The Properties of Black Cotton Soils as they Affects the Stability of Buildings and Road Constructions in Adamawa State

The purpose of this study is to determine the properties of black cotton soil and how they affect the stability of buildings and road construction in Adamawa State. The samples for the study were disturbed samples sourced in seven locations in Adamawa State. Each sample weigh 20kg transported to the laboratory for tests. The tests conducted include Sieve Analysis, sedimentation Test, Liquid Limit Test, Plastic Limit Test, Activity Ratio, Free Swell Test and Optimum Moisture Content Test. Four research questions guided the study and the findings of the study include, that the samples shows increase percentage smaller or less than 63 microns sizes, which indicate that the samples are more of silt and clay particles. The properties of black cotton soil include liquid limit ranging from 30-45, plasticity index from 20-25 percent, the activity ratio ranges from 1.1-1.6, and free swell test shows above 100 percent. Two strategies proposed for achieving stability of buildings and road construction on black cotton soils of Adamawa State. One of the recommendations made was that, buildings and road constructions in the area of the study should precede a proper soil studies that will determine the soil types and provide bases for basement and pavement design.