INSIGHTS | May 20, 2021
Concrete: So Hot Right Now
Potential, inherent problems exist for pavement due to freeze/thaw cycles where water, temperature changes, and cracks create problems waiting to happen.
But what about prolonged heat? What issues lie ahead along that road for your concrete pavement system?
This term is probably hyperbole. However, it does refer to any severe upward buckling or “tenting” on both sides of a joint. Possible in older pavement systems, this can occur in any aging concrete pavement system if proper maintenance is not used.
While the causes for these “blow-ups” can vary, they often include incompressibles entering joints or cracks, reducing the ability of the pavement to expand. Then, during long periods of high heat, usually over 90°F, and often after weather events with prolonged moisture—early Summer rains, for example—pavement can buckle creating the effect you see here.
How widespread are blow-ups? And how do I avoid them?
Any concrete system over 10-15 years old is at increased risk for blow-ups.
To mitigate this risk, two important factors should be considered:
1. Your pavement system should include expansion joints at an interval appropriate for the application (e.g. sidewalks vs. parking lots vs. roadways)
2. These joints and any cracks in the pavement should be kept free of incompressibles, like small pebbles or sand
Keeping these joints and cracks clear of debris can be accomplished by keeping them sealed. Sealing joints should happen every 5-15 years depending on the type of sealant used.
Concrete pavement construction
When constructing a new concrete pavement system or performing substantial repair work on an established one, prolonged hot weather makes ensuring the proper handling, placing, finishing, and maybe most importantly, the curing of concrete an area of major concern.
In North America, hot weather-related construction issues would most often occur in the summer but anywhere that high temps, low humidity, UV exposure, and even high winds occur can create problems with curing concrete.
These hot weather conditions produce a rapid rate of moisture evaporation from the surface of the concrete, accelerating setting time and weakening of the concrete strength.
While your contractor should be aware of these potential issues, keeping an eye on your weather when scheduling your concrete projects is a good idea.
High temperatures cause increased water demand, raising the water-cement ratio will result in lower potential concrete strength over time.
What’s the bottom line?
Keeping your pavement well-maintained is always smart. Cleaning out your joints and cracks and properly sealing them with the correct sealant will help you avoid blow-ups and myriad other problems like faulting from loss of support due to water infiltration into the subgrade/base.
Making sure your concrete construction projects are scheduled at times when the weather is conducive to long-term success is another good idea.
So, you’re not a scientist…
Never go it alone when making these decisions. Even properly training your maintenance staff to clean and seal joints might take an extra hand.
Before starting a pavement maintenance program or scheduling construction, talk to a pavement consultant, like Mantis Innovation. These experts can ensure you’re doing the right work at the right time for the best value… and that it never blows up in your face.