Thin spray-on liner adhesive strength test method and effect of liner thickness on adhesion

Ozturk, H.; Tannant, Dwayne D.

doi:10.1016/j.ijrmms.2010.05.004

Cited by 39 publications

(23 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Testing of tensile bond strength, also referred to as pull-off strength or adhesion, of sprayed membranes has been conducted by pulling the membrane off the substrate (Ozturk and Tannant 2010). This procedure uses a disc shaped plate mounted on an elevator bolt which is glued to an over-cored section of the membrane and subsequently pulled in a controlled manner.…”

Section: Tensile Bond Strengthmentioning

confidence: 99%

Performance of EVA-Based Membranes for SCL in Hard Rock

Holter

2015

Rock Mech Rock Eng

View full text Add to dashboard Cite

The bonded property of multi-layered sprayed concrete tunnel linings (SCL) waterproofed with sprayed membranes means that the constituent materials will be exposed to the groundwater without any draining or mechanically separating measures. Moisture properties of the sprayed concrete and membrane materials are therefore important in order to establish the system properties of such linings. Ethyl-vinyl-acetate based sprayed membranes exhibit high water absorption potential under direct exposure to water, but are found to be significantly less hygroscopic and exhibit lower sorptivity (water absorption rate) than sprayed concrete. This material behavior explains the relatively dry in situ condition of the membrane that was observed. Measured in situ moisture content levels of the membrane material in tunnel linings have been found to vary within the range of 30-40 % of the maximum water absorption potential, and show a decreasing trend over the first 4 years after construction has been completed. A model for the mechanical loading, moisture condition and thermal exposure of the membrane and the resulting realistic parameters to be tested is presented. Laboratory testing methods for the membrane materials are evaluated considering possible loads, moisture and freezing exposure. Material testing of membrane materials was conducted with preconditioning to realistic moisture contents and under different temperature conditions including relevant freezing temperatures for tunnel linings. The main effects of the in situ moisture condition of the tested membrane materials are favorable tensile strengths in the range of 1.1-1.5 MPa and low risk of freeze-thaw damage. The crack bridging capacity of the tested membranes is found to be sensitive to temperature. With membrane thicknesses in the range of 3-4 mm, crack bridging capacity up to 4-6 mm opening of the crack width at 23°C and approximately 1 mm opening at -3°C was measured for the tested membranes. No significant reduction of the tensile bond strength could be demonstrated after 35 freeze-thaw cycles with -3°C minimum temperature at the membrane location in the lining. Further work is required to verify the performance of the SCL system under exposure to high hydrostatic pressures and the effects of long term mechanical exposure.

show abstract

Section: Tensile Bond Strengthmentioning

confidence: 99%

Performance of EVA-Based Membranes for SCL in Hard Rock

Holter

2015

Rock Mech Rock Eng

View full text Add to dashboard Cite

show abstract

“…5, and the results indicate that the effect of loading rate is negligible. Ozturk & Tannant (2010) investigated the effect of loading rate on tensile bond strength and similar results were obtained (i.e. the effect of loading is negligible).…”

Section: Analysis Of Test Resultsmentioning

confidence: 55%

Shear strength testing of glass fibre reinforced thin spray-on liner

Qiao¹,

Nemcik²,

Porter³

2014

Géotechnique Letters

View full text Add to dashboard Cite

Thin spray-on liners (TSLs) have been attracting increasing attention as an alternative to steel mesh in underground roadway support. In order to investigate the shear strength of glass fibre reinforced TSLs, an improved punch test was developed: the steel ring is replaced by TSL plates and four screws are used to tighten the TSL sample between the clamping plates to ensure stable and symmetrical loading. Four different glass fibre contents were tested to evaluate the effect of glass fibre reinforcement on the shear strength of TSLs. The effect of loading rate was studied. The results suggest that the steel punch can shear through the polymer sheet well and the failure mode can be easily identified. The results are consistent and easily calculated. The shear strength increases with glass fibre content. The TSL material samples showed good linear behaviour prior to reaching ultimate load and ductile behaviour that reflects the fibre reinforcement of failed resin during the yielding stage of the sample, which is beneficial to support in underground mines. Although there may be some impact of the shearing rate on the shear strength, the effect is negligible for the loading rates used. Shear strength testing of glass fibre reinforced thin spray-on liner Q. QIAO*, J. NEMCIK* and I. PORTER* Thin spray-on liners (TSLs) have been attracting increasing attention as an alternative to steel mesh in underground roadway support. In order to investigate the shear strength of glass fibre reinforced TSLs, an improved punch test was developed: the steel ring is replaced by TSL plates and four screws are used to tighten the TSL sample between the clamping plates to ensure stable and symmetrical loading. Four different glass fibre contents were tested to evaluate the effect of glass fibre reinforcement on the shear strength of TSLs. The effect of loading rate was studied. The results suggest that the steel punch can shear through the polymer sheet well and the failure mode can be easily identified. The results are consistent and easily calculated. The shear strength increases with glass fibre content. The TSL material samples showed good linear behaviour prior to reaching ultimate load and ductile behaviour that reflects the fibre reinforcement of failed resin during the yielding stage of the sample, which is beneficial to support in underground mines. Although there may be some impact of the shearing rate on the shear strength, the effect is negligible for the loading rates used. INTRODUCTIONThin spray-on liners (TSLs) are a relatively new form of rock support in underground coal mines. As an active support technique, it is known that a TSL is able to take action even if only small rock movement occurs, which is desirable for rock support. As steel mesh is of a passive nature and does not contribute to roadway skin reinforcement, TSLs are currently being investigated as an effective technology. ToughSkin, a fibre glass reinforced polymeric material liner developed at the University of Wollongong, has properties that sati...

show abstract

“…Based on the percentage of substrate left on liner at the base of elevator bolt, Ozturk and Tannant [8] proposed a method to classify the failure mode for determining the tensile bond strength of TSL materials. Similarly, the failure mode for the shear bond strength test can be established based on [8], shown in Table 1.…”

Section: Failure Mode and Calculationmentioning

confidence: 99%

“…The bond strength comprises of shear-bond strength and tensile-bond strength adhesion. The tensile-bond strength test using steel dolly pull-off test [3][4][5][6][7][8][9][10] has received the common acceptance by the researchers and manufacturers. However, research on shear-bond strength is limited and there is currently no standard testing method exists for investigating the shear-bond strength of TSLs.…”

Section: Introductionmentioning

confidence: 99%