Modifying effects and mechanisms of superfine stainless wires on microstructures and mechanical properties of ultra-high performance seawater sea-sand concrete  

作　　者：YU Feng DONG SuFen ASHOUR Ashraf DING SiQi HAN BaoGuo 

机构地区：[1]School of Infrastructure Engineering,Dalian University of Technology,Dalian 116024,China [2]Faculty of Engineering&Informatics,University of Bradford,Bradford BD71DP,UK [3]Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong 999077,China

出　　处：《Science China(Technological Sciences)》2024年第10期3205-3220,共16页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52178188 and 52308236);the Natural Science Joint Foundation of Liaoning Province(Grant No.2023-BSBA-077);the Provincial-Municipal Joint Fund(Youth Fund)of Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515110437);the Major Science and Technology Research Project of the China Building Materials Federation(Grant No.2023JBGS10-02).

摘　　要：Ultra-high-performance seawater sea-sand concrete(UHPSSC)presents a prospective solution to address the natural resource shortage in marine infrastructure construction.To eliminate the corrosion risk of steel fibers and broaden the applicability of UHPSSC,this study investigates the mechanical properties and free chloride ion content as well as microstructures of UHPSSC reinforced with superfine stainless wires(SSWs)under natural curing.The results indicate that 1.5%SSWs can remarkably improve the flexural strength and toughness of UHPSSC by 127%and 1724%,respectively,and mitigate the long-term strength degradation of UHPSSC.The strong interfacial bond between SSW and UHPSSC improves the compactness of UHPSSC,thus reducing the growth space for Ca(OH)_(2) crystals and swelling hydration products generated by sulfate and magnesium ions.This can be supported by the observed reduction in the Ca/Si ratio of C–S–H gels,CH crystal orientation index,and porosity.Moreover,through mechanisms such as pull-out,rupture,overlapping network,and internal anchor interface,SSWs effectively prevent microcrack growth and propagation,transforming single long-connected microcracks into multiple-emission microcracks centered on SSW.Additionally,the free chloride ion content of the composites at 28 and 180 d meets the ACI 318-19 standard requirements for concrete exposed to seawater.This compliance is attributed to the chloride immobilization facilitated by Friedel’s salt and C–S–H gels within the interfaces around SSWs and sea-sand.Consequently,SSWs-reinforced UHPSSC exhibits considerable potential for applications in sustainable marine infrastructures,demanding long-term mechanical properties and high durability.

关 键 词：ultra-high performance seawater sea-sand concrete superfine stainless wire mechanical properties chloride ion content microstructure 

分 类 号：TU528[建筑科学—建筑技术科学]