International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) 1(1) February 2014 ©Avi-D Publishers 2014 www.avidpublishers.ca ASSESSMENT OF SOME PAVEMENT INDICES OF ADO EKITI – AKURE ROAD, SOUTH-WESTERN NIGERIA Adetoro A. E Civil Engineering Department, The Federal Polytechnic, Ado – Ekiti, Nigeria. Akinwande J. T. Civil Engineering Department, The Federal Polytechnic, Ado – Ekiti, Nigeria. Abstract Throughout the world today, there is no way road pavement can be assessed without putting into consideration its geotechnical indices. This study intends to assess and analyze some road pavement indices or properties that are related to the failure of the asphaltic or bituminous surfacing of Ado Ekiti – Akure road. Some samples were collected from the pavement and tested in laboratory for this purpose. The results showed that only one sample met specific requirement for Marshall Stability, all samples met specific requirement for Marshall Flow, while three samples met specific requirements for Optimum Bitumen Content (OBC), Void in Total Mix (VTM). These three samples also fell within Asphalt Grading envelope. It implied that the asphalt used for the surfacing of the road is not stable / adequate / suitable. There are bleeding on some part of the road caused by high percentage of VTM and poor Asphalt Grading, hence high absorption of bitumen content(s). The pavement failure along the road could be due to insufficient asphalt aggregate materials, poor quality of pavement layers materials and workmanship. Keywords: Marshall Stability, Marshall Flow, Asphalt Grading, Void in Total Mix (VTM), Optimum Bitumen Contents (OBC). facilitating the movement of people, moving 1.0 Introduction of troops and supplies in times of emergency Roads are essential equipment for the and development of land, tapping resources of description . Roads have demonstrated agriculture, mining and forestry, linking up worldwide (of all transportation systems) to different regions and thus promoting inter- be the most effective and preferred mode of regional transportation trade, increasing industrial development, linking important cities and carrying on for (Owolabi, 1996). of business goods and of all persons International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition A road pavement is a structure consisting of failed due to negligence of road superimposed maintenance, inadequacies in design and processed layers materials of selected whose and primary poor workmanship, poor soil properties like functions is to distribute the applied vehicle low CBR and high liquid limits etc among loads to the subgrade. A Flexible type of others. pavement, which is commonly used in Nigeria (and Ado-Ekiti – Akure road), This study intends to assess and analyze comprises of the sub-grade (i.e. support), some road pavement indices or properties sub-base, base course and surfacing. Its that are related to the failure of the asphaltic principal function is to receive load from the or bituminous surfacing (and materials) of traffic and transmits it through the layers to Ado-Ekiti – Akure road. The results of this the sub-grade (Adrox and Wood, 2002; study will provide dependable Engineering O’Flaherty, 1978; Kadiyali, 1989). information on the geotechnical properties of bituminous materials used in construction Of all the above stated pavement layers, this and rehabilitation of roads in Ado-Ekiti, article major its interest in the Surfacing Akure, their environs and Southwestern part layer which is the part of road that vehicles of Nigeria as a whole. rides on and is the most vulnerable part of the pavement. Its primary function is to 2.0 Materials and Methods provide a safe and comfortable riding The study is within the failed section of Ado surface for the traffic. It is also expected to Ekiti protect the layers beneath from the effects of asphaltic/bituminous samples were taken natural elements as well as the disintegrating from the surfacing layer of the road for effects caused by vehicles skidding and seven different chainages/locations. The breaking on the roadway. The layer should location for the soil samples are: also be able to shed a large portion of the - Akure road whereby (i) Chainage 0+175 - Sample A loss of its stability and subsequent softening (ii) Chainage 1+150 - Sample B of layers beneath (Adetoro, 2003; Clarkson, (iii) Chainage 2+350 - Sample C (iv) Chainage 3+500 – Sample D (v) Chainage 4+650 – Sample E rain, which falls upon the surface to prevent 2004). The past research works of Adeleke and Madebor (2007), Jegede (2004), Ogundipe (2001) etc showed that roads 2 International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition (vi) Chainage 5+800 – Sample F in Table 1 while Figure 1 to 7 show graphs (vii) Chainage 7+000 – Sample G for the results of asphalt grading tests performed on the selected samples. The asphaltic samples were selected as Table 1: Summary of test results on asphaltic samples representative samples after tests had been carried out on these samples. After collection, samples were stored in polythene bags to prevent loss of moisture contents. The samples were then taken to the laboratory where the deleterious materials were removed. All tests were performed according to standard methods contained in From Table 1, it is observed that the BS 1377 (1990). Their properties were Marshall Stability values of the asphalt studied and determined to ensure that all samples varied between 267kg and 350kg relevant factors would be available for for all the chainages (i.e. Samples A to G). establishment of correlations among them. These values are less than the specified The tests carried out on each of the selected value (i.e. Marshall Stability = 350kg) for all samples are Marshall Stability and Flow, the samples, except sample F. This shows Extraction and Grading (Asphalt). The aim that the Marshall Stability of the asphalt is of carrying out the Marshall Stability test is adequate / suitable for only Chainage 5 + to determine the asphalt stability and flow. 800 (i.e. sample F). The Marshall Flow The aim of carrying out the Extraction test is values of the compacted asphalt samples to determine the bituminous content while varied between 2.65mm and 4.00mm for all the aim of carrying out the Grading test is to the chainages (i.e. Samples A to G). These determine the particle size distribution of the values are within the specified values’ range samples. The results were compared to the (i.e. Marshall Flow = 2 – 4mm) for all the standard specified values in accordance with samples. This shows that the Marshall Flow General Specification for Roads and Bridges of the asphalt is adequate / suitable for all (FMWH, 1997). the Chainages. It is also observed from Table 1 that the 3.0 Results and Discussion Optimum Bitumen Content (OBC) values of The summary of results of respective the asphalt samples varied between 4.8% properties of selected samples is presented 3 International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition and 13.8% for all the chainages (i.e. Samples A to G). The result shows that samples C, D and E (i.e. Chainages 2+350, 3+500 and 4+ 650) values are within the specified values’ range (i.e. OBC = 5 – 8%) while the remaining samples are not. The Void in Total Mix (VTM) values also varied between 3.2% and 14.65% for all the chainages. Samples C, D and E (i.e. Figure 2: Asphalt Grading tests graph(s) for Sample B Chainages 2+350, 3+500 and 4+ 650) values are also within the specified values’ range (i.e. VTM = 3 – 5%) while the remaining samples are not. The above analysis shows that there is possibility that the high values of VTM observed lead to high values of OBC, thus, high absorption of the bitumen content. The Figure 3: Asphalt Grading tests graph(s) for Sample F implication of excess (i.e. high) bitumen contents may lead to bleeding during dry season on the road, thereby cause pavement failure. Figure 4: Asphalt Grading tests graph(s) for Sample G From Figures 1 to 4, it is observed that samples A, B, F and G graphs portrayed that the asphalt materials are not properly graded Figure 1: Asphalt Grading tests graph(s) for Sample A – some have insufficient filler materials (i.e. fines), 4 some have insufficient coarse International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition materials or it could be insufficiency of both others are not. This means that the asphalt materials. materials of these samples (i.e. chainages) are properly graded (i.e. proportionally sufficient). All these could result in increase in percentage of VTM and high absorption of bitumen content, which later result in bleeding as seen in some parts of the road pavement. 4.0 Conclusion and Recommendation Figure 5: Asphalt Grading tests graph(s) for Sample C This study shows that there is pavement failure along the road because the asphalt is not stable (i.e. Marshall Stability). However, the pavement failure along chainage 0+000 – 2+350 and chainage 5+800 – 7+000 may be due to insufficient asphaltic aggregate materials (i.e. poor asphaltic materials grading). It can also be due to poor quality of the whole pavement layers (i.e. Surfacing, Base, Subbase and Subgrade layers). While Figure 6: Asphalt Grading tests graph(s) for Sample D the pavement failure along chainage 2+350 – 5+800 can be due to poor quality of the other pavement layers (i.e. Base, Subbase and Subgrade layers). Generally, the implication of the above analyses is that the pavement failure may be due to poor quality and insufficient quantity of materials used for the pavement layers – this in turn shows poor workmanship and Figure 7: Asphalt Grading tests graph(s) for Sample E While from Figures 5 -7, it is observed that professionalism! samples C, D and E graphs fell within the structural failure on the road pavement when upper and lower limits envelopes while heavy axle loads or trucks ply it. 5 All these encourage International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition Standard Specification for Therefore, it is recommended that any Transportation Materials and materials to be used for the rehabilitation of Methods of Sampling and Testing the road should be in strict compliance with (14th ed.). USA: Washington DC, the specified values of standard road notes AASHTO. 5. BS1377. (1990). British Standard and manuals (i.e. General Specification for Methods of test for Soils for Civil Roads and Bridges, AASHTO etc). Engineering Purposes. London: British Standards Institution. References 6. Clarkson, H.O. (2004). Highway 1. Adeleke, O. A. & Madebor, A.O. Engineering (3rd ed.). New York: (1987). Effect of Hydrated Lime on John Wiley & Sons the Atterberg Limits of Black Cotton 7. Federal Ministry of Works and Soil of Nigeria. 9th Regional Housing, FMWH (1997). General Conference for Africa on Soil Specification (Roads and Bridges) – Mechanics and Foundation Revised Edition (Volume II). Abuja: Engineering, 1, 155 - 160. Federal Ministry of Works. 2. Adetoro, A. E. (2003). A Technical 8.Jegede, G. (2004). Highway Pavement Proposal for the Rehabilitation of Enugu Nigeria. – Ozalla Akure, Failure Expressway, Nigeria: section of F209 Okitipupa – Nigeria Ife Journal Science, 6(1), J. W. & Woods, W. R. 41-44. (2002), A General Characterization 9. Kadiyali, of Pavement System Failures with Process. Journal L.R. (1989). Engineering (3 Emphasis on a Method for Selecting Highway and Officials, AASHTO ed.). New Delhi: Distributors 10. O’Flaherty, C. A. (1978). Highway Engineering of Highway Pvt Ltd. 62. Association rd CBS Publishers & of Construction Education, 7(1), 58 - 4. American by Igbokoda Highway Southwestern. Technology. Repair Induced Poor Geotechnical Properties along a PGD Thesis, The Federal University of 3. Adrox, Publisher. State (2nd ed., Vol. 2). London: Edward Arnold Publisher Transportation Ltd. Pg. 151-153. (1986). 6 International Journal of Novel Research in Engineering and Applied Sciences (IJNREAS) February 2014 Edition 11. Ogundipe, O. M. (2008). Road Surveyor Pavement Failure Caused by Poor Soil Properties along Chapter. Pg 1 - 17. Aramoko- Ilesha Highway Nigeria. Medwell Journal of Engineering and Applied Science, 3(3), 239-241. 12. Owolabi, A. O. (2012): Realistic Costing of Road Construction. Paper delivered at the National Seminar of Nigerian Institute of (NIQS) - Ondo State Quantity 7