Subgrades and subbases for concrete slabs: Why having good support is critical to success Modify the Concrete Mix Use a low water-to-cement ratio Concrete admixtures that control cracking Install Joints Be active in deciding where control joints will be placed Joints in concrete slabs: Types and where to locate Properly Cure the Concrete. The following sections explore the causes of cracking in hardened concrete in more depth. Drying Shrinkage. This is the main cause of cracking in hardened concrete. This cracking takes place near the restraints due to volume changes in the concrete. This is one of the main problems when constructing with concrete. Cracking can be the result of one or a combination of factors, such as drying shrinkage, thermal contraction, subgrade settlement, and applied loads. In the case of a wall, if a crack is not structural, or not too wide.
Does Freshly Poured Concrete Normally Crack? When the installer of my new and cracking concrete patio told me that, 'All concrete cracks.' ', I told him to look down at the concrete porch that he was standing on and point to one crack. What many people are not stating is that yes, concrete has many different mix design issues, and then. But a wide majority of concrete used in residential work has too much water added to the concrete on the job site. This water is added to make the concrete easier to install. This excess water also greatly reduces the strength of the concrete. Shrinkage is a main cause.
Related Articles
- 1 Pool Refinishing: Pebbles Vs. Plaster
- 2 Stamped Concrete Edging
- 3 How Long Does Stamped Concrete Last?
- 4 Brick Pavers Vs. Cement Drive
When it is time to pick a finished surface for your patio, driveway or walkway, it is likely that you want a product that is aesthetically pleasing, durable and cost-effective. Stamped concrete is an ever-growing popular choice due to the fact that it can be made to mimic higher end materials such as brick and stone pavers at a fraction of those products' cost. Before you make your final decision, however, consider the advantages and disadvantages of stamped concrete.
Choices and Aesthetics
There certainly isn’t a lack of choices when it comes to picking a stamped concrete surface for a landscape. Stamped concrete comes in many colors, patterns and textures. Mimicking almost any surface from marble to stone to weathered lumber, stamped concrete provides and aesthetically pleasing surface that adds to the value of a home and property. Stamped concrete is a budget-friendly way to add a decorative touch to a landscape.
Installation
One of stamped concrete's advantages is its ease of installation. It is far less labor-intensive to install a stamped concrete surface than one made of pavers, for which each paver needs to be hauled and set. Installing stamped concrete is a matter of mixing, pouring and stamping. With the ease of installation, however, comes a large room for error.
Concrete is a mixture of water and cement powder. If the mixture contains too much water, a risk of rough edges and a poor finish exist because the concrete easily adheres to the stamp. Bulging and premature cracking is a problem with stamped concrete if the mixture is too dry.
Durability
Although stamped concrete may be simple to clean and requires no maintenance to retain its patterned appearance, one of its major disadvantages is that it lacks durability compared to other finished surfaces.
It is important to be careful where you install stamped concrete because it easily cracks and scratches under a heavy load. Stamped concrete is a poor choice for a driveway and any area on which cars are driven or parked. On a foot path, walkway or patio, stamped concrete is less likely to crack under pressure; however, it is still susceptible to cracking with weathering and time.
Cracks and Repair
When it comes to concrete and cracking, it is not a matter of if but when the surface will give way due weather changes and settling. In a mild, Mediterranean climate, you do not have to worry so much about stamped concrete cracking due to expansion and contraction that comes with harsh temperature fluctuations, but the surface is very likely to crack as years pass.
It is difficult to match color and surface consistency when patching a normal concrete slab, and stamped concrete makes matching color and consistency on the surface even more difficult. Although it is less expensive than other surface choices, stamped concrete may end up costing you more in the long run if you are bothered by unsightly cracks.
Considerations
Other patio and walkway surface choices, such as interlocking pavers, are more costly than stamped concrete initially but cost less in the long run because their entire surface does not have to be replaced in the event of a problem. Because each paver is an individual piece, you do not have to worry about pavers cracking from pressure or settling of the surface. As pavers begin to settle, they may loosen, which may create a trip hazard, but individual pavers are easily removed and replaced.
References (4)
Choose Citation Style
Your home’s concrete slab isn’t something you typically think about, but it’s actually one of the single most important components of your entire house. It’s responsible for stabilizing your home and any major defects can cause serious problems. As such, it’s important that you understand the different defects that are most commonly associated with concrete slabs and why they need to be immediately dealt with as soon as they’re discovered.
Understanding Your Concrete Slab’s Role
A concrete slab is one of the most common foundation types found in residential home construction. This is a flat, uniform foundation that’s made of sturdy concrete on level ground. While other materials are occasionally used when building home foundations, concrete slabs are by far the most popular. This is partly due to their strength and partly due to their overall lack of maintenance.
However, concrete slabs are not perfect or invincible. For starters, the presence of a concrete slab makes it virtually impossible to build a basement – which are considered essential in certain region of the country. Secondly, concrete slabs are exposed to the risk of cracking.
While some small cracking may not be a big deal in particular situations, even tiny hairline fractures can lead to major problems down the road. Ultimately, a crack in a home’s concrete slab foundation could affect a home’s flooring or overall stability.
Concrete Cracking Repair
Common Concrete Slab Defects
“It is to the credit of concrete that so few complaints are received on the vast amount of construction put in place,” the Portland Cement Association writes. However, issues do occur in certain situations and should be dealt with as soon as they’re identified. Here are a handful of common defects and what they mean.
1. Blisters
Blisters, as the name suggests, are formed when bubbles of entrapped air get stuck underneath an already sealed surface and produce bumps of varying sizes. These defects are typically identified when the concrete slab is being laid and simply requires some alteration to the actual concrete mix in order to prevent more blisters from appearing.
Blisters are more of an annoyance than they are a structural problem and shouldn’t cause any long-term issues for homeowners. In fact, you’ll probably never know if your concrete slab even has blisters. You may be able to identify them on a concrete floor, should you have a basement with exposed concrete.
2. Cracking
One of the biggest problems with concrete slabs is that they have a tendency to crack under certain instances. Some common causes of cracking include thermal contraction, subgrade settlement, drying shrinkage, external or internal restraint to shortening, and applied loads.
The construction crew will typically address cracks that develop during hardening. However, it’s the ones that develop over time that eventually cause issues for homeowners. These settlement cracks can develop over embedded items like reinforcing steel, or adjacent to other foundation materials.
Aside from external factors, the strength of the concrete is most important in determining how well it’s able to prevent cracking. Most people don’t realize that concrete comes in a variety of strengths, but the reality is that not all concrete mixes are equal. Inadequate strengths can lead to future cracks – especially if there are improperly placed tension control joints.
Specifically, there are three types of cracks in concrete slabs. Shrinkage cracks aren’t severe, because they rarely indicate any structural defect. However, they can occasionally be a source of radon or water entry into the structure. Settlement cracks indicate that there was inadequate site preparation when the slab was poured. These cracks need further analysis to determine whether or not they indicate a larger problem. Finally, frost heaves are the most serious. They can indicate a substantial risk and should be dealt with as soon as possible.
3. Curling
“Curling is the distortion (rising up) of a slab’s corners and edges due to differences in moisture content or temperature between the top and bottom slab,” says the Portland Cement Association. “The top dries out or cools and shrinks more than the wetter or warmer portion.”
Curling is typically dealt with before it becomes a problem, as it usually shows up during the drying process. However, if not fixed during construction, curling can lead to significant cracking in the ensuing years.
Non Cracking Concrete
4. Surface Scaling/Spalling
Surface scaling occurs when the surface of hardened concrete degrades to a depth of 1.5mm to 5mm during the first year or so of placement. This is generally the result of an issue with the curing of the concrete and cannot be controlled by the homeowner.
“Scaling is most common in concrete with poor surface strength, caused by finishing a slab while bleed water is on the surface, or overworking the surface resulting in a lower air content,” writes Dennis Yurconis of Abstract-Concrete.com.
The problem is that nobody really knows whose fault surface scaling is, and therefore the onus may ultimately fall onto your shoulders. “When scaling occurs, so does the blame game. The homeowner blames the concrete finisher, the finisher blames the homeowner or the redi-mix company. The mix company blames the finishers,” Yurconis writes.
Don’t Delay in Addressing Concrete Slab Issues
Concrete slab issues and defects aren’t always easily identifiable, but should you find an issue, it’s important that you deal with it as soon as possible. Hairline fractures and minor defects can grow into major problems in just a short period of time. While it can be easy to play the blame game, it’s important to start by addressing the issue. You can then deal with the responsibility of the problem.
Contact Edens Structural Solutions
At Edens Structural Solutions, we serve the foundation repair needs of customers throughout northern Oklahoma. Whether it’s residential or commercial foundation repair, we have more than 30 years of experience and knowledge and are more than qualified to diagnose and fix any problems you may have with your concrete slab. We run our company based on the two “I’s” of good business: intelligence and integrity. If those are characteristics you’re looking for, please don’t hesitate to contact us today. We’d be happy to provide you with a free consultation.