Why Does Concrete Get Hot | Benefits of Hot Concrete | How Much Heat Is Generated by Curing Concrete | Why Curing Produces Heat

Why Does Concrete Get Hot

Why Does Concrete Get Hot?

The sun and curing are the two main causes of concrete heating up. Sand, cement, and aggregate are the components of concrete. The chemical reaction that results from mixing these three chemicals with water dries and hardens the concrete while also generating heat.

Healing takes place throughout this procedure, which typically lasts 28 days. As concrete dries, it gets stronger and emits heat. The concrete is chilled after curing.

As we all know the sun is the 2nd most frequent cause of excess heat for concrete. Concrete is good at absorbing and retaining energy, just like all masonry products.

The heat from the sun can be effectively absorbed and retained by concrete. They frequently mention heated areas like patios, sidewalks, and concrete around swimming pools in the summer when we inquire as to why concrete heats up.

You’ll notice the change right away if you’ve ever stepped from a wood stove or deck onto a concrete patio. Concrete can get rather warm. This can occur a few hours after dusk. What gives, though?

First, we’ll talk about why concrete warms up in the sun and examine the curing procedure in more detail.

Also Read: Does Concrete Resurfacing Last?

1. Sunlight:


The sun is the most frequent cause of heated concrete. Although concrete only needs to cure for 28 days, it may be heated year-round by the sun. The primary heat source is sunlight.

Concrete can hold heat quite effectively. This indicates that it can heat up more slowly and at a higher temperature than the majority of other materials.

Concrete can reach 135 °F when exposed to direct sunshine in the summer, even though concrete in the shade typically only reaches 70 °F.

An instrument known as an infrared thermometer is used by builders to verify this. A very high heat capacity exists in the concrete. This is usually caused by 2 separate things.

Concrete’s surface is quite dull and does not reflect much light. Instead, the sun’s rays were absorbed by the concrete.
In essence, the composition of concrete makes it good for storing heat. It is a type of energy that the sun emits.

These two elements combine to explain why concrete is so effective at absorbing and holding onto heat, as well as why it feels warm in the summer.

After cooling, concrete is eventually discharged into the atmosphere, raising the ambient air’s temperature. As a result, the city is a little bit warmer at night than the countryside.

The metropolis is gradually warmed by the heat that the concrete absorbs during the day. This is also a factor in the winter because individuals are more aware of the effect when it’s cold outside.

2. Concrete Gets Very Hot:

Concrete Gets Very Hot

Concrete as we all know not only retains heat for a long time, but also it heats up quicker than most other known materials. Plants that are tested in direct sunlight all day rarely reach temperatures higher than 80°F.

Concrete can heat up to 175°F, while wood can reach 90°F and composites 100°F. Most individuals find it uncomfortable to walk barefoot in the heat. Ever witness an egg being fried on hot concrete? States like Arizona and Nevada allow it.

Except for shade, there isn’t much you can do to keep concrete from heating up in the summer. All you can truly do is try to keep concrete from absorbing sunlight.

There are no sealants or additives to stop the concrete from heating up. However, this only works if the water’s surface is wet.

Also Read: How Thick Should a Concrete Sidewalk Be?

3. Climate and Topography:

Climate and Topography

The pavement is heated by more than simply the sun’s beams. Concrete temperatures are also influenced by Earth and air temperatures.

The concrete can still be warm in the summer even if it’s gloomy outside. This is so because concrete absorbs heat from the Earth and the air in addition to sunlight.

Because of how well it absorbs energy, concrete is rarely a few degrees warmer or colder than the typical ambient temperature.

For instance, the concrete will be the hottest if placed adjacent to wood, soil, fire, and tile. In winter, concrete will be warmer than other materials, while in summer, it will be redder.

The concrete is permeable to the earth’s temperature. Concrete can therefore become too hot even in the shade in desert regions like Arizona. No matter what you do, concrete will heat up when hot air is mixed with hot air.

Benefits of Hot Concrete:

Benefits of Hot Concrete

Concrete heated by the sun can be advantageous. Many builders are employing concrete’s high energy capacity to heat the ground, despite the fact that many people complain that concrete patios are too hot to walk on in the summer.

Passive Houses are exceptionally energy-efficient constructions. The house is heated using huge insulated windows and concrete walls and flooring. The windows allowed daylight to penetrate the concrete during the day.

The concrete that warms the house emerges at night. The heat stays within the house because too Passive House’s extremely high insulation levels and airtight seals.

1. Artificially Heating Concrete:

Artificially Heating Concrete

The heated floor is ideal for both indoor and outdoor use because of how well concrete absorbs and retains heat.
A fantastic technique to heat your house is using floor lights.

Inside the concrete slab are pipes carrying hot water or electric coils. Concrete heating elements are heated if required. The floor is heated uniformly throughout the day by this energy, which emits heat into the atmosphere.

The warmth is constant and quite comforting. Turn off the heat once the concrete reaches the proper temperature to prevent the need for continuous hot water or power for hours.

It is possible to use this kind of radiant floor heating in places like patios, decks, driveways, and sidewalks. Snow and ice may be easily melted with exposed concrete slab heating, just as inside.

Although walking on hot concrete might occasionally be uncomfortable, it also offers several advantages, unlike what many people believe.

2. Curing:


The concrete goes through two procedures once it is laid. the initial dry Water evaporation causes the concrete to harden and become stronger.

The concrete isn’t entirely dry, though. Masons in some hot regions will moisten the concrete’s surface as it cures since curing requires a certain amount of water. Over time, water and cement chemically interact and combine, strengthening the concrete.

Heat is produced by the healing process outside of the construction business. Curing is a crucial step in the construction of concrete structures. The concrete won’t perform to its full potential otherwise.

Psi per square inch is the unit used to measure concrete strength. When the label on a bag of Quikrete concrete states 3500, it actually implies 3500 psi. The more concrete is stronger the higher the number.

After the entire quantity has healed, this occurs. potential power, not ultimate power. Only 1500 psi of concrete may be placed in 10 days. It reaches 3500 psi after proper curing of 28 days.

The heat created during curing is typically not a concern in small building projects. but for significant building initiatives, such as laying the groundwork for bridges or dams.

To control the temperature, concrete must be poured in a specific manner.

How Much Heat Is Generated by Curing Concrete?

How Much Heat Is Generated by Curing Concrete

Concrete should ideally be mixed and maintained indoors between 50 and 90 degrees. On a chilly day, a hot blanket must be used to warm the concrete. It might be required to moisten the concrete surface to keep it cool on a hot day.

So as the sun sets, it ought to be warm. Pour concrete in the middle of the day and keep it as cool as you can in the summer after nightfall.

Why Curing Produces Heat?

Why Curing Produces Heat

Contrary to popular belief, concrete does not necessarily dry out over time. In reality, it experiences a chemical event that modifies and solidifies water molecules. Concrete is dry as a result, but this is not due to evaporation.

This chemical reaction produces a heated result. It will continue to be created for the duration of the reaction.
Heat is not a major issue if there are many concrete structures, such as walkways, balconies, staircases, and main stairs.

Concrete is kept cold in the summer and heated in the winter by builders. However, heat management calls for certain extra precautions.

when it comes to large-scale industrial buildings, including concrete dams and substantial foundations. The structure may crack if the temperature of the concrete is too high.

Due to internal expansion brought on by heat, concrete cannot be contained without cracking. The difference in temperature between the inside and exterior of big constructions made of concrete should not be greater than 36°F.

Why Concrete’s Curing Temperature Matters?

Why Concrete’s Curing Temperature Matters

The importance of our concrete’s curing temperature can be boiled down to one word: strength. The final psi is decreased if the concrete is excessively hot because it can harden and strengthen prematurely.

Concrete may not set properly if it is left outside in the cold, and it also won’t harden; The strongest concrete is created when curing temperatures range from 50 to 90 degrees Celsius. Concrete requires a lengthy period of slow curing. Concrete becomes weaker as it is crushed or sheared.

The heat generated by hydration can also change the makeup of the concrete in addition to using external techniques like soaking when the concrete is too hot or insulating when it is too cold.

Therefore, depending on the scope of the project and the weather, the concrete composition also contributes to a powerful final result.

The formula is usually similar when you order concrete by truckload or use pre-mixed bags like Quikrete. It is up to you to make the necessary adjustments if you mix the concrete on-site yourself.

Why Hot Weather Is a Problem?

Why Hot Weather Is a Problem

Hot weather hastens the evaporation of water, which is problematic for concrete curing. The concrete dries out too quickly as a result, which hinders the cure.

The chemical process that cures and fortifies concrete depends heavily on water. Concrete will deteriorate if there isn’t enough water for the cement to react with.

Masons address this issue by pouring concrete in colder temperatures and moistening it with water afterward. Additionally, it is covered in concrete, which aids in the retention of water evaporating off the concrete surface.

Due to a phenomenon known as thermal shock, a fast change in temperature can cause concrete to crack. It’s crucial to keep an eye on water evaporation caused by temperature and sunlight when dealing with concrete.

Lack of water prevents cement from setting, resulting in weak concrete and low psi.

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Why Cold Weather Is a Problem?

Why Cold Weather Is a Problem

Concrete pouring and curing in extreme cold and heat are equally hazardous. The chemical reaction must be heated sufficiently for it to happen as the concrete cures.

This means that because water is one of the primary ingredients, the curing process will essentially freeze when the outside temperature is too low. Normally, this is at or around 50°F.

Pouring the concrete at the proper ambient temperature is crucial. The curing process suffers from extremes of temperature, which can damage the concrete.

A concrete heating blanket can be used to maintain the concrete at the ideal temperature when there is no other choice and you need to fix the temperature. When pouring concrete in the cold, be sure you have it on hand.

Types of Cement (Three Types Only):

Types of Cement

One kind of cement. The majority of concrete is made with this conventional cement mixture. No specific substances are required to lessen the quantity of heat that is emitted while cooking.

Unless a different curing method is desired, Type 1 cement is typically used in construction projects. Second kind of cement.

This mixture is intended to generate less heat over a longer duration. It is frequently employed in substantial buildings like massive walls and foundations.

Third kind of cement. cement Type 3 doesn’t generate much heat during treatment. Usually, it is employed in sizable initiatives like dam construction.

The heat produced during curing may be sufficient to crack entire concrete structures, such as gravity dams. Indoor heat management is crucial in these big projects.

Frequently Asked Question(FAQ):

Why Does Concrete Get Hot?

The heat produced by concrete during concrete curing is called heat of hydration. This exothermic reaction occurs when water and cement react. The amount of heat produced during the reaction is mostly related to the composition and fineness of the cement.

How Much Heat Does Curing Concrete Generate?

How Much Heat is Generated? As a general rule, the Portland Cement Association estimates that for every 100 pounds of cement, the concrete gains anywhere from 10 to 15 degrees Fahrenheit in temperature.

How Hot Can Concrete Get Before Cracking?

Concrete temperatures which exceed air or ground temperatures by more than 35ºF can cause thermal cracking.

How Hot Can Concrete Get While Curing?

If concrete is cured in cooler ambient temperatures (32°F to 50°F) with moisture continually present, strength gain will be slow but the concrete will eventually reach a high strength. Concrete should not be allowed to get hotter than 90°F or to dry out during the curing period.

Is Concrete Hot When Poured?

Concrete sets as the cement hydrates. Hydration is an exothermic reaction, meaning it generates heat, and that reaction goes faster when the concrete is hot. So the main concern with the concrete’s strength and set time isn’t really the air temperature but the concrete temperature.

How Hot Is Concrete on a 100 Degree Day?

On a sunny day, asphalt can quickly heat up, even if the air temperature doesn’t feel super hot to you. For example, if it’s 85 degrees, then the blacktop temperature is 110. If the air temperature is over 100 degrees, then the blacktop can reach 160 degrees.

Can Concrete Catch on Fire?

Even though concrete is non-flammable and offers excellent fire protective qualities for preventing the spread of fire, it loses most, if not all of its structural strength characteristics when exposed to extreme heat.

Effect of Hot Weather on Concrete

Hot weather accelerates the cement hydration reaction and increases the water demand and rate of slump loss of a given concrete mixture. As a result, it is often more difficult to properly adjust mixture proportions, deliver, place, consolidate, and finish concrete during hot weather.

How Hot Does Concrete Get When Curing?

A general rule of thumb with hot-weather concreting is to maintain a limit of 70°C (160°F) for concrete curing temperature during hydration.

How Hot Is Concrete When Poured?

Elements like volume changes, cracking, humidity, wind speed, and temperature all should be accounted for when pouring concrete. Experts agree that the best temperature for pouring concrete is between 40 °F and 60 °F.

Concrete Temperature Limit as Per Is Code

Generally, a concrete temperature is limited to 160°F (70°C) during hydration.

Concrete Heat of Hydration

Heat of hydration is the heat generated when water reacts in contact with the cement powder. The amount of heat released depends on the cement composition, curing temperature, water to cement ratio, and cement fineness.

Is Wet Cement Hot?

It is a little known fact that the process of curing concrete actually generates heat. This is because when you mix water with cement, the molecules in the cement begin a chemical reaction together.

What Is Curing Temperature?

It’s advised that concrete be cured at a moderate temperature between 50 °F – 90 °F.

Curing Temperature of Concrete in Celsius

At a minimum, concrete should be cured at temperatures above 7.2 degrees Celsius (45 degrees Fahrenheit). Below this temperature, concrete’s chemical reaction completely stops – which can result in costly delays and rework.

Curing Temperature of Concrete as Per Is Code

(a) Concrete, other than high-early-strength, shall be maintained at a temperature of at least 50°F and in a moist condition for at least the first 7 days after placement, except if accelerated curing is used.

Best Temperature for Concrete to Cure

It’s advised that concrete be cured at a moderate temperature between 50 °F – 90 °F. In a perfect world, the temperature of fresh concrete should be above 50 °F, but cured and maintained at 50 °F.

Effects of Hot Weather on the Body

Rapid rises in heat gain due to exposure to hotter than average conditions compromises the body’s ability to regulate temperature and can result in a cascade of illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia.

Effects of Cold Weather on the Human Body

Prolonged exposure to cold will eventually use up your body’s stored energy. The result is hypothermia, or abnormally low body temperature. A body temperature that is too low affects the brain, making the victim unable to think clearly or move well.

Medical Conditions Affected by Cold Weather

Diseases such as lupus, anemia and multiple sclerosis (MS) can all worsen with cold weather. Emotional or physical stress can make someone more susceptible to flares like difficulty moving limbs, spasms, iron deficiencies and lethargy.

Disadvantages of Cold Weather

Serious health problems can result from prolonged exposure to the cold. The most common cold-related problems are hypothermia and frostbite. When exposed to cold temperatures, your body begins to lose heat faster than it can be produced. Prolonged exposure to cold will eventually use up your body’s stored energy.

What Cold Temperature Is Dangerous for Humans?

If it is below 95°, the situation is an emergency—get medical attention immediately.

Effects of Cold Weather on Skin

The cold weather months can greatly compromise skin health, triggering such conditions as xerosis (dry skin) or eczema (itchy, dry, reddish patches or lesions on the skin) which can vary in severity.

Psychological Effects of Cold Weather

General feelings of “boredom, anxiety, irritability, loneliness and restlessness” can develop into full blown cortisol stress response. During winter months, mental health issues spike most commonly Seasonal Affective Disorder. Seasonal Affective Disorder is a subtype of depression that is caused by a lack of sunlight.

Extreme Cold Body Temperature

Hypothermia is a medical emergency. If you notice any of the above signs, take the person’s temperature. If it is below 95° F, get medical attention immediately! If you are not able to get medical help right away, try to warm the person up.

Special Types of Cement

The different types of special cements are high alumina cement, sorel cement, silicate cement, waterproof cement, high early strength cement, barsium, and strontium cement.

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