To　investigate　the　impact　of　limestone　powder　on　the　chloride　ion　concentration　coefficient　of　cement　pastes,　various　techniques　such　as　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD),　thermogravimetric　analysis　(TGA),　and　mercury-porosimetry　(MIP)　were　employed　in　this　paper.　The　findings　demonstrate　that　the　creation　of　Friedel’s　salt　is　inversely　associated　with　the　addition　of　limestone　powder,　that　is,　Friedel’s　salt　production　is　lessened　by　adding　more　limestone　powder,　however,　the　coefficient　of　chloride　ion　concentration　initially　decreased　and　then　increased　again,　as　does　the　porosity,　and　most　likely　the　pore　size　as　well.　The　specific　surface　area　of　limestone　powder　has　increased,　and　the　content　of　Friedel’s　salt　increased　first　and　then　decreased.　However,　the　shifting　trend　of　Friedel’s　salt　and　chloride　ion　concentration　coefficient　is　in　direct　opposition,　and　the　pore　structure　was　therefore　significantly　enhanced.　The　results　of　this　study　offer　robust　theoretical　backing　for　the　inclusion　of　limestone　powder　in　concrete　and　provide　a　positive　assessment　of　its　potential　applications.　©　Wuhan　University　of　Technology　and　Springer-Verlag　GmbH　Germany,　Part　of　Springer　Nature　2024.