The A side material has a specific gravity of 1.22 or 10.18 lbs./gal. The B side material has a specific gravity of 1.04 or 8.67 lbs./gal. When the 4R material is cured in free rise conditions, it will have a density of 4 pcf or 0.53 lbs./gal.
The 4R will go from liquid to fully formed solid in approximately 32 seconds. The 4F material will fully expand in 15 seconds.
The expansive force of the material is controlled by the level of confinement. In fully confined conditions, expanding rigid polyurethane foam can excerpt significant pressure. The paper titled “Analytical Modeling of the Soil Improvement by Injections of High Expansion Pressure Resin” states “the expansion pressure depends on the resin density (Fig. 2) and varies between 0.2–10.0 MPa (29 – 1450 psi) in the investigated unit weight range (γ = 0.5–10.0kN/m3). Such values are indicative of the pressure that the resin can generate when it is injected in the ground”. Typical unit weights of material when injected into soil are in the range of 5 to 20 LB/CF. According to the research this would result in between 20 – 110 psi of pressure exerted on the surrounding soils or pavement. This pressure can be converted into uplift force if you make several assumptions. Assumption 1: the material is laterally confined so all pressure is exerted in the vertical direction. Assumption 2: the material is pushing on an assumed area. For this discussion, the conservative assumption is that the material is exerting force on an 18” radius or ~7 SF area. This is reasonable based on the assumed material spread and injection pattern of a 4-foot horizontal grid. The surrounding injections will provide horizontal confinement resulting in the material exerting vertical force. Taking the midrange pressure of 60 psi acting on a 7 square foot area, there is the potential to lift 60,480 lbs. (60 lb./in2 x 144 in2/ft2 x 7 ft2 = 60,480 lb.).
The material we use achieves partial hardness in the expansion times listed above with 95% strength in 15 minutes and 100% strength not long after that but certainly within 24 hours.
The technical data sheet shows for the free rise 4 lb. material there is a shear strength of 47 psi and a tensile strength of 95 psi. The strength in soils varies significantly depending on the soil type and level of material saturation. URETEK has conducted laboratory testing on soil samples treated with URETEK 486 and seen shear strengths greater than 180 psi. The soil samples were tested in a machine with a maximum capacity of 180 psi, as is common in all soil labs, so the actual shear strength is higher than that tested.
As discussed above, the lifting force is based on confinement area the expanding material can react against. Using multiple injections at the same time will multiply the lifting force by each additional injection. 3 guns, if they can excerpt pressure on a structure simultaneously, will be able to lift 3 times the amount of 1 gun. This is a technique that is commonly used by URETEK on more complicated lifting projects. There are many factors that come into play on a project-by-project basis so these recommendations must be evaluated prior to being incorporated into a specific project.
Most of our trucks are equipped with a Graco H40 pumping unit. These units are designed to pump 40 gallons per minute. The infiltration area is highly dependent on soil type, level of compaction, and in ground conditions. If the material is injected into tight soils and it finds a weak seam, it can travel distances in that seam prior to setting up. In sandy conditions, the material mostly infiltrates and forms fins of a sandstone like material. In other soil types, polymer bulbs and compacted soils will be seen. The soil improvement for polymer grouting is not primarily achieved through permeation. UDI generally has three modes of soil improvement:
Permeation: In predominately coarse-grained soils, the polymer grout will permeate the voids in the soil matrix, essentially gluing them together. The result is similar in appearance to concrete or sandstone. This mode of soil improvement is not anticipated to occur when fine-grained soils are present.
Polymer Lattice Formation: This mode involves the formation of veins, fins, stringers, and webs of material, referred to here as a “polymer lattice”. This mode is thought to improve soil strength and stiffness in a similar fashion to geosynthetic reinforcement. It frequently occurs when there are higher fines (silt and clay) content in the soil. This mode of soil improvement does not occur with traditional permeation grouting.
In-Situ Densification: The other soil improvement mode that differentiates UDI from most traditional grouting is densification. Once any voids, fissures, and open pore spaces have been filled by the polymer, the expansion pressure of the reaction can displace soil particles, thus increasing the density, which improves the overall performance of the soil mass. This mode requires at least some confinement to occur.
The A and B sides of the system are heated to 110° F prior to being mixed at the injection gun. The formation reaction is exothermic and releases heat into the soils. The amount of heat depends on the amount of confinement and the temperature of the surrounding environment.
Based on conversation with manufacturers, it is our understanding that there is no effect.
As discussed, the maximum lifting weight will be based on the ability of the material to react against the structure. This is highly site specific; however, URETEK has lifted massive structures. In most cases, the process is to lift the structure by injecting material directly below the foundation. However, in some cases, it is better to lift from depth in order to get a more even and stronger resulting subsoil strength. These are very site specific and is an art that is learned over many projects. Because the material performance is highly dependent on subsoil conditions, the installation crews must be able to adapt the site-specific soil conditions and structural design.
When buried, rigid polyurethane is expected to last over 100 years. Water does not affect the material strength when proper material is used.
URETEK tests its materials to the highest standards in this regard. A material that will form proper linkages in the presence of excess water is very important when performing ground improvement projects. Water is almost always present in the soils, especially the weak soils that are the cause of most of the structural failures we work. We have developed testing that has been accepted by multiple state Department of Transportations to verify this.
URETEK is the pioneer in the rigid polymer ground injection industry and dates back to 1979. Since then, other companies have entered the industry. The URETEK Method process has also become known and/or referred to as: high density polyurethane resin injection, poly-jacking, concrete foam lifting, geotechnical foam lifting, foam jacking, polyurethane foam jacking, and/or polyurethane concrete raising. URETEK Deep Injection® is a process where URETEK’s high density expanding polymer material can fill and stabilize low-density compressible soils at depth.
The short version: URETEK was the first to develop and advance the technology, creating the perfect material for its success. Because URETEK was the first, it’s also had the most experience with concrete lifting, foundation repair, and soil stabilization using expanding polymer injection.
The long(er) version: URETEK is the industry pioneer for non-disruptive ground engineering by injecting expanding polymer. Therefore, URETEK’s material has undergone the most extensive research, development, and testing in the industry. In addition, URETEK’s processes have completed thousands of projects across the globe. As such, we have had the opportunity to draw on this vast experience base to perfect our material and our services.
The URETEK material is environmentally friendly and non-toxic. URETEK polymer utilizes a fully EPA approved, non-CFC, non-HFC, zero-ozone depleting blowing agent. For certain projects, URETEK material is NSF61 certified which means that it is proven to be safe when installed in and around pipes and tanks that hold our drinking water.
Once the material has set and hardened it will maintain structural stability. Material that was excavated after 10 years was found to be in excellent condition. The material is susceptible to deterioration when exposed to UV rays, so it is important that it be protected from sunlight. Used properly in the right conditions, the URETEK material has an indefinite life span.
URETEK provides long lasting solutions. Material that was excavated after 10 years was found to be in excellent condition. We have completed tens of thousands of projects over four decades with very low warranty work. In most cases there are existing factors that contributed to the soil problem, the most common of which being improper drainage. If these contributing factors to soil problems are not properly managed there is a possibility that the issue will reoccur.
Every project is unique and requires a unique solution. In situations where continued settlement is an issue, our URETEK Deep Injection® process may be the most appropriate solution. This process involves injecting the material at depth and targeting the weak soil layers that are contributing to the settlement. URETEK’s Deep Injection® process is a proven method to halt continued settlement.
URETEK is a proven solution, and we have a long record of successful projects to stand on. Our method is quick, clean, non-invasive, and, upon completion, gets the area back to its normal routine immediately. Other repair methods can be extremely destructive, take days or weeks to complete, and end up costing you more.
That said, all projects are unique and may require a combination of repair methods to provide the best solution for the customer. Our Project Managers are the best in the business and will give you their honest evaluation of your problem in question. They will never try to sell you something you don’t need.
URETEK technicians are highly skilled and use very precise measurement devices to ensure performance on each project. During injection, the URETEK material first fills voids, then compacts the surrounding soil, and finally, exerts an even pressure on the slab above. This process greatly reduces the risks of slab cracking during a repair.
URETEK’s material is hydro-insensitive, which means that it will react and form a rigid load bearing structure even in the presence of water. We have a long history of successful projects completed in very wet environments. Sealing of bulkheads is a great example of a successful URETEK application in submerged conditions. Drainage is always a concern around any structure. The URETEK material is highly resistant to erosion, however the soil around the material will still be susceptible to erosive forces. Care should always be taken to ensure proper drainage in all situations.
URETEK polymer is not a food source and contains no nutritional value to rodents and/or insects.
We have successfully leveled very heavy components resting on structural concrete slabs. Examples range from storage tanks to mechanical equipment. With URETEK’s decades of experience and well-designed project plan, there is very little that URETEK is unable to lift and stabilize.
URETEK can be safely installed with minimal invasion. A 5/8” hole is drilled through the slab and the material is strategically injected through this these drilled holes at a pattern design by the Project Manager. In the case of laminate or wood flooring, the hole can either be drilled through the flooring or preferably one plank will be removed in the location of the hole and replaced after URETEK work is complete. If drilled through the wood, the hole will be filled nicely with a cap or wood putty.
URETEK is a solution-based company and as such each job will require a unique solution with a unique cost involved. Please contact your local URETEK representative to obtain a proposal for your project.
It is no surprise we’ve seen videos go viral over settled concrete lifting back into place in a matter of seconds with what many refer to as injectable “foam”. It certainly is impressive technology… we should know – we pioneered it!
Please note: Not all expanding polymer material is created equal. We can only speak on behalf of our URETEK polymer and process, and not for our competitors.