Investigation on the Effect of Curing Time on Uni-Axial Strength of Clayey Soils Strengthened by Saturated Lime Solution
This paper describes some of the main results of an investigation on the effect of passing saturated lime solution with different curing time on the clayey soil. Six series of laboratory tests had been set up, on lean clay samples, to investigate simultaneously the effect of volume of solution and curing time. The samples were classified based on average volume of passing. Three categories were considered, 19Vv, 28Vv and 40Vv. The volume of the saturated solution was fixed and all of the samples were held in a chamber with desired condition of temperature and humidity for different curing period, followed by a mechanical and chemical test. The findings released from the tests indicated that the length of curing period and volume of saturated lime solution at which curing took place had an important influence on the amount of strength developed. An exponential evolution was found for the uni-axial strength as a consequence of the curing time. Especially after 28 days. Calcium ion consumption after 28 days and also exponential evolution for uni-axial strength demonstrated the threshold value of curing period of 28 days for treatment of soil by saturated lime solution.
Determination of optimum concentration of lime solution for soil stabilization
The main objective of this research is to determine the optimum concentration of lime solution for soil stabilization. Dry lime, either quicklime or hydrated lime is being use currently as soil stabilization agent. Although it is very useful in soil stabilization, it always causes dusting problem and is corrosive to human skin. To avoid these problems, application of lime in solution form is suggested in this research. Several soil tests had been carried out on the untreated soil and lime before the lime added to soil for stabilization to ensure the soil is suitable to be stabilized by lime. After those soil properties determined, the lime solution with different concentration will be added to the soil samples for stabilization for 0, 7, 14 and 28 days. The unconfined strength test is carried out on cured soil to evaluate the effectiveness of lime stabilization with different concentration of the lime solution. The concentration of the lime solution that gives the highest soil strength is the optimum concentration of lime solution for soil stabilization. From the result in this research, the highest Unconfined Compressive Strength achieved is 730 kPa, by stabilized the kaolin with 1.35M lime solution and cured for 28 days. Consequently, this value is the optimum concentration of lime solution for soil stabilization.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.