2. INTRODUCTION
• Pollution- mass destruction of environment -mainly
air pollution.
• Reduces -air quality- vicinity of large cities and
travel long distance -produce ozone.
• Negative impact - human health -respiratory
problems, acidifies lakes, deterioration of buildings
2
4. Main polluting agents :
• Cars emissions
• Power plants, industries, incinerators
• Heating of fossil fuel
• Pesticides
• Mining and agricultural operations
4
Vehicles emitting polluted
smoke:
5. Major Pollutants :
• Sulpur dioxide
• Nitrogen dioxide
• Volatile organic compounds
• Carbon monoxide
• Nitrogen dioxide -air pollutant - present in the atmosphere
more -due to smog ,smoke etc.
• Solution -problems -self cleansing concrete -not only
keeps itself clean -improve the air quality near by. 5
6. TITANIUM DIOXIDE AS PHOTOCATALYST
Principle behind self cleansing concrete is
photocatalytic effect of TiO2
Increases rate of reaction by absorbing sun light
and without being consumed
TiO2 through its process of oxidises the NOx into
NO and NO2 in powdered form
TiO2 is hydrophilic, attracts water between dirt and
surface
Washing off dirt
6
8. PHOTOCATALYST IN SELF CLEANSING
CONCRETE
Similar to M20 grade concrete
Addition of 3.5% to 4% of Tio2 to the 96.5% of
cement
Without -chemical admixtures
Nox level -reduced by 20% to 80%
Removal of unpleasent odour due to pollutants.
Reduces microorganism - bacteria, fungi
8
9. WORKING OF SELF CLEANING
CONCRETE
• Self cleaning effect -oxidation promoted by sunlight
• Photo induced hydrophilicity
• Decomposed pollutants - dirt over-surface
• Removed- rain fall or manual rinsing
• Light and heat should hit the surface of concrete
• Reaction takes place
9
10. MECHANISM
• UV light falls over the concrete surface
• Two photo induced process occurs:
a. photo induced redox reaction
b. photo induced super hydrophilicity
10
12. • Tio2 absorbs energy - electron hole pair further they
form OH radicals
• Hydroxyl radical attack harmful pollutants
• Decomposes-form harmless sulphate, nitrate,water ,
carbon dioxide
• By products - small quantity
12
14. SUPER HYDROPHILICITY
Hazardous gas –decomposition-powdery particle and
stay over-building like a dust
Super hydrophilicity is Occurrence of water contact
angle
TiO2 bond - broken down -Ti-OH bonds resulting in
super hydrophilicity
14
15. 15
• Absorbed water spreads out flat and rinsing the dusty
concrete surface
• Other source of rinsing is rain water or by manually.
Hydrophilicity of photocatalyst
(source:https//www.dogonews.com)
17. APPLICATIONS
Use of self cleaning concrete -widely accepted
Advantage -solar light and rain water -driving forces
TiO2 modified building materials-
cement,concrete,paving blocks etc.
De-polluting, self cleaning and self disinfecting
17
18. 18
Other applications are:
1. Paving tiles
2. Water purification system
3. Applied in tunnels
4. Pavements, road surfacing
5. Concrete masonry units, roof tiles and cement based
tiles
6. Precast and architectural concrete panels
19. PAVING TILES
• Tio2 used in concrete blocks for pavements
• Thin surface coating is provided
• Depolluting effect increases as close to source
19
Application of paving tiles(source:https//www.dissertations.wsu.edu)
20. • Removes nitrogen dioxide and VOC present - 200m3 and
60m3 per day
Self cleansing efficiency depends on :
a. Concentration of pollutants
b. Humidity of atmosphere
c. Temperature
d. Porosity of surface
e. Size of surface exposed
• Porosity of surface and concentration of TiO2 increases
depollution increases
• Deposition dust on surface reduces efficiency
20
21. WATER PURIFICATION
• Uses-Photo catalytic permeable concrete
• Waste water management system
• 20% void ratio is designed along with TiO2 content
• Most effective mix design
• Degradation of polyaromatic hydrocarbons in road
runoff
21
• Degradation of polyaromatic hydrocarbons in road
22. TUNNELS
• Tunnels - denser polluted atmosphere
• Large air pollution -by vehicles
• Photo catalyst is applied - sprayed coating over
concrete, cement plaster, tunnel vaults,ceillings
• Tunnel Pavement- provided -self cleaning concrete
• UV lamps –source-light
• Strengthening anti polluting effect
22
23. 23
• Safety aspect -visual comfort
• Reduce maintenance and cleaning
• Factors to be considered are:
a. Wind direction and speed
b. Moving traffic
UV lamps inside tunnel
24. 24
TiO2 coating is applied on concrete surface
(Source:https//:www.researchgate.com)
26. 26Before and after the renovation of the tunnel
(Source:https//:www.hsph.havard.edu)
27. MERITS OF SELF CLEANSING CONCRETE
Reduces Nox content in atmosphere
Keeps -concrete young
Depollute other pollutants
Eco friendly
Reduces depletion of ozone layer
Reduces- corrosion-patch formation in the concrete
Atmospheric pollution - reduced
27
28. CASE STUDY-1
Borg palazzo street-bergamo,italy
Requalification of pavement -length500m - surface area
7000m2
Grey concrete paving block - road and red blocks -side
walks
Monitoring campaigns:
Two campaigns conducted
Compared pollution levels - self cleaning and asphalt
pavements
Result obtained as pollution decreased 30% and 40%
28
29. Height
from the
ground
Concentration in
the Photo
catalytic
pavement
Concentration in
the Asphalt
pavement
(reference)
% difference
in the Two
monitoring
points
NOX NO NOX NO NO
X
NO
30cm 250ppb 194ppb 336ppb 270ppb 30 33
180cm 260ppb 201ppb 316ppb 248ppb 20 20
29
• Pollution decrease is compared to traffic
reduction of 150 cars/hour
• Smog from one car out of three is neutralized
Variation in concentration of NOX and NO values
30. 30
Performance test of installed concrete blocks:
• Dusty block from the street was collected
• After washing, cleaning and drying tested for self
cleansing activity
• Compared with newly manufactured ones
Block removed from pavement for testing
(Source:https//www.research.com)
31. 31
Results :
• regaining of original depolluting character
• Presence of dirt - reduce the self cleansing activity of
block
• Regular road cleaning
• Maintains good depolluting effectiveness
33. 33
CASE STUDY -2
The Dives misericordia church
• First photo catalytic cementitious material application
• Three white sails of precast concrete elements
• Tallest sail 26m height
• Sails subdivided into large double curvature precast
ashlars
• Weighing 12 tons each
• Aimed to use concrete of high strength, durability and
white colour
34. 34
• Aesthetics and eco-friendly benefits
• Used self cleansing concrete panels
Dives in misericordia church in rome
(Source:https//www.pinteres.com)
35. 35
Colour monitoring:
• Quantitative evaluation of surface by colorimetric system
• Three sail and northern wall are considered
• Examined the following chromatic components:
I. Red and green component
II. Yellowness
III. Luminance
Sails chosen for monitoring
36. 36
Results :
• Maintenance of colour of white concrete after
service life of 7 years
• Yellowness variation due to inorganic substances on
the surface
• Deposition of African sand carried by sirocco wind
• Water washing of surface recover the original
colour
• Less yellowness observed in northern wall
38. 38
Conclusion
• Self cleansing concrete is an eco-friendly approach
• Reducing harmful airborne pollutants
• Successful in vertical and horizontal applications
• Positive impact on roads ,cities ,global warming and
acid rain
39. 39
REFERENCE
1. Arafa Awadalla ,Muhammad Fauzi Mohd Zain,Abdul
Amir H. Kadhum and Zeinab Abdalla,(2011)‘‘titanium
dioxide as photocatalyses to creatself cleaning concrete
and improve indoor air quality”,international journal for
physical sciences vol.6(29),pp.6767-6774
2. E.Boonenetal (2015), “construction of photocatalytic de-
polluting field site in leopoldII tunnel in burssels”.journal
of environmental management,vol 155,pp.136-144
40. 40
3. Pawel sikora etal,(2015)“ The effect of nanaosilica and
titanium dioxide on the mechanical and self cleanin
properties of waste glass cement mortar”,7th Scientific-
technical conference material problems in civil
engineering,vol 108,pp.146-153.
4. Ranjit k.odedra , K.A.Parmar, Dr N.K.Arora,(2014)
“photocatalytic self cleaning concrete”, IJSRD-
International journal for scientific research and
development vol.1,pp.2521-2523.
41. 41
5. Kotresh K.M,Dr B.Sairam pattanaik,Mahaboob
patel,(2014) “Study on photocatalytic cement as
solution for pollution control”,Indian journal of
applied research,vol 4,pp.166-169.
