| abstract |
(57) [Summary] [PROBLEMS] To provide a cement hardening accelerator and a cement composition that exhibit a stable hardening acceleration action regardless of the type and brand of cement. SOLUTION: This is a hardening accelerator containing slaked lime and at least one or more selected from thiosulfate, formate, nitrate and nitrite, wherein slaked lime, thiosulfate, The curing accelerator has a mixing ratio of at least one selected from formate, nitrate and nitrite in a mass ratio of 97/3 to 5/95. Further, the cement composition is characterized in that the curing accelerator is blended in an amount of 0.2 to 10 parts by mass with respect to 100 parts by mass of cement. |