Experimental study on influence of fly ash on backfill strength of Sanshandao gold mine

In order to study and improve the compressive strength of the graded tailings cemented backfill in Sanshandao gold mine, fly ash and fly ash activator(CaO) are added to the backfill to improve the early strength.The backfill body strength test with different fly ash content instead of cement is designed and the filling test of different CaO content under the optimal fly ash content is studied.The fly ash content and CaO content with backfill strength are studied.The reasons for this relationship are analyzed.The test results show that when the fly ash content is 5%, the strength of the backfill samples is the largest, and the Na⁺, Ca²⁺and Cl^- ions in the filling water play a key role in improving the early strength of the backfill body.When the CaO content is 20% of the optimum fly ash content, the backfill body strength of each curing age is the largest.It is finally determined that the amount of fly ash in the graded tailings cemented backfill of the Sanshandao gold mine is 5%, and the amount of fly ash activator(CaO) is 20%.