Thesis - Open Access
Master of Science (MS)
The important influences of temperature on the compaction curves has been given little consideration, A.W. Johnson and J. K. Jallberg summarized primarily from a search of the literature that increasing the temperature leads to increase the maximum dry density 0£ the single peak curve. They explained that the water in the soil is more viscous at the lower temperature, reducing the workability of the soil, which induces a lower dry density. Some investigations which were not involved· in the compaction tests, have shown the temperature effect on some soil properties. From the results of confined and undrained compression test, M. A. Sherif and C. M. Burrous concluded that an increase in the temperature causes a decrease in the compressive strength of the soil. They reasoned that the absorbed water around the soil particles has a less rigid state as the temperature increases, thereby increasing the pore pressure and decreasing the effective stress. This conclusion, therefore, is in agreement with most investigation. although not all indicate exactly the same results. R. L. Plum and M. I. Esrig also postulate that the expansion of the electric double layer of soil particles will occur with the increase of temperature, thereby increasing the repulsive forces and decreasing the effective stress and shearing strength. Johnson and Jallberg also indicated in their summary that increasing the compaction effort by the modified compaction test for a single peak curve not only increases maximum dry unit weight and decreases optimum moisture content, but also decreases the percentage of air voids. In addition, they pointed out that very heavy clay soils may result in irregular compaction curves when tested under the standard compaction method and that increasing the compaction effort tends to decrease irregularity. However, this brief statement is based merely on limited data, and a systematic investigation is necessary. J. L. McRae and P. C. Rutledge observed that the optimum water contents at the same maximum dry densities for the kneading compaction on a single peak curve are about 1 percent higher than the standard impact-type compaction. It has been suspected that there is a difference on moisture-density curves between values obtained by reusing the same portion of soil over and over and values obtained by using a new batch of soil for each point on the compaction curve. It is noted that most of the prior investigations on1 examined the single peak compaction curve. To investigate the characteristics of irregularly shaped compaction curve is therefore necessary. This investigation, which was carried out at South Dakota State University, sponsored by the National Science Foundation, is the third stage of a series of investigations to examine the characteristics of irregularly shaped compaction curves. Because the change of temperature is an important factor in influencing the engineering properties of soil, the main objective of this research was to examine carefully the effect of temperature on the irregularly shaped compaction curve. The additional purposes were to investigate the influence of different compaction methods and the influence of soil sample preparation.
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South Dakota State University
Hsu, Ching- Yee, "Factors Influencing Irregular Compaction Curves" (1972). Electronic Theses and Dissertations. 4713.