Tackifiers and soil stabilizers are hydraulically applied chemicals derived from natural and synthetic sources used to promote adhesion among soil particles or mulch materials. In general, soil stabilizers (also known as soil binders) are used to increase soil adhesion, which improves soil stabilization by reducing water and wind driven erosion. Tackifiers are used as “glue” to bind and immobilize straw, cellulose products, pine needles, or other mulch that has been applied to a seeded area. Tackifiers protect seedbeds by holding the product to the soil surface and preventing movement. Relevant products include polyacrylamide, guar, chloride compounds, psyllium, resins, enzymes, surfactants, and various polymers, starches, and other compounds. Petroleum based tackifiers, once widely applied to straw mulch, have largely been replaced with other products that are easier to handle, break down naturally, and present fewer overall health and environmental risks.
Chemical-based soil stabilization is intended to counteract the erosive influences of rainfall, snowmelt, and wind on bare soil. The use of tackifiers to prevent the movement of mulch material by wind and rain helps to keep straw and/or other mulches in place, preventing soil erosion. Stabilizers and tackifiers are temporary measures, designed to prevent short-term (e.g., two to four weeks) erosion between construction periods, and during seed germination and early growth for permanent stabilization. While they are effective for a wide range of soil, slope, temperature, and rainfall conditions, they are not intended for use in concentrated flow locations, such as ditches and channels.
Site stabilization with soil binders and tackifier bonded mulch (e.g., straw, other fibers) applies to 1) areas of construction sites where soil disturbing activities have temporarily ceased, and measures are needed to prevent erosion and sediment runoff during rainfall or snowmelt; and 2) areas of the site that require permanent stabilization.
Construction sites often have areas where soil disturbing activities such as clearing, grading, or cut/fill work has stopped for a period of time. Bare areas that are not actively being worked need some type of cover or stabilization practice to prevent or minimize erosion in the event of rainfall or snowmelt. Tackifiers and soil stabilizers are applied hydraulically to reduce erosion by binding soil particles or mulch materials, often in conjunction with temporary or permanent seeding. Applicable areas include topsoil stockpiles, rough graded areas, sediment basin dikes, temporary earthen structures, and graded areas. Tackifiers and soil stabilizers can be used in conjunction with seed and mulch materials to achieve temporary and/or permanent stabilization.
The MPCA Construction General Permit has several requirements regarding temporary stabilization. See Section 8.
Hydraulically applied products have undergone rapid development and improvement during the past ten years and now provide seed establishment and soil protection performance equal or superior to conventional seeding and mulching practices. Temporary and permanent stabilization with mulch-adhered tackifiers and soil stabilizers is effective in reducing soil loss from construction sites by increasing mulch longevity and preventing mulch displacement via wind and heavy rain. Tackifiers used as adhesives in hydraulically applied mulches (e.g., bonded fiber matrix, other hydromulches) have been used for decades, and provide results similar to rolled erosion control products in non-channel applications when selected, prepared, and applied in accordance with manufacturer’s directions. Chemical soil stabilizers bind the soil, helping it to further resist raindrop, sheet, and rill erosion. Soil stabilizers, when used as adhesives, are effective for dust control, short-term erosion prevention, and roadway stabilization. Some stabilizers, such as anionic polyacrylamides, may be used as coagulants in sediment ponds to promote flocculation and settling. The following table summarizes expected performance for an array of typical water quantity and quality target constituents for tackifiers and soil stabilizers.
Expected performance for tackifiers and soil stabilizers.
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Water Quantity | |
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Flow attenuation | Little or no design benefit |
Runoff volume reduction | Little or no design benefit |
Water Quality | |
Pollution prevention | |
Soil erosion | Primary design benefit |
Sediment control | Little or no design benefit |
Nutrient loading | Primary design benefit |
Pollutant removal | |
Total suspended solids | Primary design benefit |
Total phosphorus | Primary design benefit |
Heavy metals | Secondary design benefit |
Floatables | Little or no design benefit |
Oil and grease | Little or no design benefit |
A key benefit of hydraulically applied products is the ability to treat large sites with steep (3H:1V to 1H:1V), long slopes or other areas where installation of ECBs or turf reinforcement mats is difficult. A nearby source of water (or water tank) to mix the slurry is necessary for large sites. Typical hydraulic soil cover applications include a slurry-like mix of seed, fertilizer, and mulch. Also available for inclusion are other amendments such as tackifier and a variety of fibrous materials that dry to form a flexible net or crust that provides excellent protection for bare soil before seed germination.
Application equipment ranges from small, hand-pulled polyethylene units with electric sprayers and tanks that hold up to 15 pounds of seed, fertilizer, and mulch, to large towed or truck-mounted machines with tanks of 100 to 2,000 gallons. Mixing ratios will vary significantly by application, but a standard turf application for one acre will typically include 100 to 150 pounds of seed (or more, depending on seed variety and site conditions), 300 to 400 pounds of fertilizer, 140 pounds of binder, and 1,500 to 2,000 pounds of fiber mulch mixed with 4,000 or more gallons of water.
As soil binder types and uses have expanded in recent years, refer to the following when selecting a binder product.
This link lists the hydraulic erosion control products currently approved/qualified by MnDOT, which requires that an Applicator’s Certification from the manufacturer be provided before applying Polyacrylamide Tackifier, Organic Fiber Matrix, Bonded Fiber Matrix or Reinforced Fiber Matrix. Below is summary information on some of the most widely used soil binders.
Use of soil binders varies by site condition and product (see table below). Most hydraulically applied products function best when used on dry soil. Use a soil test to verify the exact type of soil at the site. When using a binder slurry or tackifier/mulch blend for seeding, leaving the top two inches of the surface loose helps to ensure good germination. If the soil is compacted, seeds won’t penetrate properly and the slurry will splatter and slide, resulting in uneven application.
Polymer tackifiers are generally applied at rates of 40 to 60 pounds per acre, and organic tackifiers are typically applied at rates of 80 to 120 pounds per acre; however, manufacturers’ recommendations vary and should be followed for both product types. Applications of liquid mulch binders should be heavier at edges, in valleys, and at crests of banks and other areas where the mulch could be moved by wind or water. All other areas must have a uniform application of the tackifier.
Example properties of soil binders for erosion prevention. Source: California Stormwater Quality Association; California Stormwater BMP Handbook.
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Evaluation criteria | ||||
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Plant material based (short lived) | Plant material based (long lived) | Polymeric emulsion blends | Cementitious - based binders | |
Relative cost | Low | Moderate to high | Low to moderate | Moderate |
Resistance to leaching | High | High | Low to moderate | Moderate |
Resistance to abrasion | Moderate | Low | Moderate to high | Moderate to high |
Longevity | Short to medium | Medium | Medium to long | Medium |
Minimum curing time before rain | 9 to 18 hours | 19 to 24 hours | 0 to 24 hours | 4 to 8 hours |
Compatibility with existing vegetation | Good | Poor | Poor | Poor |
Mode of degradation | Biodegradable | Biodegradable | Photodegradable / chemically degradable | Photodegradable / chemically degradable |
Campatibility with existing vegetation | Good | Poor | Poor | Poor |
Mode of degradation | Biodegradable | Biodegradable | Photodegradable / chemically degradable | Photodegradable / chemically degradable |
Labor intensive | No | No | No | No |
Specialized application equipment | Water truck or hydraulic mulcher | Water truck or hydraulic mulcher | Water truck or hydraulic mulcher | Water truck or hydraulic mulcher |
Liquid / powder | PowderX | Liquid | Liquid / powder | PowderX |
Surface crusting | Yes, but dissolves on rewetting | Yes | Yes, but dissolves on rewetting | Yes |
Clean up | Water | Water | Water | Water |
Erosion control application rate | Varies1 | Varies1 | Varies1 | 4,000 to 12,000 lbs / acre |
1Application rate varies with slope steepness (i.e., steeper = more); see manufacturer’s recommendation.
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Crown or slope the ground while grading to avoid ponding. Follow manufacturer's written recommendations for application rates, pre-wetting of application area (if necessary), and cleaning of equipment after use. Prior to application, roughen embankment and fill areas. Also, consider the drying time for the selected soil binder and apply with sufficient time before anticipated rainfall. Soil binders should not be applied during or immediately before rainfall. Avoid overspray onto roads, sidewalks, drainage channels, sound walls, existing vegetation, etc. Spraying of hydraulic mulch should not be performed during windy conditions, which would prevent the proper placement. Do not apply to frozen soil, areas with standing water, under freezing or rainy conditions, or when the air temperature is below 40°F during the curing period. If more than one treatment is necessary, the second treatment may be diluted or have a lower application rate. Generally, soil binders require a minimum curing time of 24 hours before they are fully effective.
Additional important considerations for soil stabilizers include the following.
MnDOT Standard Specifications 2575.3 part E.1, provides guidance for placing hydraulic erosion control products including tackifiers (natural and synthetic) and polyacrylamide. Part E.2 covers soil stabilizer matrixes and application methods, rates, and timing. Specification 2575.4., Part G, covers measurement of hydraulic erosion control products. Hydraulic erosion control products should meet Specification 3884 (“Hydraulic Erosion Control Products”).
Inspect the area before anticipated storm events (or series of storm events such as intermittent showers over one or more days), within 24 hours after the end of a rainfall event of one-half inch or more, and at least once every 14 calendar days. If possible, maintenance needs identified in inspections or by other means must be addressed before the next storm event, but in no case more than 7 days after the need is identified. If properly applied, little additional maintenance is required during the first weeks. After high winds or significant rainstorms, treated areas should be checked and re-treated if necessary.
Areas where erosion is evident should be repaired and treated again as soon as possible. Care is needed to minimize the damage to protected areas while making repairs, as any area damaged will require reapplication of treatment. In all cases, follow manufacturers’ recommendations regarding initial and follow-up application of hydraulically applied products. For example, some products require reapplication after specified time intervals and/or if treated areas become disturbed.
The following table summarizes estimated BMP costs based on MnDOT data summarizing average bid prices for awarded projects.
Average bid trafficker prices for Specification Year 2014
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Bid Item | Item Description | Units | Average Price |
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2575.561/00010 | Hydraulic Tackifier Type Natural | SY | 💲0.39 |
Except where more stringent requirements are presented in this guidance, BMPs shall comply with MnDOT and other state requirements. Primary design references include the following.
The following is a list of additional resources that are not specific to Minnesota.
This page was last edited on 11 January 2023, at 18:08.