Abstract
Chalk occurs at or near the surface of nearly 15% of England. A large number of roads of all types have and will in the future be constructed over chalk areas. Because chalk is extremely frost susceptible it is usual to provide a cover over the chalk of granular soil and road construction of thickness at least 450mm. The object of this research was to attempt to find an economical method of treating the chalk so that it would be resistant to frost heave and would have a compressive strength at seven days of 3.45 MN/m2. Emphasis was placed on the use of sodium silicate to achieve these ends. The investigation was undertaken in three parts. In the "preliminary investigation" sodium silicate was used as a main additive and a number of fluid and powder setting agents were used as secondary additives. Various combinations of different types of sodium silicate and setting agents were investigated for seven day crushing strength. A number of suitable combinations were found. In the "main investigation" ordinary portland cement was used as a main additive and sodium silicate as a secondary additive. Optimum percentages of additives were determined together with optimum moisture, content. The variation in crushing strength with dry density and time was also investigated. In the final part of the project the resistance to frost susceptibility and wetting and drying was investigated for the 2 formulations that had a crushing strength at seven days of 3.45 MN/m2 . It was finally concluded that it would be possible to economically stabilize chalk so that it would be resistant to frost heave and have adequate crushing strength.