Abstract: The cement grouting material with excellent rheological properties was prepared by gold tailing sand with a fineness modulus lower than 0. 7 to improve the performance of the grouting material and to realize the resource utilization of solid waste in response to the problems of high cost and unstable volume of underground space plugging grout. The particle distribution,chemical composition,mineral composition and particle morphology of gold tailing sand were determined, and the effects of additive admixture and water-binder ratio on the rheological properties and mechanical properties of gold tailing sand cement grouting material were investigated systematically by single-factor test,and the influence of water-binder ratio on mechanical properties was revealed by SEM analysis. The results showed that the fine-grained and angular gold tailing sand with quartz as the main mineral,and the flow degree of cement grouting material can reach up to 335 mm when the surface of the tailing sand is modified by admixture,the fixed cement sand ratio is 1 ∶1. 5 and the control water-binder ratio is 0. 35. The maximum flexural strength of the cement grouting material was reached at a controlled water-binder ratio of 0. 31,with flexural strengths of 6. 87,8. 87 and 10. 5 MPa at 3,7 and 28 d,respectively,and the compressive strength of the cement grouting material reached the maximum at a water-binder ratio of 0. 32,with compressive strengths of 43. 1,59. 0,and 69. 0 MPa at 3,7 and 28 d,respectively;The brittleness coefficient of gold tailing sand cement grouting material decreases with the increase of waterbinder ratio,and the lowest 28 d brittleness coefficient is 5. 58. The SEM analysis showed that with the increase of water-binder ratio,the calcium alumina ( Aft) phase increases,the brittleness coefficient decreases and the toughness increases,but too much Aft phase led to the loosening of the structure and the decrease of strength.

Key words: cement grouting material,gold tailings,rheological properties,mechanical properties