D E Montgomery, (Nov 1998)
Soil is the major component of a stabilised soil block and consequently its properties are of great interest to the Stabilised Soil Block (SSB) manufacturer. Some soils are considered to be unsuitable for manufacturing SSBs and need to be modified or discarded, whilst satisfactory soils have certain physical characteristics that can be generally suggested. The soil properties that have been found to yield satisfactory SSBs are only a small selection of the wide range of different soil characteristics. The properties of the soil used will partly determine the way it performs under moisture attack. Other factors such as the forming technique and any stabilisation process applied will also affect the performance of the SSB during moisture attack.
The general characteristics of soil are listed in this report and special emphasis is placed on those that are known to cause detrimental effects to the SSBÕs during moisture attack. If the poorer characteristics of the soil can be isolated and rectified by some means, then the result will be an enhanced product with better qualities. Those factors that cause expansion on wetting are the ones that prove to be the most negative of the characteristics. Those can be isolated into three parts, the presence of a clay fraction, the presence of porosity and the presence of moisture movement. Only with all three parts present will expansion occur and the removal or minimising of any of them will result in the removal or minimising of potential expansion of the SSB. How this can be done is the matter for another study.