TRF - 2012

Permanent URI for this collectionhttp://192.248.9.226/handle/123/17949

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Now showing 1 - 9 of 9

item: Conference-Abstract
Applicability of HCM 2000 & 1986 to determine the level of service in urban arterial roads, Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2012-07) Mampearachchi, WK; Jayasuriya, WWC; Senaratne, SAMANI; Sumanathissa, RPP; Pasindu, HR
The objective of this research is to identify the applicability of Highway Capacity Manual (HCM)to determine the Level of service in urban minor arterial roads in Sri Lanka. HCM has been developed by the transport research board, USA. Currently most of the local road development agencies use HCM for capacity analysis of roads. There have been no researches carried out to identify the applicability of HCM to the Sri Lankan condition. To depict the quality of service of the roads quantitative measures of a traffic stream are required. Level of Service (LOS) is a quality measure describing operational conditions within a traffic stream, generally in terms of service measures such as speed and travel time, freedom to maneuver, traffic interruptions and comfort. Six LOS are defined based on service flow rates of roads. Letters designate each level from A to F with LOS A representing the best operating conditions and LOS F the worst. Though the local roads have acceptable LOS, the results obtained from both HCM 2000 and1986 have not reflected it. It is required to identify the factors which affect the LOS. For that a sample of two way - two lane roads were selected. For the selected sample flowvs.density curveshave been developed by considering traffic data and speed survey data. Based on the literature findings and data collected from the field, six LOS for the urban minor arterial roads have been defined.
item: Conference-Abstract
Challenges of wearing course mix design for Hambanthota International Airport
(Department of Civil Engineering, University of Moratuwa., 2012-07) Meegahage, JN; Mampearachchi, WK; Pasindu, HR
Hambanthota international Airport (HIA) is a major ongoing development project in Sri Lanka. Since an Airport is a very important location for a country, durability and long term performance with least maintenance is fully ensured in the selection of material to the design and the construction methods in airport runways. In HIA, wearing course of runway has been decided to construct using Polymer Modified Bitumen (PMB) which is currently unfamiliar to Sri Lankan Highway industry. The modified binder to be used in the construction is PG 76-22 SBS modified binder. Further more the specified aggregate gradation for the design is coarser than the ones currently using in Sri Lankan highway industry. So it’s a challenging task to prepare a mix design for the wearing course. Polymer modified binder properties are different from conventional bitumen with high resistance to deformation at elevated temperatures and cracking at low temperatures. Some additional tests are included for the SBS modified binder to ensure its quality such as elastic recovery test and separation tendency test which are currently unfamiliar. Establishment of Viscosity ranges of the modified binder for compaction and mixing temperatures was a challenging task since the polymer modified binder behavior is non Newtonian.. In HIA the aggregate gradation selected for the mix design is coarse than the normally used aggregate gradation for asphalt wearing course. The maximum aggregate size is 31.5mm and the minimum size is 0.063mm. The aggregate was blended to avoid the maximum density line of Thompson and fuller curve and the Superpave restricted area to meet the design criteria. The mix design for asphalt concrete was done using the marshal mix design. The asphalt mixing and compactions were conducted at different temperatures to obtain the optimum temperature for mixing and compactions. The gradation has considerable effect on satisfying the specification limits of air voids (VTM) and void in mineral aggregate (VMA). Effect of gradation, mixing and compaction temperatures were studied in the mix design using PMB binders.
item: Conference-Abstract
Development of polymer modified bitumen specification for Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2012-07) Sitinamaluwa, HS; Mampearachchi, WK; Pasindu, HR
Implementation of polymer modified bitumen (PMB) is a new movement of Sri Lankan highway industry and it has become a challenging task for many reasons. One is, currently used penetration grading system is inadequate for proper quality control of PMB. The improper use of PMB would result in poor pavement performance and will lead to serious maintenance and cost issues. And the lack of experience of Sri Lankan engineers is a problem since a very strict process control is required. Hence there is the need of a proper guideline to implement PMB in Sri Lanka. The Performance Grading system is considered as the most effective specification for bitumen since the test methods capture fundamental rheological properties of bitumen. This was successfully implemented in USA; but is lagging in other parts of the world due to the cost and complexity of the new test equipment. But the empirical tests also are taken as indirectly related to the road performance for centuries. In PMB specifications of countries such as Australia, UK, India, Brazil, China etc. it is evident that the used test methods does not necessarily measure fundamental rheological properties of bitumen, but the empirical tests which are indirectly related to the characteristics of bitumen. In this research, the possibility of developing a Sri Lankan Specification of PMB with available test methods was studied. The important bitumen properties that are necessarily needed to be controlled are identified and the test methods which can determine those characteristics are included in the specification. Requirement limits for each test are set according to literature findings. Here the controlling of mixing and compaction temperatures for PMB was specially considered since it is a major practical issue. Further development for this specification can carry out with the experience of SL engineers in future, and the developed specification would be a great assistance for earlier stages of PMB pavements in Sri Lanka.
item: Conference-Abstract
Effective DGAB construction techniques for optimizing segregation during compaction process
(Department of Civil Engineering, University of Moratuwa., 2012-07) Ariyarathne, KVRK; Mampearachchi, WK; Pasindu, HR
Road construction in Sri Lanka widely uses Graded Aggregate (Dense Graded Aggregate Base - DGAB) for base construction with RDA specified Gradation requirements. But in loading, transporting, unloading, handling and in construction processes the segregation occurs deviating specified gradation. This study covered investigation on DGAB segregation during layer compaction by focusing; (1) What factors contribute to segregation of DGAB Layers, (2) The relationship between compaction effort and segregation, (3)The co-relations between water content, compaction effort and the extent of segregation , (4) To find out practical measures to control / minimize segregation effect in layer compaction In site trials it is generally observed that following segregation effects present and those make compacted layer non-uniform throughout its depth, (1) Fine particles tend to migrate upward while course particles remain at underneath layers at high water content. And (2) Fine Particles tend to settle down at dry condition Compaction trials were done in both thin (App. 150mm Loose) and thick layers (App. 225mm Loose). A number of factors like layer thickness, water content at compaction, the type of roller used (weight, with or without vibration) gives a major impact on particle dislocation and to the extent of segregation.
item: Conference-Abstract
Mechanistic empirical method of pavement design
(Department of Civil Engineering, University of Moratuwa., 2012-07) Dahigamuwa, RMTM; Marasinghe, DL; Wanniarachchi, WDNG; Mampearachchi, WK; Pasindu, HR
The objective of this research is to analyze the reason for the failure of A15 Trinco-Batticaloa rehabilitated road with the help of mechanistic tool, KENLAYER. With the appearance of pot holes and cracks the attention was moved to this road section. Empirical methods failed to identify the reason behind this failure and therefore mechanistic tools such as KENLAYER became more useful of analyzing it. Mechanistic approach to pavement design seeks to explain phenomena only by reference to physical causes. Thus it uses stresses, strains and deflections within a pavement structure to analyze the loads and material properties of the pavement. It is planned to obtain different deflections, stresses and strains for different axle loads and different sub grade and sub base CBR values. For the analysis two type of data is required. These are CBR data obtained from the soil and the traffic data of the road section along with the material it carries. Axle load survey would be a better option but due to its expensiveness traffic load survey was selected. CBR data would be collected through DCP tests carried on site and laboratory CBR tests. This study would prevent future failures of road pavements like this and would be a great use for future highway design Engineers. Through this study, the use of KENLAYER software would improve among highway Engineers in Sri Lanka and this would be a great advancement in the highway industry of the country.
item: Conference-Abstract
Optimization of the current design practice for differently able road facilities in Sri Lanka-case study
(Department of Civil Engineering, University of Moratuwa., 2012-07) Liyanage, LDUN; Mampearachchi, WK; Pasindu, HR
We all have a social obligation to respect the rights of our fellow human beings. Even if some people may lack certain abilities we all share same needs and expectations. People having disabilities have to spend the entire life struggling with their physique itself and might not have the freedom to stand for their own rights. Thus as people with fewer difficulties we have duty to stand beside them and support them. Accessibility protects the basic rights of a human being such as the right to receive facilities like healthcare, education and the right to do an occupation to earn one’s live etc. Therefore, it is essential to develop a barrier free road environment that guarantees accessibility for all. Disabled accessibility is not a new concept to the world. There are many related codes and practices in other countries. Sri Lanka has recently introduced this concept to the road infrastructure by improving the Bambalapitiya – Kollupitiya road section as disabled friendly by following guidelines given in the Gazette of Democratic Socialist Republic of Sri Lanka (No 1,467/15-17/10/2006). In this case study the newly introduced road facility was checked for its suitability for the country considering social and economic aspects. It was checked whether the design fulfils the intended purpose. Two visually impaired people participated in this study. They were asked to walk along the tactile guide way so that their behavior can be observed. Comments were taken from them regarding their personal experience and ideas for further improvement. In order to make decisions, further knowledge was gained through several sources such as the educational video “Pathway to independence” a product of “Nebraska Commission for the Blind and Visually Impaired” and also from documents such as RTS 14 Guidelines, ESCWA design manual, TRL Overseas Road Note 21. Several problems were identified from the study of new facility. Most importantly when compared with guidelines which have been followed, there were deviations of construction due to faulty workmanship. It was obvious that the guidelines have been prepared neither with proper understanding of differently abled people nor the suitability of the design for our country. After considering all these facts, the author was able to modify some guidelines and even come up with new ones. New layouts were introduced to the pedestrian walkway.
item: Conference-Abstract
Property change of road metal with blasting effects
(Department of Civil Engineering, University of Moratuwa., 2012-07) Abeysinghe, ALNU; Mampearachchi, WK; Pasindu, HR
Road metal is the largest component which contributes for road construction. Normally, in Sri Lanka naturally occurred sources are not available to suite the construction work. So, most commonly this requirement is fulfilled by excavating of rocks and crushing to the suitable sizes. With the current development of the highway sector in Sri lanka, the demand for the road metal is gone up and it is very difficult to full fill the requirement. In some areas in the country especially in the Northern area it is hard to full fill these requirements due to several reasons like archeological areas, environmental sensitive forest areas etc. So, the quality control and fulfillment of the requirement with the available limited sources is very important. When consider the use of crushed rock for the road construction, it is important to select materials in an acceptable quality. To ensure the quality, various tests have been introduced by relevant authorities. Especially when crushed rock use for the road bases and surfacing these properties are very much important to ensure the durability. When selecting a source to produce crushed rock as road construction material, production from the selected source have to be satisfied certain requirements. The LOS ANGELES ABRASION VALUE (LAAV) and AGGREGATE IMPACT VALUE (AIV) are the two important tests to be carried out to ensure the strength requirement of the road metal. It has been noted that with the blasting operation, there is a considerable variation of rock fragmentation and it is mainly due to the quantity of explosive that use for the blasting operation. Types and features of explosives and blasting design also play an important role of rock mass fragmentation. In Sri Lanka, blasting design patterns and explosives that are using is not varying considerably. But usage of explosives changes in continuous operation even the place is unchanged. Sometimes these changes are due to environmental condition such as rainy seasons and due to some significant change of nature and properties of rock mass. The objective of this study is identify the changes of AIV and LAAV with the use of explosive percentage use for the blasting operation and improve the strength of road metal by controlling the explosive usage for the metal production. Ensure the quality control of material production with less variation of strength, due to blasting operation.
item: Conference-Abstract
Relationships between c.b.r and d.c.p testing for different soil types
(Department of Civil Engineering, University of Moratuwa., 2012-07) Wijekoon, WMISK; Mampearachchi, WK; Pasindu, HR
When planning and design a highway. Assessment of sub grade shear strength is very important General practice adapts to measure the sub grade strength is called California Bearing Ratio (CBR). Standard CBR laboratory method testing requires sampling transport of soil to laboratory and then takes at least four day period for necessary testing procedures. Field CBR method is also time consuming method. Due to these reasons Dynamic Cone Panetrometer (DCP) is used and then correlated the DCP reading to a C.B.R value for design evaluation The significant advantages of the DCP are that it is a low cost, robust apparatus that is quick and simple to use. Very little damage is done to the pavement being tested (effectively nondestructive) and very useful information is obtained. One of the major advantages of the test is that the pavement is tested in the condition at which it performs. The simplicity of the test allows repeated testing to minimize errors and also to account for temporal effects. It should be noted that there are inherent inaccuracies in most CBR test results and these coupled with the material dependency of the DCP results make the DCP interpretation a very good indicator, but it should never be used as an absolute indicator of the in situ CBR strength of a material in a pavement. However following factor will effect to change both field D.C.P and C.B.R; (1) Field Moisture content (2) Plasticity Index (3) Instrumental and other man made errors and (4) Field Density These studies show that how far this DCP CBR relationship is viable .DCP had the most consistent results within the different layers. If there is any possibility to make good correlations between the DCP with the CBR. what are the other factors to be considered when preparing relationships between D.C.P and C.B.R. However, the results of this study indicated that the DCP can give more reliable result to the field CBR values, when PI is less than 10. When PI increases it is very difficult to predict because soil characteristics drastically change with soil properties. Therefore, some detail soil investigation is necessary even to predict the design CBR at the particular locations.
item: Conference-Abstract
Study of fuel consumption efficiency of vehicle type in Sri Lanka
(Department of Civil Engineering, University of Moratuwa., 2012-07) Jayasekera, DAS; Mampearachchi, WK; Pasindu, HR
Road transportation is the dominant mode of transportation in Sri Lanka. The vehicular fleet in Sri Lanka is divided in to two categories as Petrol and Diesel. The highest expenditure in the country is spent for the imported gasoline. Studying of the fuel consumption rates for each and every vehicle type in the country is an essential need to forecast the expenditure for the fuel in future. Fuel consumption is the amount of fuel used per unit distance; litres per 100 kilometres (L/100 km). The study was conducted to survey the fuel efficiency of petrol and diesel vehicles in the whole country. The data for fuel consumption was recorded at selected fuel stations in each Executive engineers division to cover whole country. The data was collected from 6.00am to 6.00pm. Consumption was recorded from each vehicle type. The results revealed that the petrol vehicles; i.e motor cycles and three wheelers are running with their highest fuel efficiency in North Central Province while cars, jeeps and passenger vans have the highest fuel efficiency in North Western. The lowest fuel efficiency for petrol vehicles is obtained in Uva Province and in Eastern Province except for Motor Cycles. When considered diesel vehicles the highest fuel efficiency is in North Western Province except for buses, pickups and trucks. Estimation of fuel efficiency with respect to district and EE division were estimated. Study shows that fuel efficiency can be used to evaluate the condition of road network within the district or EE division.

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