The　loss　of　strength　of　MPC　in　water,　Na2SO4　solution,　and　NaCl　solution　are　studied.　The　samples　after　soaking　in　water　and　solutions　are　analyzed　by　XRD　and　SEM.　The　results　show　that,　for　the　same　type　of　the　samples　soaked　in　different　solutions　for　a　given　duration,　the　effects　of　solution　on　strength　are　in　decreasing　order:　water　＞　NaCl　solution　＞　Na2SO4　solution.　For　the　different　samples　soaked　in　the　same　solution　for　a　given　duration,　the　strength　of　samples　containing　fly　ash　is　larger　than　that　of　samples　in　absence　of　fly　ash,　and　the　strength　of　sample　containing　quartz　sand　is　larger　than　that　of　samples　in　absence　of　quartz　sand.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.