This　study　investigates　the　influence　of　the　rheological　parameters　on　the　unyielded　zone,　pressure　drop,　and　secondary　flow　pattern　of　non-Newtonian　fluid　like　fresh　cement　mortar　through　a　pipe　bend　with　different　curvatures.　The　regularized　Herschel-Bulkley　model　is　employed　in　the　framework　of　lattice　Boltzmann　method　to　model　the　effects　of　the　visco-plastic　and　shear-thickening/thinning　characteristics　with　variations　on　the　yielding　stress　σ0　and　the　power-law　index　n.　The　sharper　curvature,　higher　power-law　index　contributes　to　a　smaller　and　more　asymmetric　unyielded　zone　and　even　vanishes　for　curvature　radius　R　c　=　1　D　and　n　=　1.4,　as　the　width　and　distribution　of　plug　region　are　governed　by　the　comparison　between　yielding　stress　and　shear　stress.　The　increased　yielding　stress　and　power-law　index　lead　to　an　increase　in　the　total　pressure　drop　and　additional　pressure　loss;　however,　their　variations　with　respect　to　the　curvature　radius　display　an　opposite　trend.　The　intensity　of　the　helical　secondary　flow　in　the　elbow,　primarily　governed　by　the　competition　between　the　centrifugal　and　viscous　force,　is　reduced　to　about　one　quarter　when　σ0　and　n　increase　from　0　Pa　and　0.6　to　50　Pa　and　1.4.　©　2021　Author(s).