Designing of Bentonite Grout Mixture for Borehole Extensometer Application

• Main Author: Abdul Halim , Nur Ain Syafiqah
• Format: Final Year Project
• Language: English
• Published: Universiti Teknologi PETRONAS 2020
• Subjects: TA Engineering (General). Civil engineering (General)
• Online Access: http://utpedia.utp.edu.my/21042/1/Ain_25598.pdf; http://utpedia.utp.edu.my/21042/

Different borehole instrument applications require different type and properties of grout mixture. For the borehole extensometer application, the important grout property to be investigated is the stiffness. If the stiffness of grout is too high, then the reading of the displacement from the instrument will diminish. Therefore, a suitable bentonite grout with different water-cement ratio is needed so that its stiffness matches the Young’s Modulus of the ground. To find this, cement-bentonite mixture with different water-cement ratio is mixed and tested. To determine the stiffness of the grout, unconfined compression test was done to the sample on day 7, 14 and 21 days after sample preparation. In this study, the methodology of mixing the grout mix is developed and unconfined compressive strength and the stiffness were determined. It is found that with the increase number of curing days, the compressive strength and stiffness increase. Meanwhile, it is also observed that with the increase of the water- cement ratio, the compressive strength and stiffness decrease.