Use of Smog Eating Concrete in Road Construction

Ramya HN, Darshan MN^*, Naveen kumar GS, Gangashree AB and Sagar KS
^*Correspondence: Darshan MN, Department of Civil Engineering, Channabasaveshwara Institute of Technology, India, Email:

Keywords

• Pollution • Smog eating concrete • Titanium dioxide • Photocatalysis

Introduction

Cever since the beginning of industrial revolution, the entire planet has combatted the side effects of expanded usefulness i.e., pollution. Since the mid-1800’s, pollution levels are expanded at a fast rate. All the more as of late, pollution has been checked by the United Nations. Air pollution may causes diseases, allergies and even death to humans, it may also cause harm to other living organisms such as animals and food crops and may damage the natural environment such as climate change, ozone depletion, acid rain, etc. in recent years World health organization sets the limit for some pollution causing gases i.e. molecular matter was restricted to somewhere in range of 10 μg/m³ and 20 μg/m³, depending on size, nitrogen oxides to 40 μg/m³, sulphur dioxide to 20 μg/m³ and ozone to 100 μg/m³. These pollutants are mainly contributing to the buildup smog [1].

Presently, the world health organization exposes that 92% of the total population lives in the regions where in polluted areas i.e., air quality has not met to standards. Due to this pollution and pollution causing gases in the atmosphere many of human beings are suffering from many health issues such as chest pain, coughing, reduced resistance to infections, and fatigue, to more serious problems such as acute bronchitis, aggravated asthma, and development of chronic respiratory illnesses, irregular heartbeat and premature death [2]. The human health effects of poor air quality are far reaching, but principally affects the body’s respiratory system and cardiovascular system. The outdoor air pollution alone causes 2.1 to 4.21 million deaths annually. Overall, air pollution causes 7 million people worldwide each year, and is the world’s largest single environmental health risk.

Objectives

• All The main objective of our project is to make our environment “GREEN”

• To reduce harmful pollutants (NOx, Cox, HC, organic matter) are formed by vehicle combustion.

Materials and Methodology

The fallowing materials are generally used to produce smog absorbing concrete:

• Cement

• Aggregates

• Titanium dioxide

Cement

Cement is a binder, a substance used for construction that sets, hardens, and adheres to other materials to bind them together and also; it fills the fine voids in concrete. A cement is seldom used on its own, but rather to bind sand and gravel together. Cement mixed with fine aggregate produces mortar for masonry or with sand and gravel produces concrete.

Specific gravity test-3.15

Fineness modulus test-95.45%

Initial setting time-42 mins

Final setting time-10 hrs.

Aggregates

The particle size distribution of an aggregate as determined by sieve analysis is termed as grading of aggregate. If all the size of an aggregate are uniform size. Compacted mass will contain more voids; whereas aggregate comprising particulars of various sizes will give an ass contains lesser voids between larger particles.

The proper grading of aggregate produces a dense concrete and need less quantity of aggregate, cement, pastes. Therefore, it is essential that the coarse aggregate be well grade to produce quality concrete.

Fine aggregate: Specific gravity: 2.65; Water absorption test: 0.9%

Coarse aggregates: Water absorption test: 0.5%; Impact test: 13.67%; Specific gravity: 2.64

Titanium dioxide

Titanium dioxide is also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula Tio₂. Figure 1 shows cementations material which can replace cement concrete for some extent. As titanium dioxide blended in concrete, it helps concrete to absorb pollution from air and concrete made is self-cleaning concrete so pollution absorbed on surface of concrete in the form of powder can be washed by water. Titanium dioxide accelerates the reaction of conversion of harmful pollutants into harmless pollutants.

Chemical formula: TIO₂

Molar mass: 79.866 g/mol

Density: 4.23 g/cm³

Melting point: 1843-degree celcius.

Boiling point: 2972-degree celcius.

Specific gravity: 3.1

Results and Discussion

• Firstly, take all the materials, equipment or necessary things i.e., cement, sand, aggregates, Titanium dioxide, water, and concrete mould (150^*150^*150 mm).

• The cement and aggregates are mixed together with the replacement of cement with titanium dioxide by 2% and make the concrete cubes of mix M30.

• Increase the percentage replacement of titanium dioxide from 2% to 5% and cast the concrete cubes. And also cast the concrete cubes without replacing Tio₂.

• Place the concrete cubes into water for curing for 7 and 28 days.

• After curing period check the smog absorbing capacity of concrete cubes by the use of Multi gas analyzer machine.

• After smog absorbing test, check the compressive strength of concrete cubes. And compare the results.

Working principle and its mechanism

Photo catalytic process: Figure 2 shows oxidation of various molecules, including the pollutants in the air and on the surface, as well as the formation of hydroxyl and oxygen radicals from water and oxygen in the air. The products of these reactions then form salts. The salts are then washed off of the surface efficiently due to the super hydrophilicity of titanium dioxide [3-6]. When water normally encounters a surface, it tends to bead up due to the combination of the surface tension of the water and the difference in polarity between the water and the surface. Since both water and titanium dioxide are polar, they tend to be attracted to each other. This attraction is strong enough to compensate for the water tension, and as a result, water will run as a sheet rather than droplets across the surface, allowing for a more complete wetting of the surface [7].

Mix proportions

Table 1 shows Mix proportions for M25 grade concrete and Table 2 shows finalized mix proportions for various percentage of Tio₂.

Tests conducted

• Workability tests on concrete-confirming IS:1199-195

• Compressive strength of concrete-confirming IS 516:1959

• Smog absorbing test

Smog absorbing test

Apparatus: Two wheeler, glass chamber having two holes for inlet and outlet, concrete and mortar cubes, two pipes, multi gas analyzer.

Setup: Prepared a glass chamber having size 40 cm x 30 cm x 30 cm with two holes on cover of chamber.

1. From one hole we were supplying polluted air through the silencer of petrol engine vehicle.

2. Second hole was for the checking quality of air passing over the concrete block with the help of multi-gas analyzer machine’s probe.

3. multi-gas analyzer has a facility of providing the quantity of different pollutant.

4. The pollutants checked by the multi-gas analyzer are, CO, CO, HC (hydrocarbons).

Conclusion

The blocks prepared by replacing cement with titanium dioxide will reduce the harmful pollutants such as carbon oxides (CO_x), nitrogen oxides (NO_x), hydrocarbons (HC), particulate matter etc.

• As TiO₂ is cementitious Nano material so there is not any change in compressive strength of concrete

• This photocatalytic concrete is quite expensive, but it reduces more pollution which can save thousands of life

• The percentage replacement of TiO₂ in concrete shall be in between 2% to 3%, at which it is most economical and most helpful to reduce harmful pollutants such as HC and CO₂

References

1. Ritchie, H and M Roser. â??Air pollution.â? Our World in Data 2 (2018): 11
2. Clean Air Technology Center. â??Nitrogen oxides (NO_x), why and how they are controlled.â? Environmental Protection Agency 11 (1999)
3. Rao, TN, Tryk DA and Fujishima A. "Titanium dioxide photocatalysis," J Photochem and Photobio C (2000): 1-21
4. Henderson, MA. "A surface science perspective on TiO₂ photocatalysis.â? Surface science report 66 (2011): 6-7
5. Janes, PA, NG Jones, JA Nicholson, and KR Hallam, et al. "Photocatalytic oxidation of NO_x gases using TiO₂: A surface spectroscopic approach." Environmental Pollution 120 (2002): 415-422
6. Cassar, L. "Photocatalysis of cementitious materials: clean buildings and clean air." Mrs Bulletin (2004)
7. Ndour, M, Conchon P, D Anna, and B Ka, et al. â??Photochemistry of mineral dust surface as a potential atmospheric renoxification process.â? Res. Lett 36 (2009): L05816