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This study aims to investigate the feasibility of CLT panels fabricated from salvaged dead standing trees after the beetle outbreak by evaluating the flexural and shear properties through mechanical tests and computational analysis. White spruce (Picea glauca (Moench) Voss) lumber salvaged from the dead and dying trees resulting from recent spruce budworm (Choristoneura fumiferana (Clem.)) activity were used to fabricate Cross-laminated timber (CLT) panels of three categories in terms of tree conditions: Category I─ live; Category II─ recently dead; and Category III─ dead for some time. A total of 17 three-layer CLT panels measuring 107 × 610 × 2438 mm were fabricated, 5 for Category I, 5 for Category II, and 7 for Category III. The CLT panels were tested with the third-point and mid-point bending tests following ASTM D198 for major-axis flexural and shear properties. The results indicated that the deterioration of dead, dying standing trees resulting from the budworm activity reduced the average bending strength and shear modulus of the CLT panels. The bending stiffness of the panels was not significantly affected. The CLT panels made from salvaged spruce lumber provided adequate flexural performance per current standard PRG 320–2019. The finite element model built with orthogonal constitutive law and progressive damage criteria simulated the flexural behaviors of the tested CLT panels. The model input modulus and strength were calibrated based on the tested MOE of laminations. The simulation results compared favorably with test data and provided reasonable estimates. The results of this study suggest that CLT panels fabricated from salvaged beetle-killed spruce satisfied the baseline performance requirement of the PRG 320 standard.
Yunxiang Ma; Xiping Wang; Marshall Begel; Qingli Dai; Yvette Dickinson; Xinfeng Xie; Robert J. Ross. Flexural and shear performance of CLT panels made from salvaged beetle-killed white spruce. Construction and Building Materials 2021, 302, 124381 .
AMA StyleYunxiang Ma, Xiping Wang, Marshall Begel, Qingli Dai, Yvette Dickinson, Xinfeng Xie, Robert J. Ross. Flexural and shear performance of CLT panels made from salvaged beetle-killed white spruce. Construction and Building Materials. 2021; 302 ():124381.
Chicago/Turabian StyleYunxiang Ma; Xiping Wang; Marshall Begel; Qingli Dai; Yvette Dickinson; Xinfeng Xie; Robert J. Ross. 2021. "Flexural and shear performance of CLT panels made from salvaged beetle-killed white spruce." Construction and Building Materials 302, no. : 124381.
This study evaluated the mechanical properties of hybrid (mixed-species) cross-laminated timber (CLT) panels made of low-value sugar maple (Acer saccharum) and white spruce (Picea glauca). The modulus of elasticity (MOE) of the laminations was measured with a nondestructive method. Three-layer hybrid CLT panels with layup combinations of sugar maple–white spruce–sugar maple and white spruce–sugar maple–white spruce were prepared to evaluate the effects of layups on the performance of the CLT samples. The mechanical properties of hybrid CLT panels were evaluated with different layups and both melamine- and resorcinol-based adhesives. Both long-span and short-span third-point bending tests were conducted to study the flexural and shear behavior of each CLT panel type. It was found that the influence of adhesive types was not significant. The mechanical properties of the hybrid CLT panels with sugar maple surface layers were improved significantly compared with those of the current standard layups. Both bending tests were simulated with finite-element analysis based on measured and reference material properties. The simulated results of each case were in good agreement with the test results.
Yunxiang Ma; Ruizhe Si; Munkaila Musah; Qingli Dai; Xinfeng Xie; Xiping Wang; Robert J. Ross. Mechanical Property Evaluation of Hybrid Mixed-Species CLT Panels with Sugar Maple and White Spruce. Journal of Materials in Civil Engineering 2021, 33, 04021171 .
AMA StyleYunxiang Ma, Ruizhe Si, Munkaila Musah, Qingli Dai, Xinfeng Xie, Xiping Wang, Robert J. Ross. Mechanical Property Evaluation of Hybrid Mixed-Species CLT Panels with Sugar Maple and White Spruce. Journal of Materials in Civil Engineering. 2021; 33 (7):04021171.
Chicago/Turabian StyleYunxiang Ma; Ruizhe Si; Munkaila Musah; Qingli Dai; Xinfeng Xie; Xiping Wang; Robert J. Ross. 2021. "Mechanical Property Evaluation of Hybrid Mixed-Species CLT Panels with Sugar Maple and White Spruce." Journal of Materials in Civil Engineering 33, no. 7: 04021171.
The objective of this study is to examine the mechanical performance of cross laminated timber (CLT) panels made of low-value sugar maple under out of plane loads through mechanical tests and numerical simulation. The laminations were sorted into High and Low classes based on the measured modulus of elasticity (MOE). Two 3-layer sugar maple CLT layups as High-Low-High and Low-High-Low glued with resorcinol-based adhesive and one CLT layup of High-Low-High glued with melamine-based adhesive were prepared. Block shear, long-span bending (span-to-depth ratio of 33:1) and short-span bending (5.5:1) tests were conducted to evaluate the bonding, flexural and shear behavior of these low-value sugar maple CLTs. With a limited sample size, the lab-manufactured low-value sugar maple CLT provided a 50% to 80% higher MOE and at least two times higher MOR than CLT type E1 from APA/PRG 320. Similar MOE and MOR improvements were found by comparing CLT made with other species from literatures. The finite element simulation of bending tests was conducted with the orthogonal constitutive law and the progressive damage model based on the calibrated material properties parameters from lumber rating and references. The simulation results on each CLT panel type have a reasonable comparison with experimental test data. Therefore, these integrated experiment and simulation methods can provide detailed mechanical behaviors of the low-value sugar maple CLT, which can also be applied to other CLT species and layup.
Yunxiang Ma; Munkaila Musah; Ruizhe Si; Qingli Dai; Xinfeng Xie; Xiping Wang; Robert J. Ross. Integrated experimental and numerical study on flexural properties of cross laminated timber made of low-value sugar maple lumber. Construction and Building Materials 2021, 280, 122508 .
AMA StyleYunxiang Ma, Munkaila Musah, Ruizhe Si, Qingli Dai, Xinfeng Xie, Xiping Wang, Robert J. Ross. Integrated experimental and numerical study on flexural properties of cross laminated timber made of low-value sugar maple lumber. Construction and Building Materials. 2021; 280 ():122508.
Chicago/Turabian StyleYunxiang Ma; Munkaila Musah; Ruizhe Si; Qingli Dai; Xinfeng Xie; Xiping Wang; Robert J. Ross. 2021. "Integrated experimental and numerical study on flexural properties of cross laminated timber made of low-value sugar maple lumber." Construction and Building Materials 280, no. : 122508.
Qingli Dai; Zhanping You. Using Matlab To Solve Engineering Problems For Undergraduates. 2006 Annual Conference & Exposition Proceedings 2020, 11.1396.1 -11.1396.10.
AMA StyleQingli Dai, Zhanping You. Using Matlab To Solve Engineering Problems For Undergraduates. 2006 Annual Conference & Exposition Proceedings. 2020; ():11.1396.1-11.1396.10.
Chicago/Turabian StyleQingli Dai; Zhanping You. 2020. "Using Matlab To Solve Engineering Problems For Undergraduates." 2006 Annual Conference & Exposition Proceedings , no. : 11.1396.1-11.1396.10.
Zhanping You; Qingli Dai. Feasibility Of Virtual Laboratory For Asphalt Mixtures And Pavements. 2006 Annual Conference & Exposition Proceedings 2020, 1 .
AMA StyleZhanping You, Qingli Dai. Feasibility Of Virtual Laboratory For Asphalt Mixtures And Pavements. 2006 Annual Conference & Exposition Proceedings. 2020; ():1.
Chicago/Turabian StyleZhanping You; Qingli Dai. 2020. "Feasibility Of Virtual Laboratory For Asphalt Mixtures And Pavements." 2006 Annual Conference & Exposition Proceedings , no. : 1.
This study intends to evaluate the feasibility of the use of recycled cathode ray tube (CRT) glass in water-foamed asphalt mixtures used in low volume roads. In the asphalt mixture samples, 21.5% (wt.) aggregates were replaced by the recycled CRT glass to evaluate the mechanical performance and leaching potential. First, the leaching test was used to characterize the leaching potential of the CRT mixes since there is high lead content in CRT glass, which may be harmful to the groundwater if the hazardous lead leaches from the CRT mixes. Second, the high-temperature rutting and the low-temperature cracking performance of the asphalt mixtures were measured via the Hamburg Wheel Tracking Test (HWTT) and the Disk-Shape Compact Tension (DCT) test, respectively. In addition, the Moisture-Induced Stress Tester (MIST) was used to simulate the pore pressure generated in a wet pavement under moving traffic loading. The experimental results showed that, although the measured lead leaching of the pure CRT glass particles was higher than the regulatory level of 5 mg/L, the coated asphalt could effectively insulate the contact between CRT glass and the external environment, resolving the leaching issues. In summary, from the view of the mechanical performance of the water-foamed asphalt mixtures containing recycled CRT glass, the performance is acceptable in various temperatures when used in low volume roads. Recycling CRT glass in asphalt mixture should be carried out with extreme caution because if not done correctly, the potential leaching may eliminate the benefits of recycling unwanted waste materials.
Lingyun You; Dongzhao Jin; Shuaicheng Guo; Jiaqing Wang; Qingli Dai; Zhanping You. Leaching evaluation and performance assessments of asphalt mixtures with recycled cathode ray tube glass: A preliminary study. Journal of Cleaner Production 2020, 279, 123716 .
AMA StyleLingyun You, Dongzhao Jin, Shuaicheng Guo, Jiaqing Wang, Qingli Dai, Zhanping You. Leaching evaluation and performance assessments of asphalt mixtures with recycled cathode ray tube glass: A preliminary study. Journal of Cleaner Production. 2020; 279 ():123716.
Chicago/Turabian StyleLingyun You; Dongzhao Jin; Shuaicheng Guo; Jiaqing Wang; Qingli Dai; Zhanping You. 2020. "Leaching evaluation and performance assessments of asphalt mixtures with recycled cathode ray tube glass: A preliminary study." Journal of Cleaner Production 279, no. : 123716.
The self-compacting concrete (SCC) with the replacement of recycled rubber aggregates is limited for the field application due to high-performance requirements. The steel fiber was introduced to the rubberized SCC (RSCC) to enhance its performance and promote its application. The fresh and mechanical properties and durability performance of steel fiber-reinforced rubber self-compacting concrete (SRSCC) were evaluated. The SRSCC samples were prepared with replaced rubber aggregate based on fine aggregate volume percentages of 10%, 15%, and 25% and a consistent steel fiber ratio of 0.2%. The plain SCC and rubberized SCC samples were also produced for comparison. The fresh performance was evaluated with slump flow, J-ring flow, V-funnel, and U-box tests. The results showed that both filling and passing ability could be affected by the added steel fiber and rubber aggregate. However, the SRSCC could still meet most of the recommended criteria for passing and filling abilities when the rubber content is lower than 25%. Regarding the hardened properties, the compressive strength was reduced in rubber SCC samples with increased rubber contents by comparing with the control SCC samples. Nevertheless, SRSCC samples with 10% rubbers have higher splitting tensile strength than RSCC and plain SCC. Also, the SRSCC specimens showed excellent freeze-thaw resistance after 600 F-T cycles. The relative dynamic modulus of elasticity slightly increased without any dimensional expansion in SRSCC samples. In summary, the proposed SRSCC can meet required flowability, filling and passing abilities along with good mechanical and freeze-thaw performance. This study will provide lab test data for the applications of recycling waste tire aggregates in steel fiber-reinforced SCC.
Jiaqing Wang; Qingli Dai; Ruizhe Si; Yunxiang Ma; Shuaicheng Guo. Fresh and mechanical performance and freeze-thaw durability of steel fiber-reinforced rubber self-compacting concrete (SRSCC). Journal of Cleaner Production 2020, 277, 123180 .
AMA StyleJiaqing Wang, Qingli Dai, Ruizhe Si, Yunxiang Ma, Shuaicheng Guo. Fresh and mechanical performance and freeze-thaw durability of steel fiber-reinforced rubber self-compacting concrete (SRSCC). Journal of Cleaner Production. 2020; 277 ():123180.
Chicago/Turabian StyleJiaqing Wang; Qingli Dai; Ruizhe Si; Yunxiang Ma; Shuaicheng Guo. 2020. "Fresh and mechanical performance and freeze-thaw durability of steel fiber-reinforced rubber self-compacting concrete (SRSCC)." Journal of Cleaner Production 277, no. : 123180.
The purpose of this study was to evaluate the thermal (glass transition temperature), transport (self-diffusion), and rheological (viscosity, storage and loss modulus) properties of asphalt via laboratory experiments and molecular dynamics simulations. A 12-component asphalt model was employed in the molecular dynamics simulations with the modified Amber-Cornell force field. The asphalt model with the specific force field was validated against experimental and literature density data at various temperatures. The transition from the glassy state to the viscoelastic regime was explored by calculating the glass transition temperature. The results were compared with results from the differential scanning calorimeter (DSC) experiments. The self-diffusivity was calculated at a broad temperature range. The viscosity at the viscoelastic liquid regime was measured in the laboratory and calculated with reverse non-equilibrium molecular dynamic (rNEMD) simulations at various temperatures. Laboratory dynamic shear rheological testing was conducted for a wide frequency range at 70 °C. Oscillatory shear was applied in the asphalt model for calculating the storage and loss moduli within the experimental frequency range.
Lingyun You; Theodora Spyriouni; Qingli Dai; Zhanping You; Ashok Khanal. Experimental and molecular dynamics simulation study on thermal, transport, and rheological properties of asphalt. Construction and Building Materials 2020, 265, 120358 .
AMA StyleLingyun You, Theodora Spyriouni, Qingli Dai, Zhanping You, Ashok Khanal. Experimental and molecular dynamics simulation study on thermal, transport, and rheological properties of asphalt. Construction and Building Materials. 2020; 265 ():120358.
Chicago/Turabian StyleLingyun You; Theodora Spyriouni; Qingli Dai; Zhanping You; Ashok Khanal. 2020. "Experimental and molecular dynamics simulation study on thermal, transport, and rheological properties of asphalt." Construction and Building Materials 265, no. : 120358.
The crack development is considered to be one of the most severe threats to the durability of concrete infrastructure. This study aims to enhance the durability performance of cementitious material with the pH-responsive Superabsorbent Polymer (SAP). The SAP was synthesized with acrylic acid (AA)-methyl acrylate (MA) precursors, and three type samples with different crosslinking levels were prepared. The examination on the pH sensitivity indicated that the swelling capacity of the prepared SAP would first increase and then decrease with solution alkalinity, and the peak swelling potential was achieved around pH value of 12 for all the three type SAP with solution/gel mass ratio of 500. Further examination indicated the alkalinity of the buffer solution was reduced during the adsorption test, which can be caused by the hydrolysis of the amide groups and the crosslinker. Besides that, it was also found the solution/gel ratio and the Ca(OH)2 content could affect the swelling potential of the SAP. After that, the performance tests were conducted for the evaluation of concrete with SAP. A wax-coating protocol for the SAP was designed by using the hot-water method to prevent its swelling during mixing process. It was found that the strength reduction for samples with wax-coated SAP was insignificant compared to that of the control samples. Furthermore, durability tests supported the wax-shell could be broken by the crack propagation in concrete. And further experimental studies are needed to optimize the wax-size and shell thickness for enhanced self-sealing efficiency.
Shuaicheng Guo; Pegah Kord Forooshani; Qingli Dai; Bruce P. Lee; Ruizhe Si; Jiaqing Wang. Design of pH-responsive SAP polymer for pore solution chemistry regulation and crack sealing in cementitious materials. Composites Part B: Engineering 2020, 199, 108262 .
AMA StyleShuaicheng Guo, Pegah Kord Forooshani, Qingli Dai, Bruce P. Lee, Ruizhe Si, Jiaqing Wang. Design of pH-responsive SAP polymer for pore solution chemistry regulation and crack sealing in cementitious materials. Composites Part B: Engineering. 2020; 199 ():108262.
Chicago/Turabian StyleShuaicheng Guo; Pegah Kord Forooshani; Qingli Dai; Bruce P. Lee; Ruizhe Si; Jiaqing Wang. 2020. "Design of pH-responsive SAP polymer for pore solution chemistry regulation and crack sealing in cementitious materials." Composites Part B: Engineering 199, no. : 108262.
The supportive structures of power grids are vital but susceptible to weather-related events, such as extreme wind and icing rain with concurrent wind. The objective of this paper is to assess the reliability of the power grids subjected to high wind and ice accretion. The material and geometry uncertainty and the strength deterioration of poles due to decay are included in probabilistic models considering the bending failure of the poles and tensile failure of the wires. The extreme wind speed and icing accretion thickness are modeled with the Weibull distribution and generalized Pareto distribution, respectively. The fragility and reliability are analyzed with a Monte Carlo simulation for the comparison of two example locations with different hazard conditions. Case studies are implemented with a notional system and the system of Centerville, a fictitious study domain. The results illustrated that the fragility of wires is noteworthy in icing hazard reliability assessment. During icing rain, the concurrent wind speed significantly impacts the reliability of the power grids. The system reliability subjected to wind hazards is more sensitive to pole strength deterioration than in icing scenarios. The presented analysis framework will be beneficial for the design and maintenance of power grids subjected to both wind and icing hazards.
Yunxiang Ma; Qingli Dai; Weichiang Pang. Reliability Assessment of Electrical Grids Subjected to Wind Hazards and Ice Accretion with Concurrent Wind. Journal of Structural Engineering 2020, 146, 04020134 .
AMA StyleYunxiang Ma, Qingli Dai, Weichiang Pang. Reliability Assessment of Electrical Grids Subjected to Wind Hazards and Ice Accretion with Concurrent Wind. Journal of Structural Engineering. 2020; 146 (7):04020134.
Chicago/Turabian StyleYunxiang Ma; Qingli Dai; Weichiang Pang. 2020. "Reliability Assessment of Electrical Grids Subjected to Wind Hazards and Ice Accretion with Concurrent Wind." Journal of Structural Engineering 146, no. 7: 04020134.
This objective of this study is to utilize recycled glass powder as a partial replacement precursor of the metakaolin-based geopolymer to develop a sustainable geopolymer material. Four glass powder replacement ratios were selected for the metakaolin-based geopolymer preparation (0%, 5%, 10%, and 20% by the total precursor weight). The pair distribution function (PDF) analysis indicated that a higher amount of the four-membered ring structures in the formed gel with the added glass powder. Both PDF and EDX analysis showed that the Si/Al ratio of the binder phase increased with glass powder content in the mixtures. The added glass powder can improve the workability of the geopolymer binder and prolong the setting time of the synthesized geopolymer samples. The nanoindentation test results showed that the elastic modulus of the formed gel increased with replaced 10% and 20% glass powder. In addition, the samples with 5% of glass powder achieved the highest compressive strength among tested samples. The test results indicated that the appropriate glass powder replacement can affect the geopolymerization process and modify the formed gels in the metakaolin-based geopolymer to improve the mechanical properties of the mixture. The information obtained in this study can promote the utilization of waste glass powder as a partial replacement of the precursor for the production of sustainable alkali-activated materials.
Ruizhe Si; Shuaicheng Guo; Qingli Dai; Jiaqing Wang. Atomic-structure, microstructure and mechanical properties of glass powder modified metakaolin-based geopolymer. Construction and Building Materials 2020, 254, 119303 .
AMA StyleRuizhe Si, Shuaicheng Guo, Qingli Dai, Jiaqing Wang. Atomic-structure, microstructure and mechanical properties of glass powder modified metakaolin-based geopolymer. Construction and Building Materials. 2020; 254 ():119303.
Chicago/Turabian StyleRuizhe Si; Shuaicheng Guo; Qingli Dai; Jiaqing Wang. 2020. "Atomic-structure, microstructure and mechanical properties of glass powder modified metakaolin-based geopolymer." Construction and Building Materials 254, no. : 119303.
Asphalt-emulsion is a cleaner material in pavement constructions, which can substantially reduce energy consumption and emissions. Stability and rheology are critical issues in the applications of asphalt-emulsion. Asphalt-emulsion CSS-1h, used in this study, is a cationic slow-setting emulsion. Stability and rheology are, to some extent, determined by the interactions of asphalt and water in asphalt-emulsion. The objective of this study was to investigate the interactions of asphalt and water in asphalt-emulsion under different acidic and alkaline levels, which are reflected in the stability and rheological behaviors of CSS-1h. In order to achieve this goal, the original CSS-1h was mixed with the contents of hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions and then measured to determine its moisture retention during oven heating for characterizing the emulsification stability under different acidic and alkaline levels. The Dynamic Shear Rheometer (DSR) experiments evaluated the apparent viscosity of asphalt-emulsions and the rutting indicator of their residues. In addition, the microscopic properties of the asphalt-emulsions were characterized using the Fourier-Transform Infrared Spectroscopy (FTIR). The FTIR analyzed the influence of acidic and alkaline levels on the microscopic properties of CSS-1h using molecular chemistry. The results concluded that the acidic and alkaline levels have significant effects on the functional groups in asphalt-emulsions and their residues, as well as on the interactions of asphalt and water, which in turn affects the stability and rheology of the cationic asphalt-emulsions.
Lingyun You; Qingli Dai; Zhanping You; Xiaodong Zhou; Sarah Washko. Stability and rheology of asphalt-emulsion under varying acidic and alkaline levels. Journal of Cleaner Production 2020, 256, 120417 .
AMA StyleLingyun You, Qingli Dai, Zhanping You, Xiaodong Zhou, Sarah Washko. Stability and rheology of asphalt-emulsion under varying acidic and alkaline levels. Journal of Cleaner Production. 2020; 256 ():120417.
Chicago/Turabian StyleLingyun You; Qingli Dai; Zhanping You; Xiaodong Zhou; Sarah Washko. 2020. "Stability and rheology of asphalt-emulsion under varying acidic and alkaline levels." Journal of Cleaner Production 256, no. : 120417.
Jie Ji; Zhe Wang; Hui Yao; Di Wang; Ran Zhang; Aboelkasim Diab; Qingli Dai. A numerical study on rutting behaviour of direct coal liquefaction residue modified asphalt mixture. Road Materials and Pavement Design 2019, 22, 1454 -1468.
AMA StyleJie Ji, Zhe Wang, Hui Yao, Di Wang, Ran Zhang, Aboelkasim Diab, Qingli Dai. A numerical study on rutting behaviour of direct coal liquefaction residue modified asphalt mixture. Road Materials and Pavement Design. 2019; 22 (6):1454-1468.
Chicago/Turabian StyleJie Ji; Zhe Wang; Hui Yao; Di Wang; Ran Zhang; Aboelkasim Diab; Qingli Dai. 2019. "A numerical study on rutting behaviour of direct coal liquefaction residue modified asphalt mixture." Road Materials and Pavement Design 22, no. 6: 1454-1468.
This paper investigates the mechanical properties, nanopore structure and drying shrinkage behavior of the metakaolin-based geopolymer mixtures containing 0%–20% waste glass powder. The prepared samples were cured under ambient temperature and high temperature (60 °C), respectively. The mechanical properties of the samples can be improved by introducing the low content of glass powder (5%–10%). Microstructure and nanopore structure analysis indicated that a denser gel phase was formed in the glass powder modified geopolymer samples. The added glass powder reduced the water loss rate of the samples under drying condition, leading to a reduction of drying shrinkage at early ages. The capillary stress in the prepared geopolymer samples was analyzed based on the pore size distribution of the mixtures. The magnitude of capillary stress generated in glass powder containing samples was similar to that of geopolymers without glass powder. The improved creep modulus with added glass powder facilitated the reduction of the shrinkage of the samples at later ages. This study can facilitate the recycling of waste glass into geopolymer for sustainable construction applications.
Ruizhe Si; Qingli Dai; Shuaicheng Guo; Jiaqing Wang. Mechanical property, nanopore structure and drying shrinkage of metakaolin-based geopolymer with waste glass powder. Journal of Cleaner Production 2019, 242, 118502 .
AMA StyleRuizhe Si, Qingli Dai, Shuaicheng Guo, Jiaqing Wang. Mechanical property, nanopore structure and drying shrinkage of metakaolin-based geopolymer with waste glass powder. Journal of Cleaner Production. 2019; 242 ():118502.
Chicago/Turabian StyleRuizhe Si; Qingli Dai; Shuaicheng Guo; Jiaqing Wang. 2019. "Mechanical property, nanopore structure and drying shrinkage of metakaolin-based geopolymer with waste glass powder." Journal of Cleaner Production 242, no. : 118502.
Ideally, a complete bond between the chip-seal and asphalt pavement is achieved during the chip-seal application. However, complete and total bonding is unlikely due to environmental and material conditions. Therefore, it is critical to understand the bond qualities under varying environmental and material conditions, which is also beneficial for cleaner production of chip-seal applications. The shear bond strength is a crucial indicator for revealing the bond qualities of chip-seal with asphalt pavement. The objective of this study is to develop a laboratory approach to characterise the shear bond strength of a chip-seal application with the asphalt pavement. It is achieved by developing a laboratory approach to the shear bond test (SBT). This study investigated the shear bond strength between chip-seal and asphalt pavement of several asphalt-aggregate combinations and different asphalt-emulsion application rates. Also, in order to characterise the influence of temperatures and freeze–thaw cycles on the durability of chip-seal, several test temperatures, and the multiple freeze–thaw cycles were applied in the proposed SBT. The laboratory test outcomes recommended that the weak shear bonding of chip-seal with asphalt pavement is in part because of the multiple freeze–thaw cycles suffered and the raw materials used.
Lingyun You; Dongzhao Jin; Zhanping You; Qingli Dai; Xinfeng Xie; Sarah Washko; Samantha Cepeda. Laboratory shear bond test for chip-seal under varying environmental and material conditions. International Journal of Pavement Engineering 2019, 1 -9.
AMA StyleLingyun You, Dongzhao Jin, Zhanping You, Qingli Dai, Xinfeng Xie, Sarah Washko, Samantha Cepeda. Laboratory shear bond test for chip-seal under varying environmental and material conditions. International Journal of Pavement Engineering. 2019; ():1-9.
Chicago/Turabian StyleLingyun You; Dongzhao Jin; Zhanping You; Qingli Dai; Xinfeng Xie; Sarah Washko; Samantha Cepeda. 2019. "Laboratory shear bond test for chip-seal under varying environmental and material conditions." International Journal of Pavement Engineering , no. : 1-9.
In this study, the synergistic effect of combining macro polypropylene (PP) fiber and rubberized concrete was evaluated based on mechanical and durability performance, as well as microstructure. The specimens were prepared with two different rubber volume contents at 10% and 15%, incorporating with a consistent fiber volume fraction of 0.5%. The plain concrete specimens and specimens with only PP fiber were also produced for comparison. The mechanical test results indicated that the fracture energy of plain concrete could be enhanced with both macro PP fiber and rubber aggregates. Besides, all specimens achieved compressive strength higher than 40 Mpa, and the ultrasonic pulse velocity demonstrated the good quality of concrete specimens. The fracture morphology and ESEM imaging showed the positive function of rubber aggregates and PP fibers on the post-crack propagation. The durability performance, including drying shrinkage, ASR expansion, and frost resistance were also strengthened in macro PP fiber-reinforced rubber concrete compared with plain concrete. The macro PP fiber-reinforced rubber concrete will enlarge the post-failure flexural residual load capacity and deformation and distribute stress for multiple crack propagation, thus increasing overall fracture toughness and reducing brittleness. The sustainable applications can be further explored with the combination of macro PP fiber and recycled rubber aggregate.
Jiaqing Wang; Qingli Dai; Ruizhe Si; Shuaicheng Guo. Mechanical, durability, and microstructural properties of macro synthetic polypropylene (PP) fiber-reinforced rubber concrete. Journal of Cleaner Production 2019, 234, 1351 -1364.
AMA StyleJiaqing Wang, Qingli Dai, Ruizhe Si, Shuaicheng Guo. Mechanical, durability, and microstructural properties of macro synthetic polypropylene (PP) fiber-reinforced rubber concrete. Journal of Cleaner Production. 2019; 234 ():1351-1364.
Chicago/Turabian StyleJiaqing Wang; Qingli Dai; Ruizhe Si; Shuaicheng Guo. 2019. "Mechanical, durability, and microstructural properties of macro synthetic polypropylene (PP) fiber-reinforced rubber concrete." Journal of Cleaner Production 234, no. : 1351-1364.
Corrosion is one of the most severe threats to the stability of steel bridges and regular rust removal techniques is needed for the maintenance of steel bridges. Currently the correlation between rust development/removal process and the structural/environmental performance of the steel bridges has not been fully understood. This study intends to fill this knowledge gap through critically reviewing. The characteristic analysis of the rust on the corroded steel bridges was first introduced, which provided information that was needed to understand the corrosion mechanisms and classify the rust type. Then the related rust removal techniques (chemical and physical methods) are analyzed by considering the environmental impact and cleaning efficiency. Based on the discussion, the laser cleaning method is proposed due to its cleaning efficiency and environmentally friendliness. After that, the influence of developed rust (uniform and pitting) on the structural performance (static and dynamic) of steel members were summarized. Through the discussion, the potential environmental impact of the corroded steel bridges was identified, including runoff of heavy metal and bacteria growth caused by iron rust. Besides that, an improved kinetic model was proposed by considering the influence of rust removal on the corrosion rate. Furthermore, the structural impact of laser cleaning was simulated with the finite element analysis. This study will serve as solid base for the future studies of corrosion development and rust removal on steel bridges, and the proposed technical routes can be proceeded during future studies to better understand the environmental and structural performance of the steel bridges.
Shuaicheng Guo; Ruizhe Si; Qingli Dai; Zhanping You; Yunxiang Ma; Jiaqing Wang. A critical review of corrosion development and rust removal techniques on the structural/environmental performance of corroded steel bridges. Journal of Cleaner Production 2019, 233, 126 -146.
AMA StyleShuaicheng Guo, Ruizhe Si, Qingli Dai, Zhanping You, Yunxiang Ma, Jiaqing Wang. A critical review of corrosion development and rust removal techniques on the structural/environmental performance of corroded steel bridges. Journal of Cleaner Production. 2019; 233 ():126-146.
Chicago/Turabian StyleShuaicheng Guo; Ruizhe Si; Qingli Dai; Zhanping You; Yunxiang Ma; Jiaqing Wang. 2019. "A critical review of corrosion development and rust removal techniques on the structural/environmental performance of corroded steel bridges." Journal of Cleaner Production 233, no. : 126-146.
This paper presents the experimental study on the influence of grouting reinforcement on the fatigue behavior of cracked cement mortar under different stress ratio and levels. The compressive fatigue tests were conducted with a loading frequency of about 150 Hz. The fatigue life decreased logarithmically with the increase of the stress level, and the fatigue life threshold increased with the increase of the stress ratio. The pores near the fracture were effectively strengthened after the grouting reinforcement. The initial fatigue crack of the sample was initiated at the original crack tip when the lateral deformation reached its threshold value. A double logarithmic fatigue equation was introduced to delineate the fatigue equation. Considering the influence of stress level and stress ratio, a damage evolution equation was proposed to describe the damage evolution process. The fitting results agreed well with the test data.
Zhi Wang; Long Li; Linjian Song; Shuaicheng Guo; Qingli Dai. High-Frequency Fatigue Performance of Cracked Mortar after Epoxy Grouting Reinforcement. International Journal of Geomechanics 2019, 19, 04019035 .
AMA StyleZhi Wang, Long Li, Linjian Song, Shuaicheng Guo, Qingli Dai. High-Frequency Fatigue Performance of Cracked Mortar after Epoxy Grouting Reinforcement. International Journal of Geomechanics. 2019; 19 (5):04019035.
Chicago/Turabian StyleZhi Wang; Long Li; Linjian Song; Shuaicheng Guo; Qingli Dai. 2019. "High-Frequency Fatigue Performance of Cracked Mortar after Epoxy Grouting Reinforcement." International Journal of Geomechanics 19, no. 5: 04019035.
Application of rubber particle from the scrap tire through dry-process is a practical and economical efficient way to resolve the recycling problem and environmental concern of the disposed tires. However, the added rubber aggregate reduces both the strength and durability of the rubberized asphalt mixture. This study aims to improve the strength and durability of dry-processed asphalt mixture by using the cement (Portland Type Ⅰ) coating methods and gap-gradation system (Stone Matrix Asphalt (SMA)). The cement coating was applied to enhance the bonding performance between rubber aggregate and asphalt binder, and limits its expansion due to swelling in hot asphalt binder. The SMA mixtures were prepared with different sizes and proportions of mineral aggregates. The samples with conventional aggregate and untreated rubber aggregate both serve as control samples for the sample evaluation. Finally, tests on tensile strength, moisture susceptibility, rutting resistance, anti-stripping resistance, fatigue cracking resistance, and bonding between rubber particles and asphalt binder of SMA mixtures were conducted. The results showed that SMA mixture with pre-coated rubber aggregate owns similar performance comparing to the samples prepared with conventional aggregate and also has higher strength and better performance than that of the mixture with untreated rubber aggregate. Results also clearly indicated that the asphalt mixtures with 50% of No.16 mineral aggregates replaced by pre-coated rubber aggregates performed the best-satisfied performances; while, with a further increase in replaced size or proportion, the satisfied performances of SMA mixtures would be degenerated.
Fangyuan Gong; Shuaicheng Guo; Siyu Chen; Zhanping You; Yu Liu; Qingli Dai. Strength and durability of dry-processed stone matrix asphalt containing cement pre-coated scrap tire rubber particles. Construction and Building Materials 2019, 214, 475 -483.
AMA StyleFangyuan Gong, Shuaicheng Guo, Siyu Chen, Zhanping You, Yu Liu, Qingli Dai. Strength and durability of dry-processed stone matrix asphalt containing cement pre-coated scrap tire rubber particles. Construction and Building Materials. 2019; 214 ():475-483.
Chicago/Turabian StyleFangyuan Gong; Shuaicheng Guo; Siyu Chen; Zhanping You; Yu Liu; Qingli Dai. 2019. "Strength and durability of dry-processed stone matrix asphalt containing cement pre-coated scrap tire rubber particles." Construction and Building Materials 214, no. : 475-483.
The objectives of this study are to explore the mechanism of the self-healing or flow of asphalt binder on the surface of the aggregates and evaluate the contact angle between the asphalt binder and aggregates. The mastic samples (small size) were prepared with asphalt binder and fine aggregates of a small size (below 0.3 mm). The microscale dynamic X-ray tomography was used to observe the flow of asphalt binder in the mastic sample at 353.15 K (80 °C) using the Advanced Photon Source (APS) beamline 2-BM at Argonne National Laboratory. The activation energy for flow of the asphalt binder and the contact angle between the asphalt binder and aggregates were analyzed to explain the self-healing characteristics of the asphalt binder materials. The Molecular Dynamics (MD) method was employed to simulate the flow process of the molecules of asphalt binder at different temperatures and mimic the contact angle difference between the asphalt binder and aggregate models. Simultaneously, in the laboratory, the contact angle goniometer was selected to measure the contact angle between the asphalt binder droplet and aggregates at different temperatures. The results of tests and MD simulations show that (1) asphalt binder diffused after heating from the X-ray images, and the stages and mechanism of the flow process of asphalt binder on aggregates were investigated; (2) low contact angle was observed in the interface model of asphalt binder and aggregates at high temperatures using the MD method. The wetting condition changed from partial non-wetting to wetting after heating in the interface model; (3) contact angle results between the asphalt binder and aggregates demonstrated flow steps of the asphalt binder material. The test data was also compared with the MD simulation results at different temperatures.
Hui Yao; Qingli Dai; Zhanping You; Jinxi Zhang; Songtao Lv; Xianghui Xiao. Evaluation of contact angle between asphalt binders and aggregates using Molecular Dynamics (MD) method. Construction and Building Materials 2019, 212, 727 -736.
AMA StyleHui Yao, Qingli Dai, Zhanping You, Jinxi Zhang, Songtao Lv, Xianghui Xiao. Evaluation of contact angle between asphalt binders and aggregates using Molecular Dynamics (MD) method. Construction and Building Materials. 2019; 212 ():727-736.
Chicago/Turabian StyleHui Yao; Qingli Dai; Zhanping You; Jinxi Zhang; Songtao Lv; Xianghui Xiao. 2019. "Evaluation of contact angle between asphalt binders and aggregates using Molecular Dynamics (MD) method." Construction and Building Materials 212, no. : 727-736.