Applied Mechanics and Materials Vol. 802

Abstract: Bonding strength of bitumen is one of the most important properties in need of independent evaluation. Conducting a pull-off test to determine the bonding strength of bitumen can be done using the Universal Test Machine (UTM). In this work, the UTM was used to investigate the effect of adding an additive to with a 60/70 penetration grade bitumen; the additive used was nano-clay at a percentage of 2% and 4%. A designed mold was fabricated and used with granite and stainless steel substrates. The investigation covered the influence of variation in the mixing process (mixing duration and power of rotation during mix) on the bonding strength of the samples. X-ray diffraction (XRD) was used to discover the nano-clay exfoliation within the binder structure. Also, empirical tests - penetration and softening point tests - were conducted. The results varied according to variation in percentage of additive, substrates used and the mixing process. The bonding strength and softening point results were able to identify the effect of the additive, and were able to detect changes caused by the adding condition; both were very well correlated, unlike the penetration test result which had a weaker correlation with bonding strength.

Abstract: Age hardening of bitumen is one of the factors affecting the durability of asphaltic concrete pavements. As the bitumen ages, its viscosity increases and it becomes more stiff and brittle. Recycling agents have been used to restore or soften the aged bitumen properties to a consistency level appropriate for use in the recycling process of deteriorated pavements. This paper details a study on the use of Waste Engine Oil (WEO) from vehicles as a recycling agent for aged bitumen. The study focused on the rheological properties evaluation of virgin bitumen, aged bitumen and blended bitumen (50% of fresh bitumen + 50% of aged bitumen) mixed with waste engine oil as additive (with 0%, 3%, 6% and 9%). The aged bitumen was prepared through the process of Rolled Thin Oven Test (RTFOT) and Pressure Aging Vessel (PAV) test to simulate the aging process. The virgin bitumen, the aged bitumen, and the blended bitumen mixed with various proportions of WEO were then tested to determine their physical characteristics. Penetration, softening point, viscosity and dynamic shear rheometer (DSR) tests were conducted in order to determine rheological properties of the bitumen samples prepared. The penetration value of blended bitumen added with WEO increased with the addition of WEO. The softening point decrease with the percentage increased in WEO of the blended bitumen. The viscosity for the blended bitumen added with WEO decreases with the increase in the percentage of WEO added. The DSR results showed that the increase in the amount of WEO in blended bitumen decrease the G*/sin δ parameter. For the particular bitumen and WEO used, the optimum percentage of WEO is 6% by the total weight of bitumen as it complies with the Public Works Department of Malaysia’s specification requirements. This study suggests that WEO has ability to counteract the stiffening of aged bitumen and restore the aged bitumen to that of virgin bitumen. As the composition and performance of bitumen and WEO may be different from those used in this study, it is recommended that a detailed evaluation is carried out for the bitumen and WEO to be used in asphalt recycling.

Abstract: Malaysian Trip Generation Manual (MTGM) is an important document to assist transport planners in forecasting the estimated trip attraction and trip production from a land use. The forecast is crucial in estimating trip generation from a proposed development on the existing road network. Therefore, this study is to verify the accuracy of the existing trip generation model published in MTGM for flat/apartment/condominium and low cost housing subcategories. By applying variable transformation, four alternative models were developed. They were the logarithmic model, the inverse model, the linear-logarithmic model and the logarithmic-linear model. Using residual analysis, influential data was identified and taken out for second analysis. Model selection was based on R² value, t-test and Kolmogorov-Smirnov test results. Besides linear model, logarithmic model is also truly representing trip generation model for both subcategories. There is some difference in the trip generation estimation between the study model and the existing model in MTGM. Sensitivity analysis shows the level of sensitivity between study model and existing linear model. One of the implications in using the studied trip generation model is in evaluating level of service of the junction.

Abstract: Time gap is important for road user to make decision relative to the lad vehicle at a roadway segment. Theoretically, if the gap is larger than reaction time, drivers would maintain the safe following distance from the vehicle in front or else the probability of vehicle collusion is considerably high. In expressways, gap is important for the purpose of lane changing and overtaking. Due to high allowable speed on expressways, time gap might be affected, especially with the consideration of heavy vehicle existence. This paper attempts to statistically justify any significance correlation between speed and time gap in relative to critical gap acceptance pertaining to the heavy vehicles and cars interaction on urban expressways. Extensive data was collected through video recording before being abstracted and processed by utilizing the TRAIS software. Then, statistical analysis in relative to the speed and time gap for various vehicles interactions are presented. The results showed there is a significant correlation between speed and time gap for all vehicles interaction. When cars following other cars at allowable average speed, the time gap is relatively low leading to a lower critical gap acceptance as compared to the situation with the existence of heavy vehicles.

Abstract: This paper presents the potential benefits of using nanopolyacrylate (NP) and nanocomposite (NC) polymers as modified binders in SMA mixtures. The optimum binder content of the SMA control mix was designed using PG76 binder and Modified Lottman test (AASHTO T283) was used to determine the stripping performance. A total of six (6) SMA modified mix were prepared using NP and NC modified binder formulations at 2%, 4% and 6%. Results from tensile strength test showed that SMA-NC6 have the highest IDT (521kPa) followed by SMA-NP6 (511 kPa), SMA-Control (500 kPa), SMA-NC4 (449kPa), SMA-NC2 (403kPa) and SMA-NP2 (379kPa). The stripping test on both control and modified SMA mixtures showed that TSR values for all the mix pass the 80 percent limit which fulfils the AASTHO T283 standard requirement and are therefore least susceptible to stripping. Based on the tensile strength test results and stripping performance, it was found that the addition of NC and NP modified binder demonstrate great potential in SMA mixtures showing significantly improved cohesion as well as adhesion properties of the binder. The results from this study found that all the SMA mix are resistance to moisture damage which could sustain the load from vehicles and exposed to severe condition without large degradation of the structure.

Abstract: Highways and freeways usually experience severe traffic congestion due to the presence of toll plazas which is considered as a bottleneck. In recent years, traffic engineers around the world have utilised microscopic traffic simulation models as tools to evaluate the performance of selected freeway facilities based on known traffic pattern data. This study attempts to analyse the performance of toll plaza by utilizing the microscopic traffic simulation software VISSIM 6.0, based on two different output measures, namely: average queue length and average delay time. At the selected toll plaza, data are collected at toll booths for all three modes of payments, which are: cash mode, Touch n Go, and Smart TAG. Therefore, this study aims to build a microscopic traffic simulation model that is capable of analysing the behaviour of vehicles at toll plaza based on the mentioned output measures for each mode of payment and also to determine the type of payment mode that has the most significant impact on the overall performance of toll plazas and ultimately, to understand the causes of congestion at toll plaza.

Abstract: Roadside development plays an important role in the safety of the entire road in general and intersections in particular. Illegal and improper buildouts such as roadside kiosks, bus stops and fire stations are an accident hazard and a hindrance towards sustainable development. This paper presents the first account of analysis of safety evaluation of intersections with respect to roadside development in Malaysia. The data collected on 14 sites was analyzed. The results indicated that the bus stops and restaurants located right infront of the unsignalized intersections were the major contributory factors in decreasing the safety. Moreover it was found that facilities staggered away from the intersection such as another access point are less hazardous. It is recommended that relevant authorities should ensure the removal of such risky roadside developments.

Abstract: This study evaluated the performance of sequencing batch reactor (SBR) with and without the fibers of poultry slaughterhouse wastewater (PSWW). The fibers act as attachment materials to the suspended solids, which are considered as pollutant in PSWW. PSWW contains high-pollutant concentrations. Experiments were conducted using two 60 L laboratory SBR reactors at room temperature (25 °C) and pH 7±0.5. The removal percentage of SBR with and without the fibers was compared in terms of chemical oxygen demand and biological oxygen demand. The removal percentage of SBR with fibers showed higher overall performance, which was approximately 90%. Meanwhile, the removal of SBR without fibers achieved an average percentage of about 70%, which was slightly lower compared with SBR reactor with fibers.

Abstract: This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.

Abstract: Location of municipal solid waste landfills in Malaysia has been attributed to causing bad odour, dust, litter, unattractive neighbourhoods, groundwater contamination, hazardous waste pollution and etc. Therefore, proper selection criteria are very important in preliminary siting of new landfill to avoid undesirable long-term effects. This article presents a comprehensive review of landfill spatial siting criteria and their frequency of occurrence (ranked order) found in literatures. The highest ranked criterion is the surface water and the lowest is climate/rainfall density. The dissimilarity in the criteria is found to be specifically influenced by published guidelines or policies from respective countries. In addition, group ranking of spatial criteria from frequency study made on Malaysian local literatures shows that wind factor and infrastructure (utilities) has never been considered in landfill site selection process here. These factors cannot be ignored because enhancing the condition of social, economic and environmental efficiency is part of promoting sustainable development. Subsequently, a benchmarking process of common environmental, physical and socio-economic (EPSE) criteria made with Malaysian landfill siting guideline; National Strategic Plan for Solid Waste Management and Environmental Impact Assessment Guidelines for Municipal Solid Waste and Sewage Treatment and Disposal Project. The bench mark process is useful for research references and its uniformity provides efficient site selection process in solid waste management.