| Author | Mendoza, Florence Melvin T. |
| Call Number | AIT Thesis no.GE-04-04 |
| Subject(s) | Electrochemical analysis
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-04-04 |
| Abstract | The principles of electrochemical stabilization were applied to improve the strength properties of the soft Bangkok clay. Series of tests with varying combinations of factors such as duration of treatment, applied voltage gradient, type of stabilizing solution and the addition of current intermittence were made in order to assess the extent of improvement. Results showed that the differences in the increase in strength between set-ups with the same voltage gradient of 2 V/cm and treated for periods of 3 days and 6 days was 100% when using Anolyte 1 ( 0.5 M calcium chloride and 0.5 M calcium hydroxide) while only 35% increase was gained when using Anolyte 2 (1 M calcium hydroxide). The set-ups treated for 6 days had final increases in strength of 125% when using Anolyte 1 and 110% when using Anolyte 2. Increasing the voltage gradient to 2.5 V/cm for the same set-ups yielded increases of 140% and 120 %, still in favor of Anolyte 1. By adding current intermittence to the 2 set-ups treated for 6 days using anolyte 2, this caused a lower strength increase to around 75% to 85% at all sections of the samples aside the ones nearest to the anode, where it remained the same. There was no change in the strength increase of the set-up using Anolyte 1 and with an applied voltage of 2 V/cm even with the addition of current intermittence. However, a very abrupt increase in temperature by 9 degrees Celsius at a period of only 18 hours caused serious cracks on the same set-up but with a 2.5 V/cm voltage gradient. After treatment, the value of pH of all the different sections of all the samples was less than or equal to 6. This condition hindered the formation of calcium silicates hydrates and calcium aluminates hydrates. On the other hand, XRD patterns of the treated soils showed traces of two natural cementing agents namely Hematite (Fe2O3) and/or Goethite (FeO(OH)), which can precipitate under pH below 6. These minerals were formed from the Fe2+ ions due to the corrosion and dissolution of anode materials and are most probably a contributor to the strength improvement of treated samples. The increases in the concentration of calcium ions in the soil suggest that the method is efficient in introducing stabilizing agents into the soil. This also puts forward that ion exchange and mineralization occurred in the soil which aided in the strength improvement. |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-04-04 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Glawe, Ulrich; |
| Examination Committee(s) | Park, Kyung-Ho;
Bergado, Dennes T.; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |