Hello Group,

So currently I am looking at utilizing cement stabilized soil at one of my worksites for erosion control and subbase strengthing. Having looked into my state's highway design manual and a the "greenbook" I have not found anything discussing how to determine how much cement is needed to strengthen the soil to the levels I want. From what I have read typically the amount of cement that is added is anywhere from 5 to 15%. If anyone could point out a refence that shows how to make a mix design based on varying types of soils or simply tell me its based on setting up different mixtures and see how they do in a soils test please let me know.

Thanks,
Riveridean.

The amount of cement will depend on the soil type....the more granular the soil, the more cement will be required. For slightly clayey fine sands, the amount of cement to achieve about 200 psi will be about 3 or 4 percent. Clean sands will require more cement. Organic materials can cause set problems with the soil cement. Another consideration is that there are some soils that will absorb calcium from the cement, thus causing strength problems with the soil cement.

Check the PCA Soil Cement Handbook...it covers all these issues.

PCA has some good publications, some free if you ask nicely. cement content depends on a) the compressive strength you want and b) the type of soil you have. You will need to have a lab prepare a mix design. Your geotech can easily scope this work for you.

http://search2.cement.org/search?site=default_collection&client=my_frontend&proxystylesheet=my_frontend&output=xml_no_dtd&q=soil+cement

gravelly sands with a moderate amount of fines may work the best. Clean sands require slightly more cement and silts and clays require the most cement to coat the more numerous, smaller particles.

ASTM D558 Standard Test Methods for Moisture-Density (Unit Weight) Relations of Soil-Cement Mixtures
ASTM D559 Test Methods for Wetting and Drying Compacted Soil-Cement Mixtures
ASTM D560 Test Methods for Freezing and Thawing Compacted Soil-Cement Mixtures

AASHTO T134, T135, T136, T144

cvg...strength of soil cement does not depend on coating all particles with cement....won't happen anyway with such low cement contents and low moisture content. That is a concrete premise.

Strength is more related to particle agglomeration than particle coating.

I didn't mean to imply that, only that with more smaller particles, you will use more cement just to achieve the same strength as you would with a granular soil

cvg.... Thanks for clarification.