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Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

Quality Assurance Handbook for Rural Roads Volume-I - pmgsy

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3. Section-400<br />

4. Surface Regularity<br />

The maximum permitted difference between the lime-flyash stabilized soil subbase layer and 3 m<br />

straight edge should be 12 mm <strong>for</strong> longitudinal profile and 10 mm <strong>for</strong> cross profile.<br />

5. Minimum Compressive Strength<br />

The mix proportion should be designed to obtain a minimum unconfined compressive strength of<br />

1.5 MPa after 28 days of moist curing. The component of soil in the lime-flyash-soil mix can be<br />

omitted, provided the specified minimum strength requirement is achieved.<br />

6. <strong>Quality</strong> Control Tests<br />

<strong>Quality</strong> Control tests <strong>for</strong> Lime-Flyash Stabilized Soil Subbase and their frequency should be the<br />

same as indicated in Tables 403.2, 403.3 and 403.4 <strong>for</strong> Lime Treated Soil <strong>for</strong> Improved Subgrade/<br />

Subbase.<br />

C. Do’s And Don’ts<br />

Do’s Don’ts<br />

1. While spreading lime and flyash, ahead of mixing,<br />

take care to prevent raising of dust.<br />

2. The thickness of uncompacted layer to yield the<br />

specified compacted thickness after compaction<br />

should be determined by field trials.<br />

3. The suitability of a particular equipment <strong>for</strong><br />

pulverization of soil clods, <strong>for</strong> mixing and <strong>for</strong><br />

compaction should be verified on a test strip.<br />

4. Compaction should be completed within 3 hours of<br />

mixing or such shorter periods as may be necessary<br />

during dry weather.<br />

5. Ensure that the final surface is well closed, free from<br />

movement under compaction planes, ridges, cracks<br />

or loose material.<br />

6. All loose or segregated or otherwise defective areas<br />

on the completed surface should be made good to<br />

the full thickness of the layer and re-compacted.<br />

410. INDUSTRIAL WASTES FOR ROAD CONSTRUCTION<br />

72<br />

1. Do not carry out Lime-flyash soil stabilization when<br />

air temperature in the shade is less than 100C. 2. Do not allow any soil clods larger than 26.5 mm in size.<br />

3. Do not allow any soft yielding spots, ruts etc. on the<br />

subgrade be<strong>for</strong>e laying the subbase.<br />

4. Do not allow more than 60 minutes to elapse between<br />

the start of moist mixing and start of the compaction<br />

process.<br />

5. Do not allow the roller to bear directly on hardened or<br />

partially hardened treated material previously laid<br />

other than those what may be necessary <strong>for</strong> achieving<br />

the specified compaction at the joint.<br />

6. Do not allow traffic to ply during the curing period.<br />

This Subsection covers two commonly used industrial wastes, viz, (a) Flyash (waste material from<br />

Thermal Power Stations) in road embankment, subbase/base courses and (b) Slags (waste materials<br />

from Iron and Steel industries)<br />

A. Methodology<br />

I. Flyash (Pond Ash)<br />

1. Use in flyash embankment construction: As per Sub-section 306.<br />

2. Use in lime-flyash stabilized soil sub-base: as per Sub-section 309.<br />

3. Use in Lime-flyash bound macadam:

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