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Lingyun You, Dongzhao Jin, Shuaicheng Guo, Jiaqing Wang, Qingli Dai, and Zhanping You
Journal of Cleaner Production, ISSN: 09596526, Volume: 279, Published: 10 January 2021 Elsevier BV
Abstract 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.
Jiaqing Wang, Qingli Dai, Ruizhe Si, Yunxiang Ma, and Shuaicheng Guo
Journal of Cleaner Production, ISSN: 09596526, Volume: 277, Published: 20 December 2020 Elsevier BV
Abstract 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.
Songtao Lv, Jiang Yuan, Xinghai Peng, Milkos Borges Cabrera, Shuaicheng Guo, Xinzi Luo, and Junfeng Gao
Construction and Building Materials, ISSN: 09500618, Volume: 264, Published: 20 December 2020 Elsevier BV
Abstract Applying bio-asphalt in road engineering can effectively resolve its shortage of petroleum asphalt, and enhance its environmental friendliness and sustainability. However, the poor high-temperature stability with added bio-oil is a key obstacle restricting its wide utilization. To broaden the application of bio-asphalt in road engineering, in this research was used rock asphalt to further improve bio-asphalt through the Box-Behnken Design (BBD). During the optimization of the design, bio-oil content, rock asphalt content, and shear time were defined as independent variables. Penetration, softening point, creep rate, stiffness modulus, and irrecoverable creep compliance of the modified asphalt were considered response values. Response surface method (RSM) model and Genetic algorithm optimization artificial neural network (GA-ANN) model were utilized to analyze the behavior of bio-oil/rock asphalt composite modified asphalt. Furthermore, the feasibility of both models was verified through experimental results. The results indicated that the incorporation of bio-oil and rock asphalt improved the low-temperature and high-temperature resistance of neat asphalt, respectively. Besides, the low-temperature crack resistance of composite modified asphalt was remarkably enhanced, and the high-temperature performance was similar to the one related to neat asphalt. GA-ANN model had higher feasibility for composite modified asphalt performance optimization. The optimal bio-oil content, rock asphalt content, and shear time determined by using RSM and GA-ANN model were equal to 6.3%, 11.2%, 52.8 min, and 6.3%, 12.9%, 76.6 min, respectively. The bio-oil/rock asphalt composite modified asphalt with targeted performance requirements can be achieved by combining the proposed weight function with the RSM model and GA-ANN model. Optimization with GA-ANN can further promote the recycling of both bio-oil and Buton rock asphalt, save energy, and lead to a greener construction material. This study can serve as a solid base for more efficient utilization of bio-asphalt in road engineering.
Songtao Lv, Long Hu, Chengdong Xia, Xiaofeng Wang, Milkos Borges Cabrera, Shuaicheng Guo, and Jie Chen
Construction and Building Materials, ISSN: 09500618, Volume: 260, Published: 10 November 2020 Elsevier BV
Abstract As the primary surface type for high-grade Chinese highways, the long-term performance of asphalt pavement can affect significantly transportation efficiency. It has been confirmed that fatigue cracking is one of the major failure modes for asphalt pavement, which can cause a great reduction of asphalt pavement durability. Currently, the fatigue properties of asphalt mixtures are evaluated mainly based on traditional laboratory fatigue tests, such as bending fatigue tests and indirect tensile fatigue tests. However, none of these fatigue test methods can realistically evaluate the fatigue performance of asphalt pavement under the repeated wheel load. To resolve this issue, the model mobile load simulator (MMLS3), which is a small-scale accelerated pavement test device, was utilized to evaluate the fatigue life of six kinds of asphalt mixtures. The fatigue damage variable was defined as stiffness reduction. Based on the small-scale accelerated pavement test, a stiffness reduction model for asphalt mixtures was determined. A stiffness reduction law for asphalt mixtures during the fatigue process was proposed. The stiffness evolution process could be divided into three phases, which are the adaptation phase, the quasi-stationary phase, and the failure phase. A maximum value of the rate of stiffness reduction from the quasi-stationary phase into the failure phase was proposed as the failure threshold. Besides the fatigue life obtained from the failure criteria had a good agreement with the test results. The results from this research can be used as a theoretical reference for evaluating the fatigue life of asphalt mixtures and improving the durability of asphalt pavement.
Sai Liu, Prashant Rawat, Zheng Chen, Shuaicheng Guo, Caijun Shi, and Deju Zhu
Composites Part B: Engineering, ISSN: 13598368, Volume: 199, Published: 15 October 2020 Elsevier BV
Abstract Textile reinforced concretes (TRCs) have many extraordinary features that make them a future-ready material exposed to complex environmental situations. However, current knowledge related to TRCs under mechanical loading and environmental conditions is not fully explored as compared to conventional fiber reinforced concretes. The present work investigates the quasi-static pullout performance of single-yarn and textile type (AR-glass and basalt fiber) reinforced cement mortars under different temperatures (25 °C, 100 °C, 300 °C and 600 °C). The pullout testes were carried out at loading rates of 0.25, 2.5 and 25 mm/min on a MTS load frame setup. The reinforcement embedded length in the cement matrix was 30 mm. The pullout testing results were evaluated in terms of first-crack load and maximum pullout (or peak) load, displacement at first-crack, and energy absorption. The experimental results indicated that the textile type reinforcement was better than the yarn type reinforcement. The mechanical properties of TRCs were sensitive to loading rate and temperatures. In addition, the scanning electronic microscopy (SEM) images of the fractured samples tested at different loading rate and temperatures highlighted that quasi-static loading rate variations did not affect the fracture pattern. However, the temperature variation highly affected the epoxy resins used for filament bonding or coating) in the reinforcements which may critically affect their interfacial performances.
Shuaicheng Guo, Pegah Kord Forooshani, Qingli Dai, Bruce P. Lee, Ruizhe Si, and Jiaqing Wang
Composites Part B: Engineering, ISSN: 13598368, Volume: 199, Published: 15 October 2020 Elsevier BV
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.
Yong Yi, Deju Zhu, Shuaicheng Guo, Zuhua Zhang, and Caijun Shi
Cement and Concrete Composites, ISSN: 09589465, Volume: 113, Published: October 2020 Elsevier BV
Abstract This paper presents a review of the deterioration of concrete under seawater attack with particular interests in field exposure. The research reported in the literature has shown that salinity of seawater in different areas varies considerably but the type of ions and their proportion are similar. Because of this variation, laboratory studies should use specific artificial seawater to simulate on field environments. The phase changes induced by chloride, magnesium and sulfate ions contained in seawater are reviewed. The interaction between hydrates and chloride ion can lead to the formation Friedel's and Kuzel's salts. Magnesium ion can replace the calcium in Portlandite, and lowers the alkalinity of pore solution and eventually destabilizes C-S-H gel. The expansive ettringite is inhibited at the presence of chloride ions. At the tidal zone, the phase change mainly occurs on the surface of concrete, which weakens the structure and leads to spalling and delamination under the physical attack of the wave. Based on the existing deterioration mechanisms, the protocols to enhance the durability performance of marine concrete are also reviewed, such as using supplementary cementitious materials (SCMs) to mitigate rate of chloride penetration and, more promisingly, to use alternative binder systems. This paper also proposes a concept of designing a more durable concrete cover system by enhancing the chemical stability of cement hydrates, rapid self-healing and intelligent alkalinity control.
Azzam Ahmed, Shuaicheng Guo, Zuhua Zhang, Caijun Shi, and Deju Zhu
Construction and Building Materials, ISSN: 09500618, Volume: 256, Published: 30 September 2020 Elsevier BV
Abstract FRP reinforced seawater sea sand concrete (FRP-SWSSC) combines the advantages of corrosion-free FRP bars in the marine environment and the direct utilization of seawater and sea sand, which can lead to a more sustainable and economic-efficient construction material. This paper reports a comprehensive overview of the current works on workability, mechanical properties (tensile, interlaminar shear, transverse shear, and flexural strength), bond behavior, durability, and applications of FRP-SWSSCs. The results indicated that exposure to the saline/alkaline environment is the main threat to the long-term performance of SWSSC. Furthermore, durability performance can also be affected by the type of FRP, surface protection, and concrete. Normally, the surface enhancement of the FRP bars can enhance its durability performance under saline environment. The current study mainly focuses on the application of glass fiber reinforced polymer (GFRP) in SWSSC, while the basalt fiber reinforced polymer (BFRP) bars have gained less attention. Also, GFRP demonstrated better resistance to both simulated concrete pore solution and saline condition than BFRP. Also, the exposure test under real conditions is essential to validate the results obtained from experiments in the simulated environment. The future research directions on FRP-SWSSC systems are recommended based on the summarization of current studies and field application.
Ruizhe Si, Shuaicheng Guo, Qingli Dai, and Jiaqing Wang
Construction and Building Materials, ISSN: 09500618, Volume: 254, Published: 10 September 2020 Elsevier BV
Abstract 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.
Wenbo Ma, Wenhao Gao, Shuaicheng Guo, Yanbing Zhao, Zhiren Wu, and Caiqian Yang
Cold Regions Science and Technology, ISSN: 0165232X, Volume: 177, Published: September 2020 Elsevier BV
Abstract Stabilization of the loose and fragile Pisha with the hydrophilic polyurethane material has been proved to be a time and cost-efficient protocol for the conservation of soil and water. However, the undesirable durability performance of the original W-OH binder material deteriorate its long-term conservation ability, especially under the freeze-thaw cycles. This study aims to improve the freeze-thaw durability performance of the W-OH composites through mixture design optimization and material modification. This study first investigates the correlation between the freeze-thaw resistance of the W-OH/Pisha sandstone composites and the concentration of the applied W-OH solution. The test results indicated both the compressive strength and elastic modulus of the W-OH based composites would decrease with freeze-thaw cycles and the samples prepared with higher concentration W-OH solution own better freeze-thaw resistance. Meanwhile, the elastic modulus of the W-OH composites decreased almost linearly with the freeze-thaw cycles, which is in accordance with the linear increase of the porosity of samples determined with the ultra-depth-of-field microscope. Based on these mechanism analyses, the modification of the W-OH material was further conducted with the Ethylene-vinyl acetate (EVA) and air entrainer. The compressive strength test results indicate both the added EVA can enhance the freeze-thaw durability of the W-OH composites, which can be caused by the improved cohesion strength of the W-OH binder due to enhanced density. Similarly, the freeze-thaw durability of the W-OH composites was also enhanced with added air entrainer, which provided extra space for the freezing expansion. The research results of this study can enhance the freeze-thaw durability of the stabilized Pisha sandstone and its long-term conservation ability on soil and water.
Songtao Lv, Chengdong Xia, Qing Yang, Shuaicheng Guo, Lingyun You, Yanpeng Guo, and Jianlong Zheng
Journal of Cleaner Production, ISSN: 09596526, Volume: 264, Published: 10 August 2020 Elsevier BV
Abstract The quickly accumulated crayfish shell waste in China has led to severe environmental issues and recycling pressure. This study aims to build an efficient protocol by utilizing waste crayfish shell powder in the production of high-performance and sustainable asphalt binder. The asphalt binder modified with different contents of crayfish shell powder (5%, 10% and 20% mass ratio to control asphalt, respectively) were first prepared at the temperature of 140oC–150 °C. Then the softening point and the penetration of the prepared samples were implemented to compare the stiffness difference between the modified and original asphalt binder. The results indicated that the added shell powder increased the softening point and decreased the penetration of the control asphalt. Furthermore, the high-temperature stability of the asphalt binder was examined by the dynamic shear rheometer (DSR) tests. The DSR results revealed that adding shell powder could enhance the rutting resistance of the asphalt binder by decreasing the phase angle δ, increasing the dynamic shear modulus |G∗| and finally enhancing the rutting factor |G∗|/sinδ. After that, to compare the creep performance between the control and modified asphalt binder, the multiple stress creep recovery (MSCR) tests were employed. The results of the MSCR test showed that at the same temperature, the percent recovery was higher while the non-recoverable creep compliance Jnr of modified asphalt was lower than those of the control binder. These results indicated that the added crayfish shell powder could increase the stiffness, improve the high-temperature stability and creep resistance of the asphalt binder. Finally, fourier transform infrared spectroscopy (FT-IR) test results implied that the added CS would not affect the chemical structure of the asphalt binder, and the modification was mainly a physical process. The novelty and limitation of this study have also been detailedly explained in the discussion part. The test results could provide a reference for the engineering application of the crayfish shell powder modified asphalt material and lead to both a cleaner and greener product.
Fang Liu, Zhanping You, Aboelkasim Diab, Zhuangzhuang Liu, Chao Zhang, and Shuaicheng Guo
Construction and Building Materials, ISSN: 09500618, Volume: 249, Published: 20 July 2020 Elsevier BV
Abstract The concrete transportation infrastructures will undergo both fatigue traffic loading and environmental impacts during the whole service life, including rigid pavements, bridges decks, airfield runways, railway bridges, even high-speed railways and concrete structures in the ocean. This study aims to investigate the effects of external sulfate attack on concrete under flexural fatigue loading and drying-wetting cycles. The changes of mass loss rate and relative dynamic elastic modulus were measured to indicate the influence of the coupled effects on the integrity and mechanical performance of concrete, also the sulfate content inside concrete was determined to indicate the permeability of sulfate ion under different experimental conditions. Moreover, the phase composition of samples was analyzed using X-ray diffraction (XRD). In addition, the effect of fly ash on sulfate attack was duly studied. Fatigue loading causes cracking in the interfaces of various phases and forms cracks in the concrete. Within the influence depth of drying-wetting cycles, concrete is subjected to both water convection due to capillary action and diffusion due to concentration gradients. The results indicate the fatigue loading and drying-wetting cycles can accelerate the transportation of sulfate ion inside concrete and the deterioration degree of concrete subjected to sulfate. The findings in this study can help to understand the influence of fatigue loading and drying-wetting cycles on the development of sulfate attack.
Wenbo Ma, Zenggang Zhao, Shuaicheng Guo, Yanbing Zhao, Zhiren Wu, and Caiqian Yang
Materials, eISSN: 19961944, Published: 1 February 2020 MDPI AG
Currently the investigation on recycled cement concrete aggregate has been widely conducted, while the understanding of the recycled polymer concrete aggregate is still limited. This study aims to fill this knowledge gap through the experimental investigation on mechanical and durability performance. Specifically, the remolded polyurethane stabilized Pisha sandstone was collected as the recycled polymer concrete aggregate. The remolded Pisha sandstone was then applied to re-prepare the polyurethane-based composites. After that, the mechanical performance of the prepared composites was first examined with unconfined and triaxial compressive tests. The results indicated that the Pisha sandstone reduces the composite’s compressive strength. The reduction is caused by the remained polyurethane material on the surface of the remolded aggregate, which reduces its bond strength with the new polyurethane material. Aiming at this issue, this study applied the ethylene-vinyl acetate (EVA) to enhance the bond performance between the polyurethane and remolded sandstone. The test results indicated both the unconfined and triaxle compressive strength of the polyurethane composites were enhanced with the added EVA content. Furthermore, the durability performance of the EVA-modified composites were examined through freeze-thaw and wet-dry cycle tests. The test results indicated the EVA could enhance the polyurethane composites’ resistance to both wet-dry and freeze-thaw cycles. Overall, the modification with EVA can compensate for the strength loss of polyurethane composites because of the applied remolded aggregate and enhance its sustainability.
Ruizhe Si, Qingli Dai, Shuaicheng Guo, and Jiaqing Wang
Journal of Cleaner Production, ISSN: 09596526, Volume: 242, Published: 1 January 2020 Elsevier BV
Abstract 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.
Jiaqing Wang, Qingli Dai, Ruizhe Si, and Shuaicheng Guo
Journal of Cleaner Production, ISSN: 09596526, Volume: 234, Pages: 1351-1364, Published: 10 October 2019 Elsevier BV
Abstract 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.
Shuaicheng Guo, Ruizhe Si, Qingli Dai, Zhanping You, Yunxiang Ma, and Jiaqing Wang
Journal of Cleaner Production, ISSN: 09596526, Volume: 233, Pages: 126-146, Published: 1 October 2019 Elsevier BV
Abstract 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.
Fangyuan Gong, Shuaicheng Guo, Siyu Chen, Zhanping You, Yu Liu, and Qingli Dai
Construction and Building Materials, ISSN: 09500618, Volume: 214, Pages: 475-483, Published: 30 July 2019 Elsevier BV
Abstract 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.
Jiaqing Wang, Shuaicheng Guo, Qingli Dai, Ruizhe Si, and Yunxiang Ma
Journal of Cleaner Production, ISSN: 09596526, Volume: 226, Pages: 85-95, Published: 20 July 2019 Elsevier BV
Abstract Using the crushed waste Cathode Ray Tube (CRT) glass as fine aggregate to produce concrete can be an efficient method to resolve the recycling issue. However, the mediocre mechanical properties of CRT concrete obstructed its wide application. This study aims to resolve this issue based on the study on concrete/mortar specimen incorporating with an innovated surface treatment method. Specifically, a two-step surface treatment method was proposed to improve the performance of CRT concrete by modifying the surface layer of CRT glass sands with NaOH solution and Al(NO3)3 solution. About 30% of the portland cement was replaced with class-F fly ash to mitigate possible ASR damage by the reactive CRT aggregate. The mechanical performance (Compressive/flexural strength, dynamic modulus of elasticity, and flexural fracture energy) and the durability performance (Drying shrinkage and ASR expansion) was examined and compared among different specimens. In addition, the leaching levels of lead in different concrete specimens was evaluated by toxicity characteristic leaching procedure (TCLP). The results showed that the surface treatment method of CRT glass sands could obviously improve both the mechanical properties and durability performance. Particularly, the leaching of lead (Pb) level in all concrete specimens was much lower than the TCLP heavy metals limit of 5 mg/L. This experimental study will facilitate the production of CRT glass concrete for secondary structural applications.
Wenbo Ma, Cong Hu, Shuaicheng Guo, Zenggang Zhao, and Tianbao Huang
Journal of Materials in Civil Engineering, ISSN: 08991561, Published: 1 July 2019 American Society of Civil Engineers (ASCE)
AbstractPolyurethane materials have been widely applied in the mending of cementitious materials, and the mending efficiency is highly impacted by the bond strength between the polyurethane materia...
Zhi Wang, Long Li, Linjian Song, Shuaicheng Guo, and Qingli Dai
International Journal of Geomechanics, ISSN: 15323641, Published: 1 May 2019 American Society of Civil Engineers (ASCE)
Yanping Sheng, Haichuan Jia, Shuaicheng Guo, Assaad Taoum, Bowen Guan, Haibin Li, and Xiong Rui
International Journal of Pavement Research and Technology, ISSN: 19966814, eISSN: 19971400, Pages: 315-324, Published: 1 May 2019 Springer Science and Business Media LLC
This paper aims to study the mechanical performance and durability properties of the brucite fiber reinforced cement stabilized base at the low-temperature condition. Five type samples with different fiber content were prepared, and the related mechanical performance and durability properties were examined. The test results indicated that the added brucite fiber could enhance both the mechanical and durability performance of the cement stabilized base. Specifically, it was found that the unconfined compressive/splitting tensile strength can reach at 3-day age and 7-day age could reach 41%/37% and 67%/67% respectively compared to the results at 28-day age. Furthermore, the added brucite fiber can reduce the drying shrinkage of the cementitious material and also improve its resistance to frost damage. The X-ray diffraction and Scanning Electron Microscopy tests were further conducted to examine the improvement mechanism of the brucite fiber reinforcement. It is found that the hydration degree of cement paste was enhanced with the added brucite fiber. The designed brucite fiber cement stabilized sample in this study is suitable for pavement construction in alpine regions.
Wenbo Ma, Tianbao Huang, Shuaicheng Guo, Caiqian Yang, Yanhuai Ding, and Cong Hu
Construction and Building Materials, ISSN: 09500618, Volume: 205, Pages: 642-655, Published: 30 April 2019 Elsevier BV
Abstract Asphalt aging is one of the most severe threats to the asphalt pavement durability and rejuvenation with cooking oil can help to resolve this issue. Currently, the influence of aging/rejuvenation on the bonding performance of asphalt binder has not been fully understood. This study aims to unveil the influence of aging/rejuvenation on the adhesion performance under both micro and macro scale tests. Three type asphalt binders were examined in this study, including the original, aged and rejuvenated samples. The atomic force microscope (AFM) was first applied to examine the surface morphology and adhesion performance of the three type asphalt samples. It is found that the aging effect can increase the adhesion between asphalt binder and silica particles and the adhesion force can be further enhanced through rejuvenation. Then the three-point bending was further conducted to examine adhesion performance at the macroscale, and the obtained results are in accordance with those obtained at the microscale. However, the slant shear test indicated the shear bond strength can be reduced due to the rejuvenation with vegetable oil, which can be generated due to the lubrication effect of the oil. The results in this study can help to better understand the influence of aging and rejuvenation on the bond performance between asphalt binder and mineral aggregate.
Jiaqing Wang, Qingli Dai, Shuaicheng Guo, and Ruizhe Si
Construction and Building Materials, ISSN: 09500618, Volume: 203, Pages: 469-480, Published: 10 April 2019 Elsevier BV
Abstract The epoxy-based polymer concrete has been widely used for concrete repairing and overlays due to good mechanical properties and durability. To reduce environmental landfill problems with the accumulation of tire rubbers, scrap tire rubbers were added to epoxy polymer concrete in this investigation. The crumb rubber (with mesh size #50, 0.279 mm) were introduced into epoxy concrete with two different contents of 5% and 10% based on the epoxy monomer weight. The mechanical properties including direct tensile strength, compressive strength, splitting tensile strength and interface bond strength. Thermal- and moisture-related durability performance of rubberized epoxy concrete were measured and compared with the control samples. The compressive strength and splitting tensile strength were improved with the added 5% solid rubbers, and slightly reduced with 10% content. With a specially-designed testing method, the interface tensile bonding strength between the epoxy concrete overlay and concrete slab were measured as higher than 250 psi for both control and rubberized samples. The thermal conductivity of polymer concrete was reduced with the increase of rubber contents. In addition, very low water absorption rates (
Ruizhe Si, Shuaicheng Guo, and Qingli Dai
Journal of the American Ceramic Society, ISSN: 00027820, eISSN: 15512916, Volume: 102, Pages: 1479-1494, Published: March 2019 Wiley
Jiaqing Wang, Qingli Dai, Shuaicheng Guo, and Ruizhe Si
ACI Materials Journal, ISSN: 0889325X, Volume: 116, Pages: 21-31, Published: March 2019 American Concrete Institute