After another winter filled with rain, sleet, and snow, many homeowners find themselves waking up to a nightmare in their driveway. The effects of road salt are soon made clear once the snow starts melting and the weather starts warming. These problems mainly have to do with spalling (also referred to as scaling) and cracking.
What Is Spalling?
Spalling refers to the process where the surface of the concrete is pushed away from the rest of it, leaving it flaky and exposing the uneven concrete below. The fact is that concrete is a highly porous material and it does absorb water. When that water freezes and melts over and over, it creates a hydraulic action that separates the surface from the rest of the driveway.
What Causes It?
The main culprit behind spalling is road salt which is used to help clear the roadways during the winter. Most modern roads and pavements are made of grey-white concrete, which contains calcium hydroxide. Road salt contains calcium chloride. When the two mix they form calcium oxychloride, also known as CAOXY.
As water containing CAOXY crystals seep down into the concrete, it begins to expand when freezing. This causes the surface to start to split and crack. This is only worsened by the continual freeze-thaw cycle that is typical in many places during the winter.
It can wreak havoc on driveways and other concrete structures that are continually exposed to calcium oxychloride. Additionally, the continual weight of vehicles driving back and forth over the driveway accelerates the introduction of the CAOXY to the subsurface of the concrete.
Although road salt is the most common cause of spalling in concrete, there are a few other possibilities worth mentioning. They include:
-Improper mixing technique
-Change in temperature during setting
-Not allowing the proper amount of time to cure
Preventative and Protective Measures
Cracking is something that all concrete will go through eventually. This is due to the ground beneath it settling and shifting. In fact, most contractors only promises are that your concrete won’t be stolen and that it will crack.
However, spalling can be slowed down with a little bit of care and attention. A sealing coat can be applied to the concrete to extend its life. This can be done with different sealants to address the two different ways road salt affects concrete:
– Using a Densifier Sealant
This helps to protect the concrete surface from the abrasive properties and effects of the de-icing material.
– Using a Water Repellant Sealer
This helps to prevent water from seeping down into the surface and causing damage during the freeze-thaw cycles.
There are several things that you can do to keep your driveway in good shape, even during the winter months. However, when the damage is evident and you know it is only going to continue to deteriorate further, there is no reason in putting off maintenance and repairs. Give us a call today to find out how we can help.