Preliminary survey of polymer-impregnated rock.
Crow-LJ; Kelsh-DJ; Steinberg-M; Colombo-P
Spokane, WA: U.S. Department of the Interior, Bureau of Mines, RI 7542, 1971 Jan; :1-35
A preliminary survey was performed to investigate the impregnation of relatively weak, porous volcanic tuff and a relatively strong, dense sandstone with five different monomers. Increases in compressive strengths by factors of 2 to 5, and elastic moduli by factors of 2 to 3.5, are reported for natural rocks (tuff, sandstone, dacite), which were impregnated with five monomers (methyl methacrylate; chlorostyrene; 40% tmptma-60% styrene; 40% tmptma-60% chlorostyrene; 60% polyester-40% styrene); polymerization took place after monomers were forced into the rock. Impregnation was performed (1) by pressurizing rock specimens from one end, or (2) by a vacuum-soak operation. Polymerization was accompanied by either radiation or chemical initiation techniques. Strength improvement is dependent on (1) the type of monomer used, (2) the amount of polymer incorporated into the rock, and (3) the degree of water saturation of the rock. Water saturation strongly reduced the effectiveness of the method for the polymer systems tested. The more viscous monomers (for example, 60% polyester-40% styrene) were more effective in displacing the water from the rock, and compressive strengths of wet rock were doubled with these systems. Water saturations ranging from 25% to 100% of maximum saturation gave essentially identical results. Further tests on other types of mine rock, including shale and coal, are planned. Water-compatible polymer systems should be developed, or present systems should be suitably modified. For application to tunnel stabilization, design studies evaluating the improvement in rock strength and its influence on the support system are also recommended.
Rocks; Impregnating; Polymers; Rock foundations; Mechanical properties; Mines; Excavations; Composite materials; Extrusive rocks; Sandstone; Polymethyl methacrylate; Styrene resins; Styrene copolymers; Addition resins; Polymerization; Curing agents; Moisture content; Dacite; Polymer impregnated rock; Radiation polymerization
IH; Report of Investigations
NTIS Accession No.
Spokane, WA: U.S. Department of the Interior, Bureau of Mines, RI 7542