Introduction
Mankind is constantly developing and striving to introduce more environmentally friendly alternatives to any processes in life. This is explained by the fact that the environment cannot be neglected to achieve results, because this will lead to negative consequences. One of the innovations in the field of production and construction is dry ice, which practically does not harm nature. It is necessary to explore in more detail exactly in which cases dry ice is used, what are the alternatives and why this method is extremely dangerous when interacting with concrete.
Usage
Carbon dioxide is suitable for gentle cleaning of a variety of surfaces where abrasives are prohibited. The use of dry ice in everyday life is cryogenic blasting, which is actively spread all over the world. It is based on jet spraying of granular dry ice. This treatment is better than steam, sandblasting, abrasive or water blasting because it does not leave solid or liquid particles at the work site (Bolland & Nord, 2020). The reagent evaporates completely, taking on a gaseous form.
In the household area, this reagent may be needed for:
- Rodent control. If person pour a granular agent into the mink of animals, then carbon dioxide will displace oxygen after a certain time, thereby stopping air from entering the lungs of a rodent (Bolland & Nord, 2020). To achieve the maximum result, it is essential to find out if the hole has several exits.
- Flash removal. This tool is used to eliminate burrs and flash from vinyl, rubber, PVC and plexiglass products.
Industry Integration
The solid form of carbon dioxide is widely used to solve various industrial problems. A feature of this substance is the absorption of the thermal energy of the environment during the transition from a solid to a gaseous state – its uniqueness lies in the fact that the liquid stage is excluded. For example, in order to dismantle floor tiles as soon as possible, and avoid tedious chipping or breaking them off piece by piece, it is enough to scatter a handful of ice on the surface to be dismantled (Mindess, 2019). Due to the thermal difference, either the tile or the solution on which it is fixed will shrink. Thus, one or two tiles can be dismantled, after which all the rest can be easily beaten off with a hammer.
Benefits of Using Carbon Dioxide
This drug attracts large and small manufacturers with a number of advantages:
- Ease of use;
- Environmental safety;
- Lack of toxicity;
- Non-flammable – extinguishes the flame of gasoline;
- Efficiency – the indicator exceeds the water analogue by 2 times (Mindess, 2019);
- Affordable price.
The properties of this substance are widely used in research experiments, as well as in various areas of production. Dry ice is used as an inhibitor by many chemists: the cooling that is obtained during sublimation slows down chemical reactions. This property is used to neutralize alkali and in the transport of adhesives (Mindess, 2019). The inertness of the gas is used to displace oxygen, which is in demand when dismantling underground tanks designed to store combustible gases and liquids. The substance is used to form excess pressure inside the container.
Dry ice is used in industry for surface treatment by blasting. For this purpose, the granules are placed in special equipment – an installation, accelerated with high pressure and vacuum to supersonic speed, and fired at the surface to be cleaned. When it contacts with another materials, the granules peel off grease stains, varnish, rust, paint, glue and more with the help of a temperature difference (Mindess, 2019). The advantage of this method is that carbon dioxide evaporates quickly, leaving no traces on the surface – neither solid particles nor liquid spots. In the manufacture of metal products (agricultural greenhouses, equipment, frames), burrs and flash are removed with carbon dioxide (Mindess, 2019). The same procedure applies to PVC, vinyl and rubber products (Mindess, 2019). Another option for using the drug is the dismantling of metal parts, such as bushings or bearings. In this case, the substance is added to 90% alcohol, which allows it to cool to its melting point – then it is used in a similar way to liquid nitrogen (Novothy, 2020, p. 72). Another area of industrial application is tank degassing. This procedure can be performed effortlessly: the granules are poured into the tank, the gas formed during the sublimation process rushes to the exit from the tank, taking with it all the impurities and impurities (Novothy, 2020). In computer manufacturing, ice is used to cool processors.
Applications of Carbon Dioxide in Construction
Cryogenic blasting is widely used in the construction industry to clean ceilings, walls, floors, monuments and facades. The essence of the process is as follows: the substance hits the surface at a speed close to sonic – an explosion occurs from the impact, which repels pollution. “Thermal shock” helps to reduce the adhesion between the contamination and the material due to the difference in their coefficients of linear expansion. In shipbuilding, the substance is actively used for jet cleaning of metal structures (Novothy, 2020). Carbon dioxide is used to remove ceramic tiles (Novothy, 2020). If person pour a little ice on the surface, the tile cools and shrinks – it will be much easier to remove it.
Abrasive Processing with Organic Materials
Organic materials such as ground corn on the cob and ground nut shells are non-toxic and environmentally friendly soft materials that are good at removing paint and dirt from wood substrates. It produces a small amount of dust, but do not chip as effectively as harder, more “angular” materials, and are relatively expensive (Lauritzen, 2018). It makes them less than ideal for large projects, especially when the materials are not recyclable.
Abrasive Dry Ice
Dry ice leaves nothing for further cleaning, except for knocked-out contaminants. Dry ice is an indispensable method of getting rid of mold. The distinguishing feature of dry ice is that it sublimates (transforms from a solid to a gaseous state) and leaves no waste abrasive for cleaning and removal (Lauritzen, 2018). This is beneficial when working in attics or other tight spaces, especially if person is lying on back and blasting over his head.
However, the fact that a material sublimates does not mean that there are no residues to clean up. Whatever contaminants are removed from the substrate must be swept or vacuumed afterwards, so the amount of material to be recycled is reduced, but not removed, and this does not lead to significant savings in time or labor (Lauritzen, 2018). In addition, the use of dry ice creates logistical problems, especially on large projects: the material is supplied in large containers, their performance decreases over time, and eventually it breaks down.
Abrasive Treatment Based on Soda
Baking soda is an abrasive material widely used to repair fire damage. Its “angular” shape provides good cutting performance for such soft media (2.5 Mohs) and deodorizes surfaces on contact (Mindess, 2019). Baking soda is biodegradable but will kill vegetation, so insulation is required when doing abrasive work outdoors. Indoors, baking soda produces a strong dust that can cause indoor visibility problems and requires complete isolation, negative air pressure, and ventilation, especially when working with mold (Croft et al., 2018). It is critical that displaced spores do not circulate in untreated areas.
Such deficiencies can be remedied to some extent by suppressing dust and churning out airborne mold and soot with water. This can be achieved with a water injection nozzle or a special ring through which water is injected into the air stream. The disadvantage of this approach is that a large amount of water is required for significant dust suppression, resulting in a slurry that must be isolated and disposed of (Croft et al., 2018). Baking soda is an excellent option when surface damage is to be avoided.
Steam Cleaning
Steam blasting removes contaminants at a rate comparable to sandblasting, using a fraction of water and abrasive. Steam blasting is an intermediate process compared to soda-based blasting. In the waterjet cleaning process, soda and water are stored in a pressurized tank and then pushed out into the air stream (Havercroft et al., 2018). The soda particles are encapsulated in the water jacket, but there is no excess free water. When particles are dispersed on impact, small particles that are normally airborne are trapped in the water jacket and land on the floor where they can be swept or vacuumed (Novothy, 2020). Water blasting with soda gives the same results as dry blasting with soda, while significantly reducing the level of dust. For maximum performance, nothing beats the use of solid material. Organic materials, dry ice and soda do not have the same cutting power as glass shot, glass beads or small garnet (Havercroft et al., 2018). However, dry blasting equipment cannot effectively blast at low enough pressure to remove contaminants without damaging the substrate.
Unlike dry blasting, water blasting can process hard materials at low pressure. Wet material carries more mass, and upon impact with the surface, high-velocity water acts on the contaminants, tearing and flaking them from the substrate (Litvinenko, 2019). The impact applies more force, but over a larger area, minimizing surface profile while delivering high performance. With glass beads, glass shot and fine garnet, 25-55 psi waterjet cleaning is suitable for cleaning wood, brick, restoring monuments and other treated concrete surfaces, soft stone and aluminum (Litvinenko, 2019, p. 107). At pressures of 56–90 psi, waterjet is suitable for cleaning raw concrete. The decisive advantage of waterjet cleaning is its versatility. New generation waterjet cleaning equipment can clean sensitive substrates with mild abrasives up to 25 psi inch (Litvinenko, 2019, p. 98). Then switch to coarse garnet or coal slag for blasting heavily corroded and heavily coated steel, all the way to blasting white metals at pressures up to 170 psi inch in nozzle (Litvinenko, 2019, p. 121). No other tool allows solving such a wide range of tasks in restoration and surface preparation.
Effect of Dry Ice Cleaning on Concrete
Based on the foregoing, it must be emphasized that dry ice as a tool is suitable only for those surfaces that must be left intact after the interaction. However, this is not the case with concrete, as granules and dry ice exhalations cause the material to disintegrate. Initially, before becoming hard, concrete is in a state of dust, which is kneaded together with other elements (Havercroft et al., 2018). Dry ice can lead not only to cleaning the concrete area, but to the release of concrete dust, which, mixed with fumes, will fill the air (Novothy, 2020). This will lead to three negative consequences at once, which will be difficult to eliminate.
A sharp increase in the amount of concrete particles and dust will lead to air pollution, which will prevent the normal breathing of living beings. Dry ice is perceived as an environmentally friendly method used in industry (Havercroft et al., 2018). However, in the case of interaction with concrete, this advantage is not only leveled, but, on the contrary, creates a large amount of environmental pollution. Despite the fact that concrete dust will stay in the air for a relatively short amount of time, a second negative consequence follows from this.
After the stage of evaporation of dry ice is over, the concrete particles will be heavier than air in its pure form. This will cause the contaminants to settle on all surfaces where there has been evaporation. In addition, the dust will be carried by the wind, which means that the area of pollution increases significantly (Havercroft et al., 2018). This will lead to the fact that, firstly, the cleaning will be ineffective, since it will lead to the formation of a layer of dust, and, secondly, to a detrimental effect on plants, mail quality and insects. Dust that has settled in the environment will stay there for a long time, gradually penetrating deeper into nature (Croft et al., 2018). The situation is aggravated by possible rains, dust sticking to animals, as well as winds (Croft et al., 2018). Thus, despite the local application of dry ice to concrete, the area of damage and the consequences of this are much larger and more serious.
Finally, it is worth highlighting the negative impact of the interaction of concrete and ice on the very quality of the building and material. Due to the fact that the concrete blocks and the surface are subjected to partial decay, it is deformed from this. This, in turn, leads to weakening of building structures and building foundations (Croft et al., 2018). Depending on the doses of dry ice, such an effect can be fatal, after which the use of the room or surface for its intended purpose will not be possible.
Due to the fact that the interaction of dry ice and concrete generates a large number of risks, the materials are not recommended to be used with each other. However, this does not mean that concrete cannot be cleaned or interacted with, but that alternative processes are needed, already discussed in this text above. However, the use of dry ice on concrete not only eliminates all the positive aspects of this method, but creates a threat to the environment and people.
Conclusion
In conclusion, it should be noted that dry ice is an effective and environmentally friendly modern method that is used in construction and production. In addition, one of the advantages is the availability of the material and ease of use, but specialists need to control the nuances. For example, dry ice is forbidden to be used with concrete, because the uniqueness of the materials does not synergize with each other, but creates great threats to people and the environment. The greatest danger in this case is concrete dust and surface deformation, which are the consequences of dry ice evaporation.
References
Bolland, O. & Nord, L. O. (2020). Carbon dioxide emission management in power generation. Wiley.
Croft, C., Ostergren, G., & Macdonald, S. (Eds.). (2018). Concrete. Case studies in conservation practice. Getty Conservation Institute.
Havercroft, I., Hon, R. M., & Stewart, R. (Eds.). (2018). Carbon capture and storage. Emerging legal and regulatory issues. Bloomsbury Publishing.
Lauritzen, E. K. (2018). Construction, demolition and disaster waste management. An integrated and sustainable approach. CRC Press.
Litvinenko, V. (Ed.). (2019). Scientific and practical studies of raw material issues. CRC Press.
Mindess, S. (Ed.). (2019). Developments in the formulation and reinforcement of concrete. Elsevier Science.
Novothy, V. (2020). Integrated sustainable urban water energy, and solids management. Achieving triple net-zero adverse impact goals and resiliency of future communities. Wiley.