Road Construction Works Research Articles

PETROGRAPHIC STUDIES AND PHYSICO-MECHANICAL PROPERTIES OF BIRIMIAN GRANITOIDS – A CASE STUDY OF OYOKO GRANITOIDS COMPLEX IN KOFORIDUA

The study investigated the physico-mechanical and petrographic properties of the basin-type granitoids of the Oyoko granitoid complex, to establish their strengths for engineering properties. The results obtained from this work will therefore be necessary in knowing the competences of the rocks for various engineering construction works. The purpose of this research is to determine the physico-mechanical and microstructural features of the granitoid suites of rocks at Oyoko. Thin sections were prepared and microscope used for the petrological studies of the rocks, whilst UCS test was conducted for the strength of the rocks. The Oyoko granitoid complex rocks were petrologically identified to be biotite gneisses, pegmatite and migmatite. The rocks at the study area have received little attention in mechanical and petrographic studies. These granitoid rocks have preserved porphyritic textures and consist of mineral assemblage such as biotite, quartz, plagioclase feldspar, alkali feldspar, amphibole, clino-pyroxene, chlorite, etc. The recrystallization of the plagioclase feldspar imply that these rocks have experienced some level of deformations. The foliated granitic gneisses intruded the older rock units, some of which had been subjected to earlier tectonism. The migmatite defines the area to be closer to a contact zone. The major structural features in the migmatite rocks were ptygmatic folds. The UCS value for the biotite gneiss of 91.6 N/mm2 gives a more representation of the general rock strength of the study area. The biotite gneisses at the study area may be classified to be mechanically strong and recommended for road construction and engineering works.

АРХЕОЛОГИЧЕСКИЕ ИССЛЕДОВАНИЯ НА АЛТАЕ КУРГАНОВ СКИФО-САКСКОГО ВРЕМЕНИ В ЗОНЕ СТРОИТЕЛЬСТВА ЧУЙСКОГО ТРАКТА (1930-Е ГОДЫ)

The article presents the history of the archaeological study of the sites of the Scythian-Saka time in the 1930s during the road construction works of the Chuisky tract. An important role was played by the research and excavations of the Sayano-Altai expedition of the State Historical Museum (SHM) and the State Academy of the History of Material Culture (SAHMC) under the leadership of S.V. Kiselyov and L.A. Yevtyukhova, in the Kosh-Agachsky district of the Altai Mountains in 1935. As a result, a significant amount of factual material was obtained, some of which has not yet been introduced into scientific circulation and has significant informative potential. To do this, it is necessary to understand the entire scope of the research.

Benefits And Performance Of The Electronic Construction Journal

Electronic construction journal (later – e-journal) has been developed to replace a former paper construction journal. The purpose of e-journal is to ensure effective supervision of road construction and reconstruction works and to avoid potential abuse. Records made by contractors, supervisors and controlling institutions in e-journal enable to manage the work process in each road construction and reconstruction building site. All road construction process participants have access to the data, comments and findings entered into e-journal. E-journal accurately records all deadlines, technical supervision or control performance time. It is a significantly faster and more effective means of control and quality assurance of performed works.

Reducing Risk Habituation to Struck-By Hazards in a Road Construction Environment Using Virtual Reality Behavioral Intervention

AbstractRepeated exposure to hazards in road construction work zones often generates worker habituation to risks associated with those hazards, a key causal factor in workplace accidents. Understan...

Diabase from Drača open pit mine in central Serbia - quality assessment for building stone purposes

Vast masses of basic rocks are present as tectonic blocks and slices along the Eastern deep fault of the Vardar zone of Serbia. They are predominantly comprised of gabbro, with smaller part made up of diabase, and occurrences of granite, aplite and pegmatite dykes. Basic rock masses are trending along the line Kragujevac (Ždraljica)-Velika Pčelica-Bogalinac ~8 km west of Rekovac. A significantly smaller diabase massif is present along the same tectonic line, further toward SE, at Prevešt village by Kalenicka River, approximately 13 km south of Rekovac. Drača open pit mine is situated in this diabase massif. Geologic explorative works have confirmed the reserves of 1 846 695 t of stone mass for building purposes. For over a decade, Draca mine has been producing various types of building stone, mainly graded stone aggregate with favourable physico-mechanical properties for road-construction works. Chemical analyses and petrographic study have shown typical composition and fabric for this type of rock. Main constituents are plagioclase and pyroxene, with opaque minerals as accessory and varying secondary minerals – chlorite, calcite, in some places epidote and limonite. Pyrite enrichment is visible in some areas of the massif. Chlorite, calcite, epidote and pyrite are the products of propylitic alteration. Although products of alteration are present throughout the rock mass with variable intensity, as is typical for the basic rocks of the former ocean floor sequences, petrologic properties are favourable for building stone purposes. Physico-mechanical properties of diabase have favourable values and varying scattering degrees. Dry state uniaxial compressive strength average values from seven analyses vary in the range 130-169 MPa. Resistance to abrasion average values vary in the range 9.04-17.07 cm3/50cm2. Apparent density varies within the span 2759-2926 g/cm3 and real density 2804-2951 g/cm3. Water absorption values 0.08-1.04 %. Resistance to weathering through testing of stability using Sodium-sulphate values vary from 0.00 to 0.15 % and through frost resistance from 0.00 to 0.04 %. Porosity values are almost constant at 0.8 %. In more altered parts of the rock mass, porosity reaches 1.6 %. Graded crushed aggregate has favourable values of Los Angeles coefficient 14.2 and 14.3 % for gradation B. Taking into consideration all performed tests and analyses, it is concluded that diabase from Drača mine can be used as a building stone for production of aggregate for use in concrete and for road-construction (asphalt paving mixtures for moderate, light and very light traffic load as a top wearing layer; for lower and upper bearing layers; for classic and modern road foundations); for production of crushed and hewn stone for building; crushed stone for railroad ballast. Also, it can be and is used as a raw material for production of stone wool for thermal insulation purposes.

Development of scientific-theoretical provisions to clarify the concept of road infrastructure in the road sector

The article presents the author's view on the interpretation of the concept of «road infrastructure ». The relevance of the research is determined by the need to develop the theoretical foundations of transport logistics, due to the specifics of the road sector and its close integration with the sphere of road transport, when the implementation of road construction work on the creation and operational activities for the maintenance, improvement of reliability and extension of durability of roads are combined in time and space with the processes of transport and logistics services. The aim of the article is to clarify the theoretical provisions in terms of specifying the concepts that characterize the road component of the infrastructure of the transport and logistics system of the country, as well as to develop recommendations for its further development. The paper uses the system-structural approach to explaining the essence and content of road infrastructure, its development is proposed to be based on the logistic approach. The main provisions resulting from the study of the economic essence of road infrastructure are presented, the basic theoretical aspects are systematized with clarification of the conceptual apparatus used in the economic development of road facilities on the basis of the logistic approach. The analysis of its forming elements is performed, which allows to exclude the spontaneous use of the concepts of «roads» and «road infrastructure». The refined interpretation of the objects that form the road infrastructure is based on the selection of the main functions they perform in the process of solving relatively discrete economic problems in the service of traffic flows, as well as the physical location in relation to the road. At present, the sectoral structuring of infrastructure facilities is predominant. Having synthesized and investigated by means of the general theory of systems road and transport-logistic activity, the necessity of theoretical modeling of road infrastructure from the standpoint of processes and procedures of management of its development has been established. It is carried out to achieve the methodological goal and allows a new way to consider the ways of structural relationships and their functioning in the economic development of road facilities. As a result, the likelihood of a strategic alliance of road transport and road economy in transport and logistics systems is increased.

POTENTIAL USE OF 'ENSET' FIBER ASH AS PARTIAL REPLACEMENT OF CONVENTIONAL FILLER MATERIAL IN HOT MIX ASPHALT

The main problems in road construction and maintance work in Ethiopia availability of a large amount of appropriate quality materials in road construction sites, aggregates in different size fractions are not readily obtainable, necessitating their procurement from long distances, thereby causing an exorbitant increase in construction costs. One of the main problems in constructing the asphalt paving mixture is obtaining a sufficient amount of filler material from crushing fine rock material and low percent using ordinary Portland cement (OPC), hydrated lime (HL) and marble dust. To overcome this problem, it is important to come across alternative filler material to address this gap using naturally available material. Currently, renewed attention has been given to the use of ‘waste’ materials instead of conventional aggregates in pavement construction. This research study investigates the potential use of ‘Enset’ fiber ash as a partial replacement of conventional filler material in hot mix asphalt supported by experimental laboratory investigation. In order to achieve this study, purposive sampling techniques were adopted to select the sample size and location. The study evaluated the potential of ‘Enset’ fiber ash as filler for the design of dense-graded hot mix asphalt by referencing traditional filler control mix procedures based on standard specifications, and a crush rock filler was utilized as a conventional filler material as a control for comparison. The Marshal Stability and Rutting Test (RT) was conducted to determine the HMA specimen's performance. Several HMA specimens were prepared using aggregate blend according to ASTM D 1559 with four different percentages of ‘Enset’ fiber ash (EFA) of 15%, 25%, 35% and 45% filler replacement the total filler weight used in the control mix. Specimens were prepared and tests performed according to EN 12697-22 procedure-B for rutting test. All HMA properties were taken at 4% air void and determined their optimum bitumen content (OBC). Almost the same result with the control mix was observed in the study at 15% and 25% of the ‘Enset’ fiber ash (EFA) replacement. However, higher Marshall Stability, a lower void filled with asphalt, better flow, a good void in mineral were observed at 25% ‘Enset’ fiber ash (EFA) replacement. At this rate, the rutting performance is less than that of the control mix but is within the specifications of 2.78mm and 2.9 mm of rutting depth less than 6mm that satisfies the EN 13108 requirement. As a result, Enset fiber ash filler can replace traditional filler material up to 25% of the total filler weight used in this study. It was recommended to use ‘Enset' fiber ash (EFA) as a filler material as a partial replacement in a bituminous paving mixture up to the specificed percentage by weight replacement.

THE PROPOSED GEOBEADS ADDITION AS LIGHTWEIGHT FILL MATERIAL

The study aimed to develop an alternative material for dam and road embankments, especially in the area with soft soil, using Geobeads. There are many problems constructing embankments on soft soil, such as low bearing capacity, excessive and differential settlement, and slope stability. The subgrade must be stable to resist the weight of the fill construction and upper structure. The lightweight fill material is commonly used as an alternative to reduce the excessive and differential settlements by reducing the weight of landfills on the soft soil subgrade. In this study, the laboratory test was conducted to investigate the influence of Geobeads (GB) additions as lightweight fill material both as the dam embankment and the road embankment. This study aims to find a combination of GB, sand, and cement to fulfill the standard as an embankment material. Investigation of physical and mechanical properties represented that light embankment can be an alternative on soft soil. The Indonesia National Standard, 8062:2015, and the General Specifications for Road and Bridge Construction Work were guidelines for embankment cases. The falling head test executes the permeability coefficient. The CBR test was conducted based on ASTM D1883. The specimen has varied the percentage of EPS addition (20%, 30%, 40%) with 14 days of curing time. Based on the test results, both the permeability coefficient value and the CBR value decreased along with the increase in the percentage of EPS, where the coefficient of permeability (k) of the specimens around 10-5 cm/s and the lowest CBR at 40% GB was 30.02% which is the range still used as embankment material.

Development and scientific justification a set of the high-speed road construction machines with hardware-percent integration and intellectual interactions algorithm of various technical systems

The description of complex technical systems with the implementation of hardware and software integration through the introduction of additional controls is presented. Recommendations for increasing the service life of the road surface and preventing premature repair of asphalt concrete surfaces are presented. A review of possible difficulties in implementing new technologies in road construction companies is performed. The project of modernization of new equipment is described, considering the research conducted in the field of finding alternative solutions to eliminate the “human” factor during road construction works. The interaction of the components of the complex for high-speed construction of asphalt concrete pavements is considered. The work of machines is described from the energy point of view, which is based on various interaction processes. The main components of the system structure and principles are considered. Multi-factor processes of road construction equipment operation are explained. The structure of algorithms for implementing an integrated machine management system is presented. The structure of hardware interaction through mathematical modeling to direct control of machine functionality in real time is described. Asphalt paving is represented by a multi-factor process, where one of the significant factors of the quality of the laid asphalt concrete is the road construction equipment used, which provides the required quality parameters of the road surface. The article describes a method for creating complex structural elements that allow creating artificial intelligence systems in the future.

Susceptibility Assessment of Single Gully Debris Flow Based on AHP and Extension Method

Debris flow mainly happens in mountainous areas all around the world with deadly social and economic impacts. With the speedy development of the mountainous economy, the debris flow susceptibility evaluation in the mountainous areas is of crucial importance for the safety of mountainous life and economy. Yunnan province of China is one of the worst hitting areas by debris flow in the world. In this paper, debris flow susceptibility assessment of Datong and Taicun gully near the first bend of Jinsha River has been done with the help of site investigation and GIS and remote sensing techniques. Eight causative factors, including slope, topographic wetness index, sediments transport index, ground roughness, basin area, bending coefficient, source material, and normalised difference vegetation index, have been selected for debris flow susceptibility evaluation. Analytical hierarchy process combined with Extension method has been used to calculate the susceptibility level of Datong and Taicun gullies. The evaluation result shows that both the gullies have a moderate susceptibility to debris flow. The result suggests that all the ongoing engineering projects such as mining and road construction work should be done with all precautionary measures, and the excavated material should adequately store in the gullies. Doi: 10.28991/cej-2021-03091702 Full Text: PDF

ПРИВЕДЕНИЕ РАВНОНАПРАВЛЕННЫХ КОЛЕБАНИЙ К АСИММЕТРИЧНЫМ, ПУТЁМ ИЗМЕНЕНИЯ СООТНОШЕНИЯ ВЕЛИЧИН, СОСТАВЛЯЮЩИХ ВЫНУЖДАЮЩУЮ СИЛУ

Vibrating machines play a primary role in the implementation of programs in the construction and road construction kit. The improvement of vibration machines allows to significantly increase the speed of construction and road construction work. The main working unit of a vibrating machine is a vibrating device or vibrator. Currently, in the industry, vibration devices are used with circular or directional, along a certain straight line of vibrations. Further improvement of vibrating machines is carried out in the direction of creating vibration devices with asymmetric vibrations. At present, there are practically no vibrating machines with asymmetric vibrations. These machines allow to distinguish between the "working" process phase and the "idle" phase within each oscillation period. Moreover, the value of the driving force in the phase of performing useful work is several times higher than the value of the driving force in the direction of idling. Therefore, much less work is spent on idling. This allows to get rid of massive elements - overloads that extinguish the magnitude of the driving force in the direction of idling. Therefore, the urgency is to develop a method for converting existing machines with directional vibrations into asymmetric ones, with a given coefficient of asymmetry of the driving force. This makes it possible to reduce the specific indicators of the metal consumption of vibrating machines and the energy consumption of the work performed.

ОГЛЯД БІТУМНИХ В'ЯЖУЧИХ, ЩО ВИКОРИСТОВУЮТЬСЯ В УКРАЇНІ

Introduction. Pavement bitumen is one of general road construction materials that are used for pavement construction. The quality of bitumen binder regulates specific technical and operational characteristics of asphalt pavements and their durability Problem Statement. Nowadays in Ukraine only one refinery plant produces pavement bitumen. The volume of its production is not enough to completely satisfy the demands of Ukrainian road construction industry. Due this a lot of binders in Ukraine are imported from other countries. In recent years the highest volumes of bitumen was imported from Republic of Belarus and Poland. In 2020 the amount of road construction works was increased, particularly with pavement repairing and new pavement constructing. It resulted in increasing in need in pavement bitumen that led not only to the high volume of import bitumen but to an expansion of the list of importing counties. Purpose. The presented study is aimed on analysis of quality of bitumen imported in Ukraine from eight countries. For these binders their features are obtained and problem of their applicability and its advisability in Ukraine road industry is considered. Materials and methods. As a material of research bitumens produced in Azerbaijan, the Republic of Belarus, Greece, Spain, Italy, Poland, Turkey and Ukraine are chosen. The standard quality properties are obtained in accordance with the actual in Ukraine standards ДСТУ 4044 and ДСТУ EN 12591. Beside this the attention is paid to the finding of fundamental properties of these binders, such as adhesion, cohesion and viscosity. Results. With the experimental data it is found that all bitumens significantly differ in their structural type. It results in differences in softening point and breaking point temperatures at the equal penetration value (this difference is in the range from 4.5 °С for the closer values to 16.5 °С for the most distinct values). This fact can influence on asphalt pavement properties and durability. Besides such a difference in a temperature susceptibility of binders their adhesion and cohesion properties differ too. Bitumen that tends to sol type of structure is characterized with higher cohesion and viscosity values. This peculiarity must be taken into account in mixing and compaction operations for the asphalts with such bitumen. The temperatures of these operations must be higher than one for bitumen close to the gel type. The low temperature susceptibility and wide plasticity interval are the advantages of bitumen that tends to gel type of structure. Conclusions. All bitumens that are imported in Ukraine must be certificated with ДСТУ 4044:2019 national standard requirements. Also they must be tested with additional methods to validate the decision on their implementation in road construction industry and to specify the implementation area. Keywords: paving bitumen, bitumen binder, penetration, softening point temperature, adhesion, cohesion, viscosity

Access to malaria prevention and control interventions among seasonal migrant workers: A multi-region formative assessment in Ethiopia.

BackgroundMobile or seasonal migrant workers are at increased risk for acquiring malaria infections and can be the primary source of malaria reintroduction into receptive areas. The aim of this formative assessment was to describe access to malaria prevention and control interventions among seasonal migrant or mobile workers in seven regional states of Ethiopia.MethodsA cross-sectional formative assessment was conducted using a qualitative and quantitative mixed-method design, between October 2015 and October 2016. Quantitative data were collected from organizations that employ seasonal migrant workers and were analyzed using Microsoft Excel and ArcGIS 10.8 (Geo-spatial data). Qualitative data were collected using in-depth interview from 23 key informants (7 seasonal migrant workers, and 16 experts and managers of development projects who had hired seasonal migrant workers), which were recorded, transcribed, translated, coded, and thematically analyzed.ResultsThere were 1,017,888 seasonal migrant workers employed in different developmental organizations including large-scale crop cultivating farms, sugar cane plantations, horticulture, road and house construction work, and gold mining and panning. Seasonal migrant workers’ housing facilities were poorly structured and overcrowded (30 people living per 64 square meter room) limiting the use of indoor residual spraying (IRS), and forcing seasonal migrant workers not to use long lasting insecticidal treated nets (LLINs). Seasonal migrant workers are engaged in nighttime activities when employment includes watering farmlands, harvesting sesame, and transporting sugar cane from the field to factories. Despite such high-risk living conditions, access and utilization of preventive and curative services by the seasonal workers were limited. Informal migrant worker employment systems by development organizations and inadequate technical and financial support coupled with poor supply chain management limited the planning and delivery of malaria prevention and treatment strategies targeting seasonal migrant workers.ConclusionsSeasonal migrant workers in seven regions of Ethiopia were at substantial risk of acquiring malaria. Existing malaria prevention, control and management interventions were inadequate. This will contribute to the resurgence of outbreaks of malaria in areas where transmission has been lowered. A coordinated action is needed among all stakeholders to identify the size of seasonal migrant workers and develop and implement a comprehensive strategy to address their healthcare needs.

Эволюция карьерного автотранспорта

The article considers the possibility of using quarry technology in the construction of a roadbed. Stable roadbed is the basis of a railway track, for its construction rocky, clay soils or sedimentary massifs are usually used. During the construction of the roadbed, heavy vehicles and special equipment (ice rinks, excavators, bulldozers, etc.) are used. Mining and road construction works, despite their diversity, consist of repeated identical operations: digging of the earth (mountain) mass, its loading and transportation, unloading into the dump or laying. For the production of these works, the same type of equipment is used: excavators, bulldozers, scrapers, graders and dump trucks. Most of the newly discovered explored deposits are located in the northern territories of Russia, so there is a high probability of launching intensive construction of railways and roads. The construction of transport high-ways is the most material-intensive area for the use of non-metallic materials and is associated with the movement of significant volumes of earth mass. In addition, the cost of performing earthworks is quite significant, so the correct choice of the method and means of mechanization of these works is a necessary condition for their successful implementation. For the construction of transport corridors under conditions of low-load soils and off-road conditions of the Arctic and northern territories of Russia, it is proposed to develop new types of vehicles based on BelAZ heavy duty quarry vehicles, which allow building embankments for roads and railways up to 10 m high (and in exceptional cases even more). When building transport highways and, if possible, preserving the environment, it is of great importance to reduce the cost of transporting earthen mass by reducing the consumption of fuel and lubricants, which account for 15-25 % of the total cost of operating powerful off-road vehicles.

Analysis of an operator’s gazing points during spur road construction work.

Analysis of an operator’s gazing points during spur road construction work.

Prospects and opportunities for using foreign experience for the development of intellectual transportation systems in Ukraine

The study aims to determine the prospects and possibilities of using foreign experience for the development of intelligent transport systems in Ukraine. The article deals with the history of the emergence of intelligent transport systems in the world. We have investigated the prerequisites and promising directions for developing the global market of intelligent transport systems: traffic management, road safety, and supervision; cargo management; automotive telematics; parking management; automated vehicles. The main players in the field of business in this market have been identified. It is systematized for the adaptation of countries that are developing due to the features of the European ITS architecture, the US ITS architecture, the Japanese national ITS architecture, which are designed to improve the lives of citizens. Variants of using information and navigation systems in the framework of European projects on the example of cities are proposed. In the example of the European Union, the stages of implementation of the ITS architecture are considered, and how this affects the congestion of roads in large cities. The creation of a unified architecture of ITS allows you to control: the level of transport safety in transport and road traffic; energy consumption and environmental impact; networks of logistics systems for passenger service and cargo handling; management of transport, road construction, and repair works, parking places, collection of road tolls, equipment for improving personal services of road users. We have substantiated the necessity of using an integrated approach to improve the digitalization and intellectualization of transport systems, taking into account their advantages and disadvantages, has been substantiated. Conceptual approaches to the digitization of transport are generalized, closely related to logistics IT systems and the network of local roads. The theoretical basis of the level of intellectualization of the Ukrainian transport systems in comparison with foreign ones has been studied, the expediency of the possibility of developing this sphere in Ukraine with the implementation of the project "Transparent infrastructure" has been proved. The organizational and economic principles of the use of intelligent transport systems of the countries of the world for solving a wide range of problems have been determined: transmission of information in real-time for travelers, namely, traffic schedules, information on delays; entrance fee for the passage of vehicles to the area of the city; accident management; an electronic collection of duties. The legislative framework and the National Transport Strategy of Ukraine for the period up to 2030 are considered. The real results of the development of transport systems that are already being implemented in Ukrainian cities are displayed. A network of "smart roads" will be built in Ukraine. To implement this task, high-quality fiber-optic communications are needed, which will pass along the roads, which will allow the introduction of intelligent transport systems. The use of the world's leading experience in the implementation of intelligent transport systems is strategic for Ukraine, determines its competitiveness in the world market, and meets the requirements of integrating the national transport network into the Trans-European transport network.

Określenie charakteru i wartości ryzyka prac geodezyjnych z zastosowaniem logiki rozmytej

Artykuł jest kontynuacją cyklu prac nad metodą analizy ryzyka prac geodezyjnych w przedsięwzięciach budowy dróg. W pracy przedstawiono zastosowanie logiki rozmytej do określenia charakteru i wartości ryzyka prac geodezyjnych na podstawie bazy reguł oraz funkcji przynależności podanych przez ekspertów. Uzasadnione jest to tym, iż problem występowania geodezyjnych czynników ryzyka w pracach budowy dróg nie jest deterministyczny. W pracach tego typu występuje wiele niepewności w określaniu wartości czasu ich trwania w dłuższym okresie. Metodę przedstawiono w postaci teoretycznej wraz z przykładem jej zastosowania. Zaprezentowano również zestawienie wyników badań w formie porównawczej w odniesieniu do wcześniejszych publikacji wykorzystujących inne narzędzia badawcze.

A Case Study of Bus Line Passenger Volumes of Bakrajo Bus Lines in Sulaimani City

Transit agencies constantly need information about system operations and passengers to support their regular scheduling and operation planning processes. The lack of these processes and cultural motivations to use public transportations contributes enormously to the reliance on the private cars rather than public transportation, resulting in traffic congestions. The traffic congestions occur mainly during peak hours and the accidents happening as a result of road accidents and construction works. This study investigates the effects of weekday and weekend travel variability on peak hours of the passenger flow distribution on bus lines, which can effectively reflect the degree of traffic congestion. A study of passenger traffic flow patterns during these times can impact planning decisions on transportation engineers. It can be viewed as a building block for generating a reliable schedule for a given bus route within the context of an optimization process. Collecting data sets of a two-directional bus line in Sulaimani city, connecting a residential district to the city center, for three days (Wednesday, Thursday, and Friday), and this study analyzed the flow and distribution of weekday and weekend passenger movements along with the bus stops of each direction on-peak and off-peak periods. The results indicate that Thursday passenger volume is more similar to Friday passenger volume than on Wednesday passenger volume. The passenger volume of direction D1 (from the residential district to the city center) is double that of direction D2 (from the city center to the residential district). The maximum morning peak time is on Wednesday with 442 passengers/hr, starting from 7:30 to 9:00, and the maximum evening peak hour is on Thursday with 420 passengers/hr, beginning from 14:30 to 16:30.

Valorisation of dredged marine sediments for use as road material

The aim of this study is to investigate the suitability of using dredged marine sediments treated with a hydraulic binder in road construction works, particularly as a foundation layer. The methodology was conducted as follows. First, the geotechnical, chemical and mineralogical characteristics of the dredged sediments were determined to assess the behaviour of the materials. Second, the composition of the mixture was defined through a formulation study. In this phase of the study, the basic criteria for determining the dosage of each component of the mixture were specified. Third, the short-term and long-term mechanical behaviours of the formulation were evaluated. The experimental results show that dredged sediments treated with Portland cement can be used as a road foundation layer.

Construction of road bridges without consideration of geo-hazards and river-flow dynamics – A case study from Ghatte Khola, Myagdi, Nepal

In the past 20 years, motor road and bridge construction works have increased significantly in Nepal, in most cases with poor consideration of geo-hazards (rockfalls, landslides, debris flows) and river-flow dynamics. The National Road Construction (NRC) is further fostered by China’s Belt and Road Initiative (BRI). Currently, the Kali Gandaki (KG) road corridor is being upgraded to a 2-way black-top road as a project under BRI. The river dynamics of the KG sub-catchments is rarely considered by engineers despite it represents a common threat to the KG road, road bridges, and human lives. Here we study the Ghatte Khola (GK) sub-catchment that is located along the KG corridor in Dana, Myagdi district, West Nepal. From hydro-geomorphological mapping, hydrological and HEC–RAS analysis, historical archives and interviews, several questions have arisen regarding to the size of the under-construction GK motor bridge. The water way and freeboard of this bridge were found to be insufficient to safely pass the highest flood discharge for 100 years return-period, hence the bridge was found to be vulnerable to extreme floods. Actually, the nearly completed GK bridge was destroyed by a severe hyper-concentred flood on May 25, 2019. Active geo-hazards (rock falls, landslides) in the upper GK catchment appear as persistent drivers susceptible to aggravate sporadically the GK flows, and may pose serious threat to the future GK road bridge and to nearby infrastructure and settlements. We discuss these issues and eventually propose new technical, more sustainable solutions (e.g., fords).