Study on Test and Influence of Anti-Shear Strength of Asphalt Mixture

2012 ◽  
Vol 598 ◽  
pp. 580-584
Author(s):  
Yi Wang ◽  
Nan Xiang Zheng ◽  
Xiao Ping Ji

In order to further reveal the shear property of asphalt mixtures, shear device self-developed was used to research the variation and impact factor of anti-shear strength, cohesion and internal friction angle of different asphalt mixture types. The results show that: Modified asphalt can effectively improve the cohesion and anti-shear strength, but little effect on the internal friction angle; the internal friction angle and anti-shear strength of SAC-16 are greater than AC-16, but the cohesion is not significant different; with the nominal size of stone increased, the internal friction angle and anti-shear strength of asphalt mixtures rose, but little change in the cohesion; with temperatures increased, the anti-shear strength and cohesion of asphalt mixtures reduced gradually, but little change in the internal friction angle.

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.


Author(s):  
Khelifa Harichane ◽  
Mohamed Ghrici ◽  
Said Kenai

Cohesive soils with a high plasticity index present difficulties in construction operations because they usually contain expansive clay minerals. However, the engineering properties of soils can be improved by different techniques. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both lime and natural pozzolana on plasticity, compaction and shear strength of two clayey soils classified as CH and CL according to the unified soil classification system (USCS). The obtained results indicated that for CH class clay soil, the plasticity index decreased significantly for samples stabilized with lime. On the other hand, for the soil classified as CL class clay, a high decrease in the plasticity index value was observed for samples stabilized with natural pozzolana compared to those stabilized with lime. Also, both the cohesion and internal friction angle in lime added samples were demonstrated to increase with time. The combination of lime and natural pozzolana exhibits a significant effect on the enhancement of both the cohesion and  internal friction angle at later stages. The lime-natural pozzolana combination appears to produce higher shear strength parameters than lime or natural pozzolana used alone.


2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Guang-jin Wang ◽  
Xiang-yun Kong ◽  
Chun-he Yang

The researchers cannot control the composition and structure of coarse grained soil in the indoor experiment because the granular particles of different size have the characteristics of random distribution and no sorting. Therefore, on the basis of the laboratory tests with the coarse grained soil, the HHC-Granular model, which could simulate the no sorting and random distribution of different size particles in the coarse-grained soil, was developed by use of cellular automata method. Meanwhile, the triaxial numerical simulation experiments of coarse grained soil were finished with the different composition and structure soil, and the variation of shear strength was discussed. The results showed that the internal friction angle was likely to reduce with the increasing of gravel contents in the coarse-grained soil, but the mean internal friction angle significantly increased with the increment of gravel contents. It indicated that the gravel contents of shear bands were the major factor affecting the shear strength.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yue Qiang ◽  
Yulong Chen

In order to study the mechanical behavior of lime-treated soil under different loading rates, a series of monotonous three-axial compression tests are carried out under different lime contents, different loading rates, and different curing periods. The test results indicate that the lime content can significantly improve the mechanical behaviors of soil, such as shear strength and elastic modulus. On the other hand, three-axial compression test of soil is carried out under the loading rate ranging from 0.1%/min to 8%/min. Experimental results indicate that the mechanical behavior of lime-treated soil is sensitive to loading rate. Besides, the corresponding relationship between internal friction angle, cohesion, lime content, and loading rate is discussed. The results indicate that the loading rate almost has no influence on internal friction angle but significant influence on lime content. Cohesion is affected by lime content and loading rate. Shear strength, elastic modulus, and cohesion all increase with the increase of loading rate. Longer curing period is associated with greater parameter value. Shear strength, elastic modulus, and internal friction angle all firstly increase and then decrease when lime content increases, which all reach the maximum at 6%.


2012 ◽  
Vol 256-259 ◽  
pp. 358-361
Author(s):  
Xiang Yun Kong ◽  
Guang Jin Wang ◽  
Xiao Chao Zhou

Apparent particle size grading is the important characteristic of super-high bench dumping site, and the critical factors with the impact of its stability and disaster prevention are the fragmentation distribution and shear strength parameters of granular. With the copper mine dumping site which had the feature of apparent particle size grading, the thesis carried out the study of on-site particle size investigation and indoor laboratory. The particle-size distribution law with the changing of dumping-site height was analyzed and quantitative relationship between the fragmentation distribution and shear strength parameters of granular was discussed. The research results indicated that coarse-grain contents and maximum grain size were increased significantly according to the decreasing of dumping-site height, which showed that the dumping-site had the feature of apparent particle size grading. The coarse particle content in the grain size composition and internal friction angle φ of shear strength parameters increased with the obvious increment of the distribution value B. The relationship between distribution value B and the internal friction angle φ could be expressed by exponential function curve.


Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1234
Author(s):  
Yongsheng Yao ◽  
Jue Li ◽  
Chenghao Liang ◽  
Xin Hu

Coarse aggregate is the major part of asphalt mixture, and plays an essential role in mechanical performance of pavement structure. However, the use of poor-quality coarse recycled aggregate (CRA) reduces the strength and stability of the aggregate skeleton. It is a challenge to predict accurately the influence of CRA on the performance of asphalt mixture. In this study, both a uniaxial compression test and a direct tensile test were carried out to evaluate the failure strength of asphalt concrete with four CRA content. The discrete element method (DEM) was applied to simulate the specimen of asphalt concrete considering the distribution and properties of CRA. The results showed that temperature and loading rate have a significant influence on failure strength, especially when the CRA content was more than 20%. With the increase of CRA content, both cohesion force and internal friction angle were gradually weakened. The proposed model can be used to predict the failure strength of asphalt mixture, since both experimental and simulated results had a high consistency and repeatability. With the decrease of CRA strength, the nominal cohesion force of the specimen decreased, while the internal friction angle increased.


2016 ◽  
Vol 16 ◽  
pp. 69-81 ◽  
Author(s):  
Muhammad Karami ◽  
Ainalem Nega ◽  
Ahdyeh Mosadegh ◽  
Hamid Nikraz

The main objective this study is to evaluate the permanent deformation of buton rock asphalt (BRA) modified asphalt paving mixtures using dynamic creep test so that long term deformation behavior of asphalt mixtures can be characterized. The dynamic creep test was conducted on unmodified and BRA modified asphalt mixture using UTM25 machine. Asphalt cement of C170 from a regional supplier in Western Australia was used as the base asphalt binder for unmodified asphalt mixture; and BRA modified asphalt mixtures were made by substituting the base asphalt with 10, 20, and 30% (by weight of total asphalt binder) natural binder continuing granular BRA modified binder. The granular (pellets) BRA modified binder with a diameter of 7-10 mm was produced and extracted according the Australia Standard. Crushed granite was taken from a local quarry of the region; and dense graded for both unmodified and BRA modified asphalt mixture with the nominal size of 10 mm was used. The results of this analysis showed that BRA modified had a good performance as compared with unmodified asphalt mixtures, and increase in the content modified binder to 10%, 20%, and 30% resulted in decrease of the total permanent strain.


2011 ◽  
Vol 301-303 ◽  
pp. 530-533 ◽  
Author(s):  
Lin Lin Liu ◽  
Jian Qiao Li ◽  
Shi Chao Fan ◽  
Xiu Juan Li ◽  
Wen Feng Fan ◽  
...  

The survey shows that the bulk density of lunar soil increases with the depth. The compaction of lunar soil also differs in the depth. The lunar soil mechanical condition plays an important and non-negligible roll on the mobility of the rover. It is important to make research on the change of the mechanical parameters at different lunar soil conditions, and it is also important to research the trafficability of rover on different lunar surface condition. The presented paper simulates the lunar soil with different depth by means of three kinds of lunar soil simulant on different compact condition. Based on the direct shear apparatus, it was researched that the cohesion, internal friction angle, bull density of lunar soil simulant on different compaction conditions, including loose, normal, and compressed. The measurement results show that the bulk density and cohesion of the lunar soil simulant increase with the compact conditions in general. The bulk density changes within a narrow range from1.1 g/cm3 to 1.4 g/cm3. The cohesion increases, and changes significantly, which varies from 0 kPa to 0.5 kPa. The internal friction angle changes without regularity within a range from 30 deg to 40 deg. The measurement results can be used to explain the different trafficability of wheels after repeatedly passing the same lunar surface. Also it will be of significant to the evaluation of the rover mobility at different lunar soil condition.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Fang Tong ◽  
Qiang Ma ◽  
Xing Hu

Acid pollution weakens the bearing capacity of subgrade, and discarded concrete occupies land. The mechanical properties of hydrochloric acid-contaminated clay were investigated by triaxial consolidation undrained tests. Also, the theory of diffusion double electric layer was employed to explain the change principle of cohesion and compression characteristics of hydrochloric acid-contaminated clay. In addtion, the curing effects of lime, crushed concrete, and SAP on the shear strength of hydrochloric acid-contaminated clay were compared. The triaxial test results show that cohesion decreased with the increase of hydrochloric acid concentration. The internal friction angle firstly increased and then decreased, and the change of internal friction angle was less affected by acid concentration. The curing effect of crushed concrete was similar to that of lime, which was better than lime. SAP could only improve the cohesion of the hydrochloric acid-contaminated clay; the internal friction angle decreased significantly; the three kinds of curing materials could significantly improve the cohesion of acid-contaminated clay to be higher than the natural clay, improving the shear strength to a certain extent. Additionally, the theory analysis illustrated that due to the change in the thickness of the diffusion layer between the clay particles, the van der Waals force between the particles changed, and the colloidal formation of the micelles led to changes in cohesion. The study can provide references to the treatment of contaminated soil in engineering practice.


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