Understanding and preventing concrete cracking

Concrete cracks are caused by a variety of underlying factors, whether it be in the form of minor hairline cracks or large surface-spanning fractures. These issues can cause serious problems for any structures utilizing concrete, weakening them over time and leading to costly repairs. Therefore, it’s important to take all necessary measures to prevent cracking in concrete as much as possible. In this blog post, we’ll go over the main causes behind this phenomenon and what you can do to prevent your projects from having such issues.

Why does concrete crack?

Concrete is one of the most durable building materials, ideal for a variety of projects – from creating the foundations for structures to forming concrete slabs, driveways and more. However, even though it is durable, concrete can still crack without proper care. Here are some of the primary reasons why this may happen.

Reason #1 - Excess water in the mix

While using water is essential to form concrete and get it in its desired shape, too much of it can weaken the final product after hardening. When mixed with uncontrolled levels of moisture, an otherwise strong mix might become brittle, and prone to cracks and other issues over time. To prevent this from happening, special tools such as meters or probes which measure the amount of water content within the mixture should be used while the pouring process takes place! This way builder can ensure that there’s just enough liquid added so that cement can fully cure afterward but not too much so that it becomes soft when comes into contact with the environment around it down the line.

Reason #2 - Rapid drying of the concrete

The drying time of concrete can be affected by several factors such as air temperature and humidity. If there is extremely hot weather or even cold weather, the concrete hardens too quickly and lose its flexibility, leading to cracking. As a result, it’s essential to take all necessary precautions when working with concrete. Make sure the area is kept at an optimum temperature range, use proper ventilation systems if needed, and consider using special additives which help regulate the drying rate through a chemical reaction. It’s also important to keep in mind that different types of cement have varying curing times, so be sure to read up on this information before starting your project.

Reason #3 - Improper strength concrete poured on the job

In addition to environmental factors causing concrete cracking, the quality of the concrete poured on the job can also lead to unwanted imperfections. It’s essential to ensure that the right mix of cement, aggregates, and water is used to achieve the desired strength and durability of your structure or project. To avoid this problem, it’s encouraged to test soil samples beforehand and be aware of what type of aggregate is best for whatever task you are undertaking.

Reason #4 - Lack of control joints

Another cause of cracking in concrete is the lack of control joints. These are purposely created gaps that help reduce the chances for random cracking by creating “weaker” lines in the material. Without them, small movements due to temperature changes or other environmental conditions can lead to larger cracks and structural issues. As such, it’s recommended that professional concrete contractors add these expansion joints to your concrete project from the very beginning. This will help prolong the life expectancy of your construction and save you time and resources in maintenance down the road.

Other reasons:

Inadequate compaction of the soil underneath your concrete can cause severe and unpredictable foundation movement. This is because if soils are not adequately settled and compacted, they will not be able to hold the weight of a structure nor properly provide a stable base. If there isn’t proper support, it can lead to uneven settling of your foundation and significant stress as well as cracking on both interior and exterior concrete surfaces.

TYPES OF CRACKS IN CONCRETE

When it comes to concrete cracks, not all are created equal. The types of damage typically depend on the circumstances in which it originated as well as other conditions such as temperature or hydration levels. Here’s an overview of the usual suspects:

Hairline cracks

These are the most common type of cracks that appear on the concrete surface. They’re usually caused by shrinkage due to temperature changes or drying out over time.

Shrinkage cracks

As their name suggests, these happen when the concrete shrinks as it cures and is unable to maintain its original size. It’s a common problem in large surfaces and is often seen along edges.

Thermal cracking

This occurs when there’s a sudden change in temperature or humidity, causing the material to expand or contract more than it should – leading to structural damage.

Structural cracks:

These are usually caused by heavy loads, improper subgrade preparation, or incorrect reinforcement. They can range from small to large, and often appear due to changes in the ground like inadequate drainage or soil compaction.

Settlement cracks

As their name implies, these are caused by the ground settling over time and shifting the foundation of a structure – leading to misalignment or cracking.

How to prevent cracks in concrete?

The first step towards preventing a concrete crack is to understand the reasons behind it. Once you’ve identified the potential causes, you can take the necessary steps to reduce or eliminate them.

Here are some tips:

Start with a sound foundation:

Make sure the soil underneath any structure is well-prepared, compacted properly, and has positive drainage.

Modify the concrete mix:

If possible, adjust the mix ratio of your concrete to make it more resilient and resistant to concrete shrinkage.

Add control joints:

Control joints should be added to large surfaces and along edges, to reduce the risk of random cracking.

Properly cure the concrete:

Concrete needs to be maintained at a correct temperature and humidity, as well as kept moist to properly cure.

Mix the proper amount of water:

If there’s too much excess water or not enough, it can lead to cracking. Be sure to use a proper ratio.

Reinforce:

If needed, add reinforcement to increase the strength of your concrete and reduce the risk of structural cracks.

Is it normal for the concrete slab to crack?

Concrete will inevitably crack, however, the severity and extent of damage will depend on several factors. Many small cracks can be the result of the normal curing process, but larger cracks can be caused by improper installation or inadequate preparation. To prevent more serious cracking on your concrete slabs it is important to take the necessary steps for proper installation, such as ensuring a sound subgrade and using the right concrete mix ratio of concrete. Additionally, installing control joints along large surfaces and using reinforcement where needed can help to reduce the risk of more severe cracking.

There's always hope for a cracked concrete surface

When it comes to concrete cracks, many potential causes and factors can lead to them. However, by taking the necessary steps to identify and address the source of the problem, it is possible to reduce or even prevent future cracks from occurring.