PX300 Soil Stabilizer

Techniques of Soil Stabilization

Roads can be constructed with on-site materials, eliminating the need to import off-site soil. Native site soils can contain a wide gradation of materials which may include a high content of soil fines (passing 200 mesh). DuraRoad assists in binding fines together with larger materials into a dense, well-compacted material that provides a high degree of stabilization and resistance to moisture penetration (2.9 x 10-8 cm/sec under ASTM D 5084).

Three important factors determine a stabilization result:
Material Gradation, Moisture Content and Compactive Effort

Material Gradation

Material Gradation refers to the distribution (% by weight) of the different sizes of particles within a given soil sample. A soil sample is well-graded if it contains a good, even distribution of particle sizes. A soil sample composed of predominantly one-sized particles is said to be poorly graded.

A well-graded soil contains smaller particles which tend to fill the empty spaces between larger particles, leaving fewer voids after compaction.

Two conditions prevent a successful stabilization: The presence of large rocks; and certain types of contaminants. Large rocks can cause structural breakdown in an otherwise successful application and contaminants prevent the successful curing of the PX-300 solution in the treated soil.

Moisture Content

Moisture Content, the amount of water present in a soil, is important to any road bed project. Water lubricates the soil particles, helping them to slide into voids between larger particles and produce the greatest density. PX-300 wetting action additionally facilitates this process, along with water and enzymes. Soil fines and clay particles become "sticky" and cohesive, providing a necessary condition for stabilization. Engineers have determined that almost all soils have what they call an optimum moisture content which permits maximum density from a given amount of effort. The illustration below shows the relationship between soil dry density and moisture content.

The presence of excess moisture in site soil due to flooding or heavy rainfall will prevent an efficient cure following the DuraRoad application. In this case the project should be deferred. Usually two days of dry weather will bring the moisture level down to the point that supports a successful PX-300 application

If flooding or heaving rainfall will closely follow a DuraRoad application, that could also impair or prevent a successful soil stabilization cure by diluting and washing away the uncured PX-300. A curing/drying period of 36-72 hours following a PX-300 application is strongly recommended to ensure successful road stabilization.

Compactive Effort

Compactive effort is the process of physically increasing the weight per unit volume of road bed soil. With an unproper moisture level, compaction cannot occur successfully. If too wet, the compacted soil will push out from under the compaction equipment and, if too dry, the compacted soil will not hold together because it will lack the cohesive, "sticky" quality mentioned above in "Moisture Content." The moisture density curve above has particular significance here.