Re-weathering of stabilized clay shale with Portland cement behavior

Clay shale is a claystone which in fresh condition has a very high shear strength. When it reacts with the atmosphere or hydrosphere it will weather so that the shear strength of clay shale will drop drastically. The weathering potential of clay shale is generally done by the slake durability test and the weathering process is measured by disintegration ratio test (DR). The strength of clay shale that has fully weathered will increase again when it is stabilized with a minimum of 6% PC (Portland Cement). It was found from the wetting drying cycle process testing that durability of re-weathering of stabilized clay shale with PC is increased compared to natural clay shale. Disintegration ratio of natural clay shale DR was smaller than stabilized clay shale with 6% PC. Additionally, more than 6% PC increased the durability of re-weathering of clay shale

The effect of weathering process to determination of residual shear strength of clay shale with triaxial multi-stage system

The slope failure on clay shale with many joints under a layer of tuff breccia shortly after stress release due to cutting activity have triggered the need to investigate clay shale residual shear strength. A series of triaxial testing on undisturbed samples of clay shale have been performed to determine the residual stress for multi-stage system operation. In the first stage, residual shear strength without stress release were obtained. Then, testing continued by releasing whole-cell pressure. The triaxial test was proceed to the second multi-stage system to obtain residual shear strength parameters. Tests were conducted to investigate the effect of drying process to reduce residual shear strength up to 80 days. During the period, the maximum percentage of residual internal angle friction without stress release (Øurp) and residual internal angle friction with stress release (Øurf) were reduced by 11% and 5%, respectively. Both paremeters are compared to the peak shear strength condition

Shear strength degradation of Semarang Bawen clay shale due to weathering process

The effect of weathering processes in decreasing the shear strength of clay shale had been done in this study. The drying process of clay shale with sunlight in the laboratory up to 80 days had been conducted to create the conditions of weathered sample. The peak and residual shear strength parameters of unsaturated and saturated clay shale were obtained from triaxial laboratory test, and all samples were tested on each 8 days of weathering process. Decrease of shear strength in peak and residual condition was obtained during 80 days of the drying process. The residual shear strength parameters were distinguished between residual shear strength without stress release and with stress release of confining pressure. The results up to 80 days of unsaturated clay shale showed that the cohesion at peak stress conditions reduced to 30% based on initial shear strength before the occurrence weathering, while the internal angle friction reduced to 64%. Residual cohesion without and with stress release reduced to 4% and 1%, respectively while residual internal angle friction without and with stress release reduced to 15% and 5%. Similar situation also occurs for the saturated clay shale samples

Pengaruh Proses Pelapukan Clay Shale terhadap Perubahan Parameter Rasio Disintegritas (DR)

Abstrak Penelitian ini dilatarbelakangi oleh sering terjadinya kegagalan desain geoteknik pada clay shale yang disebabkan oleh pelapukan. Rasio disintegritas adalah perbandingan perubahan fisik akibat pelapukan pada waktu tertentu terhadap kondisi awalnya. Perubahan sifat fisik clay shale akibat pelapukan ditentukan dengan rasio disintegritas (DR). Pelapukan clay shale akan lebih cepat terjadi akibat siklus pembasahan dan pengeringan bila dibandingkan dengan proses pengeringan. Manakala akibat bertambah jumlah pembasahan dan pengeringan pada waktu yang sama, menyebabkan pelapukan pada clay shale akan lebih cepat lagi. Sampai hari ke-80 dari waktu pengeringan, DR clay shale Semarang-Bawen dan Hambalang besarnya adalah sama yaitu DR = 0,916 (completelly durable). Sedangkan akibat siklus pembasahan dan pengeringan di hari ke-32, clay shale Semarang-Bawen DR = 0,000 atau completelly non durable, manakala pada clay shale Hambalang DR = antara 0,2117 hingga 0,3344. Pada umumnya clay shale Semarang-Bawen akan lebih lebih cepat melapuk bila dibandingkan clay shale Hambalang. Ini terjadi karena perbedaan kandungan mineralogi. Clay shale Semarang-Bawen didominasi oleh mineral Smectite, sedangkan clay shale Hambalang didominasi mineral Kaolinite dan Illite.Abstract The background of this research because of the frequent occurrence of the failure in the geotechnical design of clay shale caused by weathering. Disintegration ratio is a comparison of physical changes due to weathering at certain times of the initial conditions. Changes in physical properties due to clay shale weathering determined by the disintegration ratio (DR).Clay shale weathering will occur more quickly as a result of wetting and drying cycles when compared with the drying process. While due to the increased number of cycles of wetting at the same time, causing weathering on clay shale will be faster again. Until the 80th day of drying time, the magnitude DRof Semarang-Bawenclay shaleand Hambalang are the same, namely DR = 0.916 (completelly durable). However, due to wetting and drying cycles on day 32, samples of Semarang-Bawenclay shale is DR = 0.000 or non durable completelly, while on Hambalang clay shale in same day DR between 0.2117 to 0.3344. Generally Semarang-Bawen clay shale will be faster weathered than Hambalang clay shale. It is caused by the mineralogy content of Semarang-Bawen clay shale has dominated by Smectite, and Hambalangclay shalehas dominated mineral Kaolinite and Illlite

Re-weathering of stabilized clay shale with Portland cement behavior

Clay shale is a claystone which in fresh condition has a very high shear strength. When it reacts with the atmosphere or hydrosphere it will weather so that the shear strength of clay shale will drop drastically. The weathering potential of clay shale is generally done by the slake durability test and the weathering process is measured by disintegration ratio test (DR). The strength of clay shale that has fully weathered will increase again when it is stabilized with a minimum of 6% PC (Portland Cement). It was found from the wetting drying cycle process testing that durability of re-weathering of stabilized clay shale with PC is increased compared to natural clay shale. Disintegration ratio of natural clay shale DR was smaller than stabilized clay shale with 6% PC. Additionally, more than 6% PC increased the durability of re-weathering of clay shale