Use of Thin, Spray-On Linings for Structural Material Protection and Fire Damage Mitigation

摘要

Recent research on thin, spray-on liners, or TSL's, indicated the potential benefit of using these materials to stabilize rock or concrete pillar structures when influenced by high stress or rapid convergence effects. Laboratory test works involving rock and concrete core materials subjected to pseudo static loading (pre- and post-yield) under unsupported (no lining or neat) and supported (lined) conditions have been conducted. The capabilities of thin (at thicknesses ranging from 1-3 mm), passive linings to enhance the ultimate strength of simulated pillars and to stabilize uncontrolled, post-yield failure of test specimens were assessed. Results indicated that for all uncoated specimens, catastrophic failure was induced and no residual strength behavior was observed. All of the TSL-coated samples exhibited a significantly less severe damage response. Where passive polymer coatings were applied, controlled and significant post-yield failure progression was systematically achieved in all tests.rnThe ability of TSL's to provide effective concrete structural reinforcement while providing resistance to environmental hazards, as with fires or dynamic failure events, may permit wider use of such products than is currently foreseen by the mining industry. Significant benefits for use of TSL materials in concrete liner rehabilitation and for concrete material protection have been assessed using simulated large diameter concrete cylinders. Environmental exposure tests were conducted on six columns, consisting of paired samples of non-wrapped, 1-layer glass fibre-reinforced polymer (FRP) wrapped and TSL-coated specimens, that were placed within a lake for a period of 8 months. The columns were submerged for simultaneous exposure to lake conditions, solar radiation, ice, waves, and biotic life, prior to testing. Uniaxial compression test results indicated that the addition of thin layer TSL reinforcement demonstrated strength enhancement, relative to uncoated cylinder failure tests, approximating 5-7%. Results also indicated that after achieving ultimate load, the TSL-coated concrete cylinders showed significant beneficial effects on the column axial strain behavior, compared to the FRP-coated and the uncoated cylinders.