scholarly journals The Effect of Mineral Powder on the Surface/Interface of Aggregates and Asphalt

2021 ◽  
Vol 45 (4) ◽  
pp. 281-290
Author(s):  
Peng Tian ◽  
Kaixing Peng ◽  
Hangning Dong ◽  
Yan Li ◽  
Weizhi Dong
Keyword(s):  
Surface Texture ◽  
Smooth Surface ◽  
Gravimetric Method ◽  
Asphalt Mixtures ◽  
Promotion Effect ◽  
Adhesion Promotion ◽  
Powder Particles ◽  
Mineral Powder ◽  
Asphalt Mortar

This paper attempts to analyze the effect of mineral powder on the adhesion of aggregates and asphalt. First, it employs the gravimetric method to quantitatively analyze the peeling rate of asphalt and asphalt mortar from the surface of basalt, andesite, and limestone aggregates. Then, it takes microscopic pictures of the mineral powder adhered on the surface of the aggregates to observe the distribution of mineral powder in the asphalt mixtures, and uses profiles to analyze the adhesion status of mineral powder on the surface of the aggregates. At last, this paper analyzes the effect of mineral powder particles on the surface/interface of the aggregates and asphalt, and the results indicate that mineral powder has increased the roughness of the surface of the aggregates, therefore it indirectly promotes the adhesion of asphalt on the surface of the aggregates; the mineral powder particles interact with the surface texture of the aggregates, forming an embedding and wedging structure in the texture; compared with aggregates with smooth surface, the adhesion promotion effect is stronger.

Effect of Coarse Aggregate Morphology on the Resilient Modulus of Hot-Mix Asphalt

2005 ◽  
Vol 1929 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Tongyan Pan ◽  
Erol Tutumluer ◽  
Samuel H. Carpenter
Keyword(s):  
Surface Texture ◽  
Coarse Aggregate ◽  
Resilient Modulus ◽  
Asphalt Binder ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Maximum Aggregate Size ◽  
Asphalt Mixes ◽  
Aggregate Morphology ◽  
The Relationship

The resilient modulus measured in the indirect tensile mode according to ASTM D 4123 reflects effectively the elastic properties of asphalt mixtures under repeated load. The coarse aggregate morphology quantified by angularity and surface texture properties affects resilient modulus of asphalt mixes; however, the relationship is not yet well understood because of the lack of quantitative measurement of coarse aggregate morphology. This paper presents findings of a laboratory study aimed at investigating the effects of the material properties of the major component on the resilient modulus of asphalt mixes, with the coarse aggregate morphology considered as the principal factor. With modulus tests performed at a temperature of 25°C, using coarse aggregates with more irregular morphologies substantially improved the resilient modulus of asphalt mixtures. An imaging-based angularity index was found to be more closely related to the resilient modulus than an imaging-based surface texture index, as indicated by a higher value of the correlation coefficient. The stiffness of the asphalt binder also had a strong influence on modulus. When the resilient modulus data were grouped on the basis of binder stiffnesses, the agreement between the coarse aggregate morphology and the resilient modulus was significantly improved in each group. Although the changes in aggregate gradation did not significantly affect the relationship between the coarse aggregate morphology and the resilient modulus, decreasing the nominal maximum aggregate size from 19 mm to 9.5 mm indicated an increasing positive influence of aggregate morphology on the resilient modulus of asphalt mixes.

Surface Texture and Mechanical Behavior of Claw Material in Beetle Dorcus titanus (Coleoptera: Lucanidae)

2013 ◽  
Vol 461 ◽  
pp. 305-312 ◽  
Author(s):  
Zhi Xian Yang ◽  
Ze Hua Liu ◽  
Zhen Dong Dai
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Hierarchical Structure ◽  
Surface Texture ◽  
Smooth Surface ◽  
Biological Materials ◽  
Industrial Products ◽  
Biomimetic Materials ◽  
Nanomechanical Properties ◽  
Synthetic Materials

Biomaterials have an integrated, hierarchical structure with outstanding mechanical properties which are far beyond those achieved by using the same synthetic materials. nanoindentation techniques have recently been adapted for studying the biological materials. In this paper, the surface texture and nanomechanical properties of claw material in beetle Dorcus titanus were investigated. It is founded that the claw possesses of an optimized shape as well as the non-smooth surface texture with many stripes like as the fullows close to the arc inside. The results of nanoindentation tests indicate that the modulus value of the claw cuticle near the tip (11.25±0.57 GPa) is over three times larger than that near the claw root (3.61±0.22 GPa) and there is an incremental hardness and modulus values from the claw root to the tip. Quantitive measurements on the nanomechanical properties of claw material could help to develop biomimetic materials suitable for industrial products.

scholarly journals The Effect of Ageing on Chemical and Mechanical Properties of Asphalt Mortar

2018 ◽  
Vol 8 (11) ◽  
pp. 2231 ◽  
Author(s):  
Ruxin Jing ◽  
Xueyan Liu ◽  
Aikaterini Varveri ◽  
Athanasios Scarpas ◽  
Sandra Erkens
Keyword(s):  
Mechanical Properties ◽  
Asphalt Mixtures ◽  
Pavement Performance ◽  
Frequency Sweep ◽  
Carbonyl Index ◽  
Mineral Particles ◽  
Tension Tests ◽  
Ftir Spectrometry ◽  
Diffusion Paths ◽  
Asphalt Mortar

Asphalt mortar is a mixture of bitumen, filler, and sand. Mortar plays an important role in asphalt mixtures as it serves as the adhesive between the coarser aggregates. Due to the effect of bitumen ageing, the chemical and mechanical properties of asphalt mortar evolve with time. The mortar becomes more brittle and prone to cracking, thus leading to inferior pavement performance. In this study, Fourier transform infrared (FTIR) spectrometry was used to quantify changes in the chemical functional groups related to ageing and to calculate the carbonyl and sulfoxide indices. In addition, frequency sweep tests and uniaxial tension tests were performed by means of dynamic shear rheometer (DSR) tests to determine evolution of the stiffness and strength due to ageing. Two different oven ageing protocols were used to evaluate the effect of fine mineral particles on bitumen ageing. The protocols differed with respect to the order of ageing and mixing of the constituents. The results showed that both the chemical and mechanical properties of mortars significantly changed with ageing. Specifically, the carbonyl index, stiffness, and strength of the mortar increased. Under the same ageing conditions, a higher ageing level was observed for mortars produced by first mixing and then ageing compared to the mortars produced by mixing aged bitumen with filler and sand. This could be due to the presence of sand and filler particles, which resulted in an increased length of diffusion paths and consequently a slower ageing process.

scholarly journals Rheological and Interaction Analysis of Asphalt Binder, Mastic and Mortar

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 128 ◽  
Author(s):  
Meng Chen ◽  
Barugahare Javilla ◽  
Wei Hong ◽  
Changluan Pan ◽  
Martin Riara ◽  
...  
Keyword(s):  
Phase Change ◽  
Interaction Analysis ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Physical Interaction ◽  
Fine Aggregate ◽  
Mineral Filler ◽  
Asphalt Mastic ◽  
Fine Aggregates ◽  
Asphalt Mortar

This paper investigated the rheological properties of asphalt binder, asphalt mastic and asphalt mortar and the interaction between asphalt binder, mineral filler and fine aggregates. Asphalt binder, mastic and mortar can be regarded as the binding phase at different scales in asphalt concrete. Asphalt mastic is a blend of asphalt binder and mineral filler smaller than 0.075 mm while asphalt mortar consists of asphalt binder, mineral filler and fine aggregate smaller than 2.36 mm. The material compositions of mastic and mortar were determined from the commonly used asphalt mixtures. Dynamic shear rheometer was used to conduct rheological analysis on asphalt binder, mastic and mortar. The obtained test data on complex modulus and phase angle were used for the construction of rheological master curves and the investigation of asphalt-filler/aggregate interaction. Test results indicated a modulus increase of three- to five-fold with the addition of filler and a further increase of one to two orders of magnitude with cumulative addition of fine aggregates into asphalt binder. Fine aggregates resulted in a phase change for mortar at high temperatures and low frequencies. The filler had stronger physical interaction than fine aggregate with an interaction parameter of 1.8–2.8 and 1.15–1.35 respectively. Specific area could enhance asphalt-filler interaction. The mastic and mortar modulus can be well predicted based on asphalt binder modulus by using particle filling effect. Asphalt mortar had a significant modulus reinforcement and phase change and thus could be the closest subscale in terms of performance to that of asphalt mixtures. It could be a vital scale that bridges the gap between asphalt binder and asphalt mixtures in multiscale performance analysis.

The Effect of Surface Texture on Thermal Sensation and Comfort

2017 ◽  
Author(s):  
Han Zhang ◽  
Alan Hedge
Keyword(s):  
Thermal Comfort ◽  
Spatial Patterns ◽  
Surface Texture ◽  
Smooth Surface ◽  
Thermal Sensation ◽  
Electronic Devices ◽  
Material Surface ◽  
Tablet Computer ◽  
Physical Sensation ◽  
Effect Of Surface

The study investigated how the material roughness of a tablet computer surface can affect thermal sensation and comfort of users fingers and palms at different surface temperatures. Three levels of pattern spacing were tested, and it was shown that rough material surface provided higher thermal comfort comparing to a smooth surface. In addition, the surface temperature of the material also moderates participants′ physical sensation of the roughness of the materials. The results of the study have shown evidences of the potentials to use materials with spatial patterns to improve thermal comfort while dissipating heat from electronic devices.

scholarly journals Analysis of Nanoindentation Test Results of Asphalt Mixture with Different Gradations

2021 ◽  
Vol 11 (17) ◽  
pp. 7992
Author(s):  
Yunhong Yu ◽  
Gang Xu ◽  
Tianling Wang ◽  
Huimin Chen ◽  
Houzhi Wang ◽  
...  
Keyword(s):  
Material Properties ◽  
Asphalt Mixture ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Nanoindentation Test ◽  
Test Results ◽  
Before And After ◽  
Mineral Powder ◽  
Powder Content ◽  
Interaction Surface

Nanoindentation has been applied in the field of asphalt mixtures, but, at the nano-scale, changes in the composition of the mixture and material properties can have a significant impact on the results. Therefore, it is necessary to investigate the feasibility of nanoindentation tests on different types of asphalt mixtures with different gradations and the influence of material properties and test methods on nanoindentation results. In this paper, the nanoindentation test results on three kinds of asphalt mixture (AC-13, SMA-13, and OGFC-13) with different aggregate gradations were investigated. The load-displacement curves and moduli obtained from the nanoindentation tests were analyzed. In addition, nanoindentation tests were carried out before and after polishing with different ratios of filler and asphalt (RFA) (0.8–1.6). On this basis, the morphology of asphalt specimens with different RFAs is observed by scanning electron microscopy (SEM) imaging. The results indicate that using the nanoindentation test to characterize the mechanical behavior of asphalt mixture, the confidence level of the dense-graded mixture is low, and non-dense-graded mixtures are used as much as possible. Moreover, results illustrate that the nanoindentation modulus tends to increase as the RFA increases. and the SEM chart shows that the higher the mineral powder content in the mastic, the more complex the bitumen and mineral powder interaction surface, confirming the influence of mineral powder content on the nanoindentation test results. Furthermore, the effect of polishing is almost insignificant.

scholarly journals Effects of Aggregate Mesostructure on Permanent Deformation of Asphalt Mixture Using Three-Dimensional Discrete Element Modeling

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3601 ◽  
Author(s):  
Deyu Zhang ◽  
Linhao Gu ◽  
Junqing Zhu
Keyword(s):  
Surface Texture ◽  
Deformation Behavior ◽  
Negative Impact ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Discrete Element ◽  
Asphalt Mixtures ◽  
Creep Tests

This paper investigated the effects of aggregate mesostructures on permanent deformation behavior of an asphalt mixture using the three-dimensional (3D) discrete element method (DEM). A 3D discrete element (DE) model of an asphalt mixture composed of coarse aggregates, asphalt mastic, and air voids was developed. Mesomechanical models representing the interactions among the components of asphalt mixture were assigned. Based on the mesomechanical modeling, the uniaxial static load creep tests were simulated using the prepared models, and effects of aggregate angularity, orientation, surface texture, and distribution on the permanent deformation behavior of the asphalt mixtures were analyzed. It was proven that good aggregate angularity had a positive effect on the permanent deformation performance of the asphalt mixtures, especially when approximate cubic aggregates were used. Aggregate packing was more stable when the aggregate orientations tended to be horizontal, which improved the permanent deformation performance of the asphalt mixture. The influence of orientations of 4.75 mm size aggregates on the permanent deformation behavior of the asphalt mixture was significant. Use of aggregates with good surface texture benefitted the permanent deformation performance of the asphalt mixture. Additionally, the non-uniform distribution of aggregates had a negative impact on the permanent deformation performance of the asphalt mixtures, especially when aggregates were distributed non-uniformly in the vertical direction.

Influences of Atomizing Pressure on Properties and Microstructure at Brazed Joint of Lead-Free Solder Powder

2011 ◽  
Vol 695 ◽  
pp. 89-92
Author(s):  
Tian Han Xu ◽  
Hai Yun Jin ◽  
Mai Qun Zhao ◽  
Dang Hui Wang
Keyword(s):  
Smooth Surface ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Uniform Size ◽  
Atomization Efficiency ◽  
Brazed Joint ◽  
Powder Particles ◽  
Free Solder ◽  
Uniform Size Distribution

The effects of the atomizing pressure on the microstructures and properties of the lead-free solder powder by the supersonic atomizer method were investigated. The microstructures of the brazed joint of solder paste were also observed. The results showed that with increasing atomizing pressures from 0.4 to 0.7 MPa, the powder particles are refined significantly and the effective atomization efficiency increases rapidly, but the oxygen content slightly rises. When the atomizing pressures increases from 0.7 to 0.9 MPa, the effective atomization efficiency only increases slightly, meanwhile both sphericity and roughness of the powder deteriorate. The atomized powder exhibits high effective atomizing efficiency, uniform size distribution, good sphericity and smooth surface when the atomizing pressure is 0.7 MPa. The diffusion layer brazed welded by Sn3Ag2.8Cu paste with Cu substrate is thicker and more irregular than that of by Sn37Pb paste.

scholarly journals Moisture Susceptibility Evaluation of Asphalt Mixtures Containing Steel Slag Powder as Filler

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3211 ◽  
Author(s):  
Zhifeng Xiao ◽  
Meizhu Chen ◽  
Shaopeng Wu ◽  
Jun Xie ◽  
Dezhi Kong ◽  
...  
Keyword(s):  
Particle Size ◽  
Steel Slag ◽  
Asphalt Mixtures ◽  
Moisture Susceptibility ◽  
Freeze Thaw ◽  
Slag Powder ◽  
Steel Slag Powder ◽  
Split Test ◽  
Marshall Stability ◽  
Asphalt Mortar

The primary objective of this paper was to investigate the effect of replacing steel slag powder (SSP) with limestone filler (LF) with different contents as an inorganic anti-stripping agent on the moisture susceptibility of asphalt mixtures. Two traditional inorganic anti-stripping agents were selected for comparison, namely cement (CE) and slaked lime (SL). Apparent morphology, chemical compositions, and the particle size distribution of the four fillers were firstly studied. LF was replaced by SSP, CE, and SL with different contents, and then mixed with asphalt to prepare asphalt mortars. An 80 °C water immersion test was conducted to investigate the adhesion of asphalt mortar and aggregates, and an image analysis technique was utilized to evaluate the stripping of asphalt from the aggregates. A Marshall stability test and freeze-thaw split test were then conducted to analyze the effect of different fillers on the moisture susceptibility of asphalt mixtures. The results show that SSP contains a large amount of CaO, which indicates that SSP has a certain alkalinity. Compared with LF, SSP has a rougher surface texture and a finer particle size. Image analysis results show that the partially replacement of LF by SSP increases the asphalt coverage rate of aggregates, which means that SSP can improve the adhesion between asphalt mortar and aggregates. However, the excessive addition of SSP will result in a decrease in adhesion. The results of both the Marshall stability test and freeze-thaw split test demonstrate that CE, SL, and SSP can improve the moisture susceptibility of asphalt mixtures compared with the LF group, and that asphalt mixtures containing SSP have better moisture damage resistance than those with CE, but less such resistance than those with SL. With the increase of the amount of SSP replacing LF, the moisture susceptibility of the asphalt mixture decreases gradually. The optimum substitution amount of SSP was 25% of the total volume of fillers in this test.

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