This study was designed to enhance the soft clayey soil treatment effects using an innovative mechanochemically activated geopolymer(GP)through the optimized inclusion of nano-metakaolin(NM)and polypropylene fiber.The...This study was designed to enhance the soft clayey soil treatment effects using an innovative mechanochemically activated geopolymer(GP)through the optimized inclusion of nano-metakaolin(NM)and polypropylene fiber.The study also investigated the possible improvements in the binding ability of GP stabilization under different curing regimes.To this end,binders including lime alone,LG(slag-based geopolymer),LGNM(nano-modified LG with NM)and LGNMF(LGNM/fiber)mixture were separately added to soft soil samples.The fabricated composites were then subjected to a set of macro and micro level tests.The results indicated that,adding LG binary with a 20%NM replacement can lead to a significant increase(by nearly 21 times)in soil strength and a remarkable decline(about 70%)in the compression index.In fact,NM can play a great role in accelerating the rate of hydration reactions and forming a densely packed fabric,which staggeringly improve the soil hydromechanical attributes.It was also observed that raising the curing temperature will effectively augment the polymerization kinetics,leading to a substantial increase(~2 times)in the soil solidification process.However,the stabilized composites containing NM may reveal a brittle nature under more intense stress.Such a potential drawback seems to be resolved by the integration of fibers within the matrix.LGNM combined with fiber would boost(≥10 times)the energy absorption capacity of the soil,notably enhancing its residual strength.Overall,LGNMF may not only feature a broader range of benefits(inc.economic,technical,environmental)compared to traditional binders but also promote the ductility of the GP materials.展开更多
The results of a study on the homogeneity of suspensions are described considering the effect of different types of surfactant stabilizers and their concentrations on the uniform distribution of a carbon nanotubes（C...The results of a study on the homogeneity of suspensions are described considering the effect of different types of surfactant stabilizers and their concentrations on the uniform distribution of a carbon nanotubes（CNTs）-based modifying additive to construction materials in an aqueous medium. This problem was solved herein by using surfactants and ultrasound. The sonication treatment of CNTs particle agglomerates allowed for dispersing their globules and achieving a 15-20-fold decrease in their average size, for which it became possible to make better use of the CNTs as cement modifier. As a result of the experimental studies carried out, the effect of the surfactant type and concentration promoting uniform distribution of the CNTs in the bulk of the suspension and, correspondingly, in the structural composite matrix was revealed. The CNTs-based additive improved the physical-mechanical and operational characteristics of the material.展开更多
Interlaminar shear properties of the fibre reinforced polymer composites are very important in many structured applications. It has been reported that interlaminar shear strength (ILSS) of fibre reinforced polymer com...Interlaminar shear properties of the fibre reinforced polymer composites are very important in many structured applications. It has been reported that interlaminar shear strength (ILSS) of fibre reinforced polymer composites may be improved by the modification of the matrix. In this paper, diglycidyl ether of bisphenol A (DGEBA)/triethylene tetramine (TETA) system is used as the starting epoxy matrix. Alumina nanoparticles are employed to modify the epoxy matrix at various concentrations. Unmodified and modified epoxy resins are used along with unidirectional glass fibres for fabricating composite laminates by vaccum bagging method. The interlaminar shear strength of the glass fibre reinforced composites is investigated and the results indicate that introduction of the alumina nanoparticles enhances the ILSS. In particular, the addition of 0.8 wt% alumina nanoparticles leads to maximum enhancement in the ILSS;however, there is a decrease in the value with further addition. The dispersion of alumina nanoparticles and the fracture surfaces of the fibre reinforced composites are examined by the scanning electron microscope. The graphs are employed to explain the results.展开更多
This paper reports on modem developments related to nanotechnology of cement and concrete. Recent advances in instrumentation and design of advanced nano-composite materials is discussed. New technological directions ...This paper reports on modem developments related to nanotechnology of cement and concrete. Recent advances in instrumentation and design of advanced nano-composite materials is discussed. New technological directions and historical milestones in nanoengineering and nanomodification of cement-based materials are presented. It is concluded that there is a strong potential of nanotechnology to improve the performance of cement-based materials.展开更多
文摘This study was designed to enhance the soft clayey soil treatment effects using an innovative mechanochemically activated geopolymer(GP)through the optimized inclusion of nano-metakaolin(NM)and polypropylene fiber.The study also investigated the possible improvements in the binding ability of GP stabilization under different curing regimes.To this end,binders including lime alone,LG(slag-based geopolymer),LGNM(nano-modified LG with NM)and LGNMF(LGNM/fiber)mixture were separately added to soft soil samples.The fabricated composites were then subjected to a set of macro and micro level tests.The results indicated that,adding LG binary with a 20%NM replacement can lead to a significant increase(by nearly 21 times)in soil strength and a remarkable decline(about 70%)in the compression index.In fact,NM can play a great role in accelerating the rate of hydration reactions and forming a densely packed fabric,which staggeringly improve the soil hydromechanical attributes.It was also observed that raising the curing temperature will effectively augment the polymerization kinetics,leading to a substantial increase(~2 times)in the soil solidification process.However,the stabilized composites containing NM may reveal a brittle nature under more intense stress.Such a potential drawback seems to be resolved by the integration of fibers within the matrix.LGNM combined with fiber would boost(≥10 times)the energy absorption capacity of the soil,notably enhancing its residual strength.Overall,LGNMF may not only feature a broader range of benefits(inc.economic,technical,environmental)compared to traditional binders but also promote the ductility of the GP materials.
基金the framework of the cooperation between Russian higher education institutions, state scientific institutions and organizations implementing complex projects to create hightech production (RF Government Decree No. 218 of April 9, 2010 Contract No. 02.G25.31.0123 of August 14, 2014)
文摘The results of a study on the homogeneity of suspensions are described considering the effect of different types of surfactant stabilizers and their concentrations on the uniform distribution of a carbon nanotubes（CNTs）-based modifying additive to construction materials in an aqueous medium. This problem was solved herein by using surfactants and ultrasound. The sonication treatment of CNTs particle agglomerates allowed for dispersing their globules and achieving a 15-20-fold decrease in their average size, for which it became possible to make better use of the CNTs as cement modifier. As a result of the experimental studies carried out, the effect of the surfactant type and concentration promoting uniform distribution of the CNTs in the bulk of the suspension and, correspondingly, in the structural composite matrix was revealed. The CNTs-based additive improved the physical-mechanical and operational characteristics of the material.
文摘Interlaminar shear properties of the fibre reinforced polymer composites are very important in many structured applications. It has been reported that interlaminar shear strength (ILSS) of fibre reinforced polymer composites may be improved by the modification of the matrix. In this paper, diglycidyl ether of bisphenol A (DGEBA)/triethylene tetramine (TETA) system is used as the starting epoxy matrix. Alumina nanoparticles are employed to modify the epoxy matrix at various concentrations. Unmodified and modified epoxy resins are used along with unidirectional glass fibres for fabricating composite laminates by vaccum bagging method. The interlaminar shear strength of the glass fibre reinforced composites is investigated and the results indicate that introduction of the alumina nanoparticles enhances the ILSS. In particular, the addition of 0.8 wt% alumina nanoparticles leads to maximum enhancement in the ILSS;however, there is a decrease in the value with further addition. The dispersion of alumina nanoparticles and the fracture surfaces of the fibre reinforced composites are examined by the scanning electron microscope. The graphs are employed to explain the results.
文摘This paper reports on modem developments related to nanotechnology of cement and concrete. Recent advances in instrumentation and design of advanced nano-composite materials is discussed. New technological directions and historical milestones in nanoengineering and nanomodification of cement-based materials are presented. It is concluded that there is a strong potential of nanotechnology to improve the performance of cement-based materials.
