Mechanical and hydraulic performance of sludge-mixed cement grout in rock fractures

• Main Authors: Khomkrit Wetchasat, Kittitep Fuenkajorn
• Format: Article
• Language: English
• Published: Prince of Songkla University 2014-08-01
• Series: Songklanakarin Journal of Science and Technology (SJST)
• Subjects: rock fracture; grouting; permeability; sludge; cement
• Online Access: http://rdo.psu.ac.th/sjstweb/journal/36-4/36-4-14.pdf

The objective is to assess the performance of sludge mixed with commercial grade Portland cement type I for use in minimizing the permeability of fractured rock mass. The fractures were artificially made by applying a line load to sandstone block specimens. The sludge comprises over 80% of quartz with grain sizes less than 75 μm. The results indicate that the mixing ratios of sludge:cement (S:C) of 1:10, 3:10, 5:10 with water:cement ratio of 1:1 by weight are suitable for fracture grouting. For S:C = 3:10, the compressive strength and elastic modulus are 1.22 MPa and 224 MPa which are comparable to those of bentonite mixed with cement. The shear strengths between the grouts and fractures surfaces are from 0.22 to 0.90 MPa. The S:C ratio of 5:10 gives the lowest permeability. The permeability of grouted fractures with apertures of 2, 10, and 20 mm range from 10-16 to 10-14 m2 and decrease with curing time.