CBR and unconfined compressive strength tests on a lime stabilized clay soil

Abstract

The main purpose of this study was two-fold: 1. To show any existing correlation between OBR and UCS tests. 2. To show variation in UCS due to various methods of curing

Using a Harvard miniature apparatus, compactive curves were determined for standard AASHO compactive effort for 0, 5, and 10 percent lime. From these curves the moisture contents to be used for strength tests were determined. These were dry of optimum (optimum -6 percent), optimum, and wet of optimum (optimum -̷6 percent).

CBR specimens were fabricated at the above moisture contents for 0, 5, and 10 percent line. In all, nine samples were prepared. This was repeated using the miniature apparatus for the unconfined compression test. Six samples were prepared for each test condition. Two of these were tested as molded, two after damp curing (four days 67ºF), and two after oven curing (two days 120ºF).

The results of this study indicated the following: 1. Lime increases the strength of the soil. This effect was very significant on the dry side. 2. Up to five percent addition of lime produced little increase in strength. This value may be considered as a fixation value of lime for this soil. 3. Curing increased the UCS and CBR of lime-treated soil. Accelerated oven curing 120ºF for two days given significant increase in strength, especially with 10 percent lime. 4. No definite conclusions could be derived between as molded CBR and as molded UCS, between soaked CBR and damped cured UCS, and between soaked CBR and oven cured UCS.