scholarly journals Laboratory Evaluation of a Vertical Vibration Testing Method for an SMA-13 Mixture

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4409
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Jinshun Xue ◽  
Changqing Deng ◽  
Yong Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Heavy Traffic ◽  
Asphalt Mixture ◽  
Vertical Vibration ◽  
Laboratory Evaluation ◽  
Vibration Testing ◽  
Testing Method ◽  
Vibration Compaction ◽  
Compaction Time

In order to simulate the on-site compaction conditions of a Stone Matrix Asphalt (SMA) mixture, The Vertical Vibration Testing Method (VVTM), Superpave Gyratory Compactor (SGC), and Marshall method are used to test the SMA-13 mixture, and the physical and mechanical properties of the asphalt mixture designed by these three methods are tested. Subsequently, the influences of the molding method on the mechanical properties are compared. The influence of vibration compaction time on the volume parameters of the SMA mixture is studied. Following the heavy traffic compaction standards, the vibration compaction time of the SMA mixture is determined. The results show that the densities of the heavy Marshall specimen, VVTM specimen, and SGC specimen are 1.018 times, 1.019 times, and 1.015 times greater than that of the standard Marshall specimen, respectively. The passing rate of the 4.75 mm aggregate of the standard Marshall specimen is 29.9%, and that of the VVTM specimen and SGC specimen is 31.1% and 30.5%, respectively, while that of the heavy Marshall specimen is 34.5%. The mechanical strength of the specimen can be greatly improved as the density increases. On the other hand, by the same compaction work, the mechanical strength of the VVTM specimens can be increased by at least 7% compared with the heavy Marshall specimen. The mechanical strength of the VVTM specimen is increased by at least 22% compared with the standard Marshall specimen. The results also show that under the optimal asphalt-aggregate ratio and the same compaction work, the compressive strength and shear strength of the VVTM specimens are increased by at least 6% and 9%, respectively, compared with the Marshall specimens. In summary, the performance of the asphalt mixture designed by the VVTM is superior, providing a wider choice for future asphalt mixture design.

scholarly journals Investigation on cement-improved phyllite based on the vertical vibration compaction method

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247599
Author(s):  
Yingjun Jiang ◽  
Jiangtao Fan ◽  
Yong Yi ◽  
Tian Tian ◽  
Kejia Yuan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Static Pressure ◽  
Cement Content ◽  
Vertical Vibration ◽  
Pressure Method ◽  
Vibration Compaction ◽  
Modulus Of Resilience ◽  
Compaction Method

The vertical vibration compaction method (VVCM), heavy compaction method and static pressure method were used to form phyllite specimens with different degrees of weathering. The influence of cement content, compactness, and compaction method on the mechanical properties of phyllite was studied. The mechanical properties of phyllite was evaluated in terms of unconfined compressive strength (Rc) and modulus of resilience (Ec). Further, test roads were paved along an expressway in China to demonstrate the feasibility of the highly weathered phyllite improvement technology. Results show that unweathered phyllite can be used as subgrade filler. In spite of increasing compactness, phyllite with a higher degree of weathering cannot meet the requirements for subgrade filler. With increasing cement content, Rc and Ec of the improved phyllite increases linearly. Rc and Ec increase by at least 15% and 17%, respectively, for every 1% increase in cement content and by at least 10% and 6%, respectively, for every 1% increase in compactness. The higher the degree of weathering of phyllite, the greater the degree of improvement of its mechanical properties.

scholarly journals Cement-Modified Loess Base for Intercity Railways: Mechanical Strength and Influencing Factors Based on the Vertical Vibration Compaction Method

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3643
Author(s):  
Yingjun Jiang ◽  
Qilong Li ◽  
Yong Yi ◽  
Kejia Yuan ◽  
Changqing Deng ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
High Speed ◽  
Cement Content ◽  
Vertical Vibration ◽  
Initial Growth ◽  
High Speed Railway ◽  
Growth Properties ◽  
Vibration Compaction ◽  
Growth Equations ◽  
Compaction Method

Cement-modified loess has been used in the recent construction of an intercity high-speed railway in Xi’an, China. This paper studies the mechanical strength of cement-modified loess (CML) compacted by the vertical vibration compaction method (VVCM). First, the reliability of VVCM in compacting CML is evaluated, and then the effects of cement content, compaction coefficient, and curing time on the mechanical strength of CML are analyzed, establishing a strength prediction model. The results show that the correlation of mechanical strength between the CML specimens prepared by VVCM in the laboratory and the core specimens collected on site is as high as 83.8%. The mechanical strength of CML initially show linear growth with increasing cement content and compaction coefficient. The initial growth in CML mechanical strength is followed by a later period, with mechanical strength growth slowing after 28 days. The mechanical strength growth properties of the CML can be accurately predicted via established strength growth equations. The results of this study can guide the design and construction of CML subgrade.

scholarly journals Comparison of Mechanical Properties of Cement-Stabilized Loess Produced Using Different Compaction Methods

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Yingjun Jiang ◽  
Kejia Yuan ◽  
Qilong Li ◽  
Changqing Deng ◽  
Yong Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Cement Content ◽  
Resilient Modulus ◽  
Great Influence ◽  
Field Measurements ◽  
Vertical Vibration ◽  
Dry Density ◽  
Curing Time ◽  
Compaction Method

Mechanical properties are important indexes to evaluate the improvement effect and engineering performance of cement-stabilized loess (CSL). This paper presents a comparison of the mechanical properties of CSL compacted using hammer quasi-static compaction method (QSCM) and vertical vibration compaction method (VVCM). The compaction properties, unconfined compressive strength (UCS), splitting strength (SPS), and resilient modulus (RM) of the laboratory-compacted CSL using VVCM and QSCM are tested and compared. Furthermore, the effects of compaction method, cement content, compaction coefficient, and curing time of the CSL specimens are investigated. In addition, field measurements are carried out to validate the laboratory investigations. The results show that the laboratory-compacted CSL using VVCM has a larger dry density and smaller optimum water content than that using QSCM. And the compaction method has a great influence on the mechanical strength of CSL. The UCS, SPS, and RM of the specimen produced using VVCM are averagely 1.17 times, 1.49 times, and 1.17 times that of CSL produced using QSCM, respectively, and the UCS, SPS, and RM of the specimens produced using these two methods increase linearly as the cement content and compaction coefficient increase, while the mechanical strength growth curve experiences three periods of increasing sharply, increasing slowly, and stabilizing with the curing time increased. Moreover, the results also show that the mechanical properties of laboratory-compacted CSL using VVCM have a better correlation of 83.8% with the field core samples.

scholarly journals Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5599
Author(s):  
Mohamed Samir Eisa ◽  
Ahmed Mohamady ◽  
Mohamed E. Basiouny ◽  
Ayman Abdulhamid ◽  
Jong R. Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Modified Asphalt ◽  
Indirect Tensile ◽  
Graphene Platelets ◽  
Wheel Tracking

Recently, nanomaterials have attracted attention in the field of pavement construction as modifiers to endure heavy loads and climate changes. In this study, conventional asphalt (bitumen) of penetration grade AC (60/70) was modified with graphene platelets (GnPs) at three different contents: 0.5%, 1.0%, and 1.5% by weight of asphalt content. Kinematic viscosity, softening point, penetration, and dynamic shear rheology tests were performed to evaluate the mechanical properties of modified binder. The results showed that adding GnPs improves the mechanical properties of asphalt binder; the kinematic viscosities, softening points, and rutting parameters increased but penetrations decreased with the contents of GnPs. Hot mix asphalt specimens with GnPs-modified asphalt were prepared and characterized with Marshall tests, thermal stress restrained specimen tests (TSRST), wheel tracking tests, and indirect tensile tests. Similar to the results of asphalt binder, the mechanical properties of asphalt mixture were improved by GnPs. Marshall stability increased by 21% and flow decreased by 24% with accepted value of 2.8 mm in penetration when the mixture was modified with 1.0 wt% of GnPs. At the same GnPs content, modified asphalt mixture led to lower failure temperature by 2 °C in comparison with unmodified asphalt mixture and the cryogenic failure stress was improved by 12%. The wheel tracking tests showed that GnPs-modified asphalt mixture has outstanding deformation resistance in comparison with unmodified asphalt mixtures: after 5000 cycles, 1.0 wt% of GnPs reduced the rut depth of asphalt mixture by 60%—the rut depth of unmodified asphalt mixture was 6.9 mm compared to 2.75 mm for modified asphalt mixture. After 10,000 cycles, the modified asphalt mixture showed rut depth of 3.24 mm in comparison with 8.12 mm in case of unmodified asphalt mixture. Addition of GnPs into asphalt mixture significantly improved the indirect tensile strength: 1.0 wt% of GnPs increased the indirect tensile strength of unmodified asphalt mixture from 0.79 to 1.1 MPa recording ~40% increment. The results of this study can confirm that graphene platelets enhance the mechanical properties of asphalt mixture and its performance.

Study of Rheological Properties of Modified Concrete Mixtures at Vibration

2019 ◽  
Vol 968 ◽  
pp. 96-106
Author(s):  
Oleksandr Pshinko ◽  
Olena Hromova ◽  
Dmytro Rudenko
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Physical Nature ◽  
Concrete Mixture ◽  
Practical Significance ◽  
Vibration Displacement ◽  
Concrete Mixtures ◽  
Variable Quantity ◽  
Vibration Compaction ◽  
Mechanism Of Interaction

Study of rheological properties of concrete mixtures based on modified cement systems in order to determine process parameters. Methodology. To study structural-mechanical properties of modified concrete mixtures of different consistency at their horizontal vibrating displacement an oscillatory viscometer was designed. Results. The optimization of the process of vibration displacement of concrete mixtures with the specification of parameters of vibration impacts taking into account structural-mechanical properties of the mixture is performed. It has been established that the viscosity of the modified cement system of the concrete mixture is a variable quantity, which depends on the parameters of the vibration impacts. Scientific novelty. The mechanism of interaction of the modified concrete mixture with the form and the table vibrator during its vibration compaction is determined. On the basis of this, a model of concrete laying process control is proposed, that allows to predict the ability to form a dense concrete structure. Practical significance. Disclosed physical nature of the process of vibrating displacement of modified concrete mixtures using the principles of physical-chemical mechanics of concrete allows reasonably choose the best options for vibration impacts.

scholarly journals High-strength and fibrous capsule–resistant zwitterionic elastomers

2021 ◽  
Vol 7 (1) ◽  
pp. eabc5442
Author(s):  
Dianyu Dong ◽  
Caroline Tsao ◽  
Hsiang-Chieh Hung ◽  
Fanglian Yao ◽  
Chenjue Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
High Strength ◽  
Design Principles ◽  
Fibrous Capsule ◽  
High Mechanical Strength ◽  
Capsule Formation ◽  
Locking Mechanism ◽  
Fibrous Capsule Formation

The high mechanical strength and long-term resistance to the fibrous capsule formation are two major challenges for implantable materials. Unfortunately, these two distinct properties do not come together and instead compromise each other. Here, we report a unique class of materials by integrating two weak zwitterionic hydrogels into an elastomer-like high-strength pure zwitterionic hydrogel via a “swelling” and “locking” mechanism. These zwitterionic-elastomeric-networked (ZEN) hydrogels are further shown to efficaciously resist the fibrous capsule formation upon implantation in mice for up to 1 year. Such materials with both high mechanical properties and long-term fibrous capsule resistance have never been achieved before. This work not only demonstrates a class of durable and fibrous capsule–resistant materials but also provides design principles for zwitterionic elastomeric hydrogels.

scholarly journals Rejuvenation Mechanism of Asphalt Mixtures Modified with Crumb Rubber

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 370-384
Author(s):  
Hossein Noorvand ◽  
Kamil Kaloush ◽  
Jose Medina ◽  
Shane Underwood
Keyword(s):  
Tensile Strength ◽  
Dynamic Loading ◽  
Creep Compliance ◽  
Asphalt Mixture ◽  
Crumb Rubber ◽  
Indirect Tensile Strength ◽  
Laboratory Evaluation ◽  
Strength Testing ◽  
Noise Mitigation ◽  
Indirect Tensile

Asphalt aging is one of the main factors causing asphalt pavements deterioration. Previous studies reported on some aging benefits of asphalt rubber mixtures through laboratory evaluation. A field observation of various pavement sections of crumb rubber modified asphalt friction courses (ARFC) in the Phoenix, Arizona area indicated an interesting pattern of transverse/reflective cracking. These ARFC courses were placed several years ago on existing jointed plain concrete pavements for highway noise mitigation. Over the years, the shoulders had very noticeable and extensive cracking over the joints; however, the driving lanes of the pavement showed less cracking formation in severity and extent. The issue with this phenomenon is that widely adopted theories that stem from continuum mechanics of materials and layered mechanics of pavement systems cannot directly explain this phenomenon. One hypothesis could be that traffic loads continually manipulate the pavement over time, which causes some maltenes (oils and resins) compounds absorbed in the crumb rubber particles to migrate out leading to rejuvenation of the mastic in the asphalt mixture. To investigate the validity of such a hypothesis, an experimental laboratory testing was undertaken to condition samples with and without dynamic loads at high temperatures. This was followed by creep compliance and indirect tensile strength testing. The results showed the higher creep for samples aged with dynamic loading compared to those aged without loading. Higher creep compliance was attributed to higher flexibility of samples due to the rejuvenation of the maltenes. This was also supported by the higher fracture energy results obtained for samples conditioned with dynamic loading from indirect tensile strength testing.

scholarly journals Mechanical strength and flexibility in $$\alpha '$$-4H borophene

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shobair Mohammadi Mozvashi ◽  
Mohammad Ali Mohebpour ◽  
Sahar Izadi Vishkayi ◽  
Meysam Bagheri Tagani
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
2D Materials ◽  
Group Iv ◽  
Good Stability ◽  
Free Standing ◽  
Promising Candidate ◽  
Inherent Anisotropy

AbstractVery recently, a novel phase of hydrogenated borophene, namely $$\alpha '$$ α ′ -4H, has been synthesized in a free-standing form. Unlike pure borophenes, this phase shows very good stability in the air environment and possesses semiconducting characteristics. Because of the interesting stiffness and flexibility of borophenes, herein, we systematically studied the mechanical properties of this novel hydrogenated phase. Our results show that the monolayer is stiffer (Y$$_\text {xy}$$ xy = $$\sim $$ ∼ 195 N/m) than group IV and V 2D materials and even than MoS$$_2$$ 2 , while it is softer than graphene. Moreover, similar to other phases of borophene, the inherent anisotropy of the pure monolayer increases with hydrogenation. The monolayer can bear biaxial, armchair, and zigzag strains up to 16, 10, and 14% with ideal strengths of approximately 14, 9, and 12 N/m, respectively. More interestingly, it can remain semiconductor under this range of tension. These outstanding results suggest that the $$\alpha '$$ α ′ -4H is a promising candidate for flexible nanoelectronics.

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