Muck and Fill

What is Muck and Fill?

Definition: What Does Muck & Fill  Mean?

The terms muck and fill in regard to sitework, simply means the removal of unsuitable material and the replacement with more suitable material.

Why is a material unsuitable?

There are various reasons why any material is unsuitable and it all depends on the application of the material.

1.) Structurally / if the material will not compact or is unstable due to an abundant amount of clay or silt, the material in many instances must be removed and replaced.

2.) Environmentally / if the material is environmentally unsuitable due to contaminants, then the material must be removed and replaced.

3.) Drain ability / if the material is not of the proper drainage capacity or is too permeable or not permeable enough, then the material must be removed and replaced.

What is normally the proper material to replace the unsuitable material?

In most cases, the proper material will have gone through a testing laboratory for proper sieve and density analysis.  If the material will be suitable for the application, then this approved material is transported onto the project site for replacement of the unsuitable material. 

If the material is required to be structurally suitable, then the proper gradation as well as physical components of the material must meet the requirements of the structural engineer. 

If the material has special drainage requirements, then the gradation as well as the make up of the replacement material must be of the proper permeability to allow drainage as required. 

In all cases of replacement fill, a professional laboratory must be used to determine what is required of the material as well as to approve the material for use.

What are some of the common issues to be aware of when it comes to a ” muck and fill “operation on your site?  

1.) It is highly recommended that a professional soils laboratory be hired to oversee the operation and to ensure that the material being removed is adequately removed, and the material being brought into the site to replace the mucked material is the proper material.

2.) A systematic procedure be developed that will generate the proper trucking tickets to allow proper billing and substantiation of the cost.  The use of separate tickets for each truck coming into the site and leaving is highly recommended.  In most instances, I recommend that the professional lab onsite be the ones responsible for the tickets.

3.) Remember that the quantity of material going out is not necessarily the same as the material coming back.  Due to the need to compact the material coming back, there is a packing factor, fluff factor, whatever you want to call it, that will cause the incoming material to be approximately 33% more than the outgoing material.

4.) Dependent upon the type of site and the type of material, the replacement material may need to be placed in what are called lifts.  A lift is a level of fill that is placed prior to being compacted.  Depending on the soil, the lift maybe as small as 6″ or as large as 24″. It will all depend on the structural need of the resultant material.  The professional lab will be able to test the material and determine the size of the lift to be placed.

5.) It is more economical to have the same trucks that are bringing in the material, load out the material.  A one way loaded truck is double as expensive as a two way loaded truck.  It is always best to find that replacement material at a quarry or stockpile that can also take the material being hauled out.  In many instances, the trucking is the most  expensive part of the entire operation.

6.) If the material being removed is actually contaminated, have the material checked by a qualified environmental company and have it deposited at a legitimate dump.  This is important both for your benefit and the benefit of the client.  You do not want to be associated with illegal dumping of contaminated material.

7.) If the material is contaminated, be prepared for a heavy cost burden.  The dumping of contaminated material, depending on the material is very expensive and the trucking can be several hundred miles away.

There are other methods of managing unsuitable material on site such as combining the material with stone or crushed concrete or diluting the material with clean material to reduce the amount of contaminants. 

It is recommended that a professional soils engineer and or environmental consultant be hired to review the situation and recommend a solution to your soils issue.