An Experiment and Study of M30 Grade of Concrete by Partially Replacing Fine Aggregate with Marble Dust Powder and Phosphogypsum in Rigid Pavement

The Project is to study about M30 grade of concrete by adding waste materials. Marble dust powder and phosphogypsum which is easily available marble which are standard among the most imperative materials, utilized as a part of the development business. Marble dust is a waste material from the construction site is mixed with concrete as a replacement material. Marble dust powder is acquired from sawing and moulding of marble rock. Phosphogypsum is produced as an outgrowth of the production of fertilizer from phosphate rock. There is a high gypsum content and gypsum is a widely used material in constructions. It is weakly radioactive in nature because it is a by-product of phosphate fertilizers. In the M30 grade of concrete fine aggregate is partially replaced by marble dust powder and phosphosgypsum in some proportions. The fine aggregate is replaced by 10%, 20% and 30% in which marble dust powder and phosphogypsum and are added in an equal proportion. Keywords: Marble dust powder, phosphogypsum, grade of concrete, rigid pavement, green concrete.

Investigating the Barriers to Applying the Internet-of-Things-Based Technologies to Construction Site Safety Management

The utilization of Internet-of-Things (IoT)-based technologies in the construction industry has recently grabbed the attention of numerous researchers and practitioners. Despite the improvements made to automate this industry using IoT-based technologies, there are several barriers to the further utilization of these leading-edge technologies. A review of the literature revealed that it lacks research focusing on the obstacles to the application of these technologies in Construction Site Safety Management (CSSM). Accordingly, the aim of this research was to identify and analyze the barriers impeding the use of such technologies in the CSSM context. To this end, initially, the extant literature was reviewed extensively and nine experts were interviewed, which led to the identification of 18 barriers. Then, the fuzzy Delphi method (FDM) was used to calculate the importance weights of the identified barriers and prioritize them through the lenses of competent experts in Hong Kong. Following this, the findings were validated using semi-structured interviews. The findings showed that the barriers related to “productivity reduction due to wearable sensors”, “the need for technical training”, and “the need for continuous monitoring” were the most significant, while “limitations on hardware and software and lack of standardization in efforts,” “the need for proper light for smooth functionality”, and “safety hazards” were the least important barriers. The obtained findings not only give new insight to academics, but also provide practical guidelines for the stakeholders at the forefront by enabling them to focus on the key barriers to the implementation of IoT-based technologies in CSSM.

A Mobile System for the On-Site Assembly of Timber Frame Components: The Development of an Agile, Low-Cost Alternative to Offsite Prefabrication

Prefabricated timber component-based systems are the most prevalent industrialised system used to build housing. Along with many other countries, the UK has invested in different types of factory-based prefabrication systems as a means of increasing productivity and enhancing quality. In more recent decades, prefabrication has become part of a series of ‘modern methods of construction’ employed for, and aimed at, delivering sustainable and efficient construction. However, certain pragmatic issues remain. The industry is cyclical, and during periods of declining resources, skills and technical development can be lost. Additionally, factory-based prefabrication requires substantial initial investment and an appropriate local workforce. To help address these issues, this paper presents the concept of an alternative method of production and assembly that takes a different approach to traditional industrialised systems that involve large investments and fixed-location factories. The proposition presented in this paper is that it is possible to design and develop a small, low cost, portable micro-factory that can be taken to a temporary location or construction site, where it can then be used to construct prefabricated closed panels. We describe the development of a working prototype, effectively a micro-factory, along with its potential advantages over a fixed facility.

Sustainable Recovery of Architectural Heritage: The Experience of a Worksite School in San Salvador

This paper presents the experience of both interdisciplinary and sustainable implementation of an educational construction site for the recovery of the architectural heritage in Central America. Rey Prendes House is representative of one hundred and forty-five houses made of wood, stamped steel sheet, and deployé that are located in the historical center of San Salvador. Its origin is linked to historical events, such as the strong migration of foreigners to El Salvador in the late nineteenth and early twentieth century, the presidential decrees that encouraged the reconstruction of the city with anti-seismic materials as a result of the earthquakes of 1873 and 1917. More recently, since 2017, Rey Prendes House has been included in the project funded by the Italian Agency for Development Cooperation. In this paper, the phases of the survey are documented with both materials and degradation analyses, the new design construction with BIM technology for the organization of the educational construction site, the creation of offices and laboratories for restoration and treatments of timber and metal details. Moreover, the study provides a contextual framework with the aim of describing the policies and the projects implemented, highlighting the adopted strategies, the results achieved, and outlining the path followed towards the design solutions for sustainable rehabilitation relating to future use.

A Super-Resolution Reconstruction Driven Helmet Detection Workflow

The degrading of input images due to the engineering environment decreases the performance of helmet detection models so as to prevent their application in practice. To overcome this problem, we propose an end-to-end helmet monitoring system, which implements a super-resolution (SR) reconstruction driven helmet detection workflow to detect helmets for monitoring tasks. The monitoring system consists of two modules, the super-resolution reconstruction module and the detection module. The former implements the SR algorithm to produce high-resolution images, the latter performs the helmet detection. Validations are performed on both a public dataset as well as the realistic dataset obtained from a practical construction site. The results show that the proposed system achieves a promising performance and surpasses the competing methods. It will be a promising tool for construction monitoring and is easy to be extended to corresponding tasks.

Extreme wind speed prediction in mountainous area with mixed wind climates

In addition to common synoptic wind system, the mountainous terrain forms a local thermally driven wind system, which makes the mountain wind system have strong terrain dependence. Therefore, in order to estimate the reliable design wind speeds for structural safety, the samples for extreme wind speeds for certain return periods at mountainous areas can only come from field measurements at construction site. However, wind speeds measuring duration is usually short in real practice. This work proposes a novel method for calculating extreme wind speeds in mountainous areas by using short-term field measurement data and long-term nearby meteorological observatory data. Extreme wind speeds in mountainous area are affected by mixed climates composed by local-scale wind and large scale synoptic wind. The local winds can be recorded at construction site with short observatory time, while the extreme wind speeds samples from synoptic wind climate from nearby meteorological station with long observatory time is extracted for data augmentation. The bridge construction site at Hengduan Mountains in southwestern China is taken as an example in this study. A 10-month dataset of field measurement wind speeds is recorded at this location. This study firstly provides a new method to extract wind speed time series of windstorms. Based on the different windstorm features, the local and synoptic winds are separated. Next, the synoptic wind speeds from nearby meteorological stations are converted and combined with local winds to derive the extreme wind speeds probability distribution function. The calculation results shows that the extreme wind speed in the short return period is controlled by the local wind system, and the long-period extreme wind speed is determined by the synoptic wind system in the mountain area.

Is the construction site a safer place under the USACE or local government guidelines? The case of Afghanistan

PurposeThe aim of this paper is to assess the safety level of construction sites in Afghanistan following the US Army Corps of Engineers (USACE) safety practices and compare this with other construction sites in Afghanistan that follow local government safety guidelines. The USACE oversees and funds many infrastructure projects in Afghanistan, and these projects are supposed to follow the same standards implemented in the USA, including safety standards. The local government of Afghanistan also funds infrastructure projects in Afghanistan; however, these do not follow USACE best practices. This research explores the question of whether the USACE standards provide a safer construction site. The effect of the USACE standards on safety practices in construction projects is also investigated in the Afghanistan construction industry.Design/methodology/approachA literature review and other safety checklists were used to develop a safety checklist containing 104 items (questions) in 17 categories. Subsequently, the checklist was used to assess the safety performance of 57 construction projects (25 USACE projects, and 32 governmental projects). Utilizing quantitative analysis, the Spearman rank correlation coefficient (Rho) and Mann–Whitney tests were carried out for correlation and statistical disparity between USACE and governmental projects.FindingsThe safety performance level of Afghan government projects was found to be poor in relation to other developing countries, while in USACE projects it was excellent. In addition, fire prevention, safety administration, PPE, heavy equipment, and handling and storage of materials for all types of contractors were the most overlooked aspects of Afghan Government projects.Practical implicationsThe findings clearly demonstrate the deficiencies in construction sites observed during this study and also support the adoption of USACE standards in Afghanistan projects.Originality/valueTo the best of the authors’ knowledge, this study is the first to investigate the safety of construction sites in Afghanistan. The study also demonstrates the benefits of adopting international standards (USACE) to improve the safety of construction sites in a developing country such as Afghanistan. The findings provide evidence of the safety of the Afghanistan construction industry compared to other developing countries. These findings will contribute to the Afghan Government's efforts to track injury statistics.