Applied Mechanics and Materials Vol. 802

Abstract: Arch bridges which have existed since thousands years ago showed surprising durability. Due to the aesthetic value of arch bridges, it is widely used as crossing over valleys and rivers nowadays. Closed spandrel arch bridge is one type of arch bridges that has been developed using precast concrete technology since 1965. Currently, the available Precast Concrete Arch Bridge Systems are BEBO arch, Matiere arch, CON/SPAN arch, TechSpan arch, NUCON arch, Concrete-Filled FRP Tube arch, Flexi-Arch, Rivo CS-P Series arch and Pearl Chain arch. In this paper, development of the Precast Concrete Closed Spandrel Arch Bridge System is reviewed. The advantanges of precast closed spandrel arch bridge system will also be briefly presented. Comparisons in terms of arch sections, moulding, handling, transporting and installing among different Precast Concrete Closed Spandrel Arch Bridge Systems are also highlighted.

Abstract: Cold recycled mixes are used in many parts of the world as a standardized pavement rehabilitation technique. The quality of the mixes has been so far assessed by strength characteristics, water susceptibility and stiffness. In some cases frost resistance is determined as well. Nevertheless, especially for regions with winter seasons where temperatures are reaching values below 0°C, there are no standardized procedures and sufficient findings related to resistance to cracking and fracture behavior. Experimental study done at CTU in Prague describes three types of tests performed on 15 different cold recycled mixes. In parallel three standardized hot asphalt mixes were selected and used as well for a comparison of behavior in the range of low temperatures. Finally specimens acquired from an existing construction site where cold recycled technology was applied have been cored and tested mainly for crack propagation test. In general three tests have been selected and include crack propagation text on semi-cylindrical specimens, flexural strength test and relaxation test. Behavior in low temperature range and resistance to cracking has been tested in the temperature range of 0°C to-10°C.

Abstract: Asphalt mix durability is one of the most important aspects if looking on longer lifetime of pavement structures. It is influenced by several factors whereas one of the most important is moisture susceptibility and the quality of adhesion between bitumen binder and aggregateparticles. If the coating by the bitumen is not fully provided or is affected by strongly hydrophilic aggregate type which easier creates bonds with more polar water then it is immediately attacking the aggregate surface and leads to stripping effects – ongoing loss of bitumen-aggregate bonds, mix cohesion problems, etc. With respect to improve adhesion quality different additives (surfactants) are used, whereas two factors might be critical for them: 1) thermal stability of the additive used in bitumen stored for several days at elevated temperatures; 2) bitumen ageing and the effect on additive activity. Both aspects have been studied as a key objective of an ongoing research looking fora suitable laboratory procedure for simulating the thermal stability and assess the remaining activity of the additive. Further asphalt ageing impact on moisture susceptibility is evaluated by changed ratios of indirect tensile strength values for unaged and differently aged test specimens. Results for one type of mix and different aggregates with application of straight-run bitumen 50/70 and 4 different types of adhesion promoters are summarized in the paper.

Abstract: The foamed bitumen technology is experiencing a global renaissance and rather extensive development of innovative approaches with respect to both, its application and research, is clearly visible. However, the variability of available bituminous binders for utilization within the technology is quite large; therefore, a general methodology of quality parameters determination for foamed bitumen and the requirements for mixes bound by this type of binder must be specified.In general different types of pen grade bituminous binders can be used for producing the foam. Besides the pen grades which are defined by penetration and also its viscosity, the source of the bitumen can have important effect on final foamed bitumen quality given especially by its expansion ratio and stability of the foam as well. Experimental study has been done to compare different types of bitumen from different sources to assess the effects on the foamed bitumen and on cold recycled mixes produced by these binders. In parallel the effect of a suitable foaming agent has been assessed as well. The foamed bitumen was analyzed by its expansion ration, half time defining the stability of the foam and the so called foam index. Cold recycled mixes were produced with one type of reclaimed asphalt material and different foamed bituminous binders. For the mix assessment mainly indirect tensile strength, water susceptibility and stiffness modulus have been considered. Results and comparison of the evaluated effects are presented in this paper.

Abstract: In sustainable asphalt pavement construction, the proper selection of materials can be a challenging task. This paper focuses on a newly developed asphalt modifier named calcium carbonate (CaCO₃) combined with Treated Palm Oil Fly Ash (TPOFA) to improve the properties of asphalt mastic. The rheological properties of mastic in terms of penetration, softening point, rotational viscosity and Superpave rutting factor using 60/70 asphalt binder blended with 5, 10, 15, 20 % of CaCO₃+TPOFA were calculated to evaluate asphalt binder properties subjected to different aging conditions. The rotational viscometer (RV) was used to evaluate the properties of mastic at test temperatures from 120°C to 170°C. The dynamic shear rheometer (DSR) was used in temperature sweep test from 46°C to 82°C at 6°C increments at 10 rad/sec frequency to measure the G*, δ and Superpave rutting factor G*/sinδ. A one-way ANOVA statistical analysis was used to analyze the results .The test results showed that all asphalt mastic exhibited higher viscosity compared to the base binder. The addition of CaCO₃ +TPOFA increased the G* but reduced the phase angle which indicated improved stiffness of asphalt mastic. Hence, incorporating CaCO₃+TPOFA can potentially improve the rutting resistance of asphalt mastic.

Abstract: Environmental problems caused by high temperature during the production of asphalt and road paving prompted research on alternative material that is more environmental friendly. Recent advances in asphalt technology have allowed the reduction of construction temperature using the warm mix asphalt additives. This paper presents the laboratory results on the effects of a wax warm mix additive on the asphalt binder rheological properties. The additive were blended with conventional binder using laboratory mechanical mixer at 0, 1, 2, 3, 4 and 5% by the mass of binder. Then, the binders were tested for flow properties, stiffness and its resistance to rutting and fatigue. Tests were performed using rotational viscometer and dynamic shear rheometer on unaged and aged samples. The results show that the addition of wax warm mix additive improves the flow properties by reducing the viscosity and leads to lower construction temperature. Characterization of modified binders’ rheological properties at intermediate and high temperature indicates that the amount of wax warm mix additive addition slightly affects the binder stiffness and its resistance to rutting and fatigue. Based on the rheological test results, the 3% wax warm mix additive produce comparable rheological properties with the conventional binder. Therefore 3% wax warm mix additive is suggested to be the optimum amount for the road construction application.

Abstract: Certainly, one of the most cost effective and comprehensive infrastructure assets of the build environment is road infrastructure. The environmental impacts of this asset during its life-cycle drive researchers to create a foundational framework to quantify these effects. Life cycle assessment (LCA), a method for the assessment of all modules in a life cycle, has been examined to evaluate all the environmental modules and components of road projects due to constraints of environmental assessments. The enthusiasm for enhancing the sustainable development of basic infrastructure leads to quick expansion on pavement life cycle assessment. An audit of applicable published LCA studies has recognized that environmental modules, such as the usage module (rolling resistance of pavement, carbonation, and albedo), end of life (EOL) module, and components such as traffic congestion during the construction module are not regarded in most of the articles. These modules potentially have the same environmental impact as other regularly considered modules such as materials, transportation, and construction. The goal of this study is to recognize shortfalls in the fields that bolster pavement LCA, to prepare a comprehensive and straight forward methodology, and to provide a basis on which related studies can move forward

Abstract: In the Philippines, most transportation studies focus on urban land transportation. Only few deal directly with water transportation. The Western Visayas Region is comprised of three main land masses separated by bodies of water. Recently, an ambitious inter-island bridge project for the region is proposed. The Panay-Guimaras-Negros Bridge (PGN) Project intends to connect the islands via bridges spanning approximately 23 km. In this study, survey questionnaires were administered in Dumangas, Muelle Loney, and San Lorenzo. Multinomial logit models using stated preference data were estimated to look into mode shifting behaviour of passengers to land based alternatives if inter-island bridges were built.

Abstract: Aware on the importance of upgrading and maintaining the safety level of existing road network, several attempts on localizing problematic road areas have been made. In current practice, the identification of those problematic sections was recognized based on the road’s safety level and one of the most common and acceptable method is by using crash data of the particular road network as a starting point for further actions. However, the information provided by crash data is far from providing good and broad pictures of the factors leading to crash. These circumstances have bringing out the needs to have another road safety indicator that can extensively describes actual situations at problematic road areas as well as can be used as a basis for further maintenance works. By focusing on the environment aspect of the roads, fourteen road environment indicators were chosen based on their abilities to portrayed current road environment conditions and its potential in triggering road traffic crashes. Data of these indicators were collected by means of naturalistic driving method within 80 km length road of Federal Road 2 connecting Kuantan and Maran Town in Pahang State. Composite road environment risk index was developed using these data where combination of risk generated from these environments aspects were evaluated and used in localizing problematic road sections. Apart from that, the outcomes were also used as basis in planning for road improvement plans. The development of composite road environment risk index as a proactive method in defining poor sections has proved to be very useful in identifications of problematic road sections requiring urgent road improvement works especially when crash data is not available or in poor quality.

Abstract: Four-stage demand models are the most popular travel demand forecasting models. Trip assignment which is the last stage in the four-stage demand modelling is a key element in travel demand forecasting process. Traffic assignment model is used to assign travel demands into the road network and predict network flows that are associated with future planning scenarios based on the estimates of link travel times. In order to calculate travel time between origin and destination, a function presenting the relationship between link delays and link flows is used. This function is known as Volume-Delay Function (VDF) and it is the fundamental component of equilibrium trip assignment models. This study aims to investigate and improve VDFs for heterogeneous traffic at different type of arterial roads in Malaysia by using the road network in Balik Pulau, Penang as a case study. Primary data such as traffic volume and speed are collected at three types of arterial roads, which are the principal arterial, minor arterial and collectors to derive the parameters required in the VDFs. In this study, the most well-known and most widely-used volume-delay function which is known as the BPR function developed by the U.S. Bureau of Public Roads was investigated and calibrated using the transportation planning software, EMME 4.1.3. The calibrated functions are then validated with field data. The output from this research is very important as better understanding of VDFs can produce better estimate of link travel times and hence better planning for future scenarios.