HYDRAULIC CEMENT COMPOSITION FOR INJECTION INTO SOIL, AND METHOD FOR IMPROVEMENT IN SOIL USING SAME

Disclosed are: a hydraulic cement composition for injecting into soil, which can exhibit high sinking resistance when prepared into a suspension (a cement milk), of which an injecting component cannot be swept under running water, and which has excellent penetrability and durability; and a method for improving soil using the hydraulic cement composition. Specifically disclosed are: a hydraulic cement composition for injecting into soil, which is characterized by comprising 100 parts of a blast furnace slug micropowder having a Blaine specific surface area of 7000 to 16000 cm2/g and a median diameter of 1 to 7 µm, a classified cement that meets all of the requirements (1) to (3) mentioned below in an amount of 5 to 30 parts relative to 100 parts of the blast furnace slug micropowder, and a dispersant comprising a polyacrilic acid dispersant (which may additionally contain a melamine dispersant) in an amount of 0.1 to 3 parts relative to the total amount (100 parts) of the blast furnace slug micropowder and the classified cement: (1) the classified cement is characterized by containing calcium carbonate in an amount of 6 to 20 parts relative to 100 parts of the classified cement; (2) the classified cement is characterized by having a Blaine specific surface area of 7000 to 16000 cm2/g; and (3) the classified cement is characterized by having a median diameter of 1 to 7 µm; and a method for improving soil, comprising injecting a cement milk into soil, wherein the cement milk is prepared by adding water to the hydraulic cement composition for injecting and kneading the mixture.