Rubber-Thermoplastic Compositions. Part III. Predicting Elastic Moduli of Melt Mixed Rubber-Plastic Blends

1981 ◽  
Vol 54 (1) ◽  
pp. 91-100 ◽  
Author(s):  
A. Y. Coran ◽  
R. Patel
Keyword(s):  
Shear Modulus ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Material Selection ◽  
Adjustable Parameter ◽  
Dynamic Shear Modulus ◽  
Torsion Pendulum ◽  
Molten State ◽  
Dynamic Shear ◽  
The Individual

Abstract Blends prepared by mixing rubbers with plastics in the molten state have been known and used for a number of years. The stiffness of such blends vary widely with both the proportions of rubber to plastic and with material selection, even at equivalent rubber to plastic proportions. This report describes correlations between blend stiffness and the properties of the individual blend components. Dynamic shear modulus G′, determined by torsion pendulum measurements, was used to characterize the stiffnesses of the blends. Values of G′ were related to the moduli of the hard and soft (plastic and rubber) phases, G′H and G′S, and the volume fraction of plastic ϕH through a single adjustable parameter by means of a recently proposed relationship. The adjustable parameter was then correlated with other properties of the blend components. In contrast with the work reported in the first two papers of this series, this report is on compositions in which the rubber is not crosslinked.

scholarly journals Micromechanical Prediction Model of Viscoelastic Properties for Asphalt Mastic Based on Morphologically Representative Pattern Approach

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhichen Wang ◽  
Naisheng Guo ◽  
Xu Yang ◽  
Shuang Wang
Keyword(s):  
Shear Modulus ◽  
Prediction Model ◽  
Viscoelastic Properties ◽  
Volume Fraction ◽  
Complex Modulus ◽  
Homogenization Theory ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Low Frequencies ◽  
Asphalt Mastic

This paper is devoted to the introduction of physicochemical, filler size, and distribution effect in micromechanical predictions of the overall viscoelastic properties of asphalt mastic. In order to account for the three effects, the morphologically representative pattern (MRP) approach was employed. The MRP model was improved due to the arduous practical use of equivalent modulus formula solution. Then, a homogeneous morphologically representative model (H-MRP) with the explicit solution was established based on the homogenization theory. Asphalt mastic is regarded as a composite material consisting of filler particles coated structural asphalt and free asphalt considering the physicochemical effect. An additional interphase surrounding particles was introduced in the H-MRP model. Thus, a modified H-MRP model was established. Using the proposed model, a viscoelastic equation was derived to predict the complex modulus and subsequently the dynamic modulus of asphalt mastic based on the elastic-viscoelastic correspondence principle. The dynamic shear rheological tests were conducted to verify the prediction model. The results show that the predicted modulus presents an acceptable precision for asphalt mastic mixed with 10% and 20% fillers volume fraction, as compared to the measured ones. The predicted modulus agrees reasonably well with the measured ones at high frequencies for asphalt mastic mixed with 30% and 40% fillers volume fraction. However, it exhibits underestimated modulus at low frequencies. The reasons for the discrepancy between predicted and measured dynamic shear modulus and the factors affecting the dynamic shear modulus were also explored in the paper.

Variation in dynamic elastic shear modulus of sandstone upon fluid saturation and substitution

Geophysics ◽  
2003 ◽  
Vol 68 (2) ◽  
pp. 472-481 ◽  
Author(s):  
Jalal Khazanehdari ◽  
Jeremy Sothcott
Keyword(s):  
Shear Modulus ◽  
Elastic Moduli ◽  
Frequency Dispersion ◽  
Dynamic Shear Modulus ◽  
Ultrasonic Frequency ◽  
Dynamic Shear ◽  
Fluid Saturation ◽  
Dynamic Elastic Moduli ◽  
Rock Microstructure ◽  
Elastic Shear

Experimental acoustic measurements on sandstone rocks at both sonic and ultrasonic frequencies show that fluid saturation can cause a noticeable change in both the dynamic bulk and shear elastic moduli of sandstones. We observed that the change in dynamic shear modulus upon fluid saturation is highly dependent on the type of saturant, its viscosity, rock microstructure, and applied pressures. Frequency dispersion has some influence on dynamic elastic moduli too, but its effect is limited to the ultrasonic frequency ranges and above. We propose that viscous coupling, reduction in free surface energy, and, to a limited extent, frequency dispersion due to both local and global flow are the main mechanisms responsible for the change in dynamic shear elastic modulus upon fluid saturation and substitution, and we quantify influences.

scholarly journals Comparison Study of Dynamic Elastic Moduli of Cement Mortar and No-cement Slag Based Cementitious Mortar Activated with Calcined Dolomite with Impulse Excitation Technique

2018 ◽  
Vol 186 ◽  
pp. 02004
Author(s):  
Herry Suryadi Djayaprabha ◽  
Ta-Peng Chang ◽  
Jeng-Ywan Shih
Keyword(s):  
Compressive Strength ◽  
Shear Modulus ◽  
Elastic Moduli ◽  
Cement Mortar ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Shear Moduli ◽  
Dynamic Young’S Modulus ◽  
Impulse Excitation ◽  
Dynamic Elastic Moduli

This paper presents the comparison of an experimental investigation on compressive strength and dynamic elastic moduli of mortars made of Ordinary Portland Cement (OPC) and ground granulated blast furnace slag (GGBFS) incorporating with calcined dolomite. Dolomite powder calcined at temperature 900°C emerged as a GGBFS activator for producing cementitious mortar binder. In this study, no-cement mortar is made by activating GGBFS with calcined dolomite by a fixed amount of 20 wt%. The compressive strengths and dynamic elastic moduli were measured at 7 and 28 days. Comparing with cement mortar, the compressive strength of no-cement mortar was found about 54.4 and 46.9% lower at ages of 7 and 28 days, respectively. Non-destructive evaluation of the dynamic elastic moduli was investigated by impulse excitation technique (IET). It measures the resonant frequencies of induced vibration signal in the flexural and torsional mode for determining the dynamic Young's modulus and the dynamic shear modulus. The Poisson's ratio was calculated by the dynamic Young's modulus and the dynamic shear modulus relationship. The results showed that the 28-day dynamic Young's and shear moduli of cement mortar were 31.91 and 14.43 GPa, respectively. The dynamic Young's and shear moduli of no-cement mortar were lower by 23.3 and 15.2% than that of cement mortar at the age of 28 days. The obtained results showed that the 28-day Poisson's ratio of no-cement mortar had a wider range between 0.177 and 0.209 than that of cement mortar which ranged from 0.180 to 0.185.

scholarly journals Normalized Shear Modulus and Damping Ratio of Soil–Rock Mixtures With Different Volumetric Block Proportions

2021 ◽  
Vol 9 ◽  
Author(s):  
Shengnian Wang ◽  
Xinqun Gao ◽  
Honglei Hui ◽  
Wei Ma ◽  
Chong Shi ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Large Scale ◽  
Volume Fraction ◽  
Damping Ratio ◽  
Triaxial Tests ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Confining Pressures ◽  
Gravelly Soils ◽  
Shear Behaviors

The volume fraction of rock blocks plays a particularly significant role in static/dynamic shear behaviors of soil–rock mixtures (SRM). Large-scale cyclic triaxial tests for SRM with different volumetric block proportions (VBPs) were performed at different confining pressures to investigate the reduction of dynamic shear modulus (G) and the increase of damping ratio (λ). Results indicate that VBP has a significant effect on the dynamic behaviors of SRM. The higher VBP is more likely to result in a gentler reduction of G and a faster increase of λ. The variations of dynamic shear modulus ratio (G/G0) and normalized damping ratio (λnor) fall within relatively narrow bands but are very different with gravelly soils and sands due to VBP with particle size larger than 2 mm. The G/G0 and λnor can be characterized by empirical functions about normalized shear strain amplitude (γnor).

Evaluation of Chemical and Rheological Aging Indices to Track Oxidative Aging of Asphalt Mixtures

2018 ◽  
Vol 2672 (28) ◽  
pp. 349-358 ◽  
Author(s):  
Farhad Yousefi Rad ◽  
Michael D. Elwardany ◽  
Cassie Castorena ◽  
Y. Richard Kim
Keyword(s):  
Shear Modulus ◽  
Material Selection ◽  
Asphalt Binder ◽  
Age Hardening ◽  
Dynamic Shear Modulus ◽  
Dynamic Shear ◽  
Zero Shear Viscosity ◽  
Chemical Changes ◽  
Oxidative Aging ◽  
Wide Range

Oxidative age hardening in asphalt binder leads to embrittlement. Embrittled asphalt is prone to fatigue and thermal cracking. Therefore, the ability to predict asphalt binder oxidative age hardening within a pavement throughout its service life could inform improved pavement material selection, design, and maintenance practices. Studying the evolution of oxidative aging requires the use of key properties to track oxidation levels, termed aging index properties (AIPs) here. The objective of this study is to identify suitable rheological and chemical AIPs to track oxidation levels in asphalt materials. A wide range of laboratory and field aged materials were evaluated in this study. A range of chemical AIPs determined by Fourier transform infrared spectroscopy (FTIR) absorbance peaks and areas were evaluated based on their correlation with laboratory aging duration. Rheological AIPs were evaluated based on the strength of their relationship to the chemical changes induced by oxidation. The rheological AIPs evaluated included the dynamic shear modulus, zero shear viscosity, Glover-Rowe parameter, and crossover modulus. The chemical AIP evaluation that most strongly correlated with laboratory aging duration is the carbonyl plus the sulfoxide absorbance peaks. The results indicate that both the dynamic shear modulus and Glover-Rowe parameter constitute rheological AIPs that relate directly to the chemical changes induced by oxidation.

Shear Modulus and Damping Ratio of Gravel Material

2011 ◽  
Vol 105-107 ◽  
pp. 1426-1432 ◽  
Author(s):  
De Gao Zou ◽  
Tao Gong ◽  
Jing Mao Liu ◽  
Xian Jing Kong
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Dynamic Shear Modulus ◽  
Test Results ◽  
Dynamic Shear ◽  
Data Points ◽  
Shear Strain Amplitude

Two of the most important parameters in dynamic analysis involving soils are the dynamic shear modulus and the damping ratio. In this study, a series of tests were performed on gravels. For comparison, some other tests carried out by other researchers were also collected. The test results show that normalized shear modulus and damping ratio vary with the shear strain amplitude, (1) normalized shear modulus decreases with the increase of dynamic shear strain amplitude, and as the confining pressure increases, the test data points move from the low end toward the high end; (2) damping ratio increases with the increase of shear strain amplitude, damping ratio is dependent on confining pressure where an increase in confining pressure decreased damping ratio. According to the test results, a reference formula is proposed to evaluate the maximum dynamic shear modulus, the best-fit curve and standard deviation bounds for the range of data points are also proposed.

Sign in / Sign up

Export Citation Format

Share Document