Damage Resistance Performance Research Articles

Effects of warm-mix additives, anti stripping agent, and graphene nanoplatelet on the cracking resistance, moisture susceptibility, and cost effectiveness of stone mastic asphalt

Moisture and cracking damages are two of the most common asphalt pavement distresses in the United States. The use of stone matrix asphalt mixture has gained popularity due to its high durability, resistance to permanent deformation and cracking, and reduced noise pollution. Warm-mix additives and nanomaterials have also gained significant interest as promising asphalt binder additives. In order to achieve enhanced resistance to moisture and cracking in extremely wet regions, this study investigated the effects of three warm-mix additives, an anti-stripping agent, and one nanomaterial (graphene nanoplatelet) on the cracking and moisture resistance performance of stone matrix asphalt. Fourier transform infrared spectroscopy and sessile drop tests were used to evaluate the functional groups and moisture susceptibility of the modified asphalt binder blends, respectively. The indirect tensile asphalt cracking test and the modified Lottman tests were used to evaluate the mixtures' resistance to cracking and stripping damage. A cost-effectiveness analysis as well as a two-dimensional performance interaction diagram were employed based on the laboratory performance of the mixtures. Results indicated that the graphene nanoplatelet modification of the asphalt binder had the highest wettability potential, adhesion, and debonding properties, as well as moisture resistance potential compared to other additives. In terms of mixture cracking performance, both the graphene nanoplatelet and a chemical warm-mix asphalt significantly improved the mix cracking performance by 34.1 and 30.0 %, respectively, compared to the control mix. However, the graphene nanoplatelet modification had a tensile strength ratio of 0.76, which is below the acceptance threshold of 0.80 set by AASHTO T 283 for moisture damage resistance of asphalt mixture. Overall, all mixtures with warm-mix additives showed adequate cracking and stripping damage resistance performance and are expected to be cost-effective.

Study on the influence mechanism of hydrophobic materials-MPTMS and DMDMOS on the water resistance performance of asphalt mixtures

The interfacial adhesion between aggregate and asphalt is a critical factor affecting the water damage resistance performance of asphalt mixtures. To enhance the adhesion between aggregate and asphalt, Methyltrimethoxysilane (MPTMS) and Dimethyldimethoxysilane (DMDMOS) were co-opted to modify the aggregate surface. The interfacial strength between aggregate and asphalt was analyzed by water boiling test and contact angle experiment, and the mechanism of aggregate interfacial modification was investigated by combining SEM, FTIR and MD. The results showed that: hydrophobic treatment of aggregates reduces the water absorption rate of aggregates in a wet environment and significantly improves the water damage resistance of asphalt mixtures; MPTMS and DMDMOS reduced the aggregate surface polarity component, thus improving the match between aggregate and asphalt; The optimal processing environment for aggregates is acidity and 30 minutes. Further mechanistic tests and simulations showed that the reactive Si-O portion of the polymer reacts with the Si-O-C portion of MPTMS and DMDMOS to form hydrophobic clusters on the surface of the polymer, increasing the aggregate surface roughness. The clusters attract asphalt molecules to arrange closely and orderly around them. The intramolecular interactions and molecular angular energy of asphalt molecules are significantly reduced, which improves the stability of the aggregate-asphalt system, and further enhances the bonding energy between the aggregate and the asphalt, thus improving the water damage resistance of asphalt mixtures.

Time-domain electric field analysis of few-cycle pulse damage behavior in ultra-broadband chirped mirrors

The laser-induced damage resistance performance of ultra-broadband chirped mirrors (UBCM) is a critical factor influencing the generation of petawatt or exawatt laser pulses in thin film compression techniques. In this study, a few-cycle pulse damage testing platform was set up, and two UBCMs with different designs were fabricated for a comparative study of their laser-induced damage. Because light of varying wavelengths forms an electric field at different times within UBCMs under few-cycle pulse irradiation, a time-domain electric field model was developed to obtain transient electric field variations and explain the damage behavior. The model successfully elucidated the origin of the damage and discrepancy between the two UBCMs in terms of damage thresholds, showcasing its potential applications in designing high-threshold UBCMs for high-power laser systems.

Research on the performance of pavement crack repair materials based on foaming polyurethane

In this paper, Pucs, a new two-component foaming polyurethane material, is selected to carry out a feasibility study on its application in pavement crack repair. Based on the two common crack repair materials in current projects, tests of pavement performance of repair materials are carried out, such as bonding performance, water damage resistance performance, high-temperature performance, and aging resistance performance. The comparative analysis of the results reveals that Pucs have better pavement performance than conventional crack repair materials. This indicates that Pucs is a new kind of material with excellent performance in pavement crack repair and can be widely used in the field of crack repair.

Research on the mitigation of redeposition defects on the fused silica surface during wet etching process.

The laser-induced damage of ultraviolet fused silica optics is a critical factor that limits the performance enhancement of high-power laser facility. Currently, wet etching technology based on hydrofluoric acid (HF) can effectively eliminate absorbing impurities and subsurface defects, thereby significantly enhancing the damage resistance of fused silica optics. However, with an increase in the operating fluence, the redeposition defects generated during wet etching gradually become the primary bottleneck that restricts its performance improvement. The composition and morphology of redeposition defects were initially identified in this study, followed by an elucidation of their formation mechanism. A mitigation strategy was then proposed, which combines a reduction in the generation of precipitation with an acceleration of the precipitation dissolution process. Additionally, we systematically investigated the influence of various process parameters such as extrinsic impurity, etching depth, and megasonic excitation on the mitigation of deposition defects. Furthermore, a novel multiple-step dynamic etching method was developed. Through comprehensive characterization techniques, it has been confirmed that this new etching process not only effectively mitigate redeposition defects under low fluence conditions but also exhibits significant inhibition effects on high fluence precursors. Consequently, it significantly enhances the laser damage resistance performance of fused silica optics.

Laboratory and field performance investigation of anti-ultraviolet aging of warm-mixed asphalt concretes

MgAl-Layered double hydroxides (LDHs) is commonly applied to improve the anti-ultraviolet (UV) aging performance of SBS-modified asphalt concretes. However, LDHs elevates the mixing temperature of SBS-modified asphalt, resulting in more energy consumption and more volatile organic compounds (VOCs) emission. The surface-active warm-mixed agent (W-MA) can effectively reduce the viscosity of asphalt binder. This study explored the use of W-MA in LDHs/SBS-modified asphalt binder (LA) and LDHs/SBS-modified asphalt mixtures (LAM) to reduce the mixing temperature and VOCs emission. Firstly, the structural stability of LDHs and the effect of W-MA on viscosity reduction and VOCs emission in LA were studied. Then, the physical properties, UV aging resistance, and optimal LDHs content of warm-mixed LAM were examined. Finally, the performances of the test road applying warm-mixed LAM were investigated. The results demonstrated that the excellent structural stability of LDHs and the application of W-MA could effectively reduce the viscosity of LA and VOCs emission. Warm-mixed LAM exhibited excellent UV aging resistance and high-temperature performance. However, its low-temperature performance and moisture damage resistance performance were slightly lower than warm-mixed asphalt mixtures. The optimal LDHs content in warm-mixed LAM was found to be 3 wt%. The test road showed minor differences in road performance compared to that in the laboratory, and the test road has great anti-UV aging performance.

Method for Simulating the Anti-Damage Performance of Consolidation Soil Balls at the Roots of Seedlings during Transportation Using Consolidated Soil Columns.

In the process of landscaping or afforestation in challenging terrain, in order to improve the survival rate of transplanted seedlings, it is necessary to transplant seedlings with a mother soil ball attached. During transportation, the soil ball at the root of the seedlings is very susceptible to breakage due to compression, bumps, and collisions. In order to ensure the integrity of the soil ball of the transplanted seedlings and improve the survival rate of seedlings, a method of chemically enhancing the soil surface strength was employed. Specifically, a polymer-based soil consolidating agent was used to solidify the root balls of the seedlings. To examine the abrasion resistance performance of the soil balls formed by consolidating the surface with polymer adhesive during the transportation process, we utilized a polymer-based consolidating agent to prepare test soil columns and developed a method to simulate the damage resistance performance of seedling root balls during transportation using these soil columns. The method primarily encompasses two aspects of testing: compressive strength testing of the consolidated soil columns and resistance to transportation vibration testing. The first method for testing the resistance to transportation vibration of the consolidated soil columns is a combination test that includes three sets of tests: highway truck transportation vibration testing, combined wheel vehicle transportation vibration testing, and impact testing. Although the method is cumbersome, testing is more accurate. The second method for testing the resistance to transportation vibration of the consolidated soil columns involves simultaneously testing multiple consolidated soil columns using a simulated transportation vibration test platform. The testing method is concise and efficient, and the test results are more intuitive. The combined assessment of the resistance to transportation vibration and compressive strength testing of the consolidated soil columns allows for a comprehensive evaluation of the soil columns' resistance to damage during transportation. This study mainly provides a quick and effective method for detecting the damage resistance of consolidated soil columns/balls during transportation, providing technical support for the application of polymer-based consolidation agents in the field of seedling transplantation.

Investigation on preparation and properties of carbon fiber graphite tailings conductive asphalt mixture: A new approach of graphite tailings application

The massive accumulation of graphite tailings (GT) brings huge pressure to environmental engineers. Meanwhile, the conductive asphalt pavement industry is suffering from the high construction cost and the complex acquisition of conductive materials. The application of GT in asphalt mixture as a conductive material may be a win–win solution for the above concerns. This study aims to evaluate the feasibility of preparing carbon fiber graphite tailings (CF-GT) conductive asphalt mixture. The optimum preparation technology and material ratio were explored. The service performance tests of the conductive asphalt mixture were conducted, including conductive characteristics, electrothermal performance and pavement performance. Based on the experimental results, 0.3% (mass fraction) 6 mm-polyacrylonitrile (PAN)-based carbon fiber (CF) and 12% (mass fraction) GT were selected as conductive materials to prepare conductive asphalt mixture with resistivity of 5.75 Ω∙m. The addition of GT reduced the resistance by a maximum of 59.8%. The temperature-sensitive and pressure-sensitive characteristics of the mixture have staged characteristics. Moreover, the resistance and stress of the mixture have an excellent linear correlation in the positive pressure coefficient (PPC) effect stage and negative pressure coefficient (NPC) effect stage respectively, especially NPC. Conductive asphalt mixture has a good heating effect after being powered on. GT combined with CF enhanced the high-&low-temperature performance but deteriorated the moisture damage resistance performance of the asphalt mixture. The feasibility of CF-GT conductive asphalt mixture was demonstrated.

Topological Optimization of Non-Pneumatic Unique Puncture-Proof Tire System Spoke Design for Tire Performance

<div>Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles. Finite element model (FEM) model is developed to evaluate the stiffness and damage-resisting performance of NPT-UPTIS spoke. The FEM methodology has also been validated with average accuracy of more than 95% for experimental vertical stiffness for commercial NPT-Tweel. The stiffness and damage-resisting performance of generated designs have been predicted with the help of machine learning regression models, which were trained on the FEM results of 200 such designs. These 50,000 generated designs have been categorized in four different categories based on different level of stiffness and damage resistance performance. In this study, one optimized design from each category has been selected and their performance have been validated with 3D FEM simulation. It has been found that the suggested topology optimization approach is efficient to generate UPTIS spoke designs with having ±30% stiffness with 17%, 40%, and 56% more damage resistance performances with respect to the starting reference design.</div>

Laboratory Investigation of the Water Damage Resistance of Tuff Asphalt Mixture Modified with Additives

To improve the water damage resistance performance of a tuff asphalt mixture, a tuff mixture with cement and a liquid anti-stripping agent was used as the research object, and limestone and tuff mixtures without additives were selected as contrast samples. Through an improved boiling test and a water stability test before and after aging, the modification effect of the tuff mixture with additives of different types and contents on water damage resistance was evaluated to obtain the appropriate type and content of additives. On this basis, the other road performance measures of the selected mixture were further evaluated by immersion rutting and beam bending tests to verify the modification effect of the additive on the tuff mixture. Results showed that adding the appropriate cement content to the tuff mixture provided excellent resistance to the water damage effect. An optimal content of 2% cement additive in the mixture was obtained, and its high-temperature anti-rutting and low-temperature bending performance were also verified. Adhesion between tuff aggregates and asphalt polymer under water conditions was significantly improved and close to that of limestone aggregates. The modification effect of water stability after mixture aging was better than that of the anti-stripping agent. The residual stability and freeze–thaw splitting strength ratio of 2% cement content mixture were increased by about 21.5% and 16.7%, respectively, compared with those of the tuff mixture control.

Experimental Investigation on the Effect of Stacking Sequence on Damage Resistance and Post-indentation Performance of Glass/Epoxy Laminates Under Different Loading Planes Using Acoustic Emission Monitoring

This research work focuses on the experimental investigation of indentation damage resistance and post-indented performance of different stacking sequence of glass/epoxy laminates using mechanical and acoustic responses. The laminates with stacking sequence, namely [0]12, [0/90]6S, [+45/-45]6S and [0/+45/-45/90]3S were subjected to normal and inclined indentation with acoustic emission monitoring. Quasi-static indentation (QSI) test was conducted on the center of the laminates using a hemispherical steel indenter with 12.7 mm diameter. The residual strength of the laminates was computed by conducting flexural after indentation test. Mechanical responses such as peak force, residual dent, linear stiffness and absorbed energy were employed to assess induced damages. The results reveal that the quasi-isotropic (QIS) laminates having better indentation damage resistance under 0o and 10o loading planes, whereas the angle-ply (AP) laminates performed well at 20o. Moreover, the normalised cumulative counts, energy rate, peak frequency, AE hits and sentry function were used to evaluate the damage initiation and propagation. Further, AE results show that the shear induced damage has been reduced in AP as compared with QIS laminates under 20o indentation plane. Finally, this study concluded that the QIS and AP laminates exhibited better indentation resistance under 0o and 10o, and 20o loading planes respectively.

Multi-scale concurrent analysis for bio-inspired helicoidal CFRP laminates and experimental investigation

The bio-inspired helicoidal structure has been proved to exhibit excellent load-bearing capacity and damage resistance performance. However, there are few relevant researches to analyze its failure process from micro-scale. In this study, three types of carbon fiber reinforced plastics (CFRP) laminate structures were prepared—cross-ply, quasi-isotropic, and helicoidal. The mechanical performance of the laminates was tested using an indentation test. The experiment results verified the excellent mechanical performance of the helicoidal structure. In order to analyze its intrinsic enhancement mechanism, a multi-scale damage model for self-consistent clustering analysis method was proposed, and the damage evolution process of the laminates was simulated at both macro and micro scales. The results indicated that owing to the small rotation angle between adjacent layers in the helicoidal structure, the stress distribution along the thickness direction was more uniform. Moreover, the laminate was more likely to be divided into several sub-laminates by primary delamination. The fibers of each sub-laminate would be cracked in sequence from top to bottom, accompanied by the subprime delamination, resulting in the failure of the laminate. Besides, a twisted crack path could be generated, making the helicoidal structure exhibit excellent load-bearing capacity and damage resistance.

Investigating the role of swelling-degradation degree of crumb rubber on CR/SBS modified porous asphalt binder and mixture

Porous asphalt pavement is widely used due to its adequate water permeability, noise reduction and skid resistance. The study aims at exploring the potential of using the crumb rubber/styrene–butadienestyrene (CR/SBS) modified bitumen as high-viscosity binder for porous asphalt mixture, and investigating the effect of swelling and degradation degree of crumb rubber as well as SBS dosage on the performance of porous asphalt binder and mixture. The conventional, rheological and engineering properties of CR/SBS modified high-viscosity porous asphalt binders and mixtures were characterized. The results revealed that the CR swelling-degradation degree significantly affected the physical and viscoelastic properties of CR/SBS modified high-viscosity binders. With the swelling time prolonged, the viscosity of rubber bitumen enhanced gradually until reaching the equilibrium state, which kept falling during the degradation process dramatically. The full-swelling binders exhibited the highest complex modulus, zero-shear viscosity, rutting resistance, which deteriorated as the degradation degree increasing. However, the degradation of crumb rubber would be beneficial to improve the workability, thermal cracking resistance and deformation recovery ability of high-viscosity binder. Meanwhile, the incorporation of SBS copolymer could further strengthen both high-and-low temperatures viscoelastic performance of high-viscosity bitumen. In addition, the performance of porous asphalt with CR/SBS modified high-viscosity bitumen could meet the requirements of Marshall stability, air void content, Cantabro loss, run-off loss, anti-rutting, moisture damage resistance and permeability performance. Although the full-swelling asphalt mixture presented the best rutting resistance, it showed the poor adhesive and moisture damage resistance when compared with partial and full-degradation asphalt mixtures.

Experimental study on road performance of asphalt mixture mixed with antifreeze

In order to ensure the fast and efficient snow removal of roads in winter, a kind of slow-release antifreeze combined with asphalt concrete is developed, and its road performance is studied. In this paper, a kind of antifreeze performance of AC - 13 is developed, therefore, the low and high temperature performance, water resistance, damaging antifreeze performance of asphalt mixture are studied under different dosage of antifreeze. Based on the analysis of the performance evaluation of the road at the same time the climate suitability of different antifreeze, this paper studies changes of dosage of antifreeze antifreeze performance decay law of asphalt mixture. The results show that the water damage resistance, low and high temperature performance of the antifreeze mixture are decreased with the increase of the antifreeze dosage, but under the appropriate dosage, the performance of the asphalt mixture could meet the requirements of the specification, and the optimal dosage of AC-13 antifreeze is 5.5%.

Decision support for selecting optimal method of recycling waste tire rubber into wax-based warm mix asphalt based on fuzzy comprehensive evaluation

Recycling crumb rubber (CR) derived from waste vehicle tire as asphalt modifier is an effective waste management approach with both engineering and environmental merits. However, the high viscous asphalt rubber (AR) brings higher energy consumption and hazardous construction emission. Wax-based warm mix asphalt (WMA) additive has proven to be able to alleviate these concerns. Application of WMA additives enriches the methods of recycling CR into asphalt. Preliminary investigations documented the effects of CR recycling methods on the service performance of warm crumb rubber modified asphalt mixture (WCRMA). Therefore, making a decision on the optimal recycling method considering the overall service performance is necessary. Nevertheless, there are limited studies focusing on the recycling method assessment and decision-making approach. To fill this gap, WCRMAs with different crumb rubber recycling methods were prepared and tested in laboratory. The effect of the recycling method on the overall service performance of WCRMAs was characterized. A fuzzy comprehensive evaluation (FCE) method was employed to quantify the performance grade of asphalt mixtures according to fuzzy logic. The weight matrix of all the service properties was developed based on the Analytic Hierarchy Process (AHP) under the considering of the circumstance of southern China. The experimental work revealed the significant influence of the recycling method on the service performance of WCRMAs. By means of the FCE method, this study suggested that for southern China with hot and humid climate, the optimal method of recycling CR into wax-based WCRMA is mixing AR and Sasobit first followed by incorporating them into aggregate. In rainy regions, asphalt mixture produced by directly mixing AR, Sasobit, and aggregate at 160 °C may perform better because it showed the best moisture damage resistance and good overall performance.

Damage assessment of nanofiller-reinforced woven kevlar KM2plus/Epoxy resin laminated composites

The resiliency of advanced laminated nanocomposite materials to mitigate impact load is an essential characteristic for material selection and product design. This paper investigates the effect of nanofillers and its effect on the damage resistance performance of a newly developed woven Kevlar fabric. Three types of nanofillers were investigated: (1) Silicon carbide (SiC), (2) aluminum oxide (Al2O3), and (3) multiwalled carbon nanotube (MWCNT). The nanofillers were dispersed using shear mixing and sonication into the epoxy to reinforce Kevlar fabric. Moreover, the effect of the nanofiller's concentration on the damage resistance performance was analyzed. All specimens had 10 layers of Kevlar fabric (KM2plus) stacked with a 0° angle. To evaluate the damage resistance performance a drop-weight impact test was conducted using a maximum drop height of 100 cm. X-ray diffraction was used to evaluate the level of material damage caused by the impact load. The addition of nanofillers enhanced the flexural properties of the composite and as well as its resiliency towards impact loads. In particular, the 0.5 wt% MWCNT laminated Kevlar/epoxy composite possessed the highest impact damage resistance capacity. Furthermore, the damage evolution was not observed within the impact area and in the surrounding areas for specimens with 0.5 wt% MWCNT. Therefore, the results indicate that the optimal nanofiller content for Kevlar KM2plus/epoxy nanocomposites is 0.5 wt% MWCNTs.

Fatigue behaviors of foreign object damaged Ti-6Al-4V alloys under laser shock peening

Two-sided and simultaneous laser shock peening (TSLSP) was used to strengthen the Ti-6Al-4V titanium alloy. The fatigue crack growth rate of the specimens was investigated by fatigue test. The results show that both direct TSLSP (TSLSP-D) and indirect TSLSP (TSLSP-I) can reduce the fatigue crack growth rate by producing high magnitude compressive residual stress. The maximum fatigue life increases by 94% (TSLSP-D) and 169% (TSLSP-I) compared with the original specimens. Moreover, the TSLSP-D results show decreased resistance to foreign object damage because of decreased plasticity while the TSLSP-I simultaneously achieves superior foreign object damage resistance and fatigue performance.

Design and performance of emulsified asphalt mixtures containing construction and demolition waste

The rapid increase of construction and demolition waste (CDW) brings huge pressure to environmental engineers. Meanwhile, pavement industry is suffering from the diminishing of available natural aggregate and the increasingly stringent environmental pressures. Application CDW into emulsified asphalt mixtures (EAM) as pavement materials could be a win-win solution for the above concerns. This study aims at evaluating the feasibility of replacing natural aggregate in EAM by recycled aggregates produced from CDW. To this end, the optimum moisture content and optimum emulsified asphalt content of EAM samples were determined. EAM samples containing different content of recycled aggregates were prepared in laboratory. The effect of cement and recycled aggregate content on the service performance, including moisture damage resistance performance, high- and low- temperature performance, of EAM samples were evaluated. Based on the experimental results, it was found that the recycled aggregate enhanced the high-temperature performance but deteriorated the low-temperature and moisture damage resistance performance of EAM. Adding cement improves the entire service performance of EAM. When combined with cement, CDW can be used as a substitute for natural aggregates of EAM.

Characterization of manufacturing-induced surface scratches and their effect on laser damage resistance performance of diamond fly-cut KDP crystal

Manufacturing-induced defects have drawn more and more attentions to improve the laser damage resistance performance of KDP crystal applied in high-power laser systems. Here, the morphology of surface scratches on diamond fly-cut KDP crystal is characterized and their effect on the laser damage resistance is theoretically and experimentally investigated. The results indicate that surface scratches could lower laser-induced damage threshold (LIDT) by modulating incident lasers and producing resultant local light intensifications. The induced maximum light intensity enhancement factors (LIEFs) are dependent on scratch shapes and dimensions. The diffraction effects originating from scratch edges are responsible for the strongest light intensification. Even for ultra-precision finished KDP surface with scratches that well satisfy the currently applied scratch/dig specification, the induced LIEFs are quite high, indicating that the actual defect dimension allowance should be amended and specified according to the defect-induced LIEFs. The effect of scratches on laser damage resistance is experimentally verified by the tested LIDT, which is approximately consistent with the simulation one. The morphologies of laser damage sites further confirm the role of scratches in lowering LIDT. This work could offer new perspective and guidance for fully evaluating the performance of ultra-precision manufactured optical materials applied in high-power laser facilities.

Mobile Digital TV Induction Array Four Helix Antenna

According to the performance requirements of the mobile digital TV system, the present paper originally combines polygonal four helix antenna, induction array antenna, dielectric constant gradient film, graphene conductive ink and nano silver conductive ink, designed a mobile digital TV inductive array four helix antenna. The result of test indicates that this antenna has completely covered the frequency band of the mobile digital TV system. This antenna has strong corrosion resistance and damage resistance, stable physical and mechanical performance and radiation performance, small size, thin thickness and large working bandwidth, so it has broad application prospects.