Search results

This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure (FSACWSS) for the high-speed railway subgrade through on-site tracking, monitoring and post-construction investigation.

Based on the working state of the waterproof sealing structure, the main functional characteristics were analyzed, and a kind of roller-compacted high elastic modulus asphalt concrete (HEMAC) was designed and evaluated by several groups of laboratory tests. It is applied to an engineering test section, and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.

Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits. The water content in the subgrade of the test section is maintained at 8–18%, which is less affected by the weather. However, the water content in the subgrade bed of the contrast section is 10–35%, which fluctuates significantly with the weather. The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section. The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section, but all of them meet the limit requirements. The asphalt concrete in the test section is in good contact with the base, and there are no diseases such as looseness or spalling. Only a number of cracks are found at the joints of the base plates. However, there are more longitudinal and lateral cracks in the contrastive section, which seriously affects the waterproof and sealing effects. Besides, the asphalt concrete is easier to repair, featuring good maintainability.

This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.

Particles bed binding by selective cement activation (SCA) method is a computer-aided manufacturing (CAM) technique used to produce cementitious elements. A computer-aided design file is sliced to generate G-codes before printing. This paper aims to study the effect of key input parameters for slicer software on the final properties of printed products.

The one factor at a time (OFAT) methodology is used to investigate the impact of selected parameters on the final properties of printed specimens, and the causes for the variations in outcomes of each variable are discussed.

Finer aggregates can generate a more compact layer, resulting in a denser product with higher strength. Fluid pressure is directly determined by voxel rate (r_V); however, high pressures enable better fluid penetration control for fortified products; for extreme r_Vs, residual voids in the interfaces between successive layers and single-line primitives impair mechanical strength. It was understood that printhead movement along the orientation of the parts in the powder bed improved the mechanical properties.

The design of experiment (DOE) method assesses the influence of process parameters on various input printing variables at the same time. As the resources are limited, a fractional factorial plan is carried out on a subset of a full factorial design; hence, providing physical interpretation behind changes in each factor is difficult. OFAT aids in analyzing the effect of a change in one factor on output while all other parameters are kept constant. The results assist engineers in properly considering the influence of variable variations for future DOE designs.

This study aims to carry out an investigation of design approaches that should be used for the design of unconventional, innovative transmission system for construction yards to privilege a smooth behaviour efficiency, and the use of innovative production techniques. Results are quite surprising, as with a proper method it is possible to demonstrate that a cycloidal drive with Wolfrom topology should be an interesting solution for the proposed application.

With a functional approach, also considering materials and specifications related to the investigated application, it is possible to demonstrate that possible optimal solutions should be quite different respect to the ones that can be suggested with a conventional approach. In particular for proposed applications constraints related to encumbrances, the choice of new material has led to the innovative unconventional choice of a Wolfrom cycloidal speed reducer.

Provided solution is innovative respect current state of the art for machine currently used in construction yards: in terms of adopted transmission layout; in terms of chosen materials, resulting in an innovative solution.

Current research has strong implications on the adoption of polimeric materials for the construction of reliable transmission for harsh industrial environment as the proposed case study (concrete mixer for construction yard).

Proposed transmission system is absolutely original and innovative respect current state of art also considering proposed materials and consequently production methods. This is an example of transmission designed to be built with polymeric materials by optimizing chosen topology respect to chosen material.

Construction projects usually suffer delays, and the causes of these delays and its cost overruns have been widely discussed, the weather being one of the most recurrent. The purpose of this paper is to analyze the influence of climate on standard construction work activities through a case study.

By studying the extent at which some weather variables impede outdoor work from being effectively executed, new maps and tables for planning for delays are presented. In addition, a real case regarding the construction of several bridges in southern Chile is analyzed.

Few studies have thoroughly addressed the influences of major climatic agents on the most common outdoor construction activities. The method detailed here provides a first approximation for construction planners to assess to what extent construction productivity will be influenced by the climate.

Although this study was performed in Chile, the simplified method proposed is entirely transferable to any other country, however, other weather or combinations of weather variables could be needed in other environments or countries.

The implications will help reducing the negative social, economic and environmental outcomes that usually emerge from project delays.

Climatic data were processed using extremely simple calculations to create a series of quantitative maps and tables that would be useful for any construction planner to decide the best moment of the year to start a project and, if possible, where to build it.

This study reviews the extent of application of artificial intelligence (AI) tools in the construction industry.

A thorough literature review (based on 165 articles) was conducted using Elsevier's Scopus due to its simplicity and as it encapsulates an extensive variety of databases to identify the literature related to the scope of the present study.

The following items were extracted: type of AI tools used, the major purpose of application, the geographical location where the study was conducted and the distribution of studies in terms of the journals they are published by. Based on the review results, the disciplines the AI tools have been used for were classified into eight major areas, such as geotechnical engineering, project management, energy, hydrology, environment and transportation, while construction materials and structural engineering. ANN has been a widely used tool, while the researchers have also used other AI tools, which shows efforts of exploring other tools for better modelling abilities. There is also clear evidence of that studies are now growing from applying a single AI tool to applying hybrid ones to create a comparison and showcase which tool provides a better result in an apple-to-apple scenario.

The findings can be used, not only by the researchers interested in the application of AI tools in construction, but also by the industry practitioners, who are keen to further understand and explore the applications of AI tools in the field.

There are no studies to date which serves as the center point to learn about the different AI tools available and their level of application in different fields of AEC. The study sheds light on various studies, which have used AI in hybrid/evolutionary systems to develop effective and accurate predictive models, to offer researchers and model developers more tools to choose from.

The impact of extreme heat on prisons and carceral facilities is becoming increasingly visible, yet remains overlooked by scholars, practitioners and policymakers. Prisons are a unique type of infrastructure designed to severely limit and control the movement of hundreds and even thousands of individuals as a form of punishment. This leads to many significant challenges to mitigating the risk of heat-related illness in prisons and other carceral spaces that have remained overlooked across many disciplines including emergency management, disasters, corrections and public health.

For this study, we analyzed 192 surveys from incarcerated persons in state prisons throughout Texas to understand how incarceration and the punitive prison environment create challenges to managing extreme heat in prisons.

We found that characteristics of modern incarceration, including communal distribution of resources, crowded conditions and a lack of agency for incarcerated people, create barriers to accessing resources during periods of extreme heat. Furthermore, the punitive nature of the prison environment as manifested in the relationship between staff and incarcerated persons and certain prison policies also create barriers to incarcerated persons accessing resources to reduce their risk of heat-related illness and death.

These issues are particularly relevant to the health and safety of incarcerated persons during periods of extreme temperatures but also speak broadly to the implications of incarceration, disaster risk, and the advancement of human rights for incarcerated people.

This article addresses a gap in the literature by including the perspectives of persons incarcerated in Texas prisons experiencing extreme heat and implicates the characteristics of incarceration and punishment in the production of disaster risk.

In the present study, we assessed how school improvement consultants, as part of a six-year model project conducted in North Rhine-Westphalia, Germany, were perceived by school leaders and how they defined their role(s), tasks and working methods as external consultants at the beginning of the project.

Our analyses are based on a mixed-methods approach, involving a standardized online survey of school leaders and 18 guideline-based interviews with school improvement consultants, which were conducted at the beginning of the model project. The interviews were analyzed using qualitative content analysis and typifying structuring of the interview material.

Our results based on the quantitative survey data showed that the school administrators generally rated the collaboration with the external consultants as not very positive. Furthermore, our qualitative findings showed that the school improvement consultants in the model project faced resistance to their coaching efforts, which may be attributed to the obligatory nature of their work on the project. In general, the consulting process appeared to be little differentiated according to the school principals' perceptions of the school needs, with the consultants mainly proceeding as they also do in other coaching processes.

This study contributes to our understanding of coaching in improvement activities among schools serving disadvantaged communities by offering insights into the role(s) and working methods of external school improvement consultants.

The paper seeks to bridge the already familiar benefits of 3D printing (3DP) to the rehabilitation of cultural heritage, still based on the use of complex and expensive handcrafted techniques and scarce materials.

A compilation of different information on frequent anomalies in cultural heritage buildings and commonly used materials is conducted; subsequently, some innovative techniques used in the construction sector (3DP and 3D scanning) are addressed, as well as some case studies related to the rehabilitation of cultural heritage building elements, leading to a reflection on the opportunities and challenges of this application within these types of buildings.

The compilation of information summarised in the paper provided a clear reflection on the great potential of 3DP for cultural heritage rehabilitation, requiring the development of new mixtures (lime mortars, for example) compatible with the existing surface and, eventually, incorporating some residues that may improve interesting properties; the design of different extruders, compatible with the new mixtures developed and the articulation of 3D printers with the available mapping tools (photogrammetry and laser scanning) to reproduce the component as accurately as possible.

This paper sets the path for a new application of 3DP in construction, namely in the field of cultural heritage rehabilitation, by identifying some key opportunities, challenges and for designing the process flow associated with the different technologies involved.

The purpose of this paper is to explore how posthumanism can contribute towards reframing responsible management education (RME) after the pandemic. Ethics has been a growing concern in management education for some time now, but the need to acknowledge the limitations and side effects of the global economy and the interdependences between biological and societal systems has come to the forefront in dramatic fashion during the pandemic.

Posthumanism proposes moving beyond traditional dichotomies such as nature-culture and social-material to introduce a relational epistemology in which attention is focused on local sociomaterial entanglements. This also introduces a new moral posture that is not based on formal principles but on a strong commitment to assembling the world and a capacity to cultivate response-abilities. As far as responsible management is concerned, it means moving the focus from managers to managing practices.

The contribution casts an original and critical eye on the reframing of RME and encourages a movement towards a “decolonisation” of educational methodologies. Posthumanist research acknowledges that pedagogical practices are the loci power relations and inclusion or exclusion come into play and are inscribed in the materiality of education, in the sense of objects as well as human bodies. Then, by applying on the author's experience as teacher, the paper provides inputs for developing a posthumanist research agenda for RME after the pandemic.

The contribution uses posthuman lens to explore RME and develops an original research agenda starting from the author’s teaching practices.

Studies of entrepreneurial intentions (EIs) have become increasingly common, informed usually by Ajzen’s (1991) theory of planned behaviour (TPB). Although the TPB postulates that beliefs determine EIs, the contents of the beliefs have not been properly studied, leaving EIs’ cognitive underpinnings and cognitive approaches to influencing EIs unclear. To clarify the TPB/EI-belief nexus, the study examines the conceptual background of entrepreneurial cognitions and elicits the beliefs of a group of nascent micro entrepreneurs (NMEs) to compare them with their TPB attitudes and EIs, facilitating assessing their mutual consistency as implied by the TBP.

The respondents are entrepreneurial novice clients of a micro business advisory organisation. Their TPB attitudes and EIs were measured using standard TPB/EI methods. Comparative causal mapping (CCM) combined with semi-structured interviewing was used to reveal the NMEs’ typical belief systems, presented as aggregated cause maps.

The NMEs have uniform, relatively detailed belief systems about entrepreneurship and micro business. The belief systems are consistent with theory- and context-based expectations and logically aligned with the NMEs’ expressed TPB attitudes and EIs. CCM provides an accessible method for studying contents of entrepreneurial cognitions.

It was not possible to study “entrepreneurship-negative” respondents or the intensity or origins of some specific beliefs.

Diagnosing and better understanding beliefs can benefit entrepreneurship education and development, in general or connected with TPB/EI studies.

The study reveals entrepreneurial belief systems systematically, evidently not done before generally or in terms of “everyday” micro entrepreneurship or TPB. It clarifies and supports the TPB notion that beliefs underpin actors’ attitudes and intentions.