Winter and spring often bring substantial problems and delays to earthwork projects.Soil moisture increasesdue to decreased evaporation and increased precipitation.When wet soils are excavated it can take significant amounts of time to dry soils for adequate compaction.When drying cannot occur due to cold temperatures, importing of fill or a stop work are necessary, both which are undesirable.
In order to keep your earthwork project moving and on schedule, consider chemical drying and stabilization of the soil.Wet soil treated with lime or quicklime, is a very effective method fordrying.The lime reacts with moisture in the soil to generate heat, drive off water vapor, and bind some of the waterin the chemical reaction.This reaction occurs very quickly, in a matter of 1 to 3 hours to allow for compaction to proceed.
It has beenGTA'sexperience that as long as there is someunfrozen water in the soil, the chemical reaction can begin.Generally there is enough heat generation that limetreated fill resists frost penetration the night after mixing.Thelatent heat reduces the need to sacrifice the upper layer of fill due to frost penetration, whichultimately saves project time.
Although lime will reduce the moisture in all soils, it has the added benefit of reducing the plasticity of clays.Use of sufficient lime with clays can also create a cemented layerthat hasincreased load bearing capacity for pavements and structureswhen compared to the natural clay.
When chemical stabilization of soil is specified for a project, specialty stabilization contractors are often employed to work hand in hand withthe siteearthwork contractor.The earthwork contractor will perform cut excavations, fill placement, and compaction.The specialty contractor performs lime spreading and mixing with a reclaimer or rotary mixer.The followingvideo is from a sitethat required lime drying to achieve compaction in thewinter.
Before specifying lime for an earthwork project, consult a professional geotechnical engineer experienced with lime drying and stabilization.Since every site is different, the engineer willdesign a laboratorytesting programto develop recommendations forthe appropriate application rateof lime to achieve the necessary drying or stabilization.Laboratory testing can help avoid underperformance of the lime drying and stabilization, or wasting money due to more lime being specified than is actually required.
During construction, a field representative working for the professional geotechnical engineer should perform field testing.The field representative’s duties may include spread rate determinations, field moisture determinations, compaction testing, and overall observation of the stabilization performance.If an increase in bearing is required, the field representative will also fabricate compressive strength specimens from the field mixture.Should site conditions change, the field representative can report directly to the engineer to determine if modifications to the recommendations are necessary.
Geo-Technology Associates, Inc.is a Geotechnical Engineering firm that employs registered professional engineers and field representatives experienced with chemical stabilization for grading, walls, buildings, roadways, stormwater management facilities, and parking lots. GTA has had the pleasure of working with many of the local and regional specialty stabilization contractors on successful projects.
FAQs
Nonetheless, lime treatment has a number of inherent disadvantages, such as carbonation, sulfate attack and environment impact. Magnesium oxide/hydroxide are thus proposed as a suitable alternative stabilizer to overcome at least some of the disadvantages of using lime in soil stabilization.
How much lime do I add to soil for stabilization? ›
How Much Lime is Needed? The range of lime to use is normally 4 to 6 percent and is based on the soil types on the project- the worse the soils, the higher percentage of lime should be used.
How to stabilize soil with lime? ›
Base stabilization is used for new road construction and reconstruction of worn-out roads, and generally requires adding 2 to 4 percent lime by weight of the dry soil. In-situ “road mixing” is most commonly used for base stabilization, although off-site “central mixing” can also be used.
Is lime or cement better for stabilizing soil? ›
As previously mentioned, lime works very well with fine-grained soils while coarser-grained low PI soils typically require cement.
How long does lime stabilization last? ›
Soil Stabilization:
The full-term pozzolanic reaction can continue for a very long period of time, even decades -- as long as enough lime is present and the pH remains high (above 10). As a result, lime treatment can produce high and long-lasting strength gains.
What are the negatives of liming soil? ›
Sometimes the lime interferes with fertiliser, sometimes certain plants will die if the soil is made too alkaline, like azaleas and similar plants, because they prefer acidic soils. That are the disadvantages, advantages are, the liming makes the heavy clayey soils friable and ready for planting.
What happens if you add too much lime to soil? ›
Too Much Lime May Inhibit Other Nutrients
Normally, applying lime will at least somewhat limit other essential nutrients needed by the plants to be grown there, and the grower should know whether this is the case before using significant amounts of lime.
How long does it take for lime to improve soil? ›
Often as much as six months may be needed before pH changes significantly. Neutralization will be quicker if particle size is small (less than 60 mesh) and the lime is well mixed with the soil. Typically, it will take two to three years to observe the full effect of ag-lime application on soil pH.
Which lime is best for stabilizing soil? ›
Many types and qualities of lime have been successfully used as soil stabilizing agents for many years. However, the most widely used and best performing limes in soil stabilization are the quicklime (CaO) and hydrated (Ca(OH)2) lime.
Does lime harden like concrete? ›
Non hydraulic lime hardens by a slow process of carbonation, reacting with atmospheric carbon dioxide over a period of weeks. Hydraulic limes and cements set rapidly by reacting with water in a matter of hours.
Working lime into the soil in the fall gives it several months to dissolve before spring planting. To add lime to the soil, first prepare the bed by tilling or digging to a depth of 8 to 12 inches (20-30 cm.). Spread the lime evenly over the soil, and then rake it in to a depth of 2 inches (5 cm.).
How to use lime to dry soil? ›
for drying has three simple steps: (1) lime spreading; (2) mixing lime and soil; and (3) compaction. Lime Spreading. The most rapid lime spreading is achieved with a pneumatic bulk truck equipped with a spreader at the rear, or by other mechanical delivery of bulk lime. However, bagged lime may also be used.
What are the disadvantages of limes? ›
Limes are very acidic and best enjoyed in moderation. Eating many limes can increase your risk of cavities, as the acid in limes — and other citrus fruits — can erode tooth enamel (29). To protect your teeth, be sure to rinse your mouth with plain water after eating limes or drinking the juice.
What is the common stabilizer for soil stabilization? ›
Lime occurs naturally, while cement (also known as Portland cement) is synthetic, or manmade. Although, treating the soil with cement or lime is one of the most popular means of soil stabilization, it is most prevalent in paved roads.
Will lime make dirt hard? ›
Although the term 'lime' is used loosely, it's important to know that hardening or drying soils requires either quicklime or hydrated lime.
What are the hazards of lime stabilization? ›
Eye irritation from lime dust can cause intense watering of the eyes. Prolonged exposure can potentially cause lesions and even blindness. Inhaling lime dust may lead to irritation of breathing passages, coughing and sneezing.
Does lime damage soil? ›
According to chemical definition, lime is calcium oxide (CaO). In agriculture, lime is usually defined as calcium or calcium-magnesium containing compounds capable of reducing harmful effects of an acid soil by neutralizing soil acidity and raising the soil pH.
What does lime stabilization of soil lead to? ›
Lime stabilization is used to improve the strength, stiffness and durability of fine-grained soils. Addition of lime to soils produces a maximum density under a higher optimum moisture content than in the untreated soil, thus leads to flocculated or aggregated larger particle groups which are fairly stable.
What is lime stabilization best suited for? ›
Lime stabilization of Soil:
- It is the process of stabilizing soils by adding lime to reactive soils to generate long-term strength gain through a pozzolanic reaction.
- It is used to improve the strength, stiffness, and durability of fine-grained clayey soils.
