The purpose of this experiment was to determine the relationship between molding water content and dry unit weight of soils. This was done by performing the laboratory compaction test using standard effort on the same soil at different moisture contents. When the density of the soil is plotted over moisture content, a concave down curve is generated. This is because adding moisture increases density until it reaches its optimal moisture, then adding further moisture decreases density. Understanding the relationship between moisture and density is important because density is related to the strength of the soil.
Testing was done in Brookings, South Dakota at Crothers Engineering Hall in Room #121 with the experiment beginning at approximately 14:15 on November 8, 2016.
Approximately 2000g of a soil sample that passed a No. 4 sieve was measured. Calculations were done for how much water should be added to reach the desired moisture content. The calculated moisture was added with a spray bottle and mixed thoroughly in the sample. The sample was then placed in a cover container. These steps were done prior to the experiment.
The mold, collar, and the base plate were assembled and its weight was measured. Then enough soil was added so it would equal approximately 1/3 the height of the mold. Compaction was done using a manual rammer. A total of 25 blows were equally distributed on the surface of the sample. The top of the layer was scarified with a knife and the above