LIFE CYCLE COST ANALYSIS OF ROAD PAVEMENTS IN RURAL AREAS

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1 LIFE CYCLE COST ANALYSIS OF ROAD PAVEMENTS IN RURAL AREAS 1 Mr. Akhai Mudassar Mohammed Shafi, 2 Mr. Ahmed Afaque Shakeel, 3 Prof. Siddesh Kashinath Pai 1 Student of postgraduate programme in advance construction management, National institute of construction management and research (NICMAR), Goa (India) 2 Student of postgraduate programme in advance construction management, National institute of construction management and research (NICMAR), (India) 3 Assistant professor at National institute of construction management and research (NICMAR),Goa- India & Research scholar pursuing Ph.D at University of petroleum & energy studies, Dehradun -, (India) ABSTRACT India is developing very fast and to become a developed country more importance has to be given to the infrastructure sector. Infrastructure basically consists highways, airports, seaports, bridges etc. Of these, the road sector is very necessary because more than 60 % of all goods in the country and 85% of India s total passenger traffic is transported through this network. Now the road connectivity in India is good only around the metro cities. So more emphasis has to be given to the rural areas so as to make them well connected with the major cities. Good connectivity will ensure faster movement of people and goods with safety and economy. For achieving this, an efficient road infrastructure plan has been chalked out because of which India economy will grows about 6% per annum in next 20 years. The government has planned Rs3 lakh crore of road projects in current fiscal to meet the target of 30 km per day highway construction. The transport sector contributes 6% of Indian GDP out of which 70% share comes from the road sector. The road pavement cost is around 50% of the total cost of construction of the road. This research paper deals with the cost analysis of Cement Concrete road and bituminous road. Basically it differentiates the rigid pavement and the flexible pavement and provides information about which pavement is more economical and cost effective. This is done with the help of NPV method of Life Cycle costing. In this method initial investment cost and maintenance cost are taken into consideration. With the help of LCC, alternative pavement design can be selected. This will reduce the cost and will give ample serviceability over the design life of the roads. The use of Fly ash in certain percent instead of cement will further reduce the cost. Keywords: Life Cycle Cost, Cement Concrete Roads, Bituminous Road, Flexible Pavements, Rigid Pavements. 260 P a g e

2 I OBJECTIVES Study of comparison between Flexible and Rigid pavements by using NPV method of Life Cycle Costing. Use of Fly Ash in certain proportion in place of concrete and find out the overall cost. The study shows the comparative cost of one kilometer of each flexible pavement and rigid pavement having a uniform section has been worked out at current market rate. II INTRODUCTION Pavement is a surface which is specially laid durable and serviceable to withstand traffic load. 2.1 The different types of pavements are; 1. Flexible Pavement and 2. Rigid Pavement Flexible Pavement Pavement which reflects the deformation of sub grade and subsequent layers of the surface. This pavement usually contains four layers i.e. sub-grade, sub- base, base course and wearing course or surface course. Usually Bituminous material is used as surface course and no reinforcements are placed. Since there is deformation seen in such pavements, cracks are very common. Due to excessive loading warping cracks, alligator map cracking, longitudinal cracks, Potholes etc are seen. The service life is not as great as rigid pavements. These pavements are very common and widely used because of low initial costs attached to them as compared to the rigid pavements. The maintenance costs are high Rigid Pavement The pavement acts as a rigid medium due to which the load is distributed over a wide area of sub grade soil. The rigid pavement are made of cement concrete, plain reinforced and pre-stressed concrete. Elastic theory is used to design Rigid Pavement. There are three layers i.e. Surface course, base course and sub grade. Cement and reinforcement is used in the construction of rigid pavement. The maintenance costs are very less or negligible. Initial costs are high. These pavements are very durable and service life is around 30 years and more. Initial Cost: Initial cost depends on the following factors; Pavement thickness Strength of subgrade soil Traffic load Cost of material Cost of execution of work 261 P a g e

3 Maintenance Cost: In order to increase the service life of the pavement, maintenance of pavement is carried out. The costs associated with it are called Maintenance costs. State Government is the responsible authority to look after the maintenance of rural roads. Life cycle cost analysis: Economic assessment of alternatives that considers all of the significant costs of ownership over the useful life. This includes; Initial costs Financing costs Maintenance costs Compares competing alternatives considering all significant costs. finacial feasibility of a project can be done by Profitability analysis method Some important factors to be considered: NPV (Net Present Value) shows how much value will be generated during the life cycle of the project. It takes into account time value of money and shows the present (today s) value of the project. Future Value (FV) shows the value of money/project at a specific time in the future that is equivalent in value to a specified sum today. Analysis Period - the period of time over which LCCA is performed. 2.2 Advantages and disadvantages of rigid and flexible pavement: Advantages of Rigid Pavement: Durability: Rigid pavements have a long service life of 40 years, whereas Flexible pavements last for ten years. Maintenance free: During the service life rigid pavements do not require frequent repair or patching work like Flexible pavement. Less Fuel Consumption: Since rigid pavements do not deform under the wheel loads, the fuel consumption decreases to about 10% - 20% Resistant to spillage of automobile fuel: Rigid pavements are not affected when exposed to oils, fuels etc. from automobiles. Resistant to extreme weather: Rigid pavements are unaffected by the action of rain and heat. Reduction in pollution: Since bitumen has to be burnt before paving it produces pollution in the form of toxic gases. Rigid pavements do not incorporate such methods and thus pollution is reduced. 262 P a g e

4 Conservation of natural resources: Since bitumen is produced from petroleum, which is becoming very scarce whereas rigid pavements are made from concrete (cement) which is abundant. Disadvantages of Rigid Pavements: Cost of Paving: Asphalt paving is less expensive than Concrete paving. Problems in Maintenance and Breakdown: The whole concrete slab is replaced if any failure or breakdown happens Less Safety: Due to rain and snow, vehicles generally slip on rigid pavements. Advantages of Flexible Pavements: Cost of laying: Cost of laying asphalt is less as compared to concrete Recyclable and reusable: Asphalt can be melt and reused again and again Maintenance and Repair: Small portion of asphalt can be repaired and relayed easily Safety: Flexible pavements provide more resistance and grip to the wheels of the vehicles. Disadvantages of Flexible Pavements: Less Durable: Rains, Heat and Snow have damaging effects on the asphalt road and thus they require frequent repairs and maintenance. Generation of Pollution: Greenhouse gases and toxic gases are produced when asphalt is melted. 2.3 Design and construction cost per km of flexible pavements: There are two parameters based on which the flexible pavements are designed i.e. the CBR value of the existing subgrade and the number of vehicles passing per day during design life. A typical pavement composition based upon SP: and its cost for rural road with CBR value of 4 and traffic 75 cvpd is given below GSB 250mm (Full 600 = Rs 300 per m2 WBM = Rs 180 per m2 PC 20 mm L.S = Rs 90 per m2 Including prime coat and track coat Total = Rs 570 per m2 Source: Report of PMGSY 2016 The cost will be about 21 lakh per km for 3.75 m wide pavement. Maintenance Cost: 263 P a g e

5 10th, 20th years after construction, one layer of 75 mm of WBM is laid. 20 mm PC once in 5 years is to be provided as per NRRDA guidelines. As per NRRDA norms, cost of repairs is taken as Rs14000 per Year. 2.4 Design and Construction cost per kilometer for Rigid Pavement There are two parameters based on which the flexible pavements are designed i.e. the CBR value of the existing sub grade and the number of vehicles passing per day during design life. A typical pavement composition for rural road is given below :( refers: SP: ) GSB 100mm(Full 600 = Rs 120 per m2 PQC (M35) 180 = Rs 600 per m2 Total : 280mm = Rs720 per m2 Source: Report of PMGSY 2016 The cost will be about 27 lakh per km pavement. Maintenance Cost: In order to repair and maintain concrete spalling and filling of sealing compound in the joints, the average yearly maintenance cost is about Rs10000 per km for single lane Life cycle cost analysis: Period of analysis-20 years Discount rate- 10% Inflation rate-5% Cost estimate: 1. Initial cost of flexible pavement = 82 lakh per km 2. Initial cost of rigid pavement = 27 lakh per km 3. Initial cost of rigid pavement (Using 30% fly ash as cement replacement) = lakh per km 4. Annual maintenance of flexible pavement = 0.14 lakh per km 5. Removal of wearing course of flexible pavement Every 5 years-5 th, 15thyr. After completion = 90*3.75* = Rs say Rs3.50lakh 6. Strengthening with WBM every 10 th year-10 th,20 th year WBM 100mm = 0.10*3.75*1000*800 = Rs3 lakh PC 20mm = 90*3.75*1000 = Rs Total cost = Rs say Rs6.50 lakhs 264 P a g e

6 7. Average maintenance of rigid pavement = Rs10000 per year Economic Analysis: For the flexible and rigid pavement, the economic analysis over an analysis period of 20 years based on net present value of total construction and maintenance cost are provided annexure 1 Summary of initial and life cycle cost Sr No Pavement Type Initial cost Maintenance Cost 1 Flexible/Bituminous Rigid/Concrete Rigid/Concrete with 30% fly ash Source: Report of PMGSY 2016 Life Cycle Cost Analysis: (Concrete roads in rural areas under PMGSY) Data assumption: Period of analysis-20 years Discount rate- 10% Inflation rate-5% Cost (Rs. Lakh) per km Flexible(BT) Rigid (Concrete) Construction cost Routine maintenance cost per year 0.14( Average) 0.1 (Average) Renewal (5 years) Strengthening (10 years) Year Flexible pavement Rigid Pavement Construction Maintenance Construction Maintenance NPV(1/1.10)n cost cost cost cost NPV(1/1.10)n P a g e

7 Total NPV cost Source: Report of PMGSY 2016 III CONCLUSION Study shows that comparison between Flexible and Rigid pavements by using NPV method of life cycle costing gives the initial cost of rigid pavement as 28% higher than the initial cost of flexible pavement. Thus, rigid pavements are high on initial costs but these costs get balanced during the entire life since more durability and serviceability is provided by the pavements. Through the Life cycle costing it is found that the maintenance cost of rigid pavement is 19% less as compared to flexible pavement. So, even if the initial costs of rigid pavements are high, maintenance costs are considerably low with long life span. The maintenance cost of rigid pavement was 5.3 lakh less and in case of Fly ash mixed it was 7.1 lakh less than flexible pavement The study also provides the information that the initial cost of rigid pavement is 6 lakh per km without using Fly ash and 4.25 lakh using Fly Ash. Thus, if 30% Fly Ash is used in place of cement and LCC is applied, the results shows a reduction of almost 1.75 lakh in the cost of the pavement This study also give insight on the application of the rigid pavements in regions where the subgrade soil has low CBR values such as waterlogged areas or heavy rainfall areas. So from the whole study it may be concluded that the LCC of Rigid pavement is 20% - 25% less than flexible pavement. REFERENCES [1] Pradhan Mantri Gram Sadak Yojana, Website: In text reference: (Pradhan Mantri Gram Sadak Yojana) [2] India Brand equity Foundation.( 2016, July), Website: In text reference: (India Brand equity Foundation, 2016) [3] Lohit B (2015, July 18). Indian Road Construction Industry Scenario. Dalal street Investment Journal. In text reference: (Lohit B, 2015) [4] Bright Hub Engineering.(2010, August), Website: In text reference: (Bright Hub Engineering, 2010) [5] Kai Chen Gosh. (2011). Developing financial decision support for highway infrastructure sustainability. 266 P a g e

8 In text reference: (Kai Chen Gosh, 2011) [6] T. Wang, J. Harvey, and D. Jones.(2010, November). A Framework for Life-Cycle Cost Analyses and Environmental Life- Cycle Assessments for Fully Permeable Pavements In text reference: (T. Wang, J. Harvey, and D. Jones, 2010) [7] William James Wilde, Steve Waalkes, and Rob Harrison. (1999, September). Life Cycle Cost Analysis Of Portland Cement Concrete Pavements In text reference: (William James Wilde, Steve Waalkes, and Rob Harrison, 1999) [8] Hawzheen Karim. (2011, March). Road design for future maintenance-life cycle cost analysis of road barriers. In text reference: (Hawzheen Karim, 2011). 267 P a g e