Abstract Now, it is widely accepted by civil engineers and architects that walls and masonry building units, which are made of pumice, can insulate buildings against both heat and sound, and also reduce the dead load of the building compared to traditional buildings. In this study, pumice was used as a fine aggregate in mortar and plaster instead of traditional crushed limestone sand. This study shows that the properties of pumice mortars indicate lower values compared to limestone mortars for workability durations, time of settings, and fresh and hardened unit weights. Other properties of pumice mortars indicate higher values compared to limestone mortars, such as water absorption, coefficient of capillary water absorption, drying shrinkage, flexural strength, and compressive strength. Also, wall systems made with pumice mortar and plaster show significant benefits in terms of thermal conductivity.
Purpose The purpose of this paper is to investigate the practice of stakeholder engagement as a social network dynamics for stakeholder satisfaction and project success in the lifecycle of mega transport infrastructure projects (MTIPs). Design/methodology/approach Hypotheses indicating the positive relationships between stakeholders’ effective attributes, stakeholder engagement as social network dynamics and project success through stakeholders’ satisfaction have been developed. Based on a questionnaire survey and semi-structured interviews, responses have been gathered from the representative groups and organizations on their social network dynamics for their satisfaction and project success. A hypothesized structural equation model has been tested using AMOS statistical software package. Findings The analysis highlighted the engagement of the stakeholders within the strategic intents of the project with the public needs and expectations. The model depicts the processes of building social network models based on the capturing of the project’s data in relation to the stakeholders’ communication and satisfaction across the key issues for success in the lifecycle of MTIP. Practical implications The model is applicable on most MTIP with a diverse stakeholder base and the underlying complexity associated with the community participation and consultation processes. The model will also support wider stakeholder engagement in the planning of MTIP with optimal operationalization and service delivery from a community perspective. Originality/value The research involves an approach for rationalizing the stakeholder engagement policies of the MTIPs by providing an empirically grounded model simultaneously linking various aspects of stakeholder effective attributes, stakeholder engagement and their relationships to stakeholder satisfaction and project success in MTIPs.
Building design and material type used are the two main parameters that have a significant impact on the cost of a building. Therefore, it is important for a cost estimating tool to have a mechanism that allows the designer to perform a rapid `what if' analysis on design alternatives and materials selection at the early planning stage without the accompaniment of detailed design and drawings. However, the traditional design cost estimating procedures generally focus on assessing costs after design decisions are made and conveyed to the construction drawing as a quantity take off. On the other hand, comparative cost estimating (unit cost per square meter) uses historical data collected by averaging buildings of different designs, heights and materials. Even today's computer aided design (CAD) software incorporates a mechanism to take off quantities from completed designs and drawings. However, basically they are the same as the traditional quantity take off estimating because a single specified design still controls the resulting costs, and there is no alternative materials selection integrated to the cost system. This article presents an integrated knowledge-based system for alternative design decisions, materials selection and cost estimating mainly for pre-design analysis. The knowledge-based system also includes materials selection and cost estimating for after-detailed design by providing edit tables for inputting the dimensions of building elements from completed designs and drawings or by directly importing from CAD. The system generates activities quantities, costs and lists of materials selected and their respective quantities. An analysis of alternative design and materials selection for a residential building using the integrated system is presented.
Upon the completion of national road projects, their cost and time deviations are often reported. These deviations from the projected values are a result of complications in the time and cost management of such projects. Controlling the cost and time overrun of projects is important for successful implementation and efficient project management. However, few studies have attempted to measure the project cost and time management efficiency in civil engineering. Thus, this issue requires further investigation. In this study, large road projects that had poor cost and time management were selected. The chosen projects were configured as Decision Making Units (DMUs) in a Data Envelopment Analysis (DEA). DEA is a non-parametric modern mathematical tool for measuring relative managerial performance and determining efficient DMUs. A list containing the causes of cost and time deviations and the percentage deviation for each DMU was prepared. The cost and time management efficiency of the DMUs was calculated using DEA, and the resulting values were ordered according to importance. It is believed that this process will contribute to better cost and time management.
No abstract is provided for this article.
Crusher dust is a fine material formed during the process of comminution of rock into crushed stone or crushed sand. This dust is composed by particles which pass 75 μm BS sieve. Effects of dust content in aggregate on properties of fresh and hardened concrete are not known very well. An experimental study was undertaken to find out the effects of various proportions of dust content on properties of fresh concrete and hardened concrete.
Build-Operate-Transfer (BOT) contracts have been widely implemented in developing countries facing budget constraints. Analysing the expected variability in project viability requires extensive risk analysis. An objective analysis of various risk variables and their influence on a BOT project evaluation requires study and integration of many scenarios into the concession terms, which is complicated and time-consuming. If the process of negotiating the financial parameters and uncertainties of a BOT project could be automated, this would be a milestone in objective decision-making from various stakeholders’ points of view. A soft computing model would let the user incorporate as many scenarios as could be provided. Extensive risk analysis could then be easily performed, leading to more accurate and dependable results. In this research, an artificial neural network model with correlation coefficient of 0.9064 has been used to model the relationship between important project parameters and risk variables. This information was extracted from sensitivity analysis and Monte Carlo simulation results obtained from conventional spreadsheet data. The resulting consensus would yield to fair contractual agreements for both the government and the concession company.
The traditional design, cost estimating and scheduling procedures focus on assessing costs and schedule after design decisions are made and conveyed to construction drawings and design that is, they do not have a mechanism that allow the designer to perform a rapid ‘what if’ analysis on design alternatives and cost analysis of different types of building materials and alternative schedule analysis at early stage of project without accompanying of detailed design and drawing. Moreover, the available scheduling tools are not integrated to design and cost estimating system and hence require manual input of activities lists, activities sequencing, resources, costs and durations to generate project schedule and they are unable to consider the effect of productivity factors and the resulting uncertainty inherent in each activity. This paper presents an integrated knowledge based system for construction cost estimating and scheduling. The knowledge based system supports an automated alternative design analysis with on line schematic drawing, material selection, crew selection and productivity analysis for generating activities sequencing, normal durations, productivity adjusted durations, cost estimate, list of materials selected and their respective quantities and list of assigned crew. An analysis of alternative design, cost estimating and scheduling for a residential building using the integrated system is presented.
Residential buildings consume approximately 36% of total electricity consumption in Cyprus and this is expected to continue increasing in the coming years. This study explores the potential for energy savings in residential buildings in Cyprus through optimising building envelopes and insulation materials. Using building information modelling and energy modelling software, the study analyses 120 combinations of building envelopes and eight insulation materials, identifying an optimal combination of wall, roof, and flooring materials that could result in 32% energy load reductions and 27% lower life-cycle costs compared to the median scenario. High-density rock wool insulation on roofs and double-glazed windows were also found to offer both monetary and energy performance benefits. A sensitivity analysis revealed that the current high energy prices could provide greater economic incentives to adopt these optimisation strategies. Optimising building materials in Cyprus could play a critical role in climate strategy while also offering significant economic benefits.
A knowledge based expert system for modelling the production of conventional concrete is described, which was developed to help improve the quality of concrete by minimizing mistakes and deficiencies in batching and mixing procedures. The paper describes a study of concrete batching and mixing methods and practices in conventional concrete technology, and of the decisions made by personnel involved in concrete production. The details are described of the computer program, ESCON. The knowledge acquisition for ESCON is described. ESCON is now being improved nd extended to cover other concrete operations such as transporting, placing, etc.
The influence of aggregate size and water-to-cement (w/c) ratio of the matrix on the structure of interfacial transition zone (ITZ) and the interaction between the ITZ and the matrix on the failure process of concrete under uniaxial compression were studied. The ITZ microcracking and the failure process of concrete were investigated experimentally by means of compressive and indirect tensile testing, stress–volumetric strain measurements and microscopic analyses on the model concrete containing single spherical steel aggregate with three different w/c ratios. At low w/c ratios, the rigid and smooth surface texture aggregates made by the ITZ have a significant structural difference compared to the mortar. This was more pronounced for larger aggregates. Higher structural differences between the mortar matrix and ITZ in low w/c ratio composites resulted in accelerated ITZ microcracking at high stress level. The effect of condensed microcracking in a narrower ITZ was reflected in the lower critical stress levels for the low w/c ratio composites with larger aggregates.
A simple, economical, and practical drop-weight impact testing machine was developed to determine the impact resistance for high-strength fiber-reinforced concrete (HSFRC) composite. Impact and compression tests were carried out on concrete cylinders reinforced with three different aspect ratios of hooked-end steel fibers l/d (length/diameter): 60, 75, and 83 (30/0.50, 60/0.80, and 50/0.60 mm/mm), and four different percentages of steel fibers 0.5%, 1.0%, 1.5% and 2.0% by volume of concrete. For each aspect ratio and volume of fibers, complete stress–strain curves of HSFRC were generated in order to determine the total energy absorbed for each cylindrical specimen in compression. The addition of steel fibres to concrete has improved impact resistance and also the compression toughness. The test results showed that a logarithmic relation exists between compression toughness energy (E Ct) by means of the generated stress–stress curves from the compressive tests and the impact energy (EI) by means of the modified impact machine for HSFRC at different l/d ratio of 60, 75, and 83.
Building Information Modeling (BIM) has significantly impacted the global construction industry, promising efficiency, cost savings, and improved project outcomes. However, its adoption in developing countries, such as Nigeria, remains inconsistent due to multiple barriers. This study aims to investigate the barriers hindering the adoption of BIM in Nigeria’s construction sector, with a view to providing strategic recommendations for stakeholders. A mixed-methods approach was employed, combining a comprehensive literature review with semi-structured interviews from 10 experts in Nigeria, representing both industry and academia. A hybrid analytical methodology, integrating the Analytical Hierarchy Process (AHP) and fuzzy Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS), was used to analyze the data, because they provide a comprehensive framework for informed decision-making. Technical barriers are identified as the most significant challenge to BIM adoption, particularly due to difficulties in accessing advanced technology. Educational barriers also play a major role, with limited awareness among industry professionals hindering widespread implementation. Economic constraints further contribute to the slow adoption, as financial limitations impact investment in necessary tools and training. The study provides policy implications and recommendations, including the development of a national BIM evaluation framework, improved training programs, and government support for standardization. These recommendations are expected to facilitate informed decision-making among stakeholders and promote effective BIM adoption in Nigeria’s construction industry, serving as a roadmap for other developing countries facing similar challenges.
An experimental study was performed to investigate the effects of polypropylene fibers on uncorroded and corroded reinforced concrete beams. Three different volume fractions of polypropylene fibers having 0, 0.5, and 1.5%, were tested at four corrosion levels of 0% and approximately 5, 7, and 9%. A full scale of an accelerated corrosion pool was used for the accelerated corrosion process. Reinforced concrete beams were used for an under monotonic bending test. The contribution of the actual corrosion levels of transverse and longitudinal reinforcement bars to the total corrosion levels were obtained from reinforcement bars fully extracted from concrete. Flexural strength, bond-slip, and moment-curvature relationships were examined for uncorroded and corroded reinforced concrete beams. A new model was developed to predict the flexural strength of corroded reinforced concrete beams. The proposed model for predicting the residual flexural strength of corroded beams was compared with test data published in previous studies. Furthermore, a novel model is presented for improved predictions between the actual and theoretically estimated corrosion mass losses, based on Faraday’s law, with the aid of fully extracted reinforcement bars. The model used to predict the flexural strength of corroded reinforced concrete beams with large sizes demonstrated good agreement with current and previously published literature data. In the case of corroded beams comprising differing amounts of polypropylene fibers, the performance of the corroded beams was limited by a fiber volume fraction of 1.5% at low corrosion levels.
Quality management system implementation has become a must for construction companies in some countries to be able to enter tenders. One of the most common quality standards is the ISO 9000 quality management standard and many companies seek ISO 9000 certification in today's highly competitive market. However, in getting this certification, most companies face difficulties, such as the high amount of paperwork, improper documentation, poor communication among employees and project participants, and low employee morale as a result of lack of motivation. In this study, a web-based office automation system was developed. Web facilities and the database management capabilities of Microsoft Visual Studio 2008 were applied to create a data warehouse that was aimed to reduce paperwork, create a proper documentation system, improve communication, and calculate employee performances, in order to create a motivation system for company personnel. Short-term feedback of the practical implementation of the system demonstrated its practicality and advantages, and the positive view of the managers. Also, it is anticipated that long-term feedbacks would also prove its appropriateness and ease of use.
One of the most common concerns in construction projects is changes during execution. Changes can increase the cost and duration of the construction project hereby, can lead to conflict between the parties involved in construction projects. The change causes may differ depending on the organizations and regions characteristics. The aim of this study is to investigate the impact of organizational and regional characteristics on key change factors. In this regard, top risky change factors were identified with respect to contractors, consultants, and owners located in North Cyprus, Turkey, and the U.S.A. The research findings showed that the most risky change factors differed in accordance with the characteristics of organizations and regions. It was concluded that “Errors/Inadequacies in Contract Drawing” was the riskiest factor according to contractors while “Low price due to high competition” was noted to be the riskiest change causes with respect to consultants and owners. In point of regions, “Inconsistency between different design disciplines” was identified as the top risky change factor according to the respondents in the U.S.A. located organizations. However “Low contract price” was designated as the top risky change factor according to the respondents in North Cyprus and Turkey. In addition, key measures were suggested to be able to mitigate changes in accordance with organizational and regional characteristics.
One of the most important earthquake indicators that buildings should have is ductile behavior. Due to the limited tensile strength of concrete, alternative materials such as structural Nano-synthetic fibers as three-dimensional reinforcement bars have already gained increasing popularity for several decades. However, the contribution of nano-synthetic fibers to the adherence length of reinforcement bars has not been investigated so far. Therefore, in this study, an experimental study was conducted to investigate the effects of nano-synthetic fibers on the development length of reinforcement bars. The number of experimental reinforced concrete slab specimens to be fabricated in terms of axial flexural tests was designed 33, depending on different development lengths and three different volume fractions of nano synthetic fibers as 0.0, 1.0 and 1.5%. Within the scope of the research, load displacement curves, energy absorption capacities, ductility ratios and bond-reinforcement slip relationships were obtained for different embedding lengths of reinforcement bars in 33 concrete slabs with three different amounts of nano-synthetic fibers used. As a result of the research, it has been revealed that the dominant effects of nano-synthetic fibers on structural behavior are their energy absorption capacity in plastic deformation. As a result of the research, it has also been discovered that with the help of the added nano-synthetic fibers, the ductile behavior is also regained for or reinforcement bars with reduced embedded length of more deformation capacity that can be accommodated by the reinforcement bars.
Total Quality Management (TQM) is based on the conceptions of managing and enhancing the success of construction projects. When applied, TQM improves execution of time management of project, satisfies clients’ needs, minimizes the expenses and increases the profit of contractor, and fulfils safety regulations on the construction site. This research is aimed at evaluating the impacts of employing the concepts of TQM to the construction projects in Saudi Arabia. The results of the study were obtained through utilization of a descriptive analytical approach, where 300 questionnaires were distributed to engineering firms and companies with a response rate of 200 questionnaires, hence achieving the study sample for this research. The data gathered was analyzed by applying the Statistical Package for Social Science (SPSS) program and calculating the relative importance index (RII) and the mean values. From the research conducted, the outcomes showed that the management’s ability to commit using TQM while applying BIM obtained a relative importance of (0.717), while the relative importance for the management’s ability to commit using TQM without the application of BIM is (0.552). The results showed that construction projects in Saudi Arabia still sustain setbacks from applying TQM concepts and suffer from the lack of administrative, scientific, and technical applications.
