Investigating the effect of particle size distribution and particle density of soil on the compressive strength of ISSB (Interlocking Stabilized Soil Block).

Abstract

Due to the rapid population growth in Uganda, bricks have been predominantly used in construction of houses or buildings to cope with the housing need. Due the abundance of earth and trees, manufacturing of clay bricks has continued and has resulted in increased rate of deforestation and more dangerously, carbon emissions into the atmosphere through burning. To cope with the carbon emissions, research has been made to create alternative solutions with low carbon embodied materials. ISSB blocks are a low carbon embodied technology that require only the use of soil and cement to provide sound construction of up to two floors. The strength of stabilized blocks is dependent on the soil type used are lateritic soils whose appearance and strength are governed by the geology. This greatly affects the physical properties of the soil within an area This research study looks at similar soils obtained from three different locations around Makerere University. The physical properties investigated were particle size distribution and particle density for each of the soils and the tests carried out on the soil samples attained included the maximum dry density, optimum moisture content, wet sieve analysis, specific gravity test. Compressive strength tests were carried on the finished ISSB after curing periods of 7,14 and 21 days. The results from this study have shown that lateritic soils with fair distribution of gravel and sand produce a block with optimum strength. All the blocks met the recommended values for compressive strength (i.e., 2.5N/mm2) as stipulated in the UNBS: FDUS 849 specification at the 21-day mark. In addition, that, the soil sample 2 with the highest particle density of 2.73g/cm3 performed the best followed by the soil sample 1 and sample 2 with 2.63 g/cm3 and 2.38 g/cm3 respectively.