High-efficiency disposal of dredged sediment(DS)has become an imperative geo-environmental engineering issue due to the limited landfilling space and severe environmental burdens.This study firstly developed a novel h...High-efficiency disposal of dredged sediment(DS)has become an imperative geo-environmental engineering issue due to the limited landfilling space and severe environmental burdens.This study firstly developed a novel high-efficiency nano-modified and chemical-activated binary cement(NBC),which was composed of binary cement(BC)consisting ordinary Portland cement(OPC)and ground granulated blast-furnace slag(GGBS),chemical-activator and nano-modifier.The effects of chemical-activation and nano-modification on the strength development of BC-stabilized DS(BCDS),and the optimum mix of NBC were respectively achieved via a series of unconfined compressive strength and orthogonal tests.Then,the high-efficiency and economic applicability of NBC in DS stabilization were evaluated by comparing with OPC.Furthermore,the microstructure and mineral composition evolutions inside NBCstabilized DS(NDS)were explored by conducting X-ray diffraction(XRD)and scanning electron microscopy(SEM)tests.The results show that both chemical-activation and nano-modification could effectively improve the strength gain of BCDS,and compared with single chemical-activator and nanomodifier,the composite chemical-activators and nano-modifiers exhibited better performances.Based on BC with OPC/GGBS mass ratio of 1:1,both anhydrous sodium metasilicate/anhydrous sodium sulfate(SM/SS)and nano-SiO_(2)/nano-MgO(NS/NM)with mass ratio of 1:9 were respectively determined to be optimum chemical-activator and nano-modifier.The optimum mass ratio of BC,SM/SS and NS/NM was 20:2:1,i.e.the optimum mix of NBC.Compared with OPC,NBC exhibited higher stabilization efficiency and better economic applicability.The generation of calcium silicate hydrate(CSH),calcium aluminate hydrate(CAH)and ettringite contributed to the formation of dense cemented soil matrix inside NDS,and a conceptual micro-mechanism model characterizing the strength development under the coupling action of chemical-activation and nano-modification was proposed.展开更多
基金This study is supported by the National Key R&D Program of China(Grant No.2020YFC1908703)Funds for International Cooperation and Exchange of the National Natural Science Foundation of China(Grant No.51861165104)the Major Science and Technology Project of Inner Mongolia Autonomous Region,China(Grant No.2021ZD0007-02-01).
文摘High-efficiency disposal of dredged sediment(DS)has become an imperative geo-environmental engineering issue due to the limited landfilling space and severe environmental burdens.This study firstly developed a novel high-efficiency nano-modified and chemical-activated binary cement(NBC),which was composed of binary cement(BC)consisting ordinary Portland cement(OPC)and ground granulated blast-furnace slag(GGBS),chemical-activator and nano-modifier.The effects of chemical-activation and nano-modification on the strength development of BC-stabilized DS(BCDS),and the optimum mix of NBC were respectively achieved via a series of unconfined compressive strength and orthogonal tests.Then,the high-efficiency and economic applicability of NBC in DS stabilization were evaluated by comparing with OPC.Furthermore,the microstructure and mineral composition evolutions inside NBCstabilized DS(NDS)were explored by conducting X-ray diffraction(XRD)and scanning electron microscopy(SEM)tests.The results show that both chemical-activation and nano-modification could effectively improve the strength gain of BCDS,and compared with single chemical-activator and nanomodifier,the composite chemical-activators and nano-modifiers exhibited better performances.Based on BC with OPC/GGBS mass ratio of 1:1,both anhydrous sodium metasilicate/anhydrous sodium sulfate(SM/SS)and nano-SiO_(2)/nano-MgO(NS/NM)with mass ratio of 1:9 were respectively determined to be optimum chemical-activator and nano-modifier.The optimum mass ratio of BC,SM/SS and NS/NM was 20:2:1,i.e.the optimum mix of NBC.Compared with OPC,NBC exhibited higher stabilization efficiency and better economic applicability.The generation of calcium silicate hydrate(CSH),calcium aluminate hydrate(CAH)and ettringite contributed to the formation of dense cemented soil matrix inside NDS,and a conceptual micro-mechanism model characterizing the strength development under the coupling action of chemical-activation and nano-modification was proposed.
