Effect of Particle Shape of Manufactured Sand on Coupling Corrosion Resistance of Mortar to Cl-and CO2
WANG Xiaomin
LUO Surong
DING Jinlong
TANG Guohua
Abstract：The particle shape index of standard sand,river sand,and three types of manufactured sand was measured and analyzed using digital image processing(DIP)technology.And the influence of manufactured sand particle shape on the corrosion resistance of mortar under the coupling effect of Cl-and CO2 was studied.The results indicate that the particle shape index of manufactured sand is lower than that of river sand,and is significantly affected by the content of flake particles.Under the coupling corrosion of Cl-and CO2,the pH value at the endpoint of the convective zone is 12.0-12.5.As the particle shape index of fine aggregate decreases,the content of free Cl-and the apparent Cl-diffusion coefficient in the mortar first decrease and then increase,showing a positive correlation with the proportion of risk pores with pore diameter larger than 50 nm,and are influenced by the duration of CO2 erosion within a single cycle.The decrease of particle shape index of fine aggregate enhances the tortuous effect of fine aggregate and improves the retarding effect of fine aggregates on external corrosion.It is recommended that the appropriate particle shape index for manufactured sand be set at around 0.8.
Keywords：manufactured sandparticle shape indexcoupling corrosionfree chloride ion contentapparent Cl-diffusion coefficientpH value
Publication Date：2025-07-30
Online Publishing Date：2025-08-18(First online date of this platform, not the publication date of the document)
Pages：10( 598-607 )