•The innovative grouts with high mortar ratio are prepared by ternary complex system.•The grouts have the performance of super early strength.•The grouts have 2h and 28d compressive strength of 42.6MPa and 96.3MPa.•The grouts have no retraction of late strength and possess micro-expansion.•The grouts have high initial fluidity and low fluidity loss. An innovative research on preparation of super early strength grouts is presented. A ternary complex system of sulphoaluminate cement, aluminate cement and gypsum was used in the grouts combined with a variety of additives. The effect of mortar ratio on the properties of grouts was studied, and the microstructure was observed. The results show that high mortar ratio can prepare super early strength grouts; 2h and 90d compressive strength of the grouts is 42.6 and 105.6MPa, respectively. Furthermore, the grouting material has no retraction of late strength and possesses micro-expansion property, which attribute to the formation of ettringite.