In order to solve the problems of cracking and voiding caused by uncompacted vibration or large plastic deformation of concrete in anchorage slot of unbonded prestressed structure in long-distance diversion tunnel,the effects of fly ash content,expansive agent content and water-binder ratio on strength and limited expansion rate were studied.The micro-expansion self-compacting concrete was designed,and its free volume deformation and autogenous shrinkage were measured.The results show that when the water-binder ratio is 0.40,the content of fly ash is 25%,and the dosage of expansive agent is 30kg/m3,the 28d flexural tensile strength is 4.77MPa and the 28d compressive strength is 53.6MPa,respectively,and the impermeability grade is greater than W11.The autogenous volume deformation of concrete is 20×10-6 in 60d,which tends to be basically stable,and the drying shrinkage is about-460×10-6 in 90d.The moisturizing curing of micro-expansion self-compacting concrete should be strengthened,and the time of moisturizing curing should be prolonged to facilitate the performance of expansive agent.
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