Geotextile vs Geogrid: which is the best solution?

This is a debate we are living each time we have to build internal roads on soils with a low (<5) to very low (<2) CBR.

Basically when the others alternatives (mainly soil substitution and soil improvement) are not feasible we are adopting two different solution, either a strong geotextile with reinforcement and separation properties or a geogrid (coupled with a thin geotextile used as a filter if necessary).

Presently both of them are working well, but only after many years we will know which one works best. I'm hearing very different opinion on the subject, so there is not an universal consensus.

As geotextile, both woven and nonwoven alternatives seem reasonable. Both of them provides separation of the aggregate from the subgrade and have high tensile strength and modulus, adding reinforcement to the foundation soil. Right now the woven solution is widely preferred.

As woven geotextile we have used the US250 from US Fabric, with the following properties:

PROPERTYTEST METHODENGLISHMETRIC
Tensile StrengthASTM D-4632250 lbs1,112 N
Elongation @ BreakASTM D-463215%15%
Mullen BurstASTM D-3786450 psi3,102 kPa
Puncture StrengthASTM D-4833100 lbs445 N
CBR PunctureASTM D-6241900 lbs4,005 N

And as nonwoven, something like the US Fabric US 160NW  looks like the best option:

PROPERTYTEST METHODENGLISHMETRIC
Weight - TypicalASTM D-52616.0 oz/sy203 g/sm
Tensile StrengthASTM D-4632160 lbs711 N
Elongation @ BreakASTM D-463250%50%
Mullen BurstASTM D-3786305 psi2,103 kPa
Puncture StrengthASTM D-483390 lbs400 N
CBR PunctureASTM D-6241410 lbs1,824 N

Regarding geogrid, it has been used in several wind farms all around Europe. I had a meeting with the representative from Tensar, and their product looks interesting.

It is a triangular net, providing support to the stone aggregate. It works equally well in every direction.

We have used it in Spain, and it have been used in several other projects in UK and Romania.

This entry was posted in Geology and geotechnics, Roads and tagged , , , , , by Francesco Miceli. Bookmark the permalink.

About Francesco Miceli

Hello! My name is Francesco and I'm a civil engineer specialized in EPC (that is, "turnkey") wind farms projects. I'm currently based in Hamburg, Germany and I'm developing several interesting project all around the world - southern Europe, LATAM and various other countries. If you want to contact me please don't leave a comment in the blog (I don't check them very often) - you can use the contact form. You can write me in English, Spanish and Italian. To find a (somewhat concise) description of my non-wind business activities you can visit my webpage - www.francescomiceli.com If you want to know more about my work, here you can download my CV - www.windfarmbop.com/CV_Francesco_Miceli.pdf Hope you like the blog! Francesco

2 thoughts on “Geotextile vs Geogrid: which is the best solution?

  1. It's interesting that there are ways to make ground more sturdy. It makes sense that it would be important for building big things on! If the ground buckled underneath a big construction then there would be the chance of it breaking.

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