When is Polyurethane Grout Rehabilitation an Effective Option?

The use of polyurethane grout rehabilitation for soil densification and structural rehabilitation has been revolutionizing the way public works managers and building managers think about rehabilitation vs. replacement. Due to cost-effectiveness and innovations in injection techniques, the viability of the solution has been “fast-expanding” and the applications are spanning across a variety of uses, such as roadway lifting, manhole and joint sealing, dam seepage barriers, seawall stabilization, and building foundation realignment. The question is, when does polyurethane grout make sense as a rehabilitation solution?

As you can imagine, this question is filled with a ton of variables, but we will try our best to identify typical rehabilitation opportunities and questions you should ask yourself around overall viability.

1.) Is the issue repairable via polyurethane injection?

The first thing to consider with this question is “Is the issue soil-related?” First and foremost, polyurethane injection is used to fill voids, whether large voids where no soil is present, or voids that exist between unconsolidated soils. The polymer is fast expanding, so once the voids are filled the polymer then compresses and densifies the soil and increases its weight-bearing capacity. So, if your problem is being caused by weak or weakening soils, then polyurethane may be an excellent solution.

2.) What is the condition of the structure being rehabilitated and what are your goals?

While we obviously think polyurethane injection is pretty great, the fact is, it isn’t a silver bullet. If the intended use of the structure is for continued use, the structure ought to be in a relatively operable condition. While we have been able to do amazing things with brick manholes that have lost grout, we are mainly focused on ensuring the structure can still meet current demands by rehabilitating the soil around or underneath the structure. But if the structure is crumbling or there is a focus on having the structure meet considerable volume increases, rehabilitation may not be a solution.

3.)  When considering sewer infrastructure, when is polyurethane applicable?

Polyurethane injection is highly adaptable when it comes to pipe and manhole joint rehabilitation. The reason is the application can be performed from inside the structure (access permitting) or from the surface.  The polymer is ideal for sealing leaking joints or stabilizing the structure.  Once injected, the polymer expands throughout the voids, sealing joints against Inflow and infiltration. In addition to sealing joints and filling voids, the polymer stabilizes the adjacent soil providing increased support for the structure and preventing future washout of the stabilized soil.

As mentioned in item #2, the condition of the structure and its future requirements are a consideration when determining whether polyurethane injection is a viable rehabilitation option. That being said, groundwater leakage and inflow and infiltration can be a major cause of sanitary sewer overflows and, if mitigated, can result in better utilization of your actual wastewater flows and you may find your current designs to be more adequate than thought.

4.)  Can polyurethane injection be used to increase soil load-bearing capacity to handle heavier loads?

In short, the answer is yes, but it really depends on how much weight, the soil quality, and the nature of the geology and subsurface structures. There are several instances where we have helped repurpose foundations to handle dramatically increased loads, such as silos, cranes, heavy equipment and machinery, and structural support columns. In each instance, the injection approach was uniquely designed to take advantage of the current soil and geological makeup of the site.

Not every site is capable of load-bearing increases.  In sites with highly plastic soils, the polyurethane’s bearing increase becomes limited to the bearing capacity of polyurethane itself as it is unable to permeate the soil and cannot build structural integrity by mixing with the soils. For ideal bearing-capacity increase, the ability for the polymer to saturate and bind the soil into a contiguous structural layer must be available.  The injection design can help develop a bridging technique to help distribute the loads more evenly over the newly strengthened soil.

In short, polyurethane is an excellent rehabilitation solution when structural circumstances permit, and financial conditions make sense. When determining these issues, we recommend running an ROI analysis, developing rehabilitation, and having an injection approach designed which would meet your project goals.

Settled concrete sidewalks and walkways can pose some serious risks that require attention. Sidewalks and walkways will begin to sink and shift over time as soil erosion and settlement occur. As a property owner, you have repair options to choose from to remedy these issues. A fast, effective, and affordable option to repair sinking sidewalks or walkways is with polyurethane concrete lifting. 

What Causes Concrete Sidewalks and Walkways to settle and shift?
Over time, concrete sidewalks and walkways will settle and shift naturally due to erosion and settling soil. Commonly, these things are caused by moisture from leaking pipes or weather events like rain, snow, or freezing. Tree roots growing beneath concrete slabs and digging rodents or other pests can also cause soil erosion.   Also, newly constructed concrete slabs may settle due to poorly compacted base soils beneath the concrete.  These areas may continue to densify and compact over the first few years following new construction.   

While it can be tempting to ignore the issue, there are some key benefits to having sunken or settled concrete sidewalks and walkways lifted before the problem gets worse and more expensive.  

1. Safety Hazard Mitigation
   Lifting your settled concrete sidewalks and walkways can resolve trip hazards, a serious safety issue especially in areas that experience high pedestrian traffic. Uneven or misaligned concrete slabs pose a serious risk to public safety and major liability concern for public or private property owners, HOA’s, and municipalities. If neglected, sidewalk or walkway trip hazards could cost thousands in lawsuit settlements and legal fees. Polyurethane concrete lifting raises and levels sidewalks back to the correct grade, saving you from the consequences that may occur from potential trips, falls, or injuries.
    
2. Improving Water Drainage
   Sunken sidewalks and walkways can cause water to pool and prevent proper drainage. Improper water drainage can lead to further concrete damage due to soil disruption and erosion. If the problem is ignored long enough, it can eventually cause structural damage to the surrounding property. Over time, pooled water can cause concrete surfaces to deteriorate and weaken the integrity of the slab.Standing water also poses a risk to public health. In warm climates, standing water is a breeding ground for disease-carrying insects like mosquitos. Rodents seek out water sources near their nests, so an area that frequently pools with water may attract these pests and encourage them to nest in or around your property.  In addition to being a risk to our health, rodents and other pests can cause serious and often expensive structural damage. 

   3. Preserving Property Value
   Aside from the safety, health, and financial risks associated with sunken concrete sidewalks and walkways, there are also cosmetic benefits to lifting and leveling those concrete slabs. Well maintained sidewalks and walkways add value to a property and improve curb appeal.  Sunken concrete sidewalks and walkways can be a clue to potential buyers that the property was not well kept and could be a red flag for hidden issues.  If settled and uneven concrete slabs are left untreated, voids beneath the slabs may occur due to water infiltration.  Those voided areas create unstable support systems for the concrete and can cause concrete to shift and break.

Lifting concrete sidewalks and walkways with polyurethane is a cost–effective, fast, and efficient solution that can improve safety conditions, drainage capabilities, and adds value to property while saving owners the headache and financial cost of additional, costly repairs in the future. Contact us today for a free consultation on your concrete lifting needs. 

Polyurethane foamjacking is a concrete raising solution that has captured a lot of attention over the past two decades and for good reason. The process has been deemed clean, fast, safe, and cost-effective. This article is meant to summarize what polyurethane foamjacking is and how the process is minimally disruptive for your concrete slab, your schedule, and your pocketbook. 

How Concrete Raising with Polyurethane Foamjacking Works  

Foamjacking works by addressing settlement, voids, and loose soils underneath a concrete slab with a high-density polyurethane. The concrete raising contractor injects the polyurethane through a 5/8″ hole that is drilled through the slab to give access to the void and weak soils underneath. The polyurethane initially enters the soil or void in liquid form. The material reacts and expands as it travels through the soil or void. Once the void is filled, the polyurethane densifies and recompacts the soil beneath the slab. Once soils are sufficiently compacted, the injection process is continued with careful monitoring until the pressure created by the polyurethane lifts the slab. With the right contractor, the slab can be lifted back to level, re-establishing contact between the soil and slab, and the weight load of the slab is reestablished back into the soil. 

How is Polyurethane Foamjacking Minimally Disruptive? 

Polyurethane Foamjacking requires no excavation and is very fast. The concrete raising solution only requires nickel-size holes to be drilled into the slab and that is it. After the injections are complete, the holes are filled with a non-shrink grout that hardens and is nearly imperceivable. The injection process is minimally disruptive and clean so you won’t be fretting over the condition of your concrete or yard. 

The speed of the concrete raising solution is also minimally disruptive to your time. Once the polyurethane is injected, it cures to 95% capacity within 20 minutes (you can drive your car over it!) A typical slab lifting project normally only takes a couple of hours to 1 day, depending on size and complexity. 

What About Costs? 

Concrete raising with polyurethane foamjacking is in most cases, less expensive than tearing out and replacing the concrete. This advanced technology helps save you money, extends the useful life of existing flatwork, and decreases disruption to your bank account! 

What Should You Do Now? 

Get a free estimate today!