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Anuradhapura District is considered as one of the ancient capitals of Sri Lanka, famous for its well-preserved ruins of ancient Lankan civilization. The city, now a UNESCO world heritage site, lies 205 Km North of Colombo. The District is situated in the North Central Province of Sri Lanka with the extent of 7,128 km². The city of Anuradhapura is considered as a sacred place to the Buddhists which is surrounded by monasteries covering an area of over sixteen square miles. The Population of the District is by year 2008 amounted to 886,945.
The Anuradhapura District boundaries are surrounded with the boundaries of Putthalam, Mannar, Vavuniya, Trincomalee, Polonnaruwa, Kurunegala and Mathale Districts. Anuradhapura District includes major town like Kekirawa, Medawachchiya, Horawupotana, Kebithigollewa, Rabewa, kahatagasdigiliya, Nochchiyagama and Tambuttegama.
The city of Anuradhapura is mainly considered as the main central hub of transactions, businesses and exchanging of commodities in the North Central province after the Humanitarian operation. Therefore the transportation network of the District is very much important for the District to act as the central hub of the North Central Province.
Figure 1.1 Boundaries of Anuradhapura District
The transportation network in the District is mainly relies on Macadam type Tarred and Asphalt roads which is considered as the main blood vessels of Anuradhapura. But the available roads, especially the Tarred roads can not withstand the rough climate of the District and subjected to be dilapidated coursing frequent repairs. This will badly effect the smooth functioning of transportation network in the District creating traffic jams, causing damages to the vehicles and wasting man hours and fuel. Hence this situation is turning out to be a menace for the public who are using highways of Anuradhapura District as well as it effect the economy of the District which create unrest among citizens. Therefore this research is done to find alternative methods to construct highways and roads as well as searching for preventive methods that can be adapted to reduce the damage caused by the extreme weather conditions and various other aspects of the area to the road network of the District.
The aim of this paper is to logically convince the reader about the ineffectiveness of the available roads in the Anuradhapura District due to the rough climate conditions of the area. Therefore to eliminate the issue, logically explain the impotency of constructing concrete roads to replace the existing road network in the District.
The general objective is to discuss the ineffectiveness of Tarred roads in Anuradhapura District for road transportation due to extreme climate conditions in the area. Furthermore the paper will discuss the potential to replace the Tarred roads with Concrete roads to increase the durability and effectiveness of the road network in the District. Thereby achieving the prospect of a dream of acquiring a smooth, durable and efficient road transportation network to Anuradhapura District.
Other than General Objective, following specific objectives also will be discussed under this topic.
Reasons behind the inefficiency of Tarred road in the District.
Advantages and disadvantages between Tarred roads and Concrete roads.
Technology behind constructing Tarred roads.
Technology behind constructing of Concrete roads.
Other aspects that can be used to improve the durability and efficiency of the road network in the District.
The requirement of a reliable road network for the Anuradhapura District and it's effect to the economy and efficiency of the people.
Concrete roads are more reliable and durable than the Tarred and Asphalt roads. Therefore replacing the Tarred and Asphalt roads with Concrete roads will reduce the maintenance cost and increase the durability of the road network of the District as well as increasing the efficiency and effectiveness of the road network.
STATEMENT OF THE PROBLEM
Road network has been a major source of transportation in Anuradhapura District and the city is considered as the main central hub for exchanging of commodities in the North Central Province. The Anuradhapura District is in the middle of many supply routs and there are six highways going along the Anuradhapura District which connects the areas of North to South and East to West of the country. Hence the availability of reliable road network in the District will directly effects the economy of Sri Lanka. But presently the durability of road network in Anuradhapura District is drastically reduced due to the extreme climate situation in the area including increased heavy rains due to the climate changes which is experiencing in the region.
Therefore the aim of this research project is to identify the impacts that lead to degrade the tarred road conditions in the District and to recommend new technologies to uplift the durability and efficiency of road network and thereby effectively contribute to the economy of Sri Lanka.
Condition of road network in the District
Usage of roads by public
Weather condition of Anuradhapura
INDEPENDENT INTERMEDIATE DEPENDENT
VARIABLE VARIABLE VARIABLE
Figure 2.1 Conceptual description of the problem
SCOPE OF THE STUDY
The scope of the study covers an assessment of the durability, effectiveness and the cost worthiness of Tarred roads available in the road network of Anuradhapura District. Furthermore the paper will discuss the impacts of the climate changes such as extreme rainfall and increased temperature in the area to the existing road network and the potential to replace the Tarred roads with Concrete roads. The paper will focus on identifying the advantages and weaknesses of the above stated methods of road construction as well as other aspect pertaining to improve the road condition and thereby suggesting new methods which can be utilized for the development of road network in Anuradhapura District.
METHOD OF DATA COLLECTION
The required data for the research will be drawn from the following sources;
Primary source. Will include information collected by interviewing persons who are working in following government sectors:
The weather report in formation of Anuradhapura District was obtained by Mrs Rasika Disanayaka Metrology Department Colombo.
Road network of Anuradhapura District and other technical information was obtained by Mr DM Senarath Pushpakumara Chief Engineer Provincial Road Development Authority Anuradhapura
Tender prices information of Tarred roads and concrete roads were obtained by Mr TMRS Jayampathy Senior Engineer Municipal Council Anuradhapura.
Tender prices information of Asphalt roads were obtained by Mr Senanayaka Road Development Authority Anuradhapura.
General knowledge on road construction was obtain by Mr. Ruwan Jayawardhana, Engineer Gampaha Project Division RDA Colombo.
In addition to that Information and views were gathered from road constructing engineers, contractors, personal who are serving in Government and private sector and ordinary civilians who knows the technical aspect of the problem.
A questionnaire was distributed among a population sample of Anuradhapura District consist with the personal from public and public sector, service personal, students, house wives and farmers.
d. Secondary source. Information will be gathered from relevant books, journals and treatise as well as from the internet.
DATA ANALYSE TECHNIQUES
In the research paper both qualitative and quantitative methods were used to analyze the best road construction techniques which can be used for the road network in Anuradhapura District. A major portion of the analysis consists of quantitative analysis due to the nature of the subject.
THE ROAD NETWORK OF ANURADHAPURA DISTRICT
1. The road network of Anuradhapura District consists mainly with five types of roads which connects urban and rural areas of the District to the major cities of Sri Lanka. According to their sizes, usefulness, traffic capacity and the condition, the roads and highways are categorized as follows:
a. AA -Class Roads: These are the seven high ways which are going along the District. Those are Kandy to Jaffna highway (A 9), Puthlam to Trincomalee highway (A12), Mannar to Madewachchi highway (A 14), Anuradhapura to Padeniya highway (A 28) , Anuradhapura to Baticalo highway (A11), Anuradhapura to Galkulama highway (A 13) and Anuradhapura to Rabewa highway (A 20) which connects the areas of North to South and East to West of the country.
b. AB - Class Roads: This class of roads are the next level of hierarchy comprised mainly with Anuradhapura City roads as well as main roads which are driven to combine the towns of Anuradhapura District to highways. Some of these roads are as follows:
DS Senanayaka Mawatha
Maithripala Senanayaka Mawatha
Kalaththewa Mihinthale Junctin Mawatha etc.
B-CLASS ROADS: These roads are the next level of the hierarchy and distribute traffic between residential areas, industrial areas, town centers and feed the AA and AB-class roads.
C-CLASS ROADS: These are main collectors and distributors within any zone of area of the District that feed the above A-class and B-class Roads. Also roads except A and B class roads that carry heavy traffic volume fall under this class.
D-CLASS AND E-CLASS ROADS: These types of roads are known as minor roads. These are local roads that provide access to settlements and villages, Provincial councils and Pradesheeya Sabhas.
NORTH CENTRAL PROVINCE ROAD NETWORK BELONGS TO R. D. A - 2010 (Lengths in km)
Table 3.1 North Central province road distances
2. The present condition of the available high ways and main roads in the District are as follows.
a. Kandy to Jaffna Highway (A 9) is driven through the town areas of Kekirawa, Maradankadawala, Galkulama, Mihintale and Medawachchiya in the District. The road is in dilapidated condition from Madawachchiya to Mihinthale junction.
b. Puthlam to Trincomalee road (A12) is in dilapidated condition from Nochciyagama to Trincomallee and especially the road part of the Nochchiyagama to Anuradhapura town is in a very bad condition where vehicle movement in this part of the highway is impossible.
c. The complete highway of the Anuradhapura to Rabewa (A 20) is in dilapidated condition.
d. Maradankadawala to Tirikkondiadimadu highway (A 11) is in the dilapidated condition from Maradankadawala to Habarana in Anuradhapura District
e. Madawachchiya to Talaimannar (A14) road is in average condition where some parts of the road are dilapidated due to resent rain in the area.
Anuradhapura Galkulama road (A13) is in good condition except the road part available in the Anuradhapura city area. This is the only highway which can be used effective for the transportation at present and this highway is constructed by using Asphalt technology.
Anuradhapura to Padeniya highway (A 28) is in dilapidated condition and presently the highway is under construction.
3. Furthermore, in addition to this 80% of the road network available in the Anuradhapura city itself as well as AB, B, C and D class roads available in the District are in dilapidated condition.
In addition, 85% of highways and main roads in Anuradhapura District are constructed using the Macadam Tar road technology which is considered as a primitive technology when comparing with modern highway technologies. Therefore this phenomena stimulus the dilapidation of road network in Anuradhapura District.
Table 3.2 Road Condition of Anuradhapura District
FACTORS EFFECT TO DAMAGE THE ROAD NETWORK
Weather Conditions In Anuradhapura District
1. Anuradhapura District is having an extreme climate condition where yearly rainfall and temperature are as follows:
AverageHYPERLINK "http://www.worldclimate.com/define.htm#mep" Monthly Rainfall
Annual Average Temperature in Anuradhapura District in o C
1961 - 1990
Table 4.1 Monthly Rainfall and temperature Comparison of Anuradhapura District
2. Due to the recent weather pattern changers and increased rainfall in the District, above stated weather patterns are being changed rapidly as illustrated below.
Table 4.2 Monthly Rainfall Comparison of 2005 and 2010 in Anuradhapura District
Table 4.3 Monthly Rainfall Comparison of year 2005 and 2010 in Anuradhapura District
3. The increased rain fall of the District is undoubtedly the most common cause for road failures. The rain water saturating in a road can be divided as:
Rain falling onto the roadway
Surface run-off from adjacent catchment areas
Underground water movement
Moisture rising from the water table under the roadway.
4. Water saturating a sub grade or pavement may cause pavement failures; water running along the fringe of the pavement can cause scouring and water running down the batter of an embankment or cutting may cause serious erosion of the road.
Furthermore, the available soil type in Anuradhapura District is reddish brown earths (non lateritic loamy soils) and it is scientifically proven that this soil type will be expand it's volume when it is socked with water. Therefore when rain water spilled on to this type of soil, the volume of the soil will be increased and due to this reason the outer surface of the Tarred road will be removed which course road dilapidation.
The average temperature in Anuradhapura District is 35 o C and due to this excess heat, the bonds between Tar molecules in a tarred road are being separated which ultimately courses road surface dilapidation.
The increasing of motor traffic due to reduction of import taxes is also a highly contributing factor for the dilapidated road conditions in the District. The excess movement of vehicles in a particular road will turn a slightly damaged road into a dilapidated condition. This situation is also stimulus when the road is used for the transportation of heavy vehicles like buses, lories and containers.
Over usage of some roads in the District (Anuradhapura city area main roads) is also a contributing factor to damage a particular road in the area.
Effects to the economy and efficiency of the People
Constructing of a road network is one way to bridge the communication between the people in rural areas and urban areas. In order to achieve the social and economic development it is a great need to enhance transportation infrastructure in an area.
The road network of Anuradhapura District has become so essential for social and economic development of the society which provides links between centers of production and markets. District road network facilitate the movement of people and goods along import and export corridors in the country. The road transportation in the District has remained the dominant mode of transport that carries over 80 percent of passenger traffic and 90 present of goods transportation in the District. In addition availability of a good road network reduces the travel time and cost. Efficient transportation from farmlands to markets reduces the cost of productions and it directly contributes to the economic development of the District. The road network will also provide cheap, safe and fast transportation of goods and services from rural farmlands and factories to urban centers in the country.
Availability of an efficient road network will contribute to increase the agricultural production and sails due to market accessibility. This will contribute significantly to increase the productivity in rural areas of the District and eventually improve the overall socio-economic condition of the people in the area. Because of a road net work, the trade and business activities in the District will be further be promoted. There is also a possibility of increased economic opportunities, employments and significant growth of population in the area where highways and main roads are available in the vicinity.
Table 4.4 Labor force Distribution of Anuradhapura District
The District is also famous as one of the tourist attracting area in Sri Lanka where tourism is practiced as a moneymaking economic industry in the District. Therefore the availability of an efficient and durable road network is a vital factor for the growth of tourism industry in the District.
After the recent floods which was experienced in first weeks of February in year 2011, the highways and roads available in the District were badly damaged. Due to this reason transportation network in the District is highly effected and the vehicles can not even hardly move in some areas in the District. Therefore this directly effects the tourism, public transportation and transportation of agricultural and industrial products of the District which has created social unrest in the area. People were unable to reach the market on time to sell their products and shortage of essential commodities were experienced in the market which are coming from other provinces of the country due to transportation related matters.
Furthermore the vehicles available in the District were highly subjected to breakdowns and the personal who are engaged in transportation related employments like hiring Three Wheelers, private buses and Rent a car companies were being effected and loose their income.
Furthermore a questionnaire was distributed among a selected sample of community of the District which represents the public and private sector employees, housewives, farmers, students, military personal etc. After analyzing the data given by this community sample which represent the whole citizens of the District it is revealed that100% of the community agreed that the available road network in the District is inefficient to be use for road transportation. Furthermore 73% of the community has expressed that the replacement of Tarred roads with Concrete roads will be the best method to be used for the smooth functioning of transportation.
Table 4.5 Population sample data analyzes pertaining to replacing of Tarred roads with Concrete roads in Anuradhapura District.
Hence this emphasizes the need of a reliable road network for the smooth functioning of transportation which increases the social and economic development of the District.
ROAD CONSTRUCTION TECHNIQUES
Asphalt Road Construction
1. Asphalt or bitumen can sometimes be confused with THYPERLINK "http://en.wikipedia.org/wiki/Tar"ar, which is a similar black thermo-plastic material produced by the destructive distillation of coal. Asphalt Road construction is mainly divided into two categories. Those are Hot Asphalt road construction and cold Asphalt road construction. In Anuradhapura District, the constructers are using the Cold Asphalt technology for road construction due to it's simplicity.
2. Constriction of an Asphalt road can be briefly illustrated as follows
Before constructing the Asphalt road, the road is to be leveled by using gravel and then compressed the soil up to required level by using a road roller.
Then lay the ABS mixture (A - 1, 1/2" metal, B- ¾" metal and C- metal chips) on the gravel road up to 8" height and compressed the layer and apply priming coat.
Finally lay the Asphalt carpet up to 3" height by mixing the Asphalt and kerosene by using the cooker.
Tarred Road Construction
3. Macadam Tar Roads: 85% of highways and main roads available in the District are constructed with using Macadam technology. To construct a Macadam Road you must first level the road by using gravel and lay 1½" metal and then upon it lay ¾" metal layer and compress the layers of metal up to required level. Then paw the hot liquid tar layer (12.5mm) on the mettle layer and lay chips or sand upon it.
4. DBST : Double Bituminous Surface Treatment technology is also a road constructing method which used Tar. There are two DBST roads available in the District which are driven from Anuradhapura to Thanthirimale and Anuradhapura to Thuruwila. The method of constriction of these types of roads are the same as Macadam roads discuss above but the main difference in DBST roads is after laying one layer of hot(12.5mm) Tar, it requires to lay another Tar layer up to 6mm height after three days of laying the first layer.
Concrete Road Construction
5. Concert roads are mainly divided in to two types. Those are
Structural concrete roads. This road construction technique is used to construct "A" and "B" class roads which are expected to handle heavy traffic loads. Presently these types of roads were not used for road transportation in Anuradhapura District. The construction of these roads can be briefly illustrated as follows.
Leveling of the selected road by laying gravel and compress the soil up to required level.
Laying of polyethylene sheets along the leveled road.
Laying of steel reinforcement structure along the gravel layer.
Laying of concrete mixture of 1:2:4 ratio (1- cement, 2- metal, 4- sand) up to 5" height.
Construct joints by using regifome sheets (10-20 mm) which is used to compensate thermal expansion and used as a vibration absorber.
Cure the newly constructed concrete road by using sand made water ponds for at least 8 days before using the road for the purpose of transportation.
Mass Concrete roads This technique is mainly used to construct "C" and "D" class roads where less traffic loads are expected to handle. The construction technique which is used in this road type is same as Structural concrete instead the main difference is it does not require a steel reinforcement structure and the concrete mixture ratio is 1, 3, 6 (1- Cement, 3- metal, 6- sand).
Advantages and Disadvantages of Tarred roads, Asphalt roads and Concrete roads
6. The advantages and disadvantages of Tarred roads, Asphalt roads and concrete roads are as follows:
a. Durability and maintenance freeness: Concrete roads can sustain for a long time. The Structural concrete can sustain even up to forty years and the Mass concrete can sustain up to ten years, where as Asphalt, DBST and Macadam Tar roads last for less than six, four and two year respectively. Moreover, during this long life, concrete roads do not require any frequent repairs or patching work to be carried out like Asphalt roads and Tarred roads.
b. Less fuel consumption: The vehicles which are driven in the concrete roads consumes 15 to 20 present less fuel than which is driven on Asphalt or Tarred roads. This happens because the concrete roads does not deflected it's surface due to the load of the vehicle and it gives low friction between the wheels and the road surface. Therefore constructing of concrete roads will be more economical in fuel consumption when it is considered in the long run.
c. Resistance to fuel spelling of automobiles: Unlike Asphalt roads and tarred roads, concrete roads do not get damaged due to the leakage of oil from the vehicles. Most of the vehicles availably in the District are under condition and spills fuel and oil on to the road surface when they are travelling. Therefore the road network of the District should be able to withstand the chemical reactions stimulated by the spelling oils and fuel from the vehicles.
d. Resistance for excessive weather conditions: The concrete roads can withstand the extreme weather conditions experienced in the District at present. Anuradhapura District getting monthly average rainfall of 110 mm and having extreme heat in the months of April to October. Asphalt and tarred roads can withstand excessive heat up to some extent but especially the Macadam Tar roads cannot withstand the heavy rainfall of the area where it tends to wash away the outer surface of the roads and frequent repairs are to be carried out to maintain the road network up to the required stranded. This is frequently experienced in Anuradhapura District which is considered as a major problem for road transportation in the area.
e. Greener process: Especially the Asphalt produces lots of highly polluted gasses at the time of melting it for paving. Thereby polluting the air of the area.
f. Low visibility: Asphalt roads absorb light. Therefore driving vehicles in night on asphalt roads are difficult than concrete roads.
Heat Island effect: Asphalt roads are absorbing sunlight and heat thereby increasing the temperature of the area which is called as "Heat Island effect". This will increase the temperature of the District even further in the period of April to October.
Saving of natural resources: Asphalt and Tar are produce from important natural resource of petroleum which is becoming reduced drastically in the world. Exporting of Asphalt or Tar to our country will cost foreign currency. But manufacturing of cement can be done in Sri Lanka which is used to build concrete roads that will be economical for the nation.
7. As discussed above there are some disadvantages of concrete roads. Those are:
Paving cost: The paving cost of a concrete road is higher compared to Asphalt and Tarred road paving.
Maintenance: There are no any maintenance required for the concrete roads. But if the concrete road gets damaged due to some reason, the whole concrete slab needs to be replaced. This will cost much and requires more time to repair.
Safety hazards: In rainy days the vehicles tend to slip or slide on Concrete roads due to lack of friction in the roads and will course roads accidents. This can be prevented by making the outer surface of the concrete road rough. But there are disadvantages like reducing the fuel efficiency in the vehicles.
8. At present the high ways and main roads of the Anuradhapura District is mainly constructed by using Macadam Tar, DBST and Asphalt road construction techniques. There are some advantages in using these techniques for the construction of roads in the District. Those are:
a. Less Expensive: Usage of Macadam Tar, DBST and Asphalt for road construction is still less expensive compared to construction of Concrete roads. The construction cost of a Concrete road, Asphalt road and a Tarred road are attached herewith as Annex "A".
b. Less Time Consuming: Moreover it takes less time to build Tarred road or Asphalt road than a Concrete road.
c. Recyclable: Asphalt is a recyclable material. It can be used again and again by melting it. But concrete cannot be recycled and if a Concrete road is damage, it should be fully reconstructed.
Relaying: Repairing of an Asphalt road is easy and even can relayed over the old Asphalt layer.
Safety: Asphalt roads and Tarred roads provides better traction and skid resistance for vehicles. This will reduce road accidents but decrease the fuel efficiency of the vehicles.
1. The main problem of the road network of Anuradhapura District is the durability of existing Asphalt and Tarred roads. Due to the extreme weather conditions experienced in the District, frequent repairs are to be carried out in the road network to maintain the standards. This causes traffic jams and wasting of public funds for maintenance of the roads. Therefore the durability, less maintenance, ability to withstand extreme whether conditions of the area and initial construction cost will be the main measurement that will be considered for the effective and efficient road network for the District.
2. The durability and initial cost comparison charts are given below for the easy reference of the reader. But The Structural Concrete roads are not used for the road construction of the Anuradhapura District or in elsewhere. Due to this reason, with the help of expertise information which I have gathered during my research I was able to assume the overall cost of a Structural Concrete road.
Figure 6.1 Construction of Structural Concrete roads
Table 6.1 Durability comparison chart for road construction techniques
3. When it comes to compare the durability of the road construction techniques which is considered as the most significant factor of this research paper, the durability comparison chart shows that the most durable road construction technique is the Structural Concrete road construction technique and after that is the Mass concrete roads.
Structural Concrete Roads
Mass Concrete Roads
Macadam Tar Roads
Table 6.3 Life Expectancy Comparison Table
6. The life expectancy of a Mass Concrete road is five times more than a Macadam road and two and a half times more than a DBST road. Therefore it is self explanatory that Mass Concrete will be more economical and effective than the DBST and Macadam roads.
7. When we consider the durability of a Mass Concrete road with Asphalt roads, it is less than two times durable than Asphalt road.
4. As illustrated by the cost comparison chart, the initial construction cost of a Mass Concrete road is two times more than a Macadam Tarred roads. When it compares to the Asphalt roads, the construction cost of a Mass Concrete road is one and a half times more than Asphalt road.
8. By comparing the Structural concrete road with other road constructing techniques, it is evident that though the initial cost is high the durability of a Structural concrete road is far ahead.
Furthermore when we compare the maintenance cost of a Structural and Mass Concrete roads with other road construction techniques, the maintenance cost will be negligible. This will save the money which is spent for the maintenance of roads by the Central Government.
Table 6.4 The total annual road maintenance expenditure of RDA in Sri Lanka
10. By evaluation of gathered data, it was proven that the hypotheses of my research have been achieved.
11. Though it is such, implementation of Structural Concrete technique for the road constriction of the District cannot be done due to the high initial cost and the annual budget which is allocated for the development of road network in the District will not be sufficient.
12. Furthermore the Asphalt and Tarred roads often wins out over Concrete roads when transportation authorities select the type of technology to build roads because these two methods are less expensive when it compares to initial construction cost of the Concrete roads. If a huge some of money is invested for road development of the District it will effect to fulfill other necessities of the people.
It is also a known fact that maintenance of road network of the District produce lot of job opportunities for the labors as well as a profitable income for the road constructers like MAGA, Maganeguma and other private constructers. If concrete roads are built in the District, due to irrelevancy of maintenance this segment of the society will loose their employment opportunites which create social and economic problems.
Furthermore the cold Asphalt technology is an effective and efficient road construction technique when considering the cost. Most of the Asphalt roads which are constructed in the District can withstand extreme weather condition of the District up to certain extent. The Anuradhapura Galkulama road (A13) is a good example for this where it was able to withstand the recent flooding experienced in the District. Low maintenance cost and less maintenance time will be a added advantage when suing the Asphalt technology for the road construction.
Therefore when it is considered the cost effectiveness and easy maintenance the Asphalt road construction technique is more suitable for the road network of Anuradhapura and the government has already started to relay the roads available in the Anuradhapura city area with Asphalt carpet where most of them are dilapidated due to recent floods. A decision has already taken to lay Asphalt carpet for 30km for every electoral seat in the province and it is already commenced in Polonnaruwa District.
After analyzing these facts it is understood that though the concrete roads are much more reliable and durable, the cost factor will always decide the usage of concrete road construction technique for the road network of Anuradhapura District.
2. The Structural and Mass Concrete roads have a life of up to 40 and 10 years respectively where as Macadam Tar, DBST and Asphalt roads' life expectances are 02,04 and 06 years respectively. In addition, the concrete roads require almost no maintenance, whereas other construction methods need frequent repairs due to weather and other various factors which were discuss before. Construction of concrete roads can be referred as buying a car that's going to cost you more, but doesn't require maintenance over the long time
Experts also debate that in future the price of Tar and Asphalt which are petroleum-based products will goes up. This will ultimately increase the production cost of Tarred and Asphalt roads and will be equal with the production cost of concrete roads.
1. The road Network of Anuradhapura District is a major contributing factor for the development of economy and life stranded of the citizens. The city of Anuradhapura is considered as the main transactional hub for the commodities in the north central Province. But the available Tarred road network of the District is unable to withstand the extreme weather condition of the area and subject to be dilapidated with in a short period of time. The dilapidation of road network is increased due to excess rainfall, high temperature, soil condition and other factors which are discussed in the paper.
2. Therefore, the research has been done to introduce a road construction technique which can withstand the above mentioned natural and other factors which are effecting for the durability of road network of the District. By considering the durability for extreme weather conditions, low maintenance cost and other favorable factors with Asphalt roads DBST and Tar roads, it is proven that the Concrete road construction technique is the leading road construction technique to withstand the extreme weather conditions of the area and thereby the hypothesis has been proven.
3. During the research it was also found that the allocated funds for the road construction for the District can not bare the initial cost of constructing a Structural Concrete road though it seems to be the most durable efficient and effective road construction technique. Hence the Asphalt and Mass concrete road construction techniques will win the favorability of road construction authorities.
Considering the initial cost factor, it is recommended to construct "A" and "B" class roads in the District by using Asphalt technology.
For the "C", "D" and "E" class roads it is recommended to use Mass Concrete technology for the road construction considering the initial cost as well as the durability.
It is recommended to use Structural concrete technology for "A" and "B" class roads where the areas are subjected to frequent flooding. The Structural concrete roads can withstand the damage coursed by flooding effect and does not require any maintenance.
The durability of a road depends largely upon an effective and adequate road drainage system. It is therefore necessary to construct effective drainage system to drain the rainy water. The type of drains and drainage structures can be broadly listed under four classifications:-
Culverts (pipes, box culverts)
The condition of the two road shoulders driven both sides of a road are a very much important for increasing the durability of the road. Therefore these shoulders are to be hardened so that erosion of road from the rain can be minimized.
The height of the highways is to be increased during the construction by using recommended soil types.
Before constructing a road it is recommended to measure the CBR ratio of the soil available in the area and if the ratio is below 20%, it is recommended to replace the available soil with a soil type which has high CBR ratio.
It is recommended to allocate funds from Central Government to construction a Structural Concrete highway as a pilot project which will connect the city if Anuradhapura to urban cities of the country. This can be utilized for the public as an alternative when the transportation is difficult in other roads.
When Concert roads are being contracted, it is recommend to lay an Asphalt layer up on the concrete road. This will minimize the risk of damaging the surface of the concrete road where it will be costly and time consuming task.