Are naturally occurring sulfates a problem when stabilising soils?
A. Soils that contain naturally occurring sulfate can suffer a swelling reaction if lime is added. This is dependent on the type of soil and the concentration of sulfates present. Tests for sulfates are always carried out by the specialist contractor to determine if special measures are required before any site work is undertaken. Ground granulated blastfurnace slag has been shown to reduce this swelling reaction and has been used successfully on many jobs. Guidance on this treatment technique is given in Britpave publication BP/16, ‘Stabilisation of Sulfate-Bearing Soils’, available from the library page as a download.
