Road Engineering Research Articles

Analysis and Countermeasures of Several Problems in Urban Road Engineering Design

Analysis and Countermeasures of Several Problems in Urban Road Engineering Design

Analyze vehicular flow at the intersection, Fernando Baeza avenues and Chuvíscar River, applying work sampling

It is an innovative work to carry out this analysis of vehicular flow that will be very useful for the city of Delicias Chihuahua, this town is relatively young and lacks road engineering (traffic lights) in some specific points, given the demographic growth of the neighborhoods on the outskirts, this avenue has been a key point to vent the vehicular flow to the different neighborhoods. The continuous improvement technique was applied, which is work sampling, according to ILO establishes that Work sampling is a technique to determine, through statistical analysis and random observations, the percentage of appearance of a certain activity. It will be necessary to continuously observe each of the points in the area and record the moment, at a previously selected time in the same period of time, but at different random times provided by the work sampling. For this investigation, the general objective is: identify the vehicular flow at the intersection of Fernando Baeza and Río Chuvíscar avenues in Ciudad Delicias, Chihuahua. The contribution of this study will benefit more than 79,907 vehicles that are registered in the vehicle registry of the Revenue Collection Office (2022) in the town and in this way apply continuous improvement for the benefit of citizens, identifying the hours of more vehicle capacity and consequently take advantage of cutting-edge technology, and build a road engineering focused on traffic lights for the benefit of its entire population.

VALORIZATION OF DREDGED SEDIMENTS FROM DAMS IN PAVEMENT DESIGN

Introduction: This study is part of research aimed at valorizing dredged sediments through the development of formulations for use in road engineering. The purpose of the study was to determine if the materials selected for pavement layers comply with road design standards, in particular, with specific requirements for density, grain size, plastic properties, organic matter, and mechanical performance. Methods: To determine the physical-chemical and mechanical characteristics of the dredged sediments obtained from samples taken from the Bakhadda dam located in western Algeria’s semi-arid climate, the sediments were treated with binders in small amounts (3% lime (L), 6% cement (C)) for reuse in road construction. The study focused on the evolution of physical and mechanical characteristics of the treated sediments, including LL, PI, VBS, immediate bearing index (IBI%), UCS, tensile strength Ϭt, as well as small strain modulus ESS and large strain modulus E50. The results showed that adding lime and cement to the dredged sediments improved their strength, as evidenced by the increased compressive strength (UCS) over time for the samples containing different amounts of binders (3%L, 6%C, and 3%L + 6%C). Additionally, the effect of the water content on the mechanical properties of the formulations was demonstrated. The study showed that the strength increased when the water content decreased.

Social-Cultural Factors and Performance of Roads Construction Projects in Nairobi City County, Kenya

The Kenyan Government is on the spot over stalled and poorly done roads construction projects especially in the Nairobi City County. Successful road construction is an impetus to economic development for Kenya as enumerated in the Kenya Vision 2030. However, there has been need for these road construction projects to update their systems due to the ever changing environment factors. Thisstudy therefore sought to determine the relationship between social-cultural factors and the performance of roads construction projectsin Nairobi City County, Kenya. The underpinning theory was the open system theory. Thisstudy used a positivist research philosophy. This study used the descriptive and explanatory research design. In this study, Nairobi City County refers to the five counties in the Nairobi Metropolitan Area namely, Nairobi County, Kiambu County, Kajiado County, Machakos County and Murang'a County. The target population of this research was the 176 completed roads construction projects in Nairobi City County by Kenya Rural Roads Authority (KERRA). The unit of observation was the road engineers, project planners and directors (KERRA), road supervisors, road inspectors, road surveyors, contractors, and project implementation teams’ members (KERRA). The unit of analysis wasthe completed roads construction projectsinNairobi City County. Proportional stratified sampling was used to derive a sample size of 253 respondents. A structured questionnaire was used to collect primary data. Data that was collected from the field was filtered, sorted and cleaned in line with research objectives. This study adopted both descriptive and inferential statistics. Descriptive statisticsincluding frequencies, percentages, mean scores, and standard deviation was produced for all the quantitative data. The results were presented using tables. Inferential statistics were done using the multiple linear regression. The study established a positive significant relationship between socio-cultural factors (t=2.417, p < 0.05) and project performance. The study concludes that human relationship influences project performance since projects operate within the society. Project culture is developed by communicating priority, status, and the alignment of official and operational rules. The study recommends that project leaders should be sensitive and aware of multicultural preferences guided by individual identity and role within the project versus family of origin and community, verbal and emotional expressiveness, relationship expectations, style of communication, language, personal priorities, values, and beliefs and time orientation.

Innovation of Engineering Surveying Course Teaching for Road and Bridge Engineering Technology Majors in Higher Vocational Colleges

Engineering surveying is an important course for road and bridge engineering technology majors in higher vocational colleges. With the advancement of science and technology, engineering surveying technology is also constantly developing, so the theoretical knowledge and professional skills that students need to master are also becoming increasingly complicated. To stimulate the students’ interest in learning the course, it is necessary to continuously introduce innovative teaching methods into the course. In this paper, the importance of teaching innovation in engineering surveying courses of road and bridge engineering technology majors in higher vocational colleges and the knowledge system that students need to master are analyzed. Subsequently, innovative strategies are proposed to help improve the students’mastery of engineering surveying.

Modeling of the possible negative impact of mudflows in the monitoring of mudflow basins of the river Mzymta

The article considers the identification of potential sources of formation of water and mudflows in the area of the Olympic objects of the southern slope of the Psekhako ridge and the catchment areas of the 1st, 2nd and 3rd Galion rivers (the catchment area of the Mzymta river). The collection and study of natural, climatic and morphological characteristics mudflow basins and the study of the possibility of their negative impact on the operated Olympic facilities, the creation of a database of mudflow basins. Implementation of the results of studies of the natural-climatic and morphological characteristics of the mudflow basin of the river. Mzymta is assumed in the justification of anti-mudflow measures to protect the infrastructure of operated Olympic facilities from the negative impact of water and mudflows. To ensure the reliability of the functioning of these foundations and foundations of structures. It is important to take into account the possibility of a negative impact on them of water and mudflows that form in the conditions of mountainous terrain and natural and climatic features of this region, as well as due to the extremely insufficient knowledge of the current state of development in these territories. mudflow processes and the possibility of their activation as a result of the impact on the natural landscapes of mudflow basins during the operation of the foundations and foundations of Olympic facilities and their infrastructure (access and technological roads, power lines, ski slopes, chairlifts, various sites, etc.). Taking into account the impact of the consequences of a large-scale technogenic impact on the natural landscape, in the territory of operation of the Olympic facilities along the southern slope of the Psekhako ridge, the materials of the survey confirm the conclusions about the increased mudflow hazard of the watercourses of the river. Rudnichny, r. Sumasshedshiy, r. Kamburovsky. The main reason for the descent of these mudflows is the technogenic impact on the upstream natural landscapes, including the discharge of liquefied soil dumps from steep slopes, the concentration of surface runoff into concentrated eroded, cuts, etc. Simulation modeling of the stability of the river slopes was performed. Tobias, the most dangerous combinations of impacts under static and seismic conditions, to predict the formation of mudflows.

Promotional effect of shaped coal gangue composite phase change agents doping in asphalt on pavement properties

To address issues related to the limited improvement in the performance of phase-change material (PCMs) modified asphalt and the unclear underlying mechanisms, this study developed two structurally stable and thermally efficient coal gangue composite phase-change agents. The impact on enhancing the properties of asphalt was systematically investigated. The study revealed that when the dosage of the phase-change agent is below 20%, there was a pronounced interactive effect between the agent and asphalt. This interaction had the capability to regulate both the non-polar and polar components within the asphalt colloid system. By controlling the dosage of the PCMs agent, it was possible to enhance the high-temperature rheological properties, high-temperature shear resistance and low-temperature flexibility of the asphalt. Additionally, this control improved the adhesion and moisture sensitivity of the PCMs modified asphalt and aggregate system. The maximum temperature-regulating effect of PCMs modified asphalt could reach up to 8.3 °C, with the functional attribute strongly correlated with the low-temperature performance of the asphalt. This research contributes to the promotion and application of PCMs in road engineering.

Modifying Effect and Mechanism of Polymer Powder on the Properties of Asphalt Binder for Engineering Application.

For achieving the better modifying effect of polyurethane on asphalt pavement materials, the PUA powder modifier was prepared with fine grinding at the glass transition temperature, and polyurethane-modified asphalt (PUA-MA) with different dosages of modifier was prepared. The impact of the PUA on the physical properties of asphalt binder was studied. The modifying mechanism of PUA on asphalt was explored by investigating the thermal performance and chemical composition of asphalt (thermogravimetric analysis, differential scanning calorimetry test, and Fourier transform infrared spectroscopy). The micrograph of the interactive interface was characterized by scanning an electron microscope. Furthermore, the rheological properties of PUA-MA were also investigated and analyzed. The results indicated that the PUA had a dense structure with few pores on the surface. After mixing with asphalt, it altered the asphalt's internal structure via physical fusion and chemical reaction (carbamate formation). PUA improved the thermal stability of asphalt, enhanced the asphalt's thermal decomposition temperature, and further reduced the thermal mass loss while decreasing the glass transition temperature. The addition and dosage increase in the PUA modifier significantly improved the softening point, viscosity, complex shear modulus, and rutting factor of asphalt. Also, the PUA could improve the elastic recovery ability of asphalt and enhance the rutting resistance of asphalt at high temperatures. However, the crack resistance at low temperatures was not effectively improved (ductility and penetration decreased). When the dosage was 6-9%, PUA-MA had the best high-temperature performance, but asphalt showed poor low-temperature performance at this dosage. This study provides a theoretical reference for popularizing and applying polyurethane as an asphalt modifier in road engineering.

A literature review: asphalt pavement repair technologies and materials

Asphalt pavement is the most widely used type of pavement in the world and is mainly utilised in the construction of infrastructures such as highways, urban roads, parking lots and airstrips. Pavement maintenance technology and materials are gradually developing towards systematisation and diversification with the extensive use of asphalt pavement. Choosing more economical technologies and fast and sustainable materials is the future of asphalt pavement maintenance work. This paper provides an overview of asphalt pavement repair technology and asphalt pavement repair materials. It categorises and summarises pavement repair technologies, which include cost-effective technologies such as crack sealing, overlay, seal coats and hot in-place recycling. Further, it summarises the repair materials applied in repair technologies and compares the performance, cost-effectiveness and sustainability of these materials. The study shows that asphalt and cement are the most commonly used repair materials. The higher-potential, more economical and more sustainable materials for asphalt pavement repair include epoxy resin, polyurethane and hydrogel. The future of asphalt pavement repair requires advancing towards rapid, sustainable, environmentally friendly and economical repairs. A survey indicates that in addition to improving the performance of existing repair materials (e.g. modified asphalt, binder processes, material composition or ratios), attention can be given to new materials such as polyurethanes and hydrogels that have the potential for rapid repair and are low cost. More research can be done to perfect the application of new materials in road engineering.

Leadership issues for road project engineers

Being a construction team leader is an enormous responsibility because leaders inspire and motivate others. This study aims to identify leadership development and required skills from engineers’ perspectives. Using a qualitative approach from interviews with eight civil engineers, the authors explored their leadership issues and practices, especially in handling road project delays. The participants’ diverse viewpoints and experiences led to road construction’s four most common delay factors and how they responded to them. The research findings demonstrated that engineers in road projects require leadership competencies and extensive technical knowledge and experience to keep road projects on track. Since leaders accept responsibility, they must constantly learn to expand their knowledge and find new approaches to solve problems. This study generated a leadership chart highlighting road engineers’ leadership competencies to engage, coordinate and communicate effectively with team members and other project stakeholders. Combining technical expertise and soft skills enhances engineers’ ability to navigate construction complexities and adapt to changing trends.

Assessing the Durability and Acoustic Performance of a Novel Two-Layer Pavement System

In the quest for more sustainable pavement solutions, this study demonstrates the successful strengthening of a unique noise-reducing two-layer road surface. While existing noise-reducing pavements reveal high acoustic efficiency, they lack mechanical strength, and earlier research efforts addressed the optimization of the individual components of this system, and a comprehensive perspective on its integrated performance remained elusive. Therefore, this research bridges this knowledge gap through an in-depth laboratory evaluation, in which the requirements for the realization of a full-scale demonstrator were defined, followed by a comprehensive performance assessment in terms of acoustic and mechanical strength. The post-construction assessment reveals the system’s multifaceted strengths, considering noise reduction, resilience under heavy traffic, pavement deflections, and skid resistance, assessed by CPX measurements, accelerated pavement tests using the MLS 30, skid resistance tests employing the pendulum test, as well as the slow-moving longitudinal friction test (MicroGriptester) and falling weight deflectometer (FWD) measurements. Although the optimized system implies lower noise-reduction potential, it exhibits great strength compared to previous noise-reducing pavements. In general, the system offers viable noise mitigation solutions for urban highways, particularly in settings where traditional noise abatement measures are constrained by space. The insights from this study serve as a valuable reference for the development and evaluation of innovative road engineering materials and technologies.

Structural optimization and performance testing of concentrated photovoltaic panels for pavement

Solar pavement can convert sunlight shining on the pavement surface into clean electricity through photovoltaic panels, thereby transforming the energy structure of road transportation. In order to balance the light transmittance and anti-skid resistance of the solar pavement surface, this study proposed a concentrated photovoltaic panel (CPP) structure for pavement. The panel structure was optimized, and a laboratory model was developed. The mechanical properties and durability of the panel were tested by the multi-functional material test system (MTS) and the model mobile load simulator 3 (MMLS3). Furthermore, the electrical performance was evaluated by an outdoor test, followed by an economic evaluation. The results show that the optimal structural dimensions of the CPP for pavement are 540 mm long × 540 mm in length × 144.62 mm in thickness. The maximum flexural tensile strength of its anti-skid concentrated panel is 61.67 MPa, satisfying the requirements of the traffic load. After 1.35 million cycles of loading, the surface of the anti-skid concentrated panel is free of cracks and deformation and has no obvious wear, exhibiting good transmittance durability and excellent wear resistance. In addition, the overall structure of the panel counteracts the light loss effect of the material and improves the light concentration performance, providing a gain effect on the power generation of the panel, especially in the case of high irradiance. The return on investment (ROI) of CPP for pavement is 54.42%, with cost recovery in 9.87 years. The levelized cost of energy is 0.67 CNY/kWh, indicating significant economic benefits. At the same time, 1539.3 kg/m2 of CO2 emissions can be avoided during the operation cycle, and the environmental benefits are also considerable. This study can provide a reference for the promotion and application of photovoltaic power generation technology in road engineering.

Investigation into the Enhancement Characteristics of Fly Ash and Polypropylene Fibers on Calcium Carbide-Residue-Stabilized Soil

The recycling and reuse of waste materials is an important part of promoting sustainable development. Encouraged by cleaner production and a circular economy, the introduction of calcium carbide residue (CCR) for the stabilization of soil foundations has become a hot topic in the road engineering industry. Aiming at the efficient application of CCR-stabilized soils, the optimization of the material composition was focused on in this work. Fly ash and polypropylene fibers were introduced into the preparation of CCR-stabilized soils, and their effects on the mechanical properties and water stability were tested. The findings highlight that the strength of fly-ash–carbide-residue-stabilized soil was higher than that of carbide-residue-stabilized soil at the same curing age. Furthermore, the unconfined compressive strength, splitting strength, and water stability of CCR–fly-ash-composite-stabilized soil initially increased and then decreased with a rise in polypropylene fiber content. The peak values of confining compressive and splitting strength were observed when the polypropylene fiber content was 1.2‰, while the water stability coefficient A reached its peak value at 0.8‰. From the standpoint of the comprehensive performance improvement and economy of composite-stabilized soil, it is advised that the dosage of polypropylene fibers falls within the range of 0.8–1.2‰. The engineering technical indexes of polypropylene-fiber–CCR-composite-stabilized soil fulfilled the requirements of the specification and had a satisfactory effect on delaying the cracking of the specimen. It is expected that this investigation will provide support for the resource utilization of CCR and the sustainable development of road construction.

Preparation and Road Performance Study of Rubber–Diatomite Composite-Modified Asphalt Mixture

To examine the effect mechanism of rubber and diatomite on asphalt as well as the performance of asphalt mixtures for road applications, various composite-modified asphalts are prepared using rubber and diatomite. The performance of modified asphalts with various proportions is analyzed, and the optimal dosage ratio of modifiers is determined via the response surface approach. The microstructure of rubber–diatomite composite-modified asphalt is methodically examined using Fourier transform infrared spectroscopy and scanning electron microscopy. The road performance, aging resistance, and long-term stability of asphalt mixtures are evaluated through Marshall tests, wheel tracking tests, aging wheel tracking tests, freeze–thaw splitting tests, and cyclic freeze–thaw drying aging splitting tests. The obtained results reveal that asphalt with 22% rubber and 4% diatomite exhibits the best overall performance. The composite-modified asphalt essentially demonstrates the physical blending between rubber powder, diatomite, and base asphalt. The asphalt built from them formed a uniform and stable overall structure. Compared with rubber asphalt and rubber–SBS composite-modified asphalt, rubber–diatomite composite-modified asphalt exhibits superior road performance, including better aging resistance and long-term water stability in asphalt mixtures. This study can promote the further extensive application of rubber–diatomite-modified asphalt in road engineering, while providing new ideas for cost-saving and environmentally friendly asphalt modification.

The mechanical strength, microstructure, and transport properties of steel slag reinforced loess soil system

Steel slag, as an industrial byproduct obtained from the steel manufacturing industry, may cause land occupation, resource waste, and environmental pollution. The application of steel slag as a material for soil reinforcement in road engineering is very popular due to its potential hydration activity. The unconfined compression strength, microstructure, and transport properties of loess soil with cement, lime and steel slag were investigated. The results show that the loess soil can be reinforced by cement, lime, and steel slag to varying degrees. The reinforcement mechanism of cement for loess soil is realized by pore filling by cement hydration products such as CH, C-S-H and AFt, and their unconfined compression strength is improved by reducing the porosity. The reinforcement mechanism of lime for loess soil is achieved by pore filling by hydration products such as CH and CaCO3, and their strength is improved by a refined pore structure where the porosity has not been significantly reduced. The reinforcement mechanism of steel slag for loess soil is a combined mechanism of cement and lime, including pore filling and refined pores. The pore structure of reinforced soil can be studied at different scales by the MIP, LF NMR, and X-CT test methods. The transport properties including diffusivity and permeability of reinforcing soil can be well explored by Avizo software based on the microstructure obtained from X-CT.

Applicability evaluation of a two-dimensional piezoelectric transducer to monitor dynamic soil stress in unbound granular materials of road engineering

In road engineering, the applications of piezoelectric ceramics on road energy harvesting or electronic sensing have drawn many attentions. However, the application potential of piezoelectric sensor on UGMs (unbound granular materials) in road is unclear. The main problem is the applicability of piezoelectric equation considering that the soil structure of UGMs and the working environment that the transducer may suffer may influence the transferred stress on the piezoelectric transducer and then the electricity generation. In this study, a two-dimensional piezoelectric transducer made by PZT-5H piezoelectric ceramics was installed in the sample of UGMs, and a series of cyclic tests were performed on the UGMs samples by a large-scale triaxial apparatus. This test method is specially designed for the case that the piezoelectric transducer is installed in UGMs of pavement base/subbase layers and then undergo traffic loading under complex working environment. Test results show that the electricity generation is primarily dependent on the magnitude and frequency of cyclic loading, while the influences of other factors are limited. The piezoelectric equation to calculate the open-circuit voltage is deduced and verified under the complex working environment. This indicates that the piezoelectric equation is applicable to the case that the applied stress on the piezoelectric transducer is transferred from the soil medium, and the two-dimensional piezoelectric transducer has a sensor potential to monitor the dynamic vertical and horizontal soil stresses under traffic loading.

Correlation analysis of longitudinal cracks and vertical deformation within asphalt pavement of cold regions

The asphalt pavement longitudinal crack is a common distress in cold regions, resulting from uneven deformation of the subgrade. Analysis of the correlation law between uneven deformation and crack distress is of positive significance for understanding the mechanism of crack initiation, and putting forward treatment measures. In view of the complexity of longitudinal crack inducement and road surface deformation, the grey relational method was used to analyze this relationship. Through long-term monitoring of the vertical deformation data of typical road sections, the vertical deformation law of the pavement surface and its deformation characteristics under the action of temperature field are analyzed. Parameters such as vertical relative deformation, vertical relative deformation rate and vertical differential deformation VDSr were constructed to describe vertical deformation characteristics. Typical distribution characteristics of longitudinal fractures and their length and distribution characteristics are also described. The grey correlation analysis theory was utilized to analyze the relationship between deformation characteristics of sections, cross sections and monitoring points and longitudinal crack characteristics (length and location). The analysis reveals a linear positive correlation or a high correlation between several indicators. This study can provide a deeper understanding of the occurrence and development mechanism of longitudinal cracks in asphalt pavement of cold areas, and give references for the research of road engineering structure, materials and distress prevention.

Ground stability of ellipsoidal cavity due to pipeline defects

The problem of road-related sinkhole stability has long been one of the main safety concerns to pavement engineers. Collapse and blowout failures are two typical types of pipeline-related sinkhole failures. Although much research on sinkhole stability analyses can be found in the literature, most of them assume a simple circular or rectangular shape of a cavity. In this study, the problem of sinkhole stability in an ellipsoidal cavity is investigated under both blowout and collapse conditions using advanced finite element limit analysis with adaptive meshing in an axisymmetric condition. A dimensionless pressure ratio is defined to represent sinkhole stability that is a function of many design parameters such as depth ratio, elliptical shape ratio, and soil strength ratio. Selected results are compared with published solutions, and comprehensive solutions of the parametric study are presented in the form of charts for use by design engineers. The present study contributes to the understanding of sinkhole stability under an ellipsoidal cavity, and it should be of interest to the road engineering community.

Effect of Polymeric Agent on the Strength and Water Stability of Cement-Stabilized Construction Waste Soil

Due to the large output of construction waste soils, it has become an enormous challenge for human society and the ecological environment. The purpose of this paper is to discuss the possibility of using a stabilized waste soil in road engineering. Cement and polymer stabilizers were added to the waste soil, and the effect of the stabilizer on the strength and water stability of the stabilized soil was studied. The structure and morphology of the specimens were analyzed using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The results show that the unconfined compressive strength increases by 25.0% and the 28-day water stability coefficient, K increases by 59.6% after the addition of the stabilizer. The XRD curve shows that the addition of the new stabilizer does not produce a new characteristic peak, but the diffraction peak strength of some minerals can be improved. SEM shows that the surface of stabilized soil particles is covered by materials, and the particles show obvious agglomeration, forming a network structure, which improves the strength and water stability of the soil.

Modern two-component modifiers inhibiting the aging process of road bitumen

The bitumen physicochemical properties of are constantly changing during both the production of asphalt mixtures and the service of road pavements. These changes involve bitumen hardening which consequently cause formation of defects and cracks in road pavements. Therefore, in recent years, prolonging road pavement life by inhibiting the bitumen aging process is a key trend in road engineering, bringing many economic, environmental and social benefits. In line with these trends, the main objective of this research was inhibition of short-term bitumen aging by two-component chitosan-based polymer composites containing ligands with different chemical structures, i.e. polyaniline, methacrylamide and 2-acrylamido-2-methylpropanesulfonic acid. This paper presents their effect on the TFOT aging process, as well as physicochemical and structural changes. Studies show that the strongest anti-aging properties are demonstrated by the chitosan:polyaniline composite. Its use at 2 % w/w allows it to maintain 90 % of the primary penetration value, increase the softening point by only 2°C and increase dynamic viscosity by 17% in comparison to non-aged modified bitumen. In addition, the use of the composite makes it possible to reduce the degree of bitumen components oxidation, which is seen from the reduction of carbonyl and sulfoxide indices by more than 33 % and 47 %, respectively.