WHITE CEMENT IN
SUSTAINABLE DEVELOPMENT
Y.C.P RAMANA BABUStudent, Department of Civil Engineering, KL University, Vijayawada, Andhra Pradesh, India
ramanababu91@kluniversity.in
B.SAI DOONDI
Student, Department of Civil Engineering, KL University, Vijayawada, Andhra Pradesh, India
doondiwithlove@gmail.com
N. M .V .VAMSI KRISHNA
Student, Department of Civil Engineering, KL University, Vijayawada, Andhra Pradesh, India
NMVVK.1720@gmail.com
K.PRASANTHI
Assistant Professor, Department of Civil Engineering, KL University, Vijayawada, Andhra Pradesh, India
prasanthikatneni@kluniversity.in
Abstract:
India is one among the fast developing countries in the world in the areas of Infrastructure. Now a day, Carbon monoxide (CO) and carbon dioxide (CO2) are the temporary atmospheric pollutants in the environment chiefly emitted from the fuel burning vehicles and street lights which lead to global warming and pose a major threat to the survival and sustainable development. This paper deals with the principal purpose of use of white cement in pavement design which will take care of the Green house gases (i.e., CO and CO2) and also saves lot of money
in the long run process. A small amount of these gases in environment can cause major problems over time. Use of white cement in composite pavement design where there is heavy traffic loads are acting as well as number of vehicles are more such as junctions, bus stops, check posts etc., can perform better and acts as environment friendly. Its light colour reflects more than bituminous pavement so that it can be easily identified and avoid accidents to some extent. White cement helps to lower the average bus stop, junction temperature providing comfort to the people because it has high solar reflectance there by reducing “urban heat island” effect. In addition to this it has some more advantages which increase the sustainability, durability and workability of the pavements.
Keywords—White cement, Green house effect, Heat island effect, Ultra thin pavements, Reflective surfaces.
1. Introduction
Development of road infrastructure is currently being given high priority by the government of India. Recently Government of India has sanctioned funds for development of 38,500 km road network. Generally cities and urban areas are heavily populated and the temperature is about 4° to 10°F (3° to 5°C) warmer than the surrounding area due to various reasons like Vehicular emissions, solar Radiation, Carbon dioxide concentration etc [1]. CO2 is a temporary atmospheric pollutant in the environment, which leads to global
warming and pose a major threat to the survival and sustainable development and also cause discomfort to the public by increasing temperature [2].Large amounts of rice husk ash RHA are produced every year worldwide, and difficulties related to its disposal may cause this product to become an environmental hazard. It is shown that up to 15% of OWRHA could be advantageously blended with white cement to enhance white concrete performance without modifying the aesthetics of the final product [3]. Due to urban heat island effect, the urban heat islands are primarily attributed to horizontal surfaces such as roofs and pavements that absorb solar radiation. The temperature of the surface depends on the surface reflectance and emittance as well as solar radiation. By considering these factors, this paper provides solutions for both environment as well as economical prospective concerned.
2. White cement in sustainable pavement design
Going to eco-friendly application of white cement in the pavements design there are two types of pavements associated with concrete mix they are rigid pavements and ultrathin concrete pavements (flexible pavement with thin layer of concrete layer on top).While designing the pavements, strength, visibility, skid resistant, super elevation, sight distance, and permeability are taken into consideration. The utilization of white cement (partially replaced) as a portion of mix in the pavements will result in increased improvement of these properties thereby increasing its efficiency, durability and structurally fit for all types of environment conditions thus making it as a sustainable eco-friendly pavement [5].
Pavements can performs better with white cement because white cement is finer thus by filling the voids created by grey cement and it acts as a impermeable layer thus stop the flow of water into the pavement thus preventing it from rutting of the pavement [6]. Therefore the strength increases; colour also changes and differs for various grades.
3. Heat balancing with white cement
On those sweltering summer days—when it's too hot to play at the playground, when it seems like you could fry an egg on the pavement, when your car feels like an oven after a couple hours parked at the mall—it's not just the beating sun that's driving up the temperature. It's our very urban environment, in which most of our paved surfaces are dark, absorbing almost all of the sunlight that shines down on them.
Generally a city covers 45% of pavements, 35% of roofs of the buildings and the rest of 20% by other sources
which are directly exposed to the suns heat. Although the earth receives energy continuously from the sun,
much of the absorption of the terrestrial radiation in the atmosphere is done by carbon dioxide and water vapour. If the amount of such constituents of the atmosphere increases, the temperature will rise and cause the adverse effect on the environment [7]. By using white cement as a constituent we can minimize and maintain the same temperature on the earth surface.
Assuming 100 units of energy reaching the top surface of the earth, 14 units are absorbed directly by the atmosphere, and 35 units are lost to the space through reflection. The remaining 51 units reach the surface and absorbed by the earth (Figure 3) due to which the surface gets heated up.
Figure.1 Heat Budget
In this paper, it is proposed to minimize the 51 units of the sun heat which is absorbed by the surface by the use of white cement. Mostly sun’s energy is directly absorbed by the dark coloured pavements there by passing into the ground surface resulting in the increase of temperature of the earth. If pavements are designed in such a way that these 50 units of energy reduces to 20 - 25 units, it will be a revolutionary change in the environment and today’s world.
4. How this heat budget can be achieved with white cement?
resistance, sight distance, super elevation etc. It is considered optimum solar reflectance between 0.48 – 0.54 to reduce the glaring effect. The white coloured surfaces are more inviting and can increase safety at night.
Figure.2 Illustration of the temperature difference between different pavement surfaces
The Tropical Zone receives more heat than Temperature zone and Frigid Zone because the sun rays fall vertically on these regions. In this paper, few cities having different temperatures is considered. Based on the temperature, calculated the various mix proportions required to minimize the temperature of the city with optimum Solar Reflective Index.
TABLE 1 Mix proportion for the selected Cities
S.No Name of the City Temperature of the City
Mix Proportion
SRI White Cement Grey Cement
1. Mysore (Karnataka) 25 ° 20% 80% 0.42
2. Hyderabad (A.P) 30° 23 % 77% 0.45
3. Mumbai 35° 28% 72% 0.48
4. Vijayawada(A.P) 40° 32% 68% 0.51
5. Tuni (A.P) 45° 35 % 65% 0.54
5. Rice husk ash as a partial white cement replacement
A percentage of WPC as high as 15% by weight can be replaced with OWRHA without any adverse effect on strength properties. About 70-million tons of rice husk ash RHA is produced annually worldwide FAO 2009, and since the husk does not biodegrade or burn it is considered as an environmental nuisance. When burned, the ash of rice husk contains the highest proportion of silica among all the plant residues, nearly 20% silica in amorphous [3]. Under controlled combustion conditions, this by-product can produce amorphous silica with high reactivity properties of mortars containing different percentage of RHA and noted not only an increase in compressive strength but also a reduction in water absorption characteristics and in oxygen permeability [5]. Cost reduction, performance, durability, and environmental concerns are the primary characteristics that can make RHA a valid alternative to partially substitute Portland cement.
6. Sustainable pavements provide comfort to the public when used in bus stands, railway stations, bus stops, junctions
It is very difficult to maintain air conditioners in bus stands, bus stops, railways stations and also costliest thing which government couldn’t step forward keeping long run budget into consideration. Keeping both factors into consideration we have come up with a new idea i.e. use of white cement in those areas will increase the comfort of the people. When white cement is used as flooring or pavers in those areas due to its high solar reflectance the areas are somewhat cooler when compared to the surrounding area thereby reducing the sweating of the people.
Generally in bus stops, bus stands, railway stations the concentration of CO2 is more due to more density of population so as to reduce its concentration we add little amounts of wallastonite to the white cement as a admixture it absorbs CO2 from the atmosphere thus making white cement as a eco-friendly CO2 absorbing cement.
7. White cement concrete require lesser illumination during night that often saves electricity
Figure. 3 Maintainance cost and no. of electric poles required per kilometer
Figure. 4 Light absoption and reflection between the different pavements
Figure. 5 More Refletiveness in white cement than normal cement
Our study comprises of some of the cities like Hyderabad, vizag, Vijayawada, In these cities approximately 8,00,000 streetlights are set up throughout the city. The amount of electricity spent by the government in this area is Rs. 2,88,00,000 per day. If we develop the pavements with high solar reflectance we can reduce the number of streetlights to 6,00,000 thereby reducing the cost to Rs.2,16,00,000.Hence about Rs.72,00,000 per day would be saved by the government and also we can reduce the temperature making the environment eco-friendly as well as economically preferable keeping long term effects in mind which is a revolutionary change. And that is possible only through white cement.
8. Check for major drainage problems
localized springs. The detrimental effects of water, when entrapped in the pavement structure, can reduce the strength of unbounded granular materials and sub grade soils and also affect the ground water.
9. Ultimate Solution – Use of white cement as a seal
The detrimental effects of water on pavements can be minimized by preventing it from entering the pavement by providing a seal which restricts the flow of water or by building the pavement strong enough to resist the combined effect of load and water. The prevention of water from entering the pavement structure requires intercepting groundwater and sealing the pavement surface and it can be achieved by white cement. As a result, complete prevention is possible during the useful life of a pavement. To minimize the infiltration of surface water into the pavement, a good surface white concrete seal is always required.
10. Conclusion
1.
White cement continues to play a pivotal role in overall economic growth both locally and globally.2.
Heat maintaining in the city, lowering the electricity cost for street lighting, Improvement of Indoor air quality as well as outdoor air quality are associated with light colour surfaces that is possible only with white concrete surfaces.3.
In order to improve the sustainability of all concrete structures, there is a need to understand the interactive effect of the many issues from ‘cradle to grave’ in the design phase, during construction and end-of-life and, most importantly, the energy savings achievable during the entire life of the structure.4.
Most importantly, the paper describes the role which white cement concrete can play in contributingto the sustainability of our infrastructure. References
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