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− | <p>Geotextiles prevent downward migration of smaller particles in to larger aggregates, and slump of heavier particles into finer underlying courses. <br> | + | <p>Geotextiles prevent downward migration of smaller particles in to larger aggregates, and slump of heavier particles into finer underlying courses. |
− | The formation of biofilm on geotextiles has also been shown to improve water quality:<br> | + | <br> The formation of biofilm on geotextiles has also been shown to improve water quality: |
− | *By degrading petroleum hydrocarbons[https://www.icpi.org/sites/default/files/techpapers/1309.pdf] | + | <br> |
| + | *By degrading petroleum hydrocarbons[https://www.icpi.org/sites/default/files/techpapers/1309.pdf] |
| *By reducing organic pollutant and nutrient concentrations [http://www.mdpi.com/2073-4441/7/4/1595/pdf] | | *By reducing organic pollutant and nutrient concentrations [http://www.mdpi.com/2073-4441/7/4/1595/pdf] |
| </p> | | </p> |
− | <p>When installing geotextiles an overlap of 150 - 300 mm should be used.</p> | + | <p>When installing geotextiles an overlap of 150 - 300 mm should be used.</p> |
− | Material specifications should conform to [http://www.raqsb.mto.gov.on.ca/techpubs/OPS.nsf/0/2ccb9847eb6c56738525808200628de1/$FILE/OPSS%201860%20Apr12.pdf Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics]. | + | Material specifications should conform to [http://www.raqsb.mto.gov.on.ca/techpubs/OPS.nsf/0/2ccb9847eb6c56738525808200628de1/$FILE/OPSS%201860%20Apr12.pdf Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics]. |
| *Fabrics should be woven monofilament or non-woven needle punched. | | *Fabrics should be woven monofilament or non-woven needle punched. |
| *Woven slit film and non-woven heat bonded fabrics should not be used, as they are prone to clogging. | | *Woven slit film and non-woven heat bonded fabrics should not be used, as they are prone to clogging. |
| <p>In choosing a product, consider: | | <p>In choosing a product, consider: |
− | <ol> | + | <ol> |
− | <li>The maximum forces that will be exerted on the fabric (i.e., what tensile, tear and puncture strength ratings are required?),</li> | + | <li>The maximum forces that will be exerted on the fabric (i.e., what tensile, tear and puncture strength ratings are required?),</li> |
− | <li>The load bearing ratio of the underlying native soil (i.e. is the geotextile needed to prevent downward migration of aggregate into the native soil?),</li> | + | <li>The load bearing ratio of the underlying native soil (i.e. is the geotextile needed to prevent downward migration of aggregate into the native soil?),</li> |
− | <li>The texture (i.e., grain size distribution) of the overlying and underlying materials, and</li> | + | <li>The texture (i.e., grain size distribution) of the overlying and underlying materials, and</li> |
− | <li>The suitable apparent opening size (AOS) for non-woven fabrics, or percent open area (POA) for woven fabrics, to maintain water flow even with sediment and microbial film build-up.</li> | + | <li>The suitable apparent opening size (AOS) for non-woven fabrics, or percent open area (POA) for woven fabrics, to maintain water flow even with sediment and microbial film build-up.</li> |
− | </ol> | + | </ol> |
− | <br> | + | <br> |
− | <table class = "table-responsive"> | + | <table class="table table-striped table-responsive"> |
− | <table class="table table-striped">
| + | <caption><strong>Recommended criteria for selection of geotextile fabric</strong></caption> |
− | <caption><strong>Recommended criteria for selection of geotextile fabric</strong></caption> | + | <tr class="success"> |
− | <tr class="success"><th>Percent media passing 0.075 mm (#200 sieve)</th><th>Non-woven fabric apparent opening size (AOS, mm)</th><th>Woven fabric percent open area (POA, %)</th><th>Permittivity (sec<sup>-1</sup>)</th></tr> | + | <th>Percent media passing 0.075 mm (#200 sieve)</th> |
− | <tr><td align="center" valign="middle">>85</td><td align="center" valign="middle">≤ 0.3</td><td align="center" valign="middle">-</td><td align="center" valign="middle">0.1</td></tr>
| + | <th>Non-woven fabric apparent opening size (AOS, mm)</th> |
− | <tr><td align="center" valign="middle">50 - 85</td><td align="center" valign="middle">≤ 0.3</td><td align="center" valign="middle">≥ 4</td><td align="center" valign="middle">0.1</td></tr>
| + | <th>Woven fabric percent open area (POA, %)</th> |
− | <tr><td align="center" valign="middle">15 - 50</td><td align="center" valign="middle">≤ 0.6</td><td align="center" valign="middle">≥ 4</td><td align="center" valign="middle">0.2</td></tr>
| + | <th>Permittivity (sec<sup>-1</sup>)</th> |
− | <tr><td align="center" valign="middle">5 - 15</td><td align="center" valign="middle">≤ 0.6</td><td align="center" valign="middle">≥ 4</td><td align="center" valign="middle">0.5</td></tr>
| + | </tr> |
− | <tr><td align="center" valign="middle">≤ 5</td><td align="center" valign="middle">≤ 0.6</td><td align="center" valign="middle">≥ 10</td><td align="center" valign="middle">0.5</td></tr>
| + | <tr> |
− | </table> | + | <td align="center" valign="middle">>85</td> |
| + | <td align="center" valign="middle">≤ 0.3</td> |
| + | <td align="center" valign="middle">-</td> |
| + | <td align="center" valign="middle">0.1</td> |
| + | </tr> |
| + | <tr> |
| + | <td align="center" valign="middle">50 - 85</td> |
| + | <td align="center" valign="middle">≤ 0.3</td> |
| + | <td align="center" valign="middle">≥ 4</td> |
| + | <td align="center" valign="middle">0.1</td> |
| + | </tr> |
| + | <tr> |
| + | <td align="center" valign="middle">15 - 50</td> |
| + | <td align="center" valign="middle">≤ 0.6</td> |
| + | <td align="center" valign="middle">≥ 4</td> |
| + | <td align="center" valign="middle">0.2</td> |
| + | </tr> |
| + | <tr> |
| + | <td align="center" valign="middle">5 - 15</td> |
| + | <td align="center" valign="middle">≤ 0.6</td> |
| + | <td align="center" valign="middle">≥ 4</td> |
| + | <td align="center" valign="middle">0.5</td> |
| + | </tr> |
| + | <tr> |
| + | <td align="center" valign="middle">≤ 5</td> |
| + | <td align="center" valign="middle">≤ 0.6</td> |
| + | <td align="center" valign="middle">≥ 10</td> |
| + | <td align="center" valign="middle">0.5</td> |
| + | </tr> |
| + | </table> |
| | | |
| [[category:materials]] | | [[category:materials]] |