ICAHETS - 2017

Permanent URI for this collectionhttp://192.248.9.226/handle/123/19002

Browse

Now showing 1 - 20 of 23

item: Conference-Abstract
Proceedings of Advances in Highway Engineering & Transportation Systems 2017 [Pre Text]
(Department of Civil Engineering, 2017) Pasindu, HR
item: Conference-Abstract
Minimizing highway alignment cost by optimizing horizontal curve radius
(Department of Civil Engineering, 2017-07) Sushma, MB; Maji, A; Pasindu, HR
In practice, the task of designing the horizontal alignment of a highway is done manually based on experience and engineering judgement. As a result, the work is both time and resource consuming and relies heavily on human expertise. This paper presents a general formulation for optimization of horizontal alignment, composed of tangential segments and circular curves. It consists of a constrained optimization problem where the objective function is to minimize the overall cost of the horizontal alignment. These constraints are imposed by curvatures, geometric guidelines, the presence of inaccessible regions, etc. In addition to construction costs, facts considered by this model also include highway geometric code requirements. The paper mainly focuses on fitting the curves with appropriate radius between the tangential sections obtained by connecting the optimum set of point of intersections (Pis). The available methods consider radius of the curves as a constant value, which also acts as a constraint while developing an optimal alignment. Application of the model to a real-world study area is also presented in this paper, along with a comparative study with AutoCAD Civil-3D.
item: Conference-Abstract
Effect of traffic composition on capacity of two-way two-lane, roads under mix traffic condition
(Department of Civil Engineering, 2017) Rajapaksha, RPGKS; Bandara, JMSJ; Pasindu, HR
Traffic performance of a road section is expressed in terms of Level of Service (LOS). The Highway Capacity Manual (HCM) developed by the Transportation Research Board of the National Academies of Science in the United States provides procedures to determine LOS based on analysis of capacity of a road. It divides the quality of flow into six levels ranging from level A to F. These definitions of quality are based on measures of effectiveness of the road which include speed, travel-time, density and delay. Road development authorities in Sri Lanka are adopting the methodologies given in the HCM due to the lack of guidelines specific for the country. However, the HCM methodologies may not depict the correct traffic performance of roads owing to the nature of the mix of vehicle types in the traffic stream, the lack of lane discipline and irregular road side activities. This may lead to incorrect decisions in planning, designing, maintenance, rehabilitation, and operation of roads. Therefore, it is necessary to study traffic performance in Sri Lanka, and to evaluate the transferability of methods used in other similar countries in order to develop appropriate and applicable approach to mix traffic Condition. Subsequently, in order to evaluate traffic performance, it is important to study about operational characteristics of traffic stream. In a pilot study under this work, capacity of a road was found to be affected by the traffic composition and control condition. Therefore, characteristics of vehicle composition in different capacities have been considered and study was focused to two waytwo lane roads. Different size, power, and maneuverability performance of vehicles cause significant level of friction to the movement of other vehicles in a mix traffic stream. For an example, in a high traffic volume stream, a large proportion of motorized two wheelers and three wheelers are able to move with speeds closer to their free speeds due to the ability of utilizing smaller gaps in the traffic stream, while the large-size vehicles are subjected to significant speed reduction. Characteristics of fundamental traffic flow parameters (Speed, Density and Flow) in traffic streams with different compositions of vehicles were studied. One-Sample Kolmogorov Smirnov test was performed to check normality of speed of collected data samples under prevailing conditions and it has shown that speed distribution is significantly deviate from normality (P-value < 0.05) under different compositions and traffic volumes. It is observed that speed distribution shows bi-modal distribution in roads which wheelers and three wheelers. One-way analysis of variance (One-way ANOVA) tests was carried for speed characteristics of group of two wheelers, three wheelers and four wheelers. Null hypothesis (Ho) that there will be no significant difference between different groups of vehicle speed sample means was rejected with 95% confidence level (P-value < 0.05). Therefore, vehicle composition has described as separate groups of two wheelers, three wheels and four wheelers. Modified continuity equation for heterogeneous driver population was used to calculate densities of traffic streams. Different traffic flow models which used to model two-lane traffic flow behavior had been tested under prevailing conditions. Greenshield traffic flow model has showed strong correction between flow and speed and it was chosen to develop speed-flow models. Finally, empirical speed - density and speed - flow curves were developed for different compositions of vehicles in order to evaluate the capacity variations under mix traffic condition.
item: Conference-Abstract
Passing sight distance: adequacy of aashto criteria for two lane roads in Sri Lanka
(Department of Civil Engineering, 2017-07) Masakorala, R; Mampearachchi, WK; Pasindu, HR
Freedom of overtaking maneuvers on a two-lane highway indicates the Level of Service of that particular highway according to the Highway Capacity Manual, 2010. Therefore, an adequate minimum Passing Sight Distance (PSD) would economically increase the percentage of passing zones, ultimately the highway capacity as well. Initially, American Association of State Highways Officials (AASHTO) provided a guidance for minimum PSD design criteria for passenger cars in 1954. Later, more conservative and comprehensive models and concepts were presented by Lieberman (1982), Glennon (1988), Hassan et al., (1996), and Harwood et al., (2008) etc. Typically, the effectiveness of analytical models was evaluated based on the realization of safe overtaking mechanism with a wide range of human and vehicle related parameters. This paper will present an analytical model derived and validated using empirical data for passenger cars and evaluation of the suitability of AASHTO and proposed model for local traffic conditions. The filed investigation was done using two test vehicles and a GPS data logger, on selected A & B class highways in Western and Southern Provinces of the country. The modal basis - idealized overtaking maneuver - was developed with field observations and consequently validated with empirical data. When compared to the resultant PSD values with AASHTO, new model clearly presented significantly conservative values than AASHTO for design speeds less than 80km/h. To evaluate both models for safety, a reliability index was calculated relevant to the actual PSD demand on local highways. According to the results reliability of AASHTO model extremely depreciated with increasing design speed while new model reach to a constant value at around 60km/h. Therefore, as a conclusion the adaptation of AASHTO guidelines for highway design purposes can be justifiable and recommended for Sri Lanka for design speeds less than 70km/h in the context of safety, but not conservative at lower design speeds in maximizing capacity of two lane highways.
item: Conference-Abstract
Development of speed prediction model for horizontal curves under mixed traffic conditions
(Department of Civil Engineering, 2017-07) Sil, G; Maji, A; Pasindu, HR
Speed is one of the well-known causes for crash. Radius of horizontal curve significantly affects vehicle speed. Drivers unable to manage speed within a curve can get into accident. The fatal crash rate in horizontal curve is higher than the straight section. Therefore, safety at horizontal curve is considered as serious matter of concern. Traditionally, safety is analysed by speed differentials. The differences in operating speed between successive highway elements can be used as a measure to evaluate geometric design consistency and safety. Researchers have studied homogeneous traffic with strong lane discipline to predict vehicle operating speed in two lane highways. However, Indian traffic operates differently than the one in western countries due to wide variation in vehicle’s operating and performance characteristics, and weak lane discipline. However, in India studies to predict operating speed model for four lane divided road is limited. It motivated authors to develop operating speed prediction model for four lane divided highway. In this study, car speed data at the center of seven horizontal curves in a four-lane divided highway have been collected. The 85lh percentile speeds at five sites are analysed to develop a linear speed prediction model for car. The developed model depends on curve radius and is validated at two different sites. Results show that I-value is lesser than 0.2, which confirms the applicability ofthe developed model.
item: Conference-Abstract
Application of fuzzy regression methodology in transportation engineering
(Department of Civil Engineering, 2017-07) Marisamynathan, S; Vedagiri, P; Pasindu, HR
Signalized intersection is one of the vital components of the entire road network. The operational conditions of intersections considerably affect the performance of the whole road network system. The performance level of signalized intersection is measured in terms of Level of Service (LOS). Existing studies on LOS at signalized intersections are based on conventional linear regression (CLR) techniques and those models failed to estimate accurate LOS of signalized intersections due to basic assumptions of CLR methods. This paper explores the fundamentals of most popular fuzzy linear regression (FLR) techniques and the application of FLR methods in developing the LOS model at signalized intersections. The proposed methodology derived in two steps. First step, membership function developed and the fuzzy input values defuzzified in crisp value by applying the centroid method. Second step, the fuzzy least square method is applied to develop the required model. The proposed methodology is applied in Pedestrian LOS model development. Finally, mean absolute percentage error values are compared between conventional regression and fuzzy regression models and the results shown that fuzzy regression models provide more precise and reliable solutions. The proposed new methodology can be used to develop a LOS model in the transportation field.
item: Conference-Abstract
Development of guidelines for traffic signal coordination for intersection clusters
(Department of Civil Engineering, 2017) Jayasooriya, NK; Bandara, JMSJ; Pasindu, HR
With the ever-increasing traffic congestion, it is needed to initiate sustainable traffic management solutions. There is a need to establish signal design standards taking in to account the latest trends in traffic signal development so that there will be consistency in traffic signal designs and also to make provision to incorporate future coordination and other automation such as monitoring violations and gathering traffic flow information for real time updates. More importantly standardization will minimize user confusion and improve safety at traffic signals and help improving traffic flow and user satisfaction. The congestion issues that are related to signalized intersections are not only inherent to a particular intersection, but rather can be a result of the signal arrangements at nearby intersections. This research identifies the issues with the typical intersection arrangements, and aims at developing a guideline to be followed for traffic signal designs especially when traffic signals are to be coordinated intersection clusters. The necessity of a properly calibrated software for the local condition has been identified as a key component in related literature. VISSIM traffic simulation software was calibrated for the Sri Lankan condition after collecting information from more than 10 intersections in and around Colombo. From the video surveys and manual observations considered, the traffic volumes along with the turning movements, vehicle mix and queue lengths were obtained and compared with the simulated results with an accuracy of ±10. With the calibrated VISSIM software, the guidelines to be followed were developed considering the factors such as; identification of the coordinated phase, determination of individual signal timings for intersections, determination of phase timings for coordinated & non-coordinated directions and optimizing the offsets. The developed guidelines were tested for the Baseline Road intersection cluster and simulation results shows significant delay reductions over xx% for any approach can be achieved in the coordinated directions without adversely affecting the non-coordinated directions.
item: Conference-Abstract
Influence of nanoclay and carbon nano tube on high temperature performance grade and rutting performance of asphalt binder
(Department of Civil Engineering, 2017-07) Ashish, PK; Singh, D; Pasindu, HR
The present study evaluated effects of nanoclay and Carbon Nano Tube (CNT) on high temperature Performance Grade (PG) and rutting performance of asphalt binder using Superpave rutting parameter and Multiple Stress Creep Recovery (MSCR) test. The Control binder (VG-10) was blended with 4% nanoclay and 0.75% CNT, and has been termed as Control+4%nanoclay, and ControK0.75%CNT binders in the study. The results showed that addition of both nanoclay and CNT increased stiffness and high temperature PG of Control binder. The results from MSCR test showed that Control binder after addition of nanoclay and CNT increased Recovery (%R) value and decreased non-recoverable creep compliance (Jnr)- Stress sensitivity of Control binder did not change after addition of nanoclay and CNT. The results showed that addition of nanoclay and CNT may help in improving the rutting resistivity potential of asphalt binder.
item: Conference-Abstract
Development of urban road maintenance management system using distress models of hdm-4
(Department of Civil Engineering, 2017-07) Tanuj, C; Sahil, K; Manoranjan, P; Naveen, K; Pasindu, HR
Pavement maintenance management systems are to be developed for the urban road networks for low to medium size cities in India. The study shows the results of progression of roughness of a major secondary road of a Patiala urban road network from Dukhnivarin Sahib Gurudwara to Nabha road with various alternative options and the intervention criteria’s decided in such a manner to keep this road within the serviceability level 2 of roughness i.e. IRI of 4 m/km throughout the analysis period of 15 years as per the guidelines of Ministry of Road Transport & Highways for maintenance management of primary, secondary & urban roads. Survey was conducted in order to build up the inventory data base & pavement condition was assessed using Bump Integrator and Benkelman Beam equipment. Pavement Maintenance and Management System was used for technical & economic analysis purpose. Different calibration factors were used on various distress models of HDM -4 in order to facilitate more steady and reasonable prediction of the road network for local conditions. The calibration factors were chosen on the basis of roughness close to actual measured value of roughness. Also, the comparison between scheduled and responsive criteria’s is done for knowing the effectiveness of the strategies. The purpose of present study is useful for the sound decision making and for in time allotting of funds in order to enhance & maintain certain level of serviceability throughout the analysis period.
item: Conference-Abstract
Investigation of marshal] characteristics & durability of glass powder incorporated dense-graded asphalt
(Department of Civil Engineering, 2017-07) Choudhary, J; Kumar, B; Gupta, A; Pasindu, HR
Asphalt concrete is one the most widely used paving mix and its durability is a key issue with regaids to long term pavement performance. The Cantabro durability test is one of the most practical and implementable test used to assess the durability of open graded asphalt mixes. However, previous studies have validated its superior viability in dense graded mixes as well. The durability as well as performance of asphaltic mixes is widely dependent on the nature and quantity of mineral filler. This study identifies the effect of incorporating waste glass powder as mineral filler over the Marshall Properties and durability of dense graded asphalt concrete mix. A suitable number of trail mixes were designed as Marshall mix design method having stone dust as conventional filler and glass powder as alternative filler. At optimum binder contents of both mixes, Cantabro durability tests were performed to measure their durability against raveling. It was observed that, although glass powder improve the Marshall properties of asphalt concrete mixes as compared to conventional filler, however, it also impaired the durability of same mixes against raveling.
item: Conference-Abstract
Modelling pedestrian crossing behavior through social force model
(Department of Civil Engineering, 2017-07) Siddharth, SMP; Perumal, V; Pasindu, HR
Social force model (SFM), a microscopic model, is an effective method in modeling pedestrian walking behavior. Social force model assumes that the walking behavior of pedestrian is influenced by a series of forces. Modeling Pedestrian-vehicular interactions using social forces model is in very nascent stage especially for mixed traffic conditions. Very few studies have modeled signalized crosswalk with permitted left turning vehicles which interact with pedestrians. Authors also have not found any social force models for midblock crossings which is a very important pedestrian facility from safety' point of view. Hence there is a need for vehicular social force model and gap acceptance model which will help in modeling crosswalks. The objective of this study is to create a pedestrian-vehicular Social force model which can simulate pedestrians as well as vehicles and their interactions for intersection as well as midblock crossings with modifications to represent mixed traffic conditions. The proposed model has a pedestrian SFM component. Vehicular SFM component Pedestrian Gap acceptance model which is introduced. Also, the Pedestrian- Vehicular force is modified by adding a new factor to model the difference in forces exerted by different type of vehicles.
item: Conference-Abstract
Development of logit model for estimating helmet usage in developing countries
(Department of Civil Engineering, 2017-07) Marisamynathan, S; Vedagiri, P; Gupta, S; Pasindu, HR
In Mumbai, one of the major cities in India, the total number of accidents including fatal, serious, slight and minor road accidents has risen by 766 cases in 2015 as compared to the previous year. The year 2015 has recorded the most deaths for people traveling on a motorcycle and also shows that the number of pillion riders who have died has been the highest at this year. Two-wheeler driver and pillion riders will now have to wear helmets in Maharashtra with the state Transport department on February 2016 issuing a circular to this effect as per the orders of the Bombay High Court. Thus, the study objective is to evaluate the effect of a mandatory motorcycle helmet law on helmet usage, injury, and fatalities among motorcyclists involved crash in Mumbai, India. The required data were collected in two different time frames before and after the helmet mandatory law at selected ten study locations in Mumbai, India during May to June 2015 and 2016 respectively. From the field survey, a total of 28,209 and 37,245 samples was collected during 2015 and 2016 respectively. This study was performed the statistical analysis of the impact of the state strict law of helmet usage before and after the law and it found that the helmet doesn't use decreased from 32.8% in 2015 to 16.5% in 2016. In addition, this study was performed the Pearson correlation and analysis of variance tests for identifying the impact of each variable of helmet usage behavior and personal characteristics with helmet usage. Finally, binary logit model was developed and validated to estimate the probabilities of two-wheeler driver wearing the helmet. These study findings strongly suggest that increased helmet use through strict helmet usage law would decrease the number of motorcyclist injuries in the Mumbai, India.
item: Conference-Abstract
Evaluation of water absorption characteristics of internal curing concrete aggregate with respect to the processing temperature of expanded clay types
(Department of Civil Engineering, 2017-07) Bandara, MMHW; Mampearachchi, WK; Pasindu, HR
The increase of the new technological development of any country may lead to introduce fast and sustainable construction techniques and materials. Internal curing is one of a revolutionary curing process which has more advantages than the conventional curing process. Internal Curing can supply extra water throughout the concrete mixture in order to complete the cement hydration process. This can be done by using lightweight aggregate which replaces some of the normal and conventional aggregate in the concrete mixture. Water that absorbed inside expanded lightweight aggregate can provide additional water throughout the concrete mixture for curing process. This method can be effectively used for concrete road and related infrastructure construction since the traditional curing methods have some inherent limitations in using road infrastructure construction. Expanded clays can be used to produce suitable aggregates for internal curing. So, heating temperature is a critical parameter in the production of suitable ICC aggregate using expanded clay. Water absorption and desorption are the main requirements of internal curing. This research is mainly focused on selecting suitable heating temperature which gives and optimum water absorption. It includes the selection of suitable expanded clay type to produce ICA. Different clay samples were studied to build a relationship between heating temperature and water absorption. Clay samples were prepared using a mold and that clay samples were heated at various temperatures (in the range of 800 °C to 1300 °C). Heated clay samples were analyzed through the laboratory tests. The bloating coefficient of the clay samples were varied from 1.0 to 2.2. Higher temperature has the higher bloating coefficient but at 1300oC the clay samples were begun to melt due to the phase change of the structure of clay molecules. Higher water absorption values are experienced before the phase change of the clay molecules.
item: Conference-Abstract
Mapping the relationship between modular building construction and transportation infrastructure
(Department of Civil Engineering, 2017-07) Bandara, VYJ; Taron, J; Assef, G; Kattan, L; Pasindu, HR
Currently, modular building construction (MBC) is gaining in popularity as an alternative to conventional on-site building construction (CBC). While the appearance of modular buildings is most often indistinguishable from conventionally constructed buildings, their interaction with other key infrastructural systems such as transportation, energy, water and waste management, varies greatly; however, very little if any research exists on the matter. Thus, understanding these interactions and quantifying the impacts are essential to identify ways to minimize their negative externalities. Conversely, it would be useful to understand how transportation infrastructure can be adapted such that it positively impacts the trend toward MBC. The objective of this study is to identify opportunities to understand the interactions between MBC and transportation infrastructure to provide a framework for future research that can support a positive relationship between these two inherently integrated infrastructural systems. To achieve this objective, a 2-part literature review wras conducted that maps the infrastructural systems impacted by MBC with an emphasis on transportation systems. The first section of the literature review focused on various published material on MBC methods, through which the impacts of MBC on transportation system and vice versa were identified. The analysis of this section pointed to instances of MBC which reduces the negative impact on transportation systems due to building construction such as the reduced transportation requirements of labor, site-overheads, and construction equipment to and from the site. Similarly, it also pointed to instances where MBC presents challenges to the transportation system compared to CBC such as the requirement of transporting large prefabricated building components. The second section reviews existing life cycle impact assessments of MBC methods, through which the overall impact of MBC system was mapped.
item: Conference-Abstract
Risk management and site layout optimization of ready mix concrete plants
(Department of Civil Engineering, 2017-07) Zunzunwala, S; Ranadive, MS; Pasindu, HR
Ready Mix Concrete (RMC) industry is rapidly growing in India. With the increase in infrastructure projects the use of concrete increases exponentially and so the RMC industry. All public and government projects are going for the use of RMC rather than traditional concrete manufacturing techniques. At present, nearly 6 million cubic meter RMC per month (72 million cubic meters per year) is produced by commercial plants in India. RMC industries are subjected to many risks like other industries. Also, not much importance is given for site layout optimization of RMC plants. With tremendous increase in land cost, site layout optimization should be given prime importance. If risk and optimization in RMC plants are effectively managed then RMC industry will achieve higher profit margins. As per the ICI Journal August 2016 issue, improving the efficiency by 10% in concrete production at RMC could save approximately $350m (Rs.2400crores) per year. This paper proposes an overall improvement of RMC industry by effectively managing risks that arises in the plants and its site layout optimization.
item: Conference-Abstract
Classification of man and women home based travel behavionrs at bus to bus transits in Colombo
(Department of Civil Engineering, 2017-07) Widanapathiranage, S; Pasindu, HR
Men and women travel behaviours are different during the joumev to work from their home. Men travel more length of travel and tend to work more days in a week than that of women. Study on men and women travellers’ behaviour at transit is important since it reveals the demand of passenger attraction and generation of bus travels, the nature of transit travels that it tempoial or permanent, directions of travel demands start from and to end. purposes of travel, modes of travel to reach the transit and to leave, and choice of the travel These details can be used for bus route planning and scheduling works. routes etc. The study conducted at selected bus passenger transit towns in Colombo Metropolitan Area (CMA). These are categorized in to three transport zones such as; Zone 1: Colombo city limits area, Zone 2: Colombo peripheral area, and Zone 3: Colombo suburban area with considering the number of plying bus routes per square km of area. At each bus to bus transit location, bus traveller boarding counts were collected for 12-hour bus operational period in a day and simultaneously, travel behaviour data was collected by interviewing randomly a bus traveller who waited for a travel at transit during the survey period. The random sample was represented at 95% level of confidence and the bus traveller age varies between 20 and 50 years. It was assumed that this category of age represents a majority of employed bus travellers in the study area. The survey revealed that about 0.75 million of transit bus travellers travels daily in CMA. Of them, 53 % of travellers reach to a transit location by bus, ->8% by walking and the balance by a vehicle. The travel origins observed that on average 46% of travellers start journey from home, 26% from work place, 11% from a social event, 10% from school and 7% from Business. The travel destinations observed that on average 43% of passengers’ travel to home, 28% to work place, 13% to a social event, 7% to school and 9% to Business. It also revealed that 65% of bus travellers create Home Based Worked Trips (HBWT): of them; 69% of men and 31% of women, and 35% of bus travellers create Non-Home Based Worked Trips (NHBWT): of them, 55% of men and 45% of women. Finally, it is concluded that men create 21% more bus transit trips per day on their way to work place than that of women in Colombo Metropolitan Area.
item: Conference-Abstract
Evolution of road user charging and its future
(Department of Civil Engineering, 2017-07) Perera, L; Thompson, RG; Pasindu, HR
Road user charging (RUC) has a long history as a mechanism to recover infrastructure maintenance and capital costs. The range of fees and charges include: import taxes, fees, registration, stamp duty, direct toll charges, congestion levies and fuel taxes. Frequently these charges are opaque at best and the revenue generated from road users does not always find its way back to investment in transport facilities. In recent years the fuel tax has been the most popular method of charging users in many countries. Changing road user behaviour, travel demands and expectations as well as technology changes all point to the need for alternate mechanisms for road charging that encompass broader concepts integrating traffic demand management measures, efficient and sustainable revenue sources that balance economic, environmental and social considerations. Current charging measures are struggling to meet these multi-stakeholder multi-objective mechanisms with issues for heavy vehicles (HV) such as transparency, cross-subsidisation, environmental concerns and reducing revenue due to the likes of lessening fuel tax as vehicles become more efficient. This all results in insufficient revenue to cover cost of critically needed infrastructure. licence This study reviews the evolution of RUC with more emphasis on heavy vehicles and evaluates strengths and weaknesses of the present RUC mechanisms implemented in the world with respect to stakeholder problems and demands of the freight industry. Further, this review describes and highlights the need for a more appropriate, practical and sustainable approach which can be used in the future. Promising schemes are also described. A systems approach is used to analyse the problems, identify key issues, propose a valid solution and describe the need for improved decision support to determine the level of charging. A model is proposed that is transparent and considers direct usage based charging addressing most of the weaknesses highlighted in the models reviewed. Further, it considers externalities produced by heavy vehicles into account. The model has the potential to provide answers to key stakeholder issues and will lead to more sustainable freight transport system in future. Encouraging fuel efficient and safe vehicles or modes of transport, optimization of loading, routing and logistics systems, and long-term land use planning are a few of them.
item: Conference-Abstract
Traffic speed limit modeling using support vector regression and firefly algorithm
(Department of Civil Engineering, 2017-07) Maheshwari, S; Singh, D; Zaman, M; White, L; Pasindu, HR
Setting traffic speed limits using engineering approaches is highly desirable, however, spot studies required for such approaches are tedious, subjective and time consuming, in the present study, 85 percentile speeds were modeled using tw'o machine learning approaches a) Support Vector Regression, and b) Support Vector Regression (SVR) coupled with the Firefly Algorithm (FA). The objective of the study is to model traffic speed limits using artificial intelligence tools and quantify the efficiency of metaheuristic evolutionary algorithms for optimization. Input parameters, namely, physical characteristics of road, traffic and pavement condition were used for modeling. Physical characteristics of road included shoulder width, shoulder type and surface width. The traffic parameters consisted of average daily traffic and posted speed. Skid number and international roughness index were covered in pavement condition parameters. Two statistical models (Model 1 and Model 2) were developed for the prediction of 85th percentile speed. Model 1 consisted of physical characteristics of road, pavement condition parameters and traffic parameters including posted speed. Model 2 consisted of all the parameters of Model 1 except posted speed. Statistical performance evaluators like mean absolute relative error, mean square error, coefficient of determination and over-fitting ratio were used to compare the models. It was observed that the Model 1 outperformed Model 2, conveying the importance of posted speed for accurate prediction of operating speed. Application of firefly algorithm resulted in improved prediction accuracy with reduced computational time and manual work, highlighting the need to explore its application for civil engineering problems.
item: Conference-Abstract
Effects of wax based wma additive on laboratory performance of polymer modified binder
(Department of Civil Engineering, 2017-07) Kataware, AV; Singh, D; Pasindu, HR
Hot mix asphalt concrete (HMA) is being widely used to construct flexible pavements. The HMA technology requires temperature in range of 150 to 190"C, which could cause many environmental and health issues. Moreover, high temperature oxidizes bitumen and reduces its design life and long-term performance of pavements. Researchers have reported that warm mix asphalt (WMA) technology can help in reduction of mixing and compaction temperatures by 20 to 40°C, and consequently promotes environmental and energy efficient technology for construction of pavements. There are different types of warm mix additives as organic, wax, chemical and water based. These additives are mixed with virgin binders to reduce the viscosity of asphalt binder and felicitate good working conditions by reducing temperature, emissions and increasing workability. However, concerns have been raised to evaluate moisture, rutting and fatigue performance of WMA mixes. The less mixing temperature in plant may reduce aging of a binder, which may result in high amount of rutting in the field. However, limited studies are available on performance of binders modified with WMA additives. Keeping the sustainability and energy saving requirements in view, current study aims to evaluate laboratory performance of polymer modified binder (PMB 40) modified with a wax based additives. Rutting performance using Superpave rutting parameters (G*/Sin5), and multi-stress creep recovery tests (MSCR) were evaluated in the laboratory for WMA modified and PMB 40 binders. It was found that addition of wax additive enhances high temperature grade of a binder. Also, modification showed improvement in rutting parameter (non-recoverable creep compliance) of a binder estimated from MSCR test. Overall, it was seen that addition of a wax based WMA additive results in improving rutting performance.
item: Conference-Abstract
Angularity of fine aggregates using digital image technique and conventional approach
(Department of Civil Engineering, 2017-07) Rajan, B; Singh, D; Garg, G; Pasindu, HR
Fine aggregates are one of prime constitute in asphalt mix design. However, the effect of fine a8SreSale morphology (angularity) on asphalt mixtures behaviour is well recognized in literature. For example, the excessive use of natural fine aggregates (less angular or rounded shape) over manufactured sand (angular shape) reduce shear strength of mixes and reflect premature rutting phenomena on asphalt pavements. In the other words, fine aggregate angularity largely influences particle packing behaviour and ultimately affects stability and mechanical performance of asphalt mixes. In the present scenario, the fine aggregate shape is characterized using two well-known approaches. The first is conventional approach defined by Strategic Highway Research Program (SHRP) in the early nineties. The conventional approach measure fine aggregate angularity (FAA) value as the percentage of air voids present in loosely compacted fine aggregates. The basic underlying principle is that the aggregate with more number of fractured faces will give higher air voids. However, Superpave system defined the minimum requirement of FAA is 45 for the use in high traffic pavements. The second approach uses computer automated Aggregate Image Measurement System (AIMS) to characterize fine aggregate shape. AIMS works on digital image technique and measure fine aggregate angularity in the range of 1 to 10000. In addition, it further classifies the angularity values in different ranges i.e. low or rounded (1 to 2100), moderate (2100-3975), high (3975-5400) and extreme or highly angular (5400-10000). The current study measure and compare angularity of four different sizes, namely FA1 (P2.36-R 1.18: passing through 2.36 mm and retaining on 1.18 mm sieve), FA2 (PI. 18- 0.600), FA3 (P0.600-R0.300) and FA4 (P0.300-R0.150) of basaltic type fine aggregates using digital image technique and conventional approach. Additionally, an Analysis of variance (ANOVA) statistical approach was used to study the effect of aggregate size on angularity. The result and analysis reveal that both approaches for angularity measurement were provided different ranking among aggregate sizes. Also, it is found that measured angularity from both approaches were showing a negative Pearson’s-correlation coefficient (r) 0.82, indicating strong negative correlation. The indirect measurement and associated higher subjectivity of FAA test method may be a probable cause for negative correlation with digital image technique approach. It is expected that the findings from the study will add strength to existing research repository. The study may also help over quality control of aggregates. Further, the study will pave the way to adoption of new technologies over conventional practices

Browse

Recent Submissions