Wet Winter Effects on Concrete
In the Wet Winter Effects on Asphalt article we detailed the combined effect of moisture and low temperatures on asphalt surfaces. It is sometimes thought that asphalt is more common in cold wet regions for its ability to resist moisture and that concrete is more common on hot dry regions for its ability to withstand high temperatures. Many construction projects may choose a concrete surface in a warm weather region, and asphalt in a wet region, but this isn’t to say that asphalt or concrete are impervious to certain weather conditions.
Concrete in Warm Climates
Concrete performs well in warm climates for several reasons. Unlike asphalt, warm temperatures will not soften a concrete surface. Both asphalt and concrete are certainly very hard materials, but concrete’s composition is more stone-like and does not yield in any way to high heat. Asphalt, although a very hard and robust material, does have the tendency to soften slightly when exposed to very high heats. Concrete doesn’t need to be resealed as often as asphalt, and if it’s exposure to rain is very limited, concrete may only need resealing a few times during its lifetime. Concrete is still prone to cracking over time. Because concrete is stone-like in consistency it is very inflexible, and as a result is subject to cracks. Cracks can be created as a result of shifting foundation and high amounts of traffic and surface wear. Moisture can then penetrate small surface cracks and exaggerate the effects. Still, concrete is favored in warmer weather for its ability to withstand pressure and heat as well as its ability to last decades with proper maintenance.
Concrete in Cold Wet Climates
Concrete is an amazingly strong material with a strength typically no less than 500 pounds per square inch. At 500 psi most engineers would safely say that the concrete is strong enough avoid expansion or corrosion as a result of extremely cold and wet conditions. Concrete is certainly a viable building material in regions with true winter conditions, but it has some drawbacks. Asphalt may generally be preferred for driveways and roads, but there are certain building applications such as decorative paved areas which require concrete for aesthetic purposes. Regions in the United States like the mid Atlantic and Northeast can have fairly different winters each year. Some winters may be within normal ranges of cold and wetness, and concrete surfaces may withstand these conditions without expansion, spalling, or stripping. Other winters may create more severe conditions of extreme cold and sustained snow and frost, and this leaves concrete susceptible to damage.
Frost and Snow on Concrete Surfaces
Concrete is a porous material. In extreme winter conditions a concrete surface may be covered with frost, snow, or iced over. When this happens, frozen or freezing moisture sitting on the surface seeps in the concrete’s pores. This is a natural effect of gravity as the moisture has nowhere else to go, particularly as the frost, snow, or ice begins to thaw. This moisture can freeze on the concrete surface, thaw, and then seep into the concrete’s pores, then refreeze again. Concrete can withstand a moderate amount of this process, but if a large majority of the pores contain moisture the concrete becomes saturated (meaning it can hold no more moisture). If the moisture saturating the concrete freezes again, it will expand and crack the concrete in the process – this is sometimes called freeze thaw deterioration. There are surface treatments which can be done to essentially reduce the size of the pores in the surface and prohibit the amount of moisture which can seep in, but for the reasons discussed here asphalt is generally preferable in cold moist climates if the project permits. Most concrete surfaces which experience freeze thaw deterioration which show signs of spalling. Spalling is basically what was described above – water seeps in, freezes, expands, and creates cracks. One case of spalling might go unnoticed, but if it repeats pits begin to appear, the rocky aggregate becomes exposed, and the integrity of the concrete is compromised.
FlexSet For Concrete Repair
Addressing concrete spalling, scaling, or cracking as soon as the damage appears can save the concrete surface and extend its lifespan. Our FlexSet Concrete Repair product was designed originally to allow for quick runway repairs, but is now recognized as an excellent alternative repair product for spalling repairs and general concrete restoration and maintenance. Please see Our Store to order FlexSet or Contact Us for More Information and to Request A Sample.