<p>All aggregates should meet the following criteria:
+
All aggregates should meet the following criteria:
<ul>
<ul>
<li>Maximum wash loss of 0.5%.</li>
<li>Maximum wash loss of 0.5%.</li>
Line 5:
Line 5:
<li>Maximum abrasion of 10% for 100 revolutions and maximum of 50% for 500 revolutions.</li>
<li>Maximum abrasion of 10% for 100 revolutions and maximum of 50% for 500 revolutions.</li>
</ul>
</ul>
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Granular material for underdrains should be clear crushed 50 mm diameter stone graded in accordance with ASTM D 2940. The void space ratio shall be 0.4 .</p>
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====Underdrains====
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<ul>
+
<li>Granular material for underdrains should be clear crushed 50 mm diameter stone graded in accordance with ASTM D 2940. </li>
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<li>The void space ratio shall be 0.4 .</li>
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<li>A 100 mm layer of smaller grade pea gravel should be laid over the clear stone to reduce the chance of puncture damage to geotextile fabric. </li>