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.
Effect of curing time on shear strength of cohesive soils stabilized with combination of lime and natural pozzolana.
When geotechnical engineers are faced with cohesive clayey soils, the engineering properties of those soils may need to be improved to make them suitable for construction. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both on the geotechnical characteristics of two cohesive soils. Lime or natural pozzolana were added to these soils at ranges of 0-8% and 0-20%, respectively. In addition, combinations of lime-natural pozzolana were added at the same ranges. Test specimens were subjected to compaction tests and shear tests. Specimens were cured for 1, 7, 28 and 90 days after which they were tested for shear strength tests. Based on the experimental results, it was concluded that the combination limenatural pozzolana showed an appreciable improvement of the cohesion and internal friction angle with curing period and particularly at later ages for both soils.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.