Concrete is a strong and durable material, but it can be vulnerable to crumbling if not installed correctly. Too much water in the mix, freezing temperatures, salt, and improper finishing can all cause concrete to break down over time. Contractor error is the most common cause of concrete crumbling, as they may add too much water to the mix or start finishing the concrete before the spalling water leaves the surface. Sealing concrete with a sealant once a year can help protect it from freezing temperatures.
Pressure washing and patching with a concrete filler can help repair damaged areas. Expansion joints should also be placed in large expanses of concrete to prevent cracking. When mixing concrete, it is important to follow the instructions on the bag of cement and measure out the exact amount of water needed. If too much water is added, the cement and sand cannot bond together and will break apart when it starts to dry out. This causes a crumbling zone in which the particles do not stick together.
Water trapped inside the concrete can also freeze and push the cement binder outwards, leading to crumbling. Salt is slightly acidic and can attack the bonds that hold concrete together, enlarging its pores and allowing more water to seep in. When this water freezes, it causes the surface of the concrete to splinter or flake. Over time, this can lead to real deterioration of the concrete. If you find a damaged spot on your concrete, clean it up and use a concrete filler such as Fix-All to patch it. You can also use a product like Concrete Resurfacer, which is made with Portland cement and a unique blend of polymers and additives that make it stronger and more durable.
To ensure success in applying this stucco, make sure that all weak and compromised concrete has been removed from the surface. In order to prevent crumbling, use only the amount of water indicated in the mix instructions and seal your concrete steps or walkways with a sealant once a year. Expansion joints should also be placed in large expanses of concrete to prevent cracking due to temperature fluctuations or ground movement.