Concrete

Using Asphalt To Patch Concrete

Over time, any asphalt paving will wear down. A combination of the water cycle (cooling and heating and expanding and contracting) and the pressure from vehicle tires will cause damage to any driveway, parking lot, or road. Weather and use will necessitate one thing: repairs. Asphalt, fortunately, can be repaired in various types of ways. From sealing cracks and plugging surface holes to full-bore repair, asphalt is easy to work with. Concrete on the other hand, is a bit tougher. Often, concrete can only be repaired by replacing entire slabs of it, meaning huge chunks of concrete must be removed and then new ones laid. This process is costly, time-consuming, and a main reason concrete is not the preferred road material. 

How it works

Fortunately, asphalt and concrete are very similar substances. That’s why they have so much overlap in their applications. Both concrete and asphalt are made primarily from aggregate. Aggregate are small rocks, pebbles and stones. They form the main body of asphalt and concrete. If you’ve looked at most concrete, and compared it to the asphalt in the road, you’ve probably noticed how much larger the aggregate in asphalt is. Concrete is composed of smaller particles in general, the size of grains of sand. Sometimes the size of the particles ranges up to a few millimeters, but usually it is under 1. Asphalt however is typically composed of a much coarser aggregate. Pieces of asphalt particulate range from under one millimeter up to under 10. In general, asphalt’s aggregate averages out to a larger size, of 1 or more millimeter in diameter each.

The other main ingredient in both asphalt and concrete is binder. Binder is a type of glue that holds everything together. In asphalt, binder is petroleum-based. It is made from refined oil, and it composes about 5% of the total body of the asphalt. In concrete, the binder is 10-15% cement, 15-20% water, and 65-75% aggregates. The cement is the substance that creates the glue –  functioning as a binder – in concrete. It is made from various different ingredients, such as lime, silica, sulfur trioxide, alkaline, iron oxide, alumina, and calcium sulfate. When water is applied, these ingredients form a tough and resilient binder that holds together concrete’s aggregate.

Due to the higher content of binder, and the smaller aggregate size, concrete has different uses from asphalt. Asphalt is often used for roads and other asphalt paving, like driveways, parking lots, and trails. Concrete can be structural, composing columns, walls, and more. 

Can asphalt be used to patch and repair concrete?

Simply put, the answer is yes. Now using asphalt patches to repair concrete isn’t a one-size-fits-all solution, but it is very common, and easy to do. Concrete actually makes a fantastic base material for asphalt. It allows strong compaction, and, every year, miles and miles of concrete roadway are paved over with asphalt. 

Laying asphalt on concrete provides several benefits:

  • Asphalt is highly weather resistant, especially when seal coated. Asphalt seal coating is the number one choice for durable and efficient protection.
  • Asphalt is much cheaper to lay than concrete. Rather than replacing huge slabs of concrete for repairs, you can work on the new layer of asphalt for much cheaper. Asphalt is also 100% recyclable, making it an environmentally friendly choice.
  • Because asphalt is 100% recyclable, it is easier to come by than concrete. Paving contractors can tear up existing asphalt, re-pulverize it, and lay it as new asphalt. Not only that, but they can do it all on location with the right gear.
  • Asphalt is more durable. It can handle weather and temperature fluctuations much better than concrete.

Patching concrete with asphalt

When it comes to patching holes and cracks in concrete, asphalt patch kits work great. Just follow a few steps:

  • Clean up the hole to be patched. Clean up any loose gravel or rocks, or other debris that may have made their way there. You can use a brush or broom to do so. 
  • Apply the asphalt patching material. Be sure to read instructions on the patch kit first. You may need a polymer sealant applied in the hole between the two.
  • Once the patch is applied let it set. You may need to blow hot or cold air on the patch depending on the kit you are using.

Why NOT to patch concrete with asphalt

Although it makes a good surfacing substance, there are some reasons not to use asphalt in tandem with concrete.

  • The concrete under your asphalt can crack. This can make the asphalt weaker, and be a real headache to fix. Now you have to repair two layers of different material. If you aren’t sure about the concrete you will be laying your asphalt on, then don’t do it!
  • Expansion joints. Because concrete handles temperature fluctuations differently, it has something called expansion joints. These will move over time and can cause the asphalt above to develop cracks along those lines.
  • When there is already a foundation for asphalt, the base underneath is unknown. How strong is the earth below the concrete? How many years will it last before totally new paving is required? Changes in the ground below concrete can cause the asphalt to shift, heave, and crack. This lowers the lifespan and necessitates more frequent repairs.

Figuring out how to repair your concrete?

Whether your paving conundrum is concrete, asphalt, or anything else, Reliable Paving, can fix it. We have been in the paving industry for 35 years, and offer a wide range of services.

  • Asphalt seal coating
  • Asphalt paving
  • Concrete paving
  • Concrete seal coating
  • Repairs, such as crack filling and patching
  • Re-striping
  • And much more!

Send us a message today to see how we can lay new pavement, repair damaged pavement, or see what our full range of services is.

When To Use Asphalt Instead of Concrete

If you’re reading this, you are probably trying to decide whether asphalt or concrete is right for your project. We hope that after reading this article, you will be ready to make the best-informed decision about which material to use. 

In order to understand which to use, you should know what they are.

Both asphalt and concrete are composed primarily of something called aggregate. Aggregate is a mix of small rocks, stones, and particles. It makes up over 90% of asphalt and the vast majority of concrete as well. If you’ve ever walked across a blacktop parking lot or seen a large concrete structure, you’ve probably noticed that the loose sand, pebbles, and stones in concrete are much finer and smaller than those in asphalt paving. 

Asphalt binder

Asphalt uses a petroleum-based binder, which glues everything together. It also gives asphalt it’s black appearance. Despite using oil-based products, asphalt is still relatively environmentally friendly because it is so heavily recycled.

Concrete Binder

Concrete on the other hand, uses water and (most often) Portland cement. Water mixes with the cement to create the glue that holds it together. You can read in more detail about concrete composition here.

Making your choice

You paving project probably has a great number of input factors. In order to choose the right construction materials, you will need to carefully consider each one. So we will break down each factor you must consider, and then analyze which product is right in the situation and for your priorities.

 

Environmental impact

Recycling

Both asphalt and concrete are highly recyclable. This means that whichever product you choose, you will be contributing to the circular economy instead of acquiring new resources from the Earth. Asphalt however, does use a petroleum-based binder. This means that making new asphalt has a much greater negative environmental impact than making new concrete. Asphalt however, can be recycled indefinitely, and is 100% recyclable. Concrete can not be recycled as many times, and only certain parts of it can be recycled anyway. 

Longevity and location

However, the environmental impact of laying it is not based on recycling/making new materials alone. Other factors to consider include longevity and climate where it will be laid. 

  • Concrete with proper maintenance can last 40-50 years. Used in roadways, it can last 20-40 years.
  • Asphalt with proper maintenance can last 30-40 years.
  • In extremely hot environments (such as the US Southwest) asphalt can soften and is prone to damage. When it softens its integrity can be damaged, and poisonous runoff can be created.

Color

Although this may not seem important, it actually is quite. Concrete has a gray/white hue, while asphalt is famously dark, and is also called blacktop. 

Concrete’s lighter color confers several benefits:

  • Reflects heat back to the atmosphere. It contributes less to urban heat islands that asphalt creates.
  • It’s reflectivity means it requires less light at night. This saves taxpayers on paying for electricity, and decreases emissions from creating that electricity.

Upkeep

One of the biggest reasons asphalt is usually the choice for roadway paving is maintenance. Concrete may last longer, but both materials will develop holes, cracks, and deform over time. To repair concrete, entire slabs of concrete must be replaced. Asphalt, on the other hand, can be patched. Asphalt repair kits that fill cracks and potholes can be purchased at just about any hardware store. Of course, there are concrete repair kits too, but they are typically for residential sidewalks and non-structural surfacing.

Even when significant repairs are needed with asphalt, it can be resurfaced completely or to a very deep layer. These repairs are still much cheaper and less time consuming than replacing entire concrete blocks.

Roadway pros and cons

Although both materials can be used for roads, asphalt has won out in most locations. 

Concrete pros/cons

Pros

  • Long-lasting.
  • Strong.
  • Environmentally-resistant.

Cons

  • Doesn’t provide good tire grip.
  • Less absorption. Gasoline, oil, and other chemicals that spill on concrete will not soak into the same way they do with asphalt. This creates runoff problems with asphalt.
  • Expensive and time-consuming to repair entire blocks.

Asphalt pros/cons

Pros

  • Smoother drive for motorists.
  • Better traction.
  • Quieter driving than concrete.
  • Cheaper.
  • Can be repaired.

Cons

  • Requires more repair because it wears out faster.
  • Heat can damage asphalt and surrounding environs.

 

Setting

Both materials are made from a combination of aggregate and glue-like binder. These compounds need to be mixed and poured, after which, they harden. The process from which they turn from liquid to solid is called “setting.” This is a process that they share with many different composites, from fiberglass to Pyrex. Another one of asphalt’s advantages over concrete is that asphalt poured for a purpose similar to concrete will set much faster. Asphalt can go from an input material to a usable surface for roads in less time, and at lest cost than concrete. This feature is one of the many things solidifying asphalt’s use as the primary roadway material.

Making the right choice

Although concrete is by and far the world’s most-used building material, asphalt seems to win for roadways. However, the specific benefits and drawbacks of the use of each is understood best by professionals. If you are trying to figure out which is best for your construction, then you are in the right place. Reliable Paving has been in the paving contractor game for nearly four decades. We know how to get our paving projects done on-time, on-budget, and keep our standards to the absolute highest quality. If you aren’t sure whether concrete or asphalt paving is the right way to go, then let us know what you need. We will provide you with the best material possible for the job, and deliver the best service along the way.

Self-Consolidating Concrete

What is self-consolidating concrete?

Self-consolidating concrete (SCC), or self-compacting concrete, is known for low yield stress, high deformability, and good particle separation resistance, as well as mid-range viscosity. Now, unless you are already a paving contractor or in the asphalt/paving industry, you are probably wondering what all that stuff means. Don’t worry, at Reliable Paving, concrete is our bread and butter, and we are happy to walk you through what it all means.

Low yield stress

Without getting into the specific mathematics of yield stress, yield stress level basically means the force required to permanently deform something. When many materials, namely metals, are submitted to force or pressure, they will bend. At a certain force level, the bending is “elastic.” This means that the material will revert to its original shape. The low yield stress of SCC tells us that it takes relatively little force to permanently change its shape.

Deformability

High deformability, like low yield stress, sounds like a bad thing for concrete right? Deformability is the ability for something’s shape to be changed without breaking it. For example, iron is much more deformable than asphalt. And aluminum is much more deformable than iron. We will later get into how high deformability and low yield stress is a good thing.

Segregation (particle separation) resistance

Segregation resistance is how much an aggregate material — like asphalt or concrete — resists separating. Paving materials are made with binder and aggregate. Asphalt paving, for example uses a petroleum-based binder, which glues everything together, and various aggregate. The aggregate particles are made from small rocks and stones of various sizes. Basically, segregation resistance is the ability of the material to prevent the particles from coming apart in the mix. This can be during transport, placement, and as it sets.

Viscosity

If you’ve ever worked with oil, you know what viscosity means. It’s essentially the “thickness” of a fluid. The more viscous it is, the more resistance to flow. The moderate viscosity and segregation resistance of SCC means that it’s suspended particles are uniformly-distributed.

What are the uses of self-consolidating concrete?

Although it can be used much like normal concrete, SCC’s unique characteristics open it up to more advanced uses.

  • Highly-complex formwork. The nature of this work make it a good candidate for SCC. It doesn’t require compaction, so it can simply be poured, and then it sets. Unlike normal concrete, it doesn’t develop honeycombs when setting in formwork. This makes it a great solution for architectural concrete as well, which often needs to have smooth surfaces.
  • Locations where reinforcing rebar is not available. In some complex work, or crowded architecture, it may not be possible to use reinforced concrete. In comes SCC. It’s ability to resist particle separation helps keep it extremely strong throughout.
  • Columns and beams. These structural concrete pieces often have to be shaped specifically, and can’t always accept reinforcing steel. Thus, SCC is a good solution, it is structurally robust and can be shaped variously. This is where its deformability and low yield strength come in handy.
  • Pumped concrete and foundations. Because it compacts itself, SCC is great for solutions requiring concrete to be piped or pumped to a location. Unlike traditional concrete which must be laid and compacted, SCC can simply be pumped into an area, and will set itself. This means that no heavy compacting equipment is needed, as well as the space to perform compacting. The moderate viscosity helps it flow into compact and complex places and shapes, where it sets and becomes extremely strong.

What are the benefits of self-consolidating concrete?

Thanks to the section above, we can see where it is a useful addition to a construction. But what about the specific benefits to construction and paving contractors? How about benefits to the end users, who put this material in their buildings?

Savings on labor, time, and equipment

Because the concrete can simply be pumped into a location where it will set, it is faster and easier to install. Traditional concrete must be laid in segments, compacted with heavy equipment or screed. Screeding is the process of using a long tool (sort of like a car windshield wiper) on newly-poured concrete. The process removes excess concrete, flattens it, and ensures that the concrete is the right grade. Some concrete must be heavily compacted with heavy equipment. SCC is simply poured or pumped to a location, formed, and it does the rest. Vibrators are another tool used in setting concrete that ensure air bubbles come out and that the concrete is uniform. The vibrations from them though, can be deleterious to other newly-built structures at a job site.

  • Less labor required.
  • Less time required to place and set.
  • Less equipment needed.
  • Elimination of vibrations at the job site.

Easier to fill restricted areas

Viscosity level promotes it being pumped into small areas that traditional concrete is not feasible for.

Better properties when hard

Because it has deformability and low yield strength, it will change shape rather than break. This is good for finishing touches, and for repairs. It also makes it structurally more sound. SCC is simply a better structural material, with a smoother surface than traditional concrete. It’s improved uniformity helps it stay stronger and smoother.

You can read more about its benefits, construction, and its notable disadvantages in this article from NY Engineers.

Not sure which concrete is right for you?

If you aren’t sure what to use for your building project, leave it up to the experts. Reliable Paving has been in the industry for over 35 years. We know the best ways to do concrete and asphalt paving traditionally, as well as the newest trends and innovations. Come rely on our large, experienced, and professional team. Contact us today about what we can do to help you.

How To Move Large Pieces Of Concrete Safely And Effectively

If you’ve ever done a large paving project at your house or business, you’ve probably had to deal with moving massive chunks of concrete and/or stone. Pavers are a functional, and pretty addition to a building exterior. They are not poured in place like much paving. They need to be brought to their final resting location. These materials can range from large rocks that will be in landscaping/pavement to giant blocks/slabs of concrete. 

Large chunks of paving material are difficult to move around because of their size and heaviness. The fact that they are rough, stiff, and hard increases the likelihood of them damaging the things around them as they move as well. The ground, such as a carefully paved walkway or manicured lawn can be ripped, scraped, and dug up by awkward concrete block corners. Other stacks of materials can be knocked over, scraped, and damaged as well. You also run the risk of spilling knocking over chemicals/paints that may be in the area while it is moved and causing damage and hassle. Finally, the paving block yourself can also be hurt during movement. If it rubs against anything else hard, it can get it’s own scratches, cracks, and broken corners. 

What is the safest way to move large slabs or blocks of pavement? Fortunately, there are a few different solutions that will help you figure out what to do. Each movement tactic is useful in a given context, so there isn’t really a one-size-fits-all answer. 

Biophysical force

You got this. Don’t get intimidated by the size and weight of what you are working with. Even if it’s a couple hundred pounds, you can probably handle it. Remember, to simply move something, you don’t need to dead lift it or pick it up cleanly from the ground. You (and maybe a few others) have all the strength you need to move massive concrete. Here’s how to do so safely, and with minimal contact with surroundings.

Roll/flip the pavers

Flipping concrete blocks over and over again to get them where you want is time and energy consuming. Be ready to sweat. Also make sure you have some tough work gloves for this task.

If you are dealing with something more cubic, like chunks or blocks of concrete, this solution is viable. It’s also best when the ground you are rolling it across is incomplete and soft. Because the pavers are hard and tough, they will dig into soil and scratch other pavement. Be sure to NOT do this on a nice looking lawn or finished pavement. Use the flip method on ground that still needs work, so you can cover any torn up areas after. If flipping is your only solution and you have a mostly finished lawn/courtyard/outdoor area, you can put down mats or other layers to protect surfaces.

Walk the slabs/blocks

This method takes a big more finesse than rolling. It also tends to work better with more oblong or slab-shaped blocks. When you walk the blocks, you will balance them on a smaller face (the flat side of a block/slab/paver). Once the concrete is balanced on a smaller face, tilt it onto a corner, and then swivel the other corner in the direction you want it to go. Land the other corner gently, and then tilt up the concrete on the just-landed corner. Now, swing the opposite corner in the direction you want to go, safely land it, and repeat. This process is much faster than rolling, but is associated with more damage to the ground.

As the corners will dig into the ground below them, make absolutely sure that you have some protection laid down. Rubber mats or padding, like those shown here, are ideal ways to protect your land. You will also want some heavy duty gloves for this activity, and some back-up, to prevent dropping anything.

Using equipment

These solutions come closest to providing a general solution that will work in most situations. The ground may not always be level or sturdy enough for wheeled or heavy equipment use. However, most construction areas will allow at least one of these methods.

Use a dolly

Use a dolly with two or four wheels for the following reasons:

  • A dolly doesn’t require you to lift the whole paver off the ground.
  • Cost effective. 
  • A dolly will have other uses in a construction site too.

You can use a four-wheeled dolly or even a cart when the area is flat and wide. Use a two-wheeler when you are moving things up and down slopes. Honestly, you should have a dolly at just about any construction site. It will pay for itself on day 1.

PVC piping

Get higher schedule (higher wall thickness) PVC pipes. Lay them down in the area you wish to slide your concrete. Slowly roll the concrete across the pipes. As the concrete rolls off the pipes in back, move them to the front, and continue until you get it where you want it to go. The ancient Egyptians used this same method with logs to move the blocks that the pyramids were made from. Just be sure to use thick enough walled pipe so it doesn’t collapse. 

Just like a dolly, PVC piping is easy to get, cheap, and inherently transportable.

Heavy equipment

If the pavers or concrete blocks you have to move really are beyond your means, then bring in the big guns. Unless you are a trained professional with cranes, bulldozers, or boom trucks, then you will want to get a professional construction or paving contractor to handle this for you. Fortunately, that’s where we come in.

Choose a reliable contractor for your paving needs

If you are in over your head paving your house or business, then reach out to Reliable Paving. We are an experienced and large team of professional paving contractors, with a whole range of service capabilities. Whether you need asphalt paving, repairs, painting/striping, ADA compliance, or anything else related to the pavement and asphalt industry, we can help. Let us do the heavy lifting so you can focus on what’s important to you.

Zero Carbon Concrete

Concrete is affordable, durable, recyclable, and strong. It resists water and extreme weather, provides foundations, and is one of the building blocks of climate-resilient infrastructure. Concrete is key for meeting various sustainability goals throughout the world.

Concrete is the second most consumed material in the US. The only substance in the world that is consumed more than concrete is water. Concrete is also one of the most consumed materials throughout the world, and the use of concrete and cement is expected to go up. This means that finding a way to make concrete less destructive for the world we live in can have massive benefits. Concrete is not great for the environment, it is responsible for 4-8% of the world’s carbon dioxide production, and uses 1/10th of the world’s industrial water. If we can decrease the environmental impact of concrete production, then we can significantly decrease climate change, pollution, and environmental degradation. As the world urbanizes, we can expect the amount of concrete used to grow up. In modern cities, concrete is the foundation as well as one of the primary building blocks.

Why bother decreasing carbon dioxide emission?

Carbon dioxide, or CO2, is a greenhouse gas. This means that when the sun’s light enters the atmosphere, it CO2 and other greenhouse gasses trap it, causing a heating effect. CO2 is not the most dangerous greenhouse gas, others, like methane, are far more effective at trapping the sun’s heat. However, CO2 is vastly overproduced. Yes, almost every breathing animal (including people) inhales oxygen and exhales CO2. Yes, decomposing plants emit CO2. But, human interaction with nature has resulted in too much CO2 being produced. The natural world has had ways of balancing its own CO2 production. But as 80% of the greenhouse gas emitted by human activity is CO2, that production over the years has been enough to tip the world’s ability to handle the gas. This is why you will find CO2 reduction as a major goal of climate change.

How concrete can become CO2 neutral

What parts of the concrete production process produce the most carbon dioxide?

In order to understand exactly how concrete can not be a producer of carbon dioxide, we need to know how it produces the stuff. What parts of the concrete manufacturing process produce CO2? What parts produce the most, and how can they be improved?

Turning limestone into cement

The process of making limestone into cement involves a chemical reaction at extremely high temperatures. It must be heated to 1500° F, which requires immense amounts of fuel. This is the main factor in cement CO2 production, and the area where it can best be made more efficient. Some estimates deduce that as much as 2/3 of the CO2 produced during the cement-making process happens during this chemical reaction.

Transportation

Of course, raw and finished materials have to be transported. As the main engine for moving around our world is internal combustion, this means more gasses are produced in moving concrete.

The challenges

Reducing the carbon footprint of transportation is the easy part

Fortunately, transportation is already moving in a greener direction. More and more electric cars, trucks, and trains are being produced and used. Electric and wind-powered shipping vessels are moving things across the oceans as well. The US is already — slowly but surely — on the way to making all of its transportation carbon-neutral. As battery technology and electric motors improve, it will only get easier.

It’s the cement production process that poses the real problems

Most of the cement made in the US is Portland Cement. It is effective, durable, and has all the other positive qualities that makes cement so ubiquitous. The problem with it is that it was invented nearly 200 years ago. As such, it’s manufacturing process hasn’t changed much since.

Besides the manufacturing process requiring huge amounts of fuel, the chemical reaction used to make cement leaves behind calcium oxide. When the other substances exit limestone to make calcium oxide, where do you think they go? Into the atmosphere, as CO2.

The main greenhouse emitting agent in cement is called clinker. Clinker is a nodular substance used in the kilning stage of cement and is also a binder in many cement products. It is produced by heating limestone and clay to liquefaction in a kiln (around 1400-1500° F).

The solutions

  • Electric kilns for heating the cement are beginning to be implemented. These use lower carbon or renewable energy sources for heating cement to its required temperature.
  • Alternative fuels and electricity-powered vehicles are already driving CO2 out of the transportation process of cement.
  • Clinker is being substituted with alternative materials in some cases. It can be replaced with recycled byproducts like chemically treated steel slag and fly ash.
  • Concrete can be made from upcycling, that is captured CO2 from other industrial activities. This “Co2ncrete” shows much promise in creating carbon-neutral (or even negative) concrete.
  • Concrete itself naturally absorbs CO2. So the longer concrete lasts, the more CO2 it sucks out of the atmosphere. Longer-lasting concrete is a great way to facilitate this process.

Of course, there is a lot more work to do in order to decrease concrete’s global emissions. The Global Cement and Concrete Association even has a climate ambition plan. Concrete, may be one of the worst construction materials for the environment. However, the production of concrete is slowly moving towards reducing, or even neutralizing it’s greenhouse emissions.

Paving the way for a better future

If you have a paving project in mind, but would rather keep it lower-emission, then Reliable Paving has got you covered. We are am experienced, professional, and large paving contractor, who already recycles the vast majority of the asphalt we use. Our asphalt paving and concrete is built to last which saves our clients time and money. It also decreases the strain on the Earth from constant material consumption. If you’d like to get started on your paving project, let us know today.

Repair Or Resurface Your Concrete?

When pavement gets damaged it causes with all sorts of problems. 

  • It looks unappealing.
  • It can be a danger to people and vehicles. Cracks and potholes damage tires and the underside of cars, and pose a tripping hazard.
  • It lowers property values of both businesses and homes.
  • Damage will only get worse over time, exacerbating all the above problems, and costing more to repair later on. 

Whether it’s concrete paving or asphalt paving, damage isn’t a good thing. When it becomes immediately obvious, the property owner needs to take action. But the question remains: how? Should you completely replace the paving? Repair it? Or maybe it just needs some surface work. Replacing it is a lot easier to figure out, and should be saved for the most damaged pavement. But figuring out whether to replace or repair is quite a bit tricker.

The rules are a bit different for asphalt and concrete. Thus, we are starting with our guide on concrete

Concrete repair or resurface

If you aren’t sure if your concrete needs work, look for the following signs:

  • Sunken areas of pavement.
  • Cracked and crumbling slab edges.
  • Divots and pockmarks.
  • Large Cracks.
  • Areas of uneven concrete, or places where the slabs are tilting up/down.

Concrete can get damage from a wide variety of sources. Some of the more common ones have less to do with environment, and more with how it was built in the first place. If you can visually assess where the damage is coming from, then that will make a big difference in whether you should resurface vs repair.

When to repair

As a rule, repairs are required when deep parts of the concrete show signs of damage. Read on for how to spot when that is the case.

Sunken parts of concrete

This indicates a bad subgrade was used in the initial construction. There isn’t much you can do about it besides starting over. Make sure you use a reputable paving contractor — someone who will prepare the concrete mix correctly as well as set up the subgrade and install everything right.

Frost heave

This occurs when large quantities of water have got into/under the concrete slabs. It causes the slabs to rise up above others, sort of like continental plates. Sometimes they will break where the rise is especially prominent. 

Deep cracking

This problem is also usually caused by water in the concrete. It’s made worse in climates with freeze/thaw cycles. When the cracks become especially large, or large parts of concrete starts chunking out, resurfacing won’t help anymore. Also be on the lookout for spreading or spider webbing cracks. This means a network of cracks starting at a central spot and quickly spreading. This indicates a serious problem at the center of the “web.” Almost always, water is the culprit.

Tree roots

Tree roots can grow fast and far, so they aren’t always easy to spot as the culprit of damage. Obviously, if a tree is right next to your pavement, then it’s a pretty good guess what the cause of unevenness is. Tree root damage is characterized by steeply slanted broken concrete slabs. Another thing to look for is whether your concrete is between a tree and a water source. If so, a tree that’s far away may be growing its roots towards the water, and through your concrete.

Age

Nothing lasts forever. Even with the best care, no concrete driveway or surface paving will last more than a couple of decades. Thousands of tons of steel driving over it every day combined with water and heat takes its toll. If you notice your concrete is old it should probably simply be replaced. Signs of age include crumbling, an overly-porous surface, brittleness, general (if not severe) unevenness.

Here is Lowe’s helpful concrete repair guide if you’d like to take matters into your own hands.

When to resurface

As you might guess, the general trend for resurfacing is when the damage doesn’t go deep. In the case that your damage appears to be superficial or light, resurfacing is probably right for you.

Small cracks

Are the cracks in your pavement less than a quarter of an inch wide? If so, then filler will probably handle them. Filler does one simple job of taking up space, it makes it so that water can’t get inside those cracks and expand/contract to make them worse. The other benefit is that the filler helps the sides of the cracks adhere to one another, hopefully preventing the cracks from widening.

A faded surface or paint

This is a sign of age right? So a repair is what you need right? Not always. UV damage from the sun is a killer too. Besides being responsible for skin cancer, UV fades paint, weakens surfaces, and generally ages things. If your concrete is new, and it’s getting faded, then most likely it’s just the sun and a paint job/resurfacing will fix it right up. Be especially on the lookout for this in desert climates like the South West.

When the damage is widespread but not deep

If your concrete is covered in a network of cracks, marks, and divots, it may seem like repair is the way to go. However, it may be that resurfacing is all you need to get rid of the superficial damage. Widespread damage is difficult to assess, so you may want to get professional help inspecting it.

For details on resurfacing your concrete yourself, here’s a guide.

When to get professional help

If your concrete is beyond the pale, then it’s time to call in the pros. Fortunately, at Reliable Paving, that’s our bread and butter. We specialize in paving repair and surfacing of all kinds, including concrete. Our experienced team of paving contractors can assess, repair, and resurface your damaged pavement. Not only do we keep the highest standards on repairs, but we can finish the surface too, to ensure your paving lasts for years. Contact us today for our services and rates.

Freeze-Thaw Cycles in Concrete

The effects of the freeze-thaw cycle in concrete and how you can prevent them.

The freeze-thaw cycle is one of the main catalysts of erosion. Yes, water and wind impact can also slowly wear down even the toughest rock over millions of years. But one of the fastest and most efficient ways to break stone, rock, asphalt, brick, and concrete, is the freeze-thaw cycle. In fact, water penetration/expansion is the primary cause of concrete and asphalt degradation.

What is this cycle?

The freeze-thaw cycle is something we have covered quite bit, and is the primary reason to get your asphalt seal coated. Basically, what happens is that water gets inside and below the surface of the asphalt. From there it naturally expands and contracts as the weather changes. Normally, this change in water volume damages concrete, but doesn’t totally destroy it. The weather change from night to day, or spring-fall is not too serious. It’s when the water that’s inside concrete starts to freeze that it becomes a serious problem.

When water gets into concrete at all, you are going to have a bad time. It will bleed into small cracks, and then get into smaller and smaller crevices, all the while creating more. Basically, water gets in through a crack system and then extends and deepens that same crack system. Imagine it like a network, or the shape of a spider web.

Once water that’s inside your concrete freezes, then you have an even bigger problem. Freezing water takes up significantly more volume than liquid water, whether the liquid water is hot or cold. This seriously expands the cracks, making existing ones much larger and creating new ones for the water to get deeper inside. Untreated, freezing and melting water can completely destroy concrete or asphalt paving in just a few years.

What to look for

Crack propagation

Unfortunately, freezing water may cause internal cracking, which is hard to notice. If you notice cracking that looks like it originated from its interior, or beneath it, then you may have damage from the freeze-thaw cycle. Here is a good guide for identifying various types of concrete cracks.

Surface spalling

This happens when chunks break off of the surface of the concrete. It is a problem that gets worse over time, because when the surface breaks off, the aggregate beneath is exposed. The concrete below the surface is not usually sealed against water, so once it is exposed, expect the damage to come in even faster. Spalling can even reveal the rebar/structure at the core of the concrete. If this happens, you may need a replacement if the concrete is structural.

Heaving

Heaving, often called frost heave, is when the ground below the concrete lifts many inches and the concrete can not move with it. This causes the concrete to lift and break. Frost heave is one of the main ways that concrete is damaged. It’s incredibly difficult to make sure that moisture stays out of the ground below concrete thanks to groundwater and seepage from underground pipes.

The problem may not be due to water though. Tree roots beneath the concrete can cause the same issue.

Preventing freeze-thaw damage to your concrete

Deicing

One of the best ways to ensure your concrete doesn’t get water in it is the use of deicing chemicals. These chemicals work by lowering the temperature needed by water to freeze. When these chemicals, like sodium chloride (you know, salt), are placed on the concrete surface, they mix with water that falls on that surface. When the water does penetrate the concrete, it is unable to freeze and will (mostly) harmlessly drain out. If you live in a place that gets snow, then keeping all moisture out of your concrete is a lost cause, and you need to adapt to what does get in. Here’s a great list of other deicing mixtures.

Applying a sealer

Just like asphalt, you can apply a sealer to the surface of concrete. A hydrophobic coating will help make the concrete resistant to water penetration. Apply a sealer only after the concrete has fully-cured, and before you use an deicing agent. It also needs to be used before a freeze-thaw cycle has occurred on the concrete, usually in warmer temperatures, so before autumn has set in.

Good construction practices

One of the best ways to ensure your concrete isn’t damaged in the first place is to make sure the construction is done right from the get-go.

Controlling environmental water

Before beginning a paving project, you should make sure that the area is well-irrigated. Gutters, drip edges, and slightly inclined concrete planes help ensure that water drains away from and off of concrete.

This goes for groundwater as well. Before concrete is placed, the earth around it should be well-drained. Earth around concrete should also slope away from it a little to prevent groundwater from flowing toward the concrete. Flashing can also be used to ensure water flows away from the wall structures.

Concrete slabs need to have some wiggle room

No matter your best efforts, water will sometimes get into and under concrete. This will cause expansion and if the concrete has nowhere to expand to, it will break. Make sure that concrete slabs are able to move a little bit with the earth below them. If they can do this, then heaving will cause significantly less fracturing and cracking of concrete than it would otherwise. You can place small barriers between slabs of concrete, using asphalt, wood, or rubber to give your concrete expansion joints. These joints provide some cushion so the concrete can expand without breaking.

Is your concrete damaged?

Do you have freeze-thaw damage on your concrete? Would you like to get it fixed or prevent future damage? If so, you’re at the right place. Reliable Paving, is a large, experienced paving contractor company with the skill and professionalism to get your paving fixed, or done right the first time. Our concrete services include (but are not limited to): repair and sealing. If you want to make sure you can resist the frost, then let us know today, and we can start weatherproofing your concrete.

How To Repair And Seal Cracks in Concrete

A guide for repairing concrete damage.

Cracks in concrete aren’t just an eyesore. They pose a hazard for tripping, and will result in more damage down the line. Cracks allow in water, water expands and contracts over the course of a day/year. This change in volume causes cracks to expand and causes all kinds of other types of damage. Broken out pieces, rutting, and uneven surfaces can all happen to concrete. Repairs will keep damage from spreading and getting worse. Fortunately, we’ve got a handy guide for repairing damage and cracks.

Required tools and materials

  • A tub/bucket for mixing the concrete sealant.
  • Two trowels/floats.
  • Paint brush.
  • A chisel.
  • Hammer/sledgehammer (depending on the size/depth of the crack).
  • Concrete product. This can be epoxy/latex or a mortar mix. These mixes can be called filler, sealer, and more. They vary differently according to the size and requirements of the repair job.

Mortar mix is made from:

  • Portland cement
  • Vinyl
  • Sand
  • Water


Optional:

  • Stiff fiber brush/ wire brush
  • Putty knife (for more delicate/detailed work).

Step 1

Choose your concrete repair product. There are many. You should NOT fill a concrete crack with more concrete. You will need something to fill the patch and something to seal it afterwards.

Products include:

  • Concrete sealant
  • Ready-mix concrete
  • Patching compound
  • Vinyl patch repair
  • Epoxy
  • Latex
  • Polymer structural concrete repair product
  • Self-leveling sealant

And much more. You can even by full-on kits that have just about everything you need. Choosing the right product is important, and based on a few considerations. A marine environment will require a heavy-duty seal that won’t be damaged by salt water. Structural repairs may require their own special mixtures. Light/surfaces scratches or cracks can sometimes get by with epoxy/resin mixtures. For this guide, we are assuming you are fixing outdoor concrete for general business/home use.

For general outdoor concrete repairs, you can use the following two fillers:

  • Epoxy/latex for cracks whose width is 1/8 an inch or less.
  • Mortar mix is best for larger imperfections. Big cracks and full-on holes will require mortar mix. The surface can be covered with a sealant after the main repair is complete.

Step 2

This may seem counterintuitive, but you will start by making the crack bigger. Use the chisel to make the crack wider at one side than at the other. The crack should be shaped like a carrot or daikon. The main area to be filled should be the widest. The narrow area helps to anchor the filler by providing more contact area per filler volume.

Widen the crack at the top by using your chisel and hammer. If the crack is shallow, chip away until it is about 1 inch below the surface of the plane of concrete. If the crack is especially deep, or the concrete is especially hard, you may need a sledge hammer instead. Lightly tap the chisel with the sledge hammer so you don’t accidentally do too much damage. You should also make sure to remove large loose rocks from the crack with your hammer/chisel. 

Step 3

Use your paintbrush to clean out the crack. Every small pebble and shard of loose concrete weakens the fillers grip on the inside of the crack. They take away from purchase area, and they weaken the sealer itself. Ideally your crack will have nothing but filler when it is repaired. You can use also use the stiff fiber/wire brush if the paint brush and your fingers aren’t enough for the job.

Step 4

Inexperienced people working on their homes, and sometimes even paving contractors who like to cut corners will treat this as step 1. Additionally, people will often simply use more concrete to fill the crack. This will not result in as secure and permanent a repair as using the proper product.

Using epoxy/resin in small cracks

For 1/8 an inch or less width cracks, use your epoxy/latex mix. Before use, you may have to mix the two substances. Be sure to follow the manufacturer’s guide on what ratio to use. Use the trowel to force the mix into the crack. You may prefer using a putty knife for this. After the crack has been filled, smooth it so it is level with the surrounding concrete. Afterwards, consult the directions on the packaging again so you know how long it will take to cure. It may need to be covered during the curing process.

Using a mortar mix in large Cracks

Mix your Portland cement, vinyl, and sand. Use as little water in the mix as possible. Blend 1 part Portland cement to 3 parts sand. A ready-mix will have the Portland cement and sand already combined. Mix 1 part water to 3 or 4 parts mix. Make sure the mortar mix is not too thick and not too runny. Stir for 5-10 minutes and let it rest 10 minutes before stirring again. The process should take at least 2 hours.

Now it’s time to fill the crack. Use the trowel to ensure the crack is completely filled. When filling with this substance, be sure to frequently press down on the area with the trowel to eliminate air bubbles. Once the crack is completely filled, make sure to level its surface with the trowel, so it is the consistent with the rest of the concrete. Let it sit for about 2 hours afterwards. Next, cover it with a plastic sheet to keep humidity levels high. Sprinkle water once per day over the next several days on the surface until it has fully hardened.

Does your asphalt or concrete need some love?

At Reliable Paving, cement, concrete, and asphalt is our bailiwick. We are consummate professionals when it comes to asphalt paving, concrete and asphalt repairs, striping, and seal coating. If you want your pavement fixed right the first time, come to us. Contact us today and we can get the job started — and finished, sooner.

Causes of Concrete Deterioration

Concrete has enjoyed a reputation as a “set it and forget it” building material since it became popular in the mid-twentieth century. However, concrete definitely is victim to plenty of external influences. Many of those influences can cause serious degradation. 

Builders today are realizing that existing concrete structures won’t last forever. Many buildings from the 20th century, and even some built in the last few decades, show significant damage. Let’s look at what these signs are, and the causes for concrete deterioration.

General signs of deterioration

Fortunately, concrete, as well as most paving work, wears its heart on its sleeve. It’s easy to see damage to concrete and find it. On the other hand, it’s rare for the damage to be totally hidden. So here’s what you should look for:

  • Cracking: This is the most common type of damage sustained by concrete. Fortunately, cracks are easily visible, and thus easy to treat once spotted. Be aware though, that hairline cracks can become massive over time, as they allow water inside. When that water expands and contracts, you get small cracks becoming bigger and radiating out more fractures.
  • Discoloration: A change in the color of the concrete is not a good sign. If the concrete is changing to a brown/reddish color, it means that there are other chemicals in it. Often the change in color is from corrosion from metals or exposure to other outside chemicals.
  • Erosion/Disintegration: These two (used interchangeably), are denoted by cracks and crumbling. They are often caused by the freeze thaw cycle, or heavy precipitation.

 

Specific signs of degradation

Sometimes very specific elements cause concrete to deteriorate. For example cracks can be caused by a huge variety of things, but the specific cracks that look like scales are caused by an alkali-silica reaction. Here is a list of specific types of damage often sustained by concrete. 

  • Spalling: Spalling is basically when the concrete flakes away. It can be unimportant or extremely serious. Spalling occurs when the concrete is installed poorly in the first place OR when it is under too much structural stress. 
  • Alkali-Silica reaction: This chemical reaction in the concrete causes a scale-like cracking pattern. The concrete swells outward and in doing so the surface cracks like the surface of a desert drying after the rain. Also called concrete cancer, it can read to serious degradation, and might even require demolition after being untreated for some time.
  • Delamination: Caused when the top surface of the concrete (the laminate) separates from the lower levels. It is found by tapping on the concrete, if a hollow sound is made, the concrete is delaminated.
  • Scaling: Scaling occurs when the mortar covering concrete begins to wear away. The mortar is an outside protective layer, so when it goes, the aggregate underneath the surface becomes exposed. 
  • Chemical diffusion: Also called chemical corrosion or penetration, this happens when a chemical is exposed to the concrete and works its way through the layers. This is a common occurrence with solvents and acids. Chemical diffusion causes cracks, divots, and pits. 

 

Causes of the degradation

Now that you know what to look for, let’s take a look at what causes the problems listed above. Looking through the specific causes of concrete degradation will help create some insights on how to avoid them.

Exposure to chemicals

Chemicals exposed to concrete can wreak all sorts of havoc. From erosion to chemical penetration, there are many threats posed by various chemicals to concrete. 

Some of the chemicals might come from routine maintenance:

  • Antifreeze agents put on pavement in the winter. These include liquid chemical compounds and salt.
  • Cleaning agents for concrete.

Many of the chemicals that damage concrete come from tangential outside sources.

  • Vehicles leaking oils/other fluids on pavement.
  • Concrete in industrial buildings becoming exposed to solvents or other agents used in manufacturing, agriculture, etc.
  • Paint or graffiti. 
  • Accidents and spills.
  • Natural solvents. Carbonic acid, acid rain, and other solvents from nature can seep into the ground and damage concrete. This is especially a threat to underground concrete (foundations). Concrete structures at the bases of hills and mountains may have similar exposure.
  • Degradation of the reinforcing steel. When the steel that supports concrete starts rusting or dissolving. 

Weather

Weather – most notably water is probably the number one destroyer of concrete. The freeze-thaw cycle erodes mountains over time. Concrete is not immune. When water freezes, it expands by 9%, according to a Cement.org study (look at page 4).  It’s not hard to imagine water getting into small cracks and freezing to break them open further. The problem is degenerative, once water is in your concrete, it can be impossible to get out.

The freeze thaw cycle also effects the ground. The ground sets differently in the warm months than when it is frozen. This setting can crack and break concrete foundations. Weather damage most often is in the form of cracking and potholes.

Structural stress

When the concrete begins to degrade, or the reinforcing steel begins to degrade, it can not take as much stress. This means that structural concrete may no longer be up to the job it was built for once the deterioration begins. 

Adding new levels to a building, placing heavy machinery, or building with heavy materials may induce too much stress on concrete, and cause serious damage. Stress can show up in many forms, spalling, scaling, and cracking.

Improper installation

Just about all of the problems and signs of bad concrete can be caused by one other thing as well: improper installation. If the concrete is mixed poorly, sets poorly, or installed poorly, a myriad of issues can arise. The rebar can dissolve, cracking can occur, delamination…the list goes on. 

Get your concrete installed right

If you want your asphalt paving, concrete, or cement inspected for issues, don’t hesitate to contact Reliable Paving. We are an experienced paving contractor who can check your concrete for damage, do repairs, and entire new installations. You want your concrete installation to be done right, the first time, so get a service that’s reliable.

Ancient Concrete and New Construction

In modern Italy, a unique question has only been answered in the last several years. Modern concrete constructions built at the seaside have degraded and crumbled after only a few years. The salty sea waves and ocean wind had destroyed creations of modern technology while ancient concrete has lasted thousands of years. Why do our modern buildings collapse while ancient concrete islands can withstand the elements for millennia? 

How the Romans did it

Ingredients

The ancient Romans started building concrete thousands of years ago. They used various ingredients, including some of which are hard to reproduce in modern labs. 

Opus caementicium, or concrete, was used commonly in ancient times. It was made in the same over all method that modern concrete is. It consists of an aggregate and a mortar. The aggregate was made from small rocks, pebbles, and hard pieces, just as it is now. The mortar functioned as the binding agent, keeping everything together as an extremely tough glue. However, a few different construction ingredients and methods keep ancient Roman constructions in good working order while our own fall apart. Opus caementicium used aggregate made from tuff. Tuff is a rock made from volcanic ash, ejected from vents during a volcano’s explosion. There are many types of tuff, but the tuff was not the most important ingredient.  

What really keeps the Roman buildings together is how the binder and aggregate interacts. Gypsum and quicklime were used, as well as pozzolana. Pozzolana is a volcanic ash that is resistant to sea salt – more so than modern concrete. The pozzolana was used in conjunction with the binders to create a cement that strengthened and became more resistant over time. 

Reactions with the outside world

Pozzolana and quicklime benefits from interacting with salt water over time. A rare crystal, tobermorite, formed over time as these three materials were exposed to one another. As seawater washed between the natural cracks in the concrete, it reacted with materials found in the volcanic rock. 

As the seawater flowed in the concrete, it would wash away the volcanic ash. It might seem that washing away part of the ingredients of the concrete would weaken the concrete, but it actually had the opposite effect. As the ash washed away, it allowed new formations. In particular, crystals could form and make interlocking “plates” that strengthen the concrete over time. Phillipsite, naturally found in volcanic rock, and seawater builds up a special type of tobermorite crystals. These crystals are called aluminous tobermorite crystals. Aluminous refers to the element aluminum. Aluminum is a light metal that is known for it’s low weight and tensile strength. These new crystals form over time, filling in tiny fissures and making the building stronger over time. 

Thanks to the unique reactions of the Roman concrete with seawater, it has the reputation of being the strongest, longest lasting concrete.

Other elements of construction also aided Roman buildings. The dome-shaped tops of many Roman buildings and their foundations aided longevity as well. The tops of many Roman structures were made of a less-dense, lighter weight concrete. The foundations were made of denser, harder, tougher concrete. The heavy foundations and light tops kept the buildings in place and stable. This type of construction is especially useful in the earthquake-prone Italian peninsula. 

What we can learn from ancient concrete

After reading the first half of this article, what we have to tell you now might seem like a surprise. Roman concrete has some amazing properties, but it is not actually better over all than modern concrete. There are quite a few reasons why this is true, and we will take a look at them. 

Benefits of Roman concrete

  • It gets stronger over time with reaction to sea water.
  • It is more natural, and has a lower environmental footprint.

Why it’s not quite as good as we think it may be

To most people, the idea of concrete that strengthens over time seems amazing. However, to any paving contractor or mineralogist, the idea of a concrete strengthening with crystals is pretty normal. Crystals form on all kinds of surfaces. The combination of materials that makes up cement makes the appearance of crystals pretty common. 

This article covers the following points, and some of the articles you might find about Roman seawall cement quite well.

There are a few other factors that really do effect how fast deterioration of modern cement occurs.

  • Roman cement did not have reinforcing steel. Rebar, or steel beams in the cement changes the chemical structure. Embedded steel actually corrodes the concrete when exposed to seawater. Modern cement has this steel, and thus is more inclined to degrade. Simply not using rebar extends the life of modern cement.
  • The southern Italian peninsula has a very temperate weather cycle. Unlike many other places where sea cement building might be compared, there is no freeze/thaw cycle. One of the main reasons for the breakdown of cement is water freezing in it’s small pores. 
  • Survivor bias is the idea that old things are better than new things. We believe this, because the old things that last are still there, and we don’t see the old things that no longer exist. This goes for buildings, societies, appliances, and vehicles. 

Looking for the best cement work?

Here at Reliable Paving, we follow the newest and most accurate data regarding cement and asphalt paving. Our over 35 years of experience and 200 plus person team means that no paving job is too big or difficult. We can make our paving ideal for the location and climate of your choice. If you have any questions, or would like a consultation about your paving job, don’t hesitate to contact us today.