纳米钙矾石对超硫酸盐水泥基泡沫混凝土性能的影响OA

Supersulfated cement-based foamed concrete(SSC-FC)has broad application potential in the field of building energy conservation due to its lower carbon emissions and cost.However,its slow early hydration and insufficient formation of hydration products of SSC-FC result in poor pore-wall compactness,leading to inadequate mechanical properties and carbonation resistance,which significantly limit its engineering applications.In this study,nano ettringite(nano AFt)was incorporated to enhance the pore-wall structure of SSC-FC through its nucleation-induced effect.The influence of nano AFt content on the mechanical properties and carbonation resistance of SSC-FC was systematically investigated,and the mechanisms on hydration process,phase composition,and pore-structure evolution were analyzed using isothermal calorimetry,XRD,SEM.The results show that the incorporation of nano AFt accelerates early hydration and promotes the formation of AFt at the pore-wall interface,leading to a denser pore-wall structure.When the nano AFt content reaches 8%(mass fraction),the 7 d compressive strength of SSC-FC increases from 1.26 MPa to 2.08 MPa,and the 28 d compressive strength increases from 2.37 MPa to 3.61 MPa.In addition,nano AFt refines the pore size distribution,reduces the pore coordination number,and decreases the number of connected pores,thereby restricting CO2 transport.Under 1 d accelerated carbonation conditions,the sample with 8%nano AFt retains an uncarbonated region of 25 mm,and its carbonation coefficient increases from 0.88 to 0.92.