To provide a material for soil-sand structure having the strength same as or more than the strength of a structure added with a cement based solidification agent, without inducing destruction accompanied with weathering or fouling, free from generating industrial waste in repairing and trimming, and friendly to plant growth and to the environment, applicable to various protecting construction methods and foundation improving construction methods, and to provide a method for protecting a slope face by using the same.

The material for soil-sand structure comprises 1-2000 pts.wt. of aggregate per 100 pts.wt. of soft-burned magnesia, 0-10 wt.% of at least one admixture selected from an AE water reducing agent, a high performance water reducing agent, a high performance AE water reducing agent, citric acid, a soil dispersing agent, magnesium sulfate, phosphoric acid, sodium citrate, an iron salt, soluble silicic acid, soluble silicates and soluble alumina, based on the soft-burned magnesia, and 0-500 wt.% of at least one admixture selected from fly ash, silica fumes, slugs and sepiolite based on the soft-burned magnesia, and the composition is free from cement based solidification agent.