Assessing the Effectiveness of an Enzyme Soil Stabilizer
Red River valley soils are rich in clay and silt. While this may be beneficial for agricultural uses, fine-grained soils can be problematic as construction materials for roads and foundations. Clay soils have an affinity for weakening during wet weather. They often experience considerable swelling and shrinkage in response to moisture changes. If silt is present, it can be prone to frost heaving in the winter. A number of solutions are applied to mitigate potential construction problems. They range from replacing the fine-grained soil with granular material and the use of geosynthetic reinforcement, to the use of soil additives.
An emerging category of soil additives are natural, organic and biodegradable products. Although this type of additive has been applied to stabilizing soils for more than twenty years, there is still very little information describing its use in road construction. A characteristic of enzyme additives is that they include proteins that act as surfactants. This means they reduce the surface tension of the water in partially saturated pore spaces. Enzyme products have no negative environmental effects, as might be the case with lime, cement, bitumen, chlorides, synthetic polymers, or acid-based additives.
THIS ABSTRACT IS AN EXPERIMENTAL PROGRAM TO ASSESS OF THE ATTRIBUTES OF AN ENZYME SOIL STABILIZER
The enzyme additive is typically applied to marginal clay-based soils to improve the performance of road subgrades. The study investigates the potential increase in strength and reduction in swelling. Two long-term soil column tests were conducted to measure water absorption due to capillary rise with. They were conducted both with and without enzyme treatment. The test results demonstrated that the addition of the enzyme soil additive had the effect of reducing water retention. The soil treated with the enzyme additive absorbed a lower quantity of water in the capillary rise test, and at a slower rate of absorption. Partially-saturated clay having lower moisture content was linked to an increase in strength.