Concrete

AbstractRecently, dynamic modulus (|E*|) test has gained substantial acceptance for Superpave mix performance evaluation and in designing asphalt pavements for rutting and fatigue cracking. Mechanistic empirical pavement design guide (MEPDG currently branded as AASHTOW are ME pavement design) is currently the state-of-the-art method of designing asphalt pavements and it utilizes |E*| data. Unfortunately, neither Superpave mix design method nor ME pavement design has used |E*| to evaluate asphalt concrete (AC) moisture damage. Though |E*| based rut and fatigue models are available in ME pavement design, there has not been any model for moisture damage of AC. To this end, this study attempts to correlate |E*| with moisture damage as a first step to moving toward mechanistic understanding. Moisture-induced sensitivity tester (MIST) is used for moisture conditioning of asphalt samples. Moisture damage resulting from MIST conditioning is evaluated using the dynamic modulus ratio (DMR) of wet to dry samples. MI...

Dynamic Properties of Rubber Cement Stabilized Soil Based on Resonant Column Tests

A series of resonant column tests were conducted on waste tire rubber cement soil (RCS) to examine the effect of different rubber content and confining pressure on the dynamic behavior of rubber cement soft cohesive soil. Rubber content and confining pressure had important influence on the dynamic properties of the rubber cement soil. The test results showed that the shear modulus of RCS decreases and damping ratio increases with increasing rubber content. With the confining pressures increases, dynamic modulus ratio of the rubber cement soil gradual increases and the damping ratio decreases. Several scanning electron microscope (SEM) images of the powdered rubber and rubber cement soil were analyzed. The micro-structure analysis indicated that rubber cement soil has better dynamic damping performance than untreated soil. An empirical model was developed to evaluate the relationship between the dynamic shear modulus, damping ratio of RCS and the amplitude of shear strain. By comparison, the measured results were in good agreement with the calculated results.

Analysis of Soil Arch under Dynamic Load

Aroused by the differential stiffness of pile and soil, the upper load on subgrade is apt to be transferred to pile rather than soil among piles in pile supported embankment(soil arching effect), which optimizes the load-transfer path and effectively limits total settlement of the subgrade. In this paper the properties of soil arch under dynamic load have been investigated by performing numerical studies using the Finite Element Method. The influence of stiffness difference between soil and pile on the soil arch is also proposed in this paper. According to the calculation results, the softer the soil between piles is, the larger proportion of load imposes on pile. Dynamic load has negative effects on the static soil arch, but it does not ruin the shape of the arch. Simultaneously, the larger N (the ratio of dynamic modulus of pile to that of soil)is, the weaker the negative effects of dynamic load on static soil arch are. The static soil arch (soil arch formed when the model only bears static load) has optimized the load transformation path, leading more load undertaken by the pile. Besides, When the stiffness difference between pile and soil among piles is relatively small, the height of soil arch increases sharply with the decrease of N; while when the stiffness difference reaches some certain value, the further increasing of N has little influence on soil arch’s height.

Impact of Lime and Liquid Antistrip Agents on Properties of Idaho Hot-Mix Asphalt Mixture

In 2005, the Idaho Transportation Department constructed a field project on State Highway 67 (SH-67) to evaluate the impact of hydrated lime and a liquid antistrip agent on the mechanical properties of an Idaho hot-mix asphalt (HMA) mixture. This paper documents the results of a laboratory evaluation on field-produced HMA mixtures sampled from lime and liquid antistrip test sections on SH-67. As the two mixtures were subjected to multiple freeze-thaw (F-T) cycles, the mixture treated with hydrated lime (lime mixture) maintained good resilient-modulus properties over the entire 21 F-T cycles. The mixture treated with the liquid antistrip agent (liquid mixture) fully disintegrated after 22 F-T cycles. The results of a mechanistic analysis showed that, as a result of multiple F-T cycling, the liquid mixture will incur a 220% increase in potential rutting compared with the lime mixture, which will incur only a 65% potential increase in rutting. The dynamic moduli in compression demonstrated that both dry and moisture-conditioned lime mixtures can be considered less susceptible to rutting compared with liquid mixtures. Furthermore, the lime mixtures demonstrated better resistance to moisture damage than the liquid mixtures on the basis of the ratio of dynamic modulus in tension of moisture-conditioned to dry mixtures. The additional stiffness of the lime mixtures did not contribute to premature fatigue cracking when mixtures were subjected to dynamic creep testing in the tensile mode of loading.

Dynamic Property Determination for Early-Age Concrete

Test results are reported of the dynamic modulus (DM) elasticity and Poisson's ratio of concrete at early age by means of nondestructive evaluation. The DM was measured by a new test apparatus that includes a free-free boundary vibration chamber and a dynamic resonance measurement system with a fast Fourier transform analyzer. The measurement was conducted on concrete cylinder specimens. The DM and Poisson's ratio were calculated using the first 2 natural frequencies of a cylinder. The measured dynamic response showed good consistency and reproducibility. This method enables a measurement of progressive changes in the stiffness of the concrete without damaging the specimen and provides reliable values of DM. It is found that the age of concrete has a significant influence on resonance frequencies; herein, the resonance frequencies shift from lower to higher values in a regular pattern with the age of concrete.

Correlation between Laboratory and Road Rubber Wear Tests

Abstract The wear resistance ranking of three rubber compounds A, G and K measured in the laboratory at medium to high slip on sharp silicon carbide (SiC) grinding wheels was similar to that determined by road tests at Pecos, Texas. The wear resistance ranking of the three compounds changed on blunt alumina grinding wheels compared to wear resistance rankings on sharp SiC grinding wheels. The change was most probably due to a change of mechanism from mainly cutting on sharp surfaces to predominantly fatigue on blunt surfaces. For these three compounds a change in the ambient temperature from 23 to 75°C during laboratory testing had no effect on the wear resistance ranking. The wear of the rubber compounds on the abrasive grinding wheels and during road tests followed Zapp's relation in which the wear is proportional to the ratio of dynamic modulus to rupture energy.