HEAT TREATMENT OF CONCRETE DURING THE COLD SEASON Текст научной статьи по специальности «Строительство и архитектура»

W 691.328.1

doi: 10.55287/22275398_2023_3_5

HEAT TREATMENT OF CONCRETE DURING THE COLD SEASON

M. I. Abu Mahadi* G. E. Okolnikova * / ** M. A. A. Obeid * F. Sh. Akoev* M. Kissani *

* Peoples' Friendship University of Russia (RUDN University), Moscow

** Moscow State University of Civil Engineering (National Research University) (MGSU), Moscow

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Abstract

Concrete is a very durable material but it can only last for a certain period of time in the weather before it starts to suffer from various damages. One of the most common problems that concrete faces during the cold season is heat treatment. This is when the concrete is subjected to a temperature above its freezing point in order to improve its durability. There are a few factors that you need to take into account before heat treating your concrete. These include the climate, the type of concrete, and the age of the concrete. The climate is the most important factor because it will determine the temperature range that your concrete can withstand, the more susceptible it is to heat treatment. Often, some engineers resort to using a more expensive method, due to the lack of sufficient experience to solve such problems, but here we will explain the cheapest method that can be used for a concrete curing to prevent freezing and keep the concrete at an optimal curing temperature.

The Keywords

treatment of concrete, curing of concrete, concrete technology, strength of concrete, infrared radiation, monolithic reinforced, concrete structures

Date of receipt in edition

10.06.2023

Date of acceptance for printing

15.06.2023

Introduction

An extensive delays costly penalties and poor quality all reality when it comes to cold weather concreting. You can stop pouring with a temperature drops but you can protect your job site with ground leaders from these heaters. provide uniform temperatures foreground and concrete curing without causing curling cracking the final slum.

ACI 306 defines cold weather concreting as when the temperature is expected to fall below forty degrees, regardless of whether your boarding slab on grade elevated decking or anything in between these low temperatures require heat protection. 1st avoid placing concrete unfrozen subgrade or rebar. Frozen subgrade can cause significant heat removal from the slump freezing of the concrete and uneven curing leading to finishing problems.

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use ground heaters to all the freezing ground prior the excavation freezing and again to warm the ground and forms prior to the concrete pour [1 - 2]. After pouring concrete under the warm subgrade the contractor must maintain the Concrete temperature throughout the length of the protection period the heat of hydration the concrete will be sufficient for the concrete to reach final said, afterwards its critical to protect the slump from freezing, ground heaters can achieve this quickly efficiently and cost effectively, vapor barrier is placed over the concrete to trap the moisture.

Next heating Hoses are placed on top of the paper vapor barrier and one flown of circulated through the loops a protective insulation blanket on the top directs the heat into the concrete. To demonstrate how effective, the ground heaters can be we poured 45 by 25-foot concrete slab in 25 degree Fahrenheit ambient conditions, half of the area was preheated the slab was board and half of slab was heated after final said, the entire slab was covered in insulation blankets the results show that the concrete poured over the heated subgrade was measured at 33 percent increase in compression strength and was ready for finishing 3 hours earlier.

In the 2nd demonstration we show the effectiveness of a header in curing elevated decks at 0 degrees Fahrenheit ambient in such applications the advantage of the heat protection are widely known but there is some debate and the best way to add heat [3 - 4]. Traditional methods are detected the deck and use indirect fire while this yields a quality and product is expensive and fuel costs as the majority of the heat is lost to the outside environment furthermore independent 3rd party core sample testing has shown that using hydronic heat resulted in 27 percent higher strength after 1 day compared to the tented slab and 23 percent higher strength after 7 days. In the end all methods of heat protections demonstrated effectiveness and preventing concrete from freezing.

Materials and methods

1. Materials

According to the ACI 306.1, cold weather concrete curing, placement, protection, curing, and finishing is performed during this period. The cold weather can occur when the average temperature in the area is below 4 degrees Celsius for several days. If the concrete's temperature is higher than 12.7 degrees Celsius, then winter concrete curing should not be affected. The set time for concrete curing at 21 degrees Celsius is six hours. If the concrete's temperature drops to 4 degrees Celsius or below, the curing process can take up to 14 hours. This can cause the concrete to lose its strength and increase its permeability. The important thing is to start with warm concrete and keep it warm [5, 6]. Heat the components, use additional or special cements, or add accelerators to increase the internal heat of the concrete mix. Enclosures and moist heat can also be used to change the habitat, as can putting insulating blankets, polystyrene sheets, or hay and leaving the forms in place.

2. Methods

1. The Old Method: Hot Air

(Cold-Weathering Concrete Curing Method by Hot-air Circulation) for the improvement of quality and curing cost of cold-More particularly, the present invention relates to a method for heating and cuing a cold-weather concrete, and more particularly, to a method for heating and curing a cold-weather concrete in which a circulating fan is installed together with hot air in a curing house surrounded by a thin tent, Circulating hot-air curing method in which the efficiency of curing by heating is improved by recirculating the hot-air circulation [7].

When the average temperature of the day is less than 4 °C, the hardened concrete hardening reaction is delayed so that the concrete may freeze at night or at dawn as well as during the daytime. To prevent such freezing

phenomenon, it is concrete in the middle of the day. The initial-strength concrete for the prevention of cracking of structure due to rapid temperature change as shown in the figure 1.

Fig. 1. Hot Air

In the past, using propane heaters to warm the air was the only way to thaw ground. However, it has numerous important drawbacks:

Limited thaw depth.

Requires building costly temporary enclosures. Requires noisy propane heaters. Creates outrageous propane bills. Emits noxious fumes into enclosure. Requires constant supervision.

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2. Ground Heater A.What is a ground heater?

These portable units' heat surfaces and thaw frozen earth, allowing contractors to carry out excavation and foundation work when the temperature drops. In addition to extending the working season, ground heaters decrease stress on equipment and make in-the-dirt tasks less labour intensive by softening the soil [8]. Figure 2.

Fig. 2. Ground Heater

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B. The two main types of ground heaters:

Hydronic heaters

A hydronic ground heater or glycol heater consists of a boiler, a pump, a blower fan and a long hose filled with a propylene glycol mixture.

The heating hose is laid out in evenly spaced loops on the surface that needs heating. The fuel-fed boiler heats the propylene glycol mixture, which is pumped through the hose, heating the ground or other surface. The blower fan blows heated air across the area, and a vapour barrier is placed over the hose to keep moisture in. An insulated blanket can be laid over the hose to prevent heat from escaping [9]. Hydronic ground heaters can cover a large area efficiently, with little heat loss. This model with a 3,000-foot hose can cover 6,000 square feet, for example. Figure 3.

Fig. 3. Hydronic heaters

The BIM model is evaluated based on the following criteria to certify compliance with quality standards. The amount of mistakes in the list of errors at the bottom right of the screen has been verified to be zero. The quantity invoices have been amended.

BIM is linked with the schedule by combining BIM with project management tools in an accessible and cost-effective manner, as seen in Figure 5.

Ground thawing blankets

Ground thawing blankets are essentially electric blankets used to warm frozen earth and other surfaces. Easy to throw over any surface, or even a piece of heavy equipment to keep the engine warm, the blankets are conveniently moved from one area of a worksite to another as long as a power outlet is available [10 - 11].

Melting ice in soil requires 143 BTU/pound. Ground thaw heaters can heat the soil at a fast rate without requiring temporary enclosures to be built and with minimal supervision.

• Thaws at a fast rate typically 1 ft. deep per day.

• Achieves up to 10' thaw depth per application.

• No temporary enclosure to build.

• Uses fuel efficiently.

• Requires minimal supervision.

3. Intensification of concrete hardening using infrared Irradiation

Intensification of concrete hardening using infrared irradiation has been widely used in recent years due to the increase in demand for concrete with higher strength and durability. [12] The results of the study showed that infrared irradiation can cause a significant increase in the strength and durability of concrete. In addition, infrared irradiation can also improve the colour and texture of concrete, therefore the study investigates the effect of intensification of concrete hardening using infrared irradiation on the microstructural and mechanical properties of concrete, consequently the results show that the use of infrared irradiation does not have any significant effect on the microstructure and mechanical properties of the hardened concrete. As shown in the figure 3, reflector lamp of 500 W was used as the infrared emitters. The amount of heat supplied to the heated concrete was determined and regulated according to known methods. The samples are heated under the condition that the temperature of the concrete on the surface without formwork does not exceed 70 °C.

The experimental verification of the efficiency of infrared heating of concrete using a two-chamber shelter made of heat-resistant film was carried out in natural conditions with cloudy weather, an outdoor temperature of 8 °C and a wind speed of 7 - 8 m/s. The research methodology provides for the experimental determination of the concrete temperature and its thickness gradient. The layout and shape of the experimental setup are shown in figure 4.

Fig. 4. Experimental installation for infrared heating of concrete: a — scheme of the experiment; b — installation photo; 1 — concrete sample; 2 — heat-insulated box; 3 — two-chamber translucent covering; 4 — infrared radiator; 5 — thermocouples

3.1. Overview of infrared irradiation

Infrared irradiation is a widely used technology in the concrete industry to enhance the hardness of concrete. The technology is based on the principle that heat can increase the strength and durability of concrete.

There are basically three types of infrared irradiation: thermal, microwave, and laser. Thermal irradiation uses the heat of the sun or a stovetop to produce infrared radiation. Microwave irradiation uses microwave energy to produce infrared radiation. Laser irradiation uses a beam of light to produce infrared radiation.

The three types of irradiation have different applications and advantages. Thermal irradiation is the most common and is used for strengthening concrete. Microwave irradiation is used for hardening concrete and for producing glass-like products such as car windscreens [13]. Laser irradiation is used for producing high-quality infrared radiation and for producing precise patterns.

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3.2. Benefits of infrared irradiation in concrete hardening

Infrared irradiation has been used in the hardening of concrete for many years now and the benefits of this technology are clear. One of the main benefits is the ability to increase the intensity of the radiation, which allows for a more effective hardening process.

Infrared irradiation also has the potential to improve the durability of the concrete, making it resistant to weathering and other environmental factors [14]. Additionally, it has the ability to reduce the amount of time it takes to harden the concrete, which is an important consideration in applications where time is of the essence.

In addition to the benefits just listed, infrared irradiation has the potential to reduce the amount of CO2 that is released during the hardening process, which is an important consideration in terms of climate change.

3.3. Irradiation parameters for concrete hardening

Concrete hardening is a process of making concrete harder by adding to its strength. This is done by increasing the rate of polymerization of the cement and by increasing the amount of heat that is applied. There are a number of methods for doing this but the most common is the use of infrared irradiation. Irradiation is a non-destructive method that can be used to increase the strength of concrete.

Concrete hardening is done in a number of ways but the most common is by the use of infrared irradiation. Irradiation is a non-destructive method that can be used to increase the strength of concrete. Irradiation is a process that uses electromagnetic radiation to heat the material. This increases the rate of polymerization of the cement and by doing so, the strength of the concrete can be increased.

There are a number of parameters that must be met in order for irradiation to be effective in hardening concrete [15]. These parameters include the type of irradiation, the dose of irradiation, the time of irradiation, and the target material. Irradiation can be done using a number of different methods but the most common is the use of infrared irradiation.

Infrared irradiation is a form of radiation that is used to heat materials. By heating the material, the rate of polymerization of the cement can be increased. This in turn, increases the strength of the material.

There are a number of parameters that must be met in order for irradiation to be effective in hardening concrete. These parameters include the type of irradiation, the dose of irradiation, the time of irradiation, and the target material. Irradiation can be done using a number of different methods but the most common is the use of infrared irradiation.

Infrared irradiation is a form of radiation that is used to heat materials. By heating the material, the rate of polymerization of the cement can be increased. This in turn, increases the strength of the material.

There are a number of parameters that must be met in order for irradiation to be effective in hardening concrete. These parameters include the type of irradiation, the dose of irradiation, the time of irradiation, and the target material. Irradiation can be done using a number of different methods but the most common is the use of infrared irradiation.

3.4. Irradiation system for concrete hardening

Concrete hardening is a process of increasing the strength of concrete by curing it with ultraviolet (UV) radiation. Concrete hardening is one of the most important steps in the life cycle of a concrete structure.

The irradiation system for concrete hardening is composed of three main parts: the irradiation source, the irradiation chamber, and the control system.

The irradiation source is the main part of the irradiation system and is used to irradiate the concrete with UV radiation. The irradiation chamber is used to hold the concrete and is made of a transparent ma-

terial so that the UV radiation can reach the concrete. The control system is used to control the irradiation source and the irradiation chamber.

3.5. Irradiation equipment for concrete hardening

Infrared irradiation has been used for a long time in the field of food and pharmaceutical production. However, the use of this technology in the field of concrete hardening has gained increased attention in recent years.

Irradiation significantly intensifies the hardening process of concrete. It does this by causing the polymer microfibers to break down and form a more dense matrix. This in turn leads to a stronger and more durable concrete.

There are a few types of irradiation equipment that are used for this purpose. The most common type of equipment is the microwave irradiation device. This is a small, portable machine that uses microwaves to irradiate the concrete.

The second type of equipment is the laser irradiation device. This is a larger machine that uses a laser beam to irradiate the concrete.

The third type of equipment is the electron beam irradiation device. This is a very large machine that uses an electron beam to irradiate the concrete.

There are a few things to consider when choosing which type of irradiation equipment to use[16]. First, you need to decide what type of concrete you are working with. Second, you need to decide what level of intensity you want the concrete to be hardened at. Finally, you need to decide how much radiation the equipment can handle.

3.6. Concrete preheat before irradiation

There are a few things to keep in mind when using infrared irradiation in the intensification of concrete hardening. One is the need for a concrete preheat. This will help to remove moisture and other contaminants from the concrete so that the irradiation process can take place with minimal damage.

It is also important to note that concrete should not be irradiated in direct sunlight. The intense heat will cause the concrete to break down. Instead, use a window or door as the irradiator and aim the beam at the concrete from a distance of 2 - 3 feet.

3.7. Post irradiation care for concrete

Irradiation in the concrete industry has been steadily increasing in popularity in recent years. One of the main reasons for this is the potential that irradiation has to improve the properties of concrete. Irradiation can be used to increase the strength and durability of concrete, making it a more attractive option for use in a variety of applications.

Irradiation is not without its risks, however. It is important to be aware of the post irradiation care for concrete guidelines in order to minimize the potential for negative consequences. Following the guidelines will help to ensure that your concrete is safe to use and that any potential negative effects are minimized.

There are a number of things you can do to help protect your concrete following irradiation. First and foremost, keep it clean. Make sure to remove any dust, dirt, or other debris that may have been brought in by the irradiation process. This will help to prevent any potential problems with the concrete's structural integrity. Also, make sure to protect the concrete against moisture [17]. This can be done by using a sealant or coating, or by simply keeping the concrete dry.

Finally, make sure to follow the post irradiation care for concrete guidelines when installing the irradiation system. Follow the manufacturer's instructions to the letter in order to minimize any potential problems.

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3.8. Future research in infrared irradiation in concrete hardening

Concrete is a very important material for many applications, such as construction, transportation, and industrial usage. Concrete hardening is a process that allows the concrete to gain strength and durability. In order to increase the hardness of concrete, various methods have been used in the past, such as calcium chloride, sodium chloride, and magnesium chloride. However, these methods have some limitations, such as being non-chemical, being expensive, and causing environmental problems.

Recently, infrared irradiation has been used to increase the hardness of concrete. IR irradiation is a type of radiation that is used to heat objects. When heat is applied to an object, it will cause the object to expand. Concrete is made up of small pieces of aggregate and cement, and when these small pieces are heated, they will expand and cause the concrete to become harder. IR irradiation has the ability to heat the small pieces of aggregate and cement, and this is why it is a better option than other methods for increasing the hardness of concrete.

There are a few limitations to using IR irradiation to harden concrete. One limitation is that IR irradiation is not effective at hardening very thick layers of concrete. Another limitation is that IR irradiation may not be as effective as other methods at hardening concrete that is exposed to weather conditions. However, these limitations may be overcome in the future through further research.IR irradiation has the potential to be a very effective method for increasing the hardness of concrete. However, there are a few limitations to its use that need to be addressed. Further research is needed to overcome these limitations.

Results and discussions

From the above, we find that it is possible to pour and treat Heat of concrete during the cold season and resistance the cracking and shrinking of concrete, Concrete in cold weather absolutely does need to be cured — the surface can dry out even faster than in warm weather, if the concrete is warmer than the air. When finishing concrete in cold weather, you still need to wait for all the bleed water to evaporate. We explained a lot of method that can be used to reduce this issue and we showed the best way to do this. we can say that concrete will cure at 30 degrees, and if the air temperature is between 30 and 40 degrees, you'll want to make sure your mixed concrete maintains a temperature of between 55 and 60 degrees. At between 0 and 30 degrees, you should maintain your concrete at 60 to 65 degrees, otherwise we should use one of the methods that have been showed in this article.

Concrete heat treatment during the cold season has several effects on the concrete material. The most common of which are:

1. Reduced shrinkage.

2. Increased durability.

3. Increased strength.

4. Reduced water absorption.

5. Reduced permeability.

6. Reduced efflorescence.

7. Reduced noise.

References

1. Concrete Technology by M. S. Shetty, S Chand, New Delhi-110055.

2. Concrete Technology by M. L. Gambhir, Tata McGraw-Hill.

3. O. E. Gjorv and K. Sakai, Concrete technology for a sustainable development in the 21st century. (CRC Press, Boca Raton, Florida, United States, 1999), pp. 400.

4. Ferrocement Construction Manual by Dr. D. B. Divekar-1030, Shivaji Nagar, Model Colony, Pune.

5. Concrete Mix Design by A. P. Remedios, Himalaya Publishing House.

6. ACI 306R-16: Guide to Cold Weather Concreting.

7. American Concrete Institute, Report on High-Strength Concrete, ACI 363R-10, Farmington Hills, MI, March 2010.

8. Real, S.; Gomes, M.G.; Rodrigues, A.M.; Bogas, J.A. Contribution of structural lightweight aggregate concrete to the reduction of thermal bridging effect in buildings. Constr. Build. Mater. 2016, 121, 460 - 470.

9. Vijayalakshmi, R.; Ramanagopal, S. Structural concrete using expanded clay aggregate: A review. Indian J. Sci. Technol. 2018, 11, 1 - 12.

10. Klyuev, S.V.; Khezhev, T. A.; Pukharenko, Y.V.; Klyuev, A.V. To the question of fiber reinforcement of concrete. Mater. Sci. Forum 2018, 945, 25 - 29.

11. Fediuk, R. S.; Lesovik, V. S.; Svintsov, A. P.; Mochalov, A.V.; Kulichkov, S.; Stoyushko, N.Y.; Gladkova, N. A.; Timokhin, R. A. Self-compacting concrete using pretreatmented rice husk ash. Mag. Civ. Eng. 2018, 79, 66 - 76.

12. Svintsov A. P., Cisse A. Thermal processing of fresh concrete with infrared radiation. Structural Mechanics of Engineering Constructions and Buildings. 2021; 17(5): 528 - 537.

13. Wang, M.; Cao, P.; Wan, W.; Zhao, Y. L.; Liu, J.; Liu, J. S. Crack growth analysis for rock-like materials with ordered multiple pre-cracks under biaxial compression. J. Cent. South Univ. 2017, 24, 866 - 874.

14. Lou, Q.; He, X.Q. Experimental Study on Infrared Radiation Temperature Field of Concrete under Uniaxial Compression. Infrared Phys. Technol. 2018, 90, 20 - 30.

15. Sun, H.; Liu, X. L.; Zhang, S. G.; Kumar, N. Experimental investigation of acoustic emission and infrared radiation thermography of dynamic fracturing process of hard-rock pillar in extremely steep and thick coal seams. Eng. Fract. Mech. 2020, 226, 1 - 10.

16. Miao, B.; Wang, X.Y.; Li, H. R. Quantitative analysis of infrared thermal images in rock fractures based on multi-fractal theory. Sustainability 2022, 14, 6543.

17. Hao, J. W.; Qiao, L.; Li, Z. J.; Li, Q. W. Analysis on rock fracture signals and exploration of infrared advance prediction under true triaxial loading. J. Mater. Civ. Eng. 2022, 34, 04022058.

ТЕРМООБРАБОТКА БЕТОНА В ХОЛОДНОЕ ВРЕМЯ ГОДА

М. И. Абу Махади* Г. Э. Окольникова * / ** М. А. А. Обейд * Ф. Ш. Акоев * М. Киссани*

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* Российский Университет Дружбы Народов (РУДН), г. Москва

** Национальный исследовательский Московский государственный строительный университет (НИУ МГСУ), г. Москва

Аннотация

Бетон является очень прочным материалом, но со временем начинаются процессы его разращения под воздействием негативных факторов, например таких как процесс замораживания и оттаивания в зимний период года. Одной из самых распространенных проблем, с которой сталкиваются строители при работе с бетоном в холодное время года, является применение термообработки для ускорения твердения бетона. При термообработке бетон подвергается воздействию температуры выше его точки замерзания, чтобы улучшить его процесс схватывания и твердения. Есть несколько факторов, которые необходимо учитывать перед термообработкой бетона. К ним относятся климат, тип бетона и возраст бетона. Климат является наиболее важным фактором, поскольку от него будет зависеть диапазон температур, который

может выдержать ваш бетон. Часто некоторые инженеры прибегают к использованию более дорогих методов из-за отсутствия достаточного опыта для решения таких задач. В данной статье приводится обзор оптимальных способов, которые эффективно применяют для ускорения твердения бетона в зимний период времени с целью предотвращения замерзания и сохранности бетона в оптимальном состоянии.

Ключевые слова

обработка бетона, выдержка бетона, технология бетона, прочность бетона, инфракрасное излучение, монолитные железобетонные конструкции

Дата поступления в редакцию

10.06.2023

Дата принятия к печати

15.06.2023

Ссылка для цитирования:

M. I. Abu Mahadi, G. E. Okolnikova, M. A. A. Obeid, F. Sh. Akoev, M. Kissani. Heat treatment of concrete during the cold season. — Системные технологии. — 2023. — № 3 (48). — С. 5 - 14.