THE EFFECT OF PURE MICROBIAL CULTURE VARIATIONS ON THE VALUE OF SOIL DENSITY

Abstract

The fineness and roughness of soil grains are represented by the texture of the soil. Classifying soil texture can be known by the percentage of how many fractions it contains. Sand, clay, and silt are the main fractions of fine soil texture, as determined by soil particle size distribution. The increased soil density is achieved by shortening the spacing between soil particles, resulting in a reduction in air volume but no significant change in water volume in the soil. Soil stabilization procedures are used to improve the characteristics of the natural soil to meet the construction requirements. The pure microbial culture stabilization material used is Bacillus subtilis bacteria produced through the inoculation process. The inoculation process was carried out by using a slanted agar culture method, by swiping the ose onto the slanted agar medium surface from the bottom of the test tube to the mouth of the test tube which was carried out in a zigzag manner, then incubating the results of the inoculation at room temperature 37°C (degrees Celsius) for 24 hours. The purpose of this study was to find the effect of pure microbial culture variations on the value of soil density. The laboratory compaction test method uses Proctor Compaction Test (ASTM D 698/D 1567). Variations of pure microbial culture which were added as stabilizing agent, 4%, 6%, 8%, 10%, 12% and 14%. Classification of coarse and fine grain fractions contained in the soil sample based on the results of the distribution of soil particle size obtained, 0.20% gravel, 2.60% sand, 94% silt, and 3.20% clay. The results obtained from each addition of pure microbial culture variations were 13.79 kN/m³, 13.82 kN/m³, 13.84 kN/m³, 13.98 kN/m³, 14 kN/m³, and 13.74 kN/m³. Soil density values increased when Bacillus subtilis bacteria were added at a percentage of 4%, 6%, 8%, 10%, and 12%, but decreased when Bacillus subtilis bacteria were added at a percentage of 14%