It's that time of year again. As temperatures drop, take a moment to review this previously posted article packed with cold-weather tips.

Contrary to popular opinion, as a contractor, you don’t have to put up your equipment and rigs due to cold weather. There are many jobs to be done and many ways to keep your material conditioned. Use this season to your advantage and gain valuable business.

Cold Weather Markets

Seasonal attractions such as theme parks are a great place to start looking for winter work. Many of these parks (the ones that aren’t in Orlando) shut down for the winter and this is the time they do maintenance and repairs. Think of all the concrete lifting and leveling that can be done.

Factories can be less active in the winter months with production slowing down in many industries. This is a good time for them to do maintenance and floor repairs as well.

Warehouses typically operate year-round, so there is always work available. Warehouse floors are used and abused on a daily basis and will sooner or later need some form of repairs done to keep business running at a steady pace. In addition, many warehouses have dangerous voids beneath their floors that require repair.  

Exterior concrete slabs are still worth considering, even in cold weather. These slabs experience the most wear and tear from the environment itself (think erosion) and daily traffic. You’ll need to lift concrete slabs before the ground freezes and only after your materials have been thoroughly conditioned.

Conditioning Materials

Your slab lifting equipment probably has built-in heaters and a heated hose. Each brand and model of pump has different-sized pre-heaters and different ∆T (∆ = Delta and T = Temperature). This sounds complicated but is actually quite simple.  ∆T is simply the change in temperature.  Let’s say your material has been sitting in a cold trailer all night and the temperature has dropped to 40 degrees F. If the required temperature of your B side material is 120 degrees F, then your pump better be rated with a ∆T of at least 80 degrees. However, if your material is preconditioned to 70 degrees F, then your machine only has to be rated for a ∆T of 50 degrees. As I said, every machine is rated differently based on the size of the heaters. What is important to know is that there are limitations to how much heating your machine can do.

Keeping your materials conditioned in the winter months is a lot easier than it sounds. The main point is to keep your AP Lift products above 60 degrees at all times. Keeping the polyurethane at or above that temperature can be accomplished in a number of ways.

If you have an insulated rig, it should stay around 40 degrees warmer than outside temperatures. Most foam rigs have built-in electric heaters that require an extension cord to a power outlet at the job site or at your facility for overnight storage. Alternatively, you could buy an electric radiator heater. Other available heating devices include drum band heaters and heated drum mats (be careful not to scorch the polymers by turning band heaters up too high). For a more DIY approach, you could build a hot box around the material storage area in your rig.

Heat Sink

Another consideration when lifting cold slabs is the heat sink factor. AP Lift products come out of the gun hot and get even hotter as they react. However, cold concrete acts as a heat sink and sucks the energy out of the foam as it starts to react. This can slow down the reaction speed of the foam. If you are pumping into a void, it will have little effect because most of the foam is not in contact with the concrete. If you are trying to lift a slab with little void, it will have more of an effect because more of the foam is in contact with the cold concrete and cold soil. More volume = more energy.

Conclusion

Don’t let common preconceptions deter you from slab lifting in cold weather. As noted above, there is no need to shut down completely for the upcoming winter months if you don’t want to. Opportunities still exist and one of them may just be the job you’ve been looking for all year. There are many ways to keep your equipment and materials conditioned to efficiently work in lower temperatures. Have more questions about slab lifting in cold weather? Call us at 404-618-0438.

Want more in-depth info on slab lifting?

The Geotechnical Applications for Polyurethane presentation explains and demonstrates how concrete leveling and soil stabilization resins can be used to stabilize soil and repair structures. The presentation covers the following topics:

• Single Component Polyurethane Grout Applications
• Two-Component Polyurethane Grout Applications
• Acrylic Grout Applications

This one-hour CE/PDH accredited presentation is ideal for engineers who are interested in learning about next-generation geotech repair methods for pavement lifting and stabilization, excavation support, erosion control, infrastructure infiltration control, etc.

Click here and submit your info for a follow-up call on scheduling an accredited presentation.

Want more information on geotech products and equipment?

Sometimes lifting concrete slabs with polyurethane is about more than just making something structurally sound and level again. In every town, there are buildings sitting empty because the floors are not in sufficient shape for use by a business. Imagine the service a concrete leveling contractor can provide by bringing slabs back into tolerance and allowing an empty space to become a revenue stream for the building owner. This is what one of our contractors in Omaha, Nebraska did.

In downtown Omaha, there are a lot of historic buildings. Located on an old stockyard site, there is a building that was constructed in 1911. It had been used as a parts depot for many years; including parts for World War II-era Jeeps. The owners of the building have converted some of it into a commercial laundry equipment distribution facility, but there was a section with sagging floors that really couldn’t be used effectively.

Some research on the internet led them to one of our contractors. This particular lift was a little tricky because the concrete literally had a belly, or sag, down the center. The owner’s idea was to create an office space with partitions/cubicles for small businesses. However, the current floor condition would have everyone’s office chair rolling to the center of the building. Not good! How would the floor react as they tried to bring it up a couple of inches? I was onsite as a consultant to help them find out!

We gave ourselves a reward to shoot for if the lift was successful; a big slab of Omaha prime rib. With that as motivation, we slowly worked our way across the floor and back. Using zip levels, dial indicators, and instinct developed from other jobs, we gradually brought the old floor back into tolerance. The product we selected for this project was AP Lift 430 and it worked beautifully. The MixMaster Pro injection gun performed as advertised and allowed for an efficient installation of the lifting foam. Although we had to drill multiple holes for the targeted injections, we only used three total injection ports.

Now the final touches are being added to this soon-to-be office space. The owners will have multiple tenants paying rent and a once unusable space as a revenue-generating property. If you’re a property owner with a similar issue, call us to get hooked up with a contractor who can help. If you’re a contractor, keep your eyes peeled for similar opportunities. They are all over the place. Now, about that prime rib…

Want more information on polyurethane slab lifting?

Many of the contractors I’ve worked with over the years have had to give a presentation at one time or another. In some cases, they need to make a pitch to a potential client (for example at municipality or state agency contract meetings). In other cases, they have the opportunity to market their services by giving presentations at trade shows, “lunch and learn” seminars, webinars, homeowner association meetings, professional association events, etc.

Presentation opportunities can sometimes arise on short notice. This is why you can benefit from creating presentations ahead of time. If you’d like, you can ask our marketing team to critique your presentation. You can also inquire about getting a member of our sales team to co-present when an opportunity does come along.

Incorporate the following tips to create a powerful presentation for your contracting business. Some of these suggestions may seem contrary to everyday conventional practice, but who wants a run-of-the-mill presentation? We’ve tested this approach time and time again, with consistently positive results. It will be worth your while to at least give it a shot.

Fewer Words

As a detail-oriented professional, you may be inclined to pack your presentation slides with lots of text in order to get all your important points across. This is not the most effective way to give a presentation. It can lead to information overload and a drowsy, impatient audience. When creating a presentation, you want to condense the information and only include text that is absolutely essential.

Powerful Images

Now that you have seriously scaled back your text use, the next step is to make the presentation lively. The audience needs to be actively engaged rather than bombarded with data. If you associate a powerful image with each essential point, the audience is better able to visualize and remember the concept.

Engaging Stories

Once you have simplified your text and added visually striking images, you can add extra punch by incorporating stories to get your points across. As a contractor, you probably have many stories from the trenches. Telling a story is a surefire way to make sure a message sticks.

White Paper Instead of Note-Taking

One thing that dilutes the impact of even the most powerful presentations is audience note-taking. This habit guarantees that half their time is spent looking down at their desk rather than paying attention to you. That’s why it’s helpful to prepare a whitepaper (basically an essay with any essential graphics) that summarizes all the key points from your presentation. Inform the audience upfront that there is no need to take notes, as they will receive a written summary afterward. Explain to them that they’ll get a lot more out of the presentation if they provide their full attention.

Conclusion

Since I believe in giving credit where credit is due, I'd like to acknowledge that most of these ideas came from the book Presentation Zen: Simple Ideas on Presentation Design and Delivery by Garr Reynolds.

For more tips on how to create a powerful presentation for your contracting business, or to inquire about co-presenting with one of our specialists, give us a call at 404-618-0438.

Want more information about marketing your contracting business?

When an old brick retaining wall in downtown Greenville collapsed and crushed three cars, Wurster Engineering and Construction was called in to stabilize the embankment and install a new wall system. Based out of Greenville, SC, Wurster is a geotechnical engineering and construction firm that specializes in soil and embankment stabilization. The project would require removal of the remaining brick wall, soil nailing the embankment, installing a shotcrete wall, and then tying in a new brick wall to the stabilized embankment.

However, one problem remained. There was one area where there was a portion of the brick wall that needed removal, but the temporary concrete retaining wall to protect the property had been poured on a bed of gravel that was being held in place by the remaining brick. The gravel under the temporary wall footing was contained by the remaining brick, which when removed would cause all of the gravel to run out. This section was about 30-35’ long, 2’ high, and 4-5’ deep from the face of the wall to the back.

Powerful Polymer

In order to solve this issue, Wurster Engineering and Construction selected AP Fill 720 to permeate the gravel and hold it in place while the brick was removed. This polyurethane resin was the ideal choice because of its ability to thoroughly permeate the gravel, lock it all together, and then cure to a high compressive strength. With the gravel locked in place, Wurster Engineering and Construction was able to install supplemental support jacks under the temporary retaining wall. After the jacks were in place, they were able to install the soil nails followed by the shotcrete.

Painless Procedure

Approximately 50 gallons of AP Fill 720 were used to build this solidified wall of gravel behind the remaining brick wall. Injection probes were spaced 18” apart to ensure proper permeation and coverage needed to create one solid mass. The crew came in at a steep 20 to 30-degree angle behind the brick and put in about 2 gallons of polyurethane per probe, with 5% catalyst mixed in. The crew then installed more probes at a shallow 60-degree angle in the areas that needed further permeation and coverage. These extra placements of approximately 2 gallons per probe were essential to keeping the gravel in place from side to side and front to back. This entire process took one day to complete with a small crew of three people.

Rapid Result

The day after grouting, the site work demolition subcontractor chiseled off the remaining brick from the solidified AP Fill 720 gravel wall - and the project was determined to be a complete success. The entire job was finished quickly with minimal mobilization costs. We appreciate our friends at Wurster Engineering and Construction for trusting Alchemy-Spetec’s material and consultation for geotechnical projects such as this one.

Want more information about soil stabilization?

It has become an Alchemy-Spetec holiday tradition to re-post this safety blog I wrote a few years ago.  Merry Christmas and Happy New Year!  (Andy Powell - Alchemy-Spetec Southeast Regional Manager.)

This time of year, most people will spend a little extra time with their loved ones.  It is also a time to reflect on the loved ones we miss that are no longer with us.  Like most of us, I know people who have either been lost or have suffered through a loss.  In those cases, there was nothing that could have been done to stop it.  However, there are things that we can do to guard against job-related safety hazards.

I've been fortunate enough to spend time in an OSHA safety training class.  It was required in order to be present supervising a project at a chemical facility.  Signing in at 6 AM, I’ll admit I was not looking forward to spending all day there.  By the end of the day, I was glad that I went.

In an intro video, the narrator said that every morning when you kiss your loved one goodbye before you go to work, keep in mind that someone, somewhere will not come home from work that day.  Workplace accidents are almost entirely preventable.  Investigations typically find the cause quite easily. 

The class I attended contained a dozen or so modules, each one with a video case study followed by the teaching.  Every case study module covered a different accident where people didn’t come home from work that day.  All of them could have been prevented.  I learned about fire, electrical and chemical safety; as well as confined space, ladders, scaffolds, and working in trenches.  I have worked in the construction industry since my teenage years, so it was sobering to look back and think about some of the close calls I had.

If you're a contractor or industry-related business owner looking for a good investment, send your employees to one of these classes.  It’s an excellent opportunity for them to learn safety principles that can protect you, your other employees, and your business from being lost.  It’s a gift that will keep on giving.  You don’t need Christmas as a reason to do this, but in the spirit of the season, you may want to make it the reason.  

Click here to find an OSHA safety class near you.

Merry Christmas and Happy New Year!

When an old brick retaining wall in downtown Greenville collapsed and crushed three cars, Wurster Engineering and Construction was called in to stabilize the embankment and install a new wall system. Based out of Greenville, SC, Wurster is a geotechnical engineering and construction firm that specializes in soil and embankment stabilization. The project would require removal of the remaining brick wall, soil nailing the embankment, installing a shotcrete wall, and then tying in a new brick wall to the stabilized embankment.

However, one problem remained. There was one area where there was a portion of the brick wall that needed removal, but the temporary concrete retaining wall to protect the property had been poured on a bed of gravel that was being held in place by the remaining brick. The gravel under the temporary wall footing was contained by the remaining brick, which when removed would cause all of the gravel to run out. This section was about 30-35’ long, 2’ high, and 4-5’ deep from the face of the wall to the back.

Powerful Polymer

In order to solve this issue, Wurster Engineering and Construction selected AP Fill 720 to permeate the gravel and hold it in place while the brick was removed. This polyurethane resin was the ideal choice because of its ability to thoroughly permeate the gravel, lock it all together, and then cure to a high compressive strength. With the gravel locked in place, Wurster Engineering and Construction was able to install supplemental support jacks under the temporary retaining wall. After the jacks were in place, they were able to install the soil nails followed by the shotcrete.

Painless Procedure

Approximately 50 gallons of AP Fill 720 were used to build this solidified wall of gravel behind the remaining brick wall. Injection probes were spaced 18” apart to ensure proper permeation and coverage needed to create one solid mass. The crew came in at a steep 20 to 30-degree angle behind the brick and put in about 2 gallons of polyurethane per probe, with 5% catalyst mixed in. The crew then installed more probes at a shallow 60-degree angle in the areas that needed further permeation and coverage. These extra placements of approximately 2 gallons per probe were essential to keeping the gravel in place from side to side and front to back. This entire process took one day to complete with a small crew of three people.

Rapid Result

The day after grouting, the site work demolition subcontractor chiseled off the remaining brick from the solidified AP Fill 720 gravel wall - and the project was determined to be a complete success. The entire job was finished quickly with minimal mobilization costs. We appreciate our friends at Wurster Engineering and Construction for trusting Alchemy-Spetec’s material and consultation for geotechnical projects such as this one.

Want more information about soil stabilization?

It's that time of year again. As temperatures drop, take a moment to review this previously posted article packed with cold-weather tips.

Contrary to popular opinion, as a contractor, you don’t have to put up your equipment and rigs due to cold weather. There are many jobs to be done and many ways to keep your material conditioned. Use this season to your advantage and gain valuable business.

Cold Weather Markets

Seasonal attractions such as theme parks are a great place to start looking for winter work. Many of these parks (the ones that aren’t in Orlando) shut down for the winter and this is the time they do maintenance and repairs. Think of all the concrete lifting and leveling that can be done.

Factories can be less active in the winter months with production slowing down in many industries. This is a good time for them to do maintenance and floor repairs as well.

Warehouses typically operate year-round, so there is always work available. Warehouse floors are used and abused on a daily basis and will sooner or later need some form of repairs done to keep business running at a steady pace. In addition, many warehouses have dangerous voids beneath their floors that require repair.  

Exterior concrete slabs are still worth considering, even in the cold weather. These slabs experience the most wear and tear from the environment itself (think erosion) and daily traffic. You’ll need to lift concrete slabs before the ground freezes and only after your materials have been thoroughly conditioned.

Conditioning Materials

Your slab lifting equipment probably has built-in heaters and a heated hose. Each brand and model of pump has different sized pre-heaters and different ∆T (∆ = Delta and T = Temperature). This sounds complicated but is actually quite simple.  ∆T is simply the change in temperature.  Let’s say your material has been sitting in a cold trailer all night and the temperature has dropped to 40 degrees F. If the required temperature of your B side material is 120 degrees F, then your pump better be rated with a ∆T of at least 80 degrees. However, if your material is preconditioned to 70 degrees F, then your machine only has to be rated for a ∆T of 50 degrees. As I said, every machine is rated differently based on the size of the heaters. What is important to know is that there are limitations to how much heating your machine can do.

Keeping your materials conditioned in the winter months is a lot easier than it sounds. The main point is to keep your AP Lift products above 60 degrees at all times. Keeping the polyurethane at or above that temperature can be accomplished in a number of ways.

If you have an insulated rig, it should stay around 40 degrees warmer than outside temperatures. Most foam rigs have built-in electric heaters that require an extension cord to a power outlet at the job site or at your facility for overnight storage. Alternately, you could buy an electric radiator heater. Other available heating devices include drum band heaters and heated drum mats (be careful not to scorch the polymers by turning band heaters up too high). For a more DIY approach, you could build a hot box around the material storage area in your rig.

Heat Sink

Another consideration when lifting cold slabs is the heat sink factor. AP Lift products come out of the gun hot and get even hotter as they react. However, cold concrete acts as a heat sink and sucks the energy out of the foam as it starts to react. This can slow down the reaction speed of the foam. If you are pumping into a void, it will have little effect because most of the foam is not in contact with the concrete. If you are trying to lift a slab with little void, it will have more of an effect because more of the foam is in contact with the cold concrete and cold soil. More volume = more energy.

Conclusion

Don’t let common preconceptions deter you from slab lifting in cold weather. As noted above, there is no need to shut down completely for the upcoming winter months if you don’t want to. Opportunities still exist and one of them may just be the job you’ve been looking for all year. There are many ways to keep your equipment and materials conditioned to efficiently work in lower temperatures. Have more questions about slab lifting in cold weather? Call us at 404-618-0438.

Want more in-depth info on slab lifting?

For any Deep LiftⓇ or deep stabilization project, we want to gather as much information as possible about the project site.  This information falls into a few different categories, in no particular order:

• The Cause(s) of the Settlement or Void

• Information on the Structure

• Geotechnical Data

• General Observations and Measurements

• Site Evaluation Tools

Now I will break down each category into a checklist. 

The Cause(s) of the Settlement or Void

It's important to identify the Causes of Settlement in a structure so that you can do a proper repair and not have the problem reoccur.  Things to look for include:

• Broken pipes - is there a known plumbing issue, has it been resolved, have the drainage lines been scoped, are there unusually high water bills, have the owners observed persistent, soggy ground?
• Are there stormwater or sewer culverts that run below the property?
• Is there a seawall, retaining wall, or bulkhead supporting soil in the vicinity of the building?
• Downspouts and gutter issues - do the downspouts discharge onto the ground next to the building or into pipes, are those buried drain pipes intact, are the gutters large enough to convey the rainwater to the downspouts, or do they overflow onto the ground next to the building?
• Are there any known trash pits or large trees that have been taken out next to the building?
• Do the building owners know any history about the site, was this building constructed on land that was already suspect?  Any kind of history you can get is valuable information.
• Are there site drainage issues like water runoff coming in contact with the building?
• Is there evidence of poor compaction?
• Have there been any construction projects next to the property where dewatering has been done?

Information on the Structure

What kind of structure are we proposing to stabilize or lift? Information about the Structure includes but is not limited to the following:

• Are there drawings, plans, or as-builts, for the structure?  Particularly we are interested in what kind of foundation the building is on.
• Is the structure on pilings?
• How deep are the footings?
• How wide are the footings?
• Are there interior strip footings?
• Do the interior slabs rest on the footing or are they floating slabs?
• What is the footing construction - poured concrete, concrete block, a combination of block on top of concrete?
• Is the building structure made of wood, block, steel frame, poured concrete, a combination?
• Is there siding or a brick facade on the building?
• Is it a single or multi-story building?
• Where are the plumbing and other utilities located?
• Are there overhead power lines?
• Can you reach the areas to be grouted with your equipment, do you have enough hose?

Geotechnical Data

Sometimes it is impossible to determine the causes of settlement without getting a Geotechnical engineer involved.  The kinds of Geotechnical Data we are looking for include:

• Surveys
• Dynamic Cone Penetrometer tests (DCP)
• Hand auger results
• Standard Penetration Test borings (SPT's)
• Soil profile reports - these tell you compaction, soil type, and water table elevation
• Ground Penetrating Radar (GPR) scans

Observations and Measurements

Finally, we need to put our Observations and Measurements together so we can complete the estimate, determine the full scope of the project, and set customer expectations accordingly.

• How much has the structure settled?
• Is the roofline affected?
• Is the brick or block separating, are there stair-step cracks?
• How many square feet of the interior slab has settled, how many inches down?
• Perform soundings on the slab to determine if there are voids underneath.
• Drill holes and use a probe or borescope camera to look underneath.

Tools for Site Evaluation

Of course, it is hard to get some of this information without the proper Tools for Site Evaluation.

• Measuring wheel.
• Camera for still pics and for video (I like to narrate my observations while I video record my walkthrough.  That way I don't have to remember what each still picture means.
• Measuring tape.
• Rotating laser with transit stick - or use a Zip Level to measure elevation changes.
• Flashlight.
• Drill.
• Soil probe.
• Borescope camera.
• Drill hole patching material
• Laptop, tablet, or a notepad and pen (for recording your information).

Want more information on the Deep LiftⓇ process?

Lifting a settled bridge approach slab with polyurethane foam requires specific knowledge of proved repair procedures for these types of structures. Here's an overview...

Look for a Hidden Sleeper Slab

Larger roads and highways will often have a hidden sleeper slab that spans underneath the pavement and the approach slab. It is designed to help transfer the traffic load from the roadway to the approach slab. If there is settling at a bridge approach you must determine if there is a sleeper slab in place. Drill through the pavement where it meets the approach slab and if you hit more concrete underneath the pavement you have found the sleeper. If there is a sleeper present where there is settling you will need to perform deep injection a couple of feet below the sleeper - just for soil stabilization. Rural roads and private roads typically do not have a sleeper slab present. Always ask the client if there are drawings available.

Deep Soil Stabilization Followed by Lifting

At least one level of deep injection is required for approach slab/pavement lifting. This is for soil stabilization. 4' spacing and 4' below the pavement is standard. Do not exceed more than 30 lbs per point at a given depth. It is advised to always have a DCP (dynamic cone penetrometer) test done in order to determine the blow counts. Low blow counts indicate weak soil zones that need to be targeted for deep injection. Lifting will be done directly through the pavement/approach slab, the same way you do standard slab lifting. Do the deep injections first and then finish with the injections directly beneath the slab.

Fill Voids with Polyurethane

Watch for voids under the approach slabs where they meet the bridge abutments. There are typically voids in this area that need to be filled. When filling them, it is good to have an observer under the bridge because the foam can fill the void up and come over the abutment, depending on how the structure is designed.

Want more info on geotech repair products?