Physical and Chemical Properties of Recycled Tire Shreds for Use in Construction

The purpose of this study was to determine the physical and chemical properties of tire shreds for use in engineering construction as a replacement for aggregates in embankments or as backfill. In general, test results revealed that tire shreds can be utilized in construction applications. As the size of tire shreds increases, physical properties such as specific gravity remained constant at 1.06–1.1. Gradation of tire shreds was also tested, and the results were comparable to other researchers (i.e., ranging from 50 to 300 mm). As the tire shred size increased, the hydraulic conductivity increased from 0.2 to 0.85 cm/s. Increasing the compaction energy had little effect on the final compaction density. The angle of friction and cohesion ranged from 15 to 32° and 349 to 394?N/m2, respectively. As the particle size (from 50 to 300 mm) of the tire shreds increased, the shear strength of the scrap tire increased. Moreover, as the tire shred size increased, compressibility increased. Chemical analysis of tire shreds was conducted to illustrate how properties such as total organic carbon (TOC), pH, and turbidity change with tire size. As tire shred size increases, the results illustrated a decrease in TOC (from 22.7 to 3.1 ppm) and turbidity (from 254 to 99 NTU). Continuous flow column tests were conducted on tire shreds and showed improved water quality (TOC, turbidity, and iron) with time. However, pause flow column tests showed reduced water quality, which implies that placement of a tire embankment below the water table where ponding can occur may reduced water quality. TGA tests were also conducted to determine the thermal stability of tire shreds. In general, tire shreds are stable up to temperatures of 200°C. This indicates that other mechanisms may be attributed to the exothermic reactions, which occurred in tire fills.     

Application Framework for Mapping and Simulation of Waste Handling Processes in Construction

This research is focused on modeling waste-handling processes in construction, with particular emphasis on how to map out and simulate on-site waste sorting processes. The research proposes an application framework for (1) guiding the development of process mapping models and simulation models; and (2) further assessing the cost effectiveness of on-site waste sorting efforts under practical site constraints (such as labor resource availability, time control on refuse chute usage, and limited working area space in a building site). The connection has been established between the mapping and simulation techniques in the context of modeling waste handling processes in construction sites, such that the process flowchart resulting from the mapping technique can serve as convenient model input to facilitate the creation of a “dynamic” operations simulation model. A case study of the on-site waste sorting method with one refuse chute for waste classification is presented to demonstrate the complete application framework spanning (1) process mapping; (2) mapping-to-simulation model conversion; and (3) method optimization based on valid simulations.     

Service Distance and Ratio-Based Location-Allocation Models for Siting Recycling Depots

Siting appropriate locations for placing recycling depots is essential for promoting an efficient recycling program. This study develops three optimization models to facilitate siting analysis for district-based, district open, and nondistrict situations. An enhanced model to improve drawbacks of locating recycling depots that mainly serve residents in adjacent districts using the district open model is also proposed. Three factors of service distance, local service ratio, and service ratios for different distance ranges are used to compare the effectiveness of alternatives obtained from different models. A case study involving 16 city districts is implemented to demonstrate the applicability of the proposed models. Findings show that the district-based alternatives have best overall service distance and service ratio, but with a poor local service ratio. The enhanced model obtains alternatives that achieve good local service ratio with acceptable service distance and service ratios for different distance ranges.     

Potential Construction Applications for Thermoset Composite Scrap Material

Thermoset composites are types of advanced plastics that perform well in high temperatures and pressures, can achieve tensile strengths similar to carbon steel, and have suitable electrical resistance properties. Because of these characteristics, engineers are increasing their use in the designs of both mechanical and electrical products, thus increasing the amount of thermoset scrap material sent to landfill sites (estimated to be approximately 1.2 billion kg per year (920,000 t). As a way to reduce the amount of this scrap material taken to landfill sites, possible construction applications are being investigated. Using American Society of Testing and Materials standards, a better understanding of its material properties are being explored, such as strength, density, uniformity, chemical resistance, and impact resistance. One potential application, developed and tested for its suitability as a construction material, was as a flooring substitute for traditional ceramic tile.     

By-Products in Earth Construction: Environmental Assessments

In Finland, some industrial residuals (by-products) have been used in earth construction since the 1970s. The lack of a general code of practice on environmental assessments of by-product utilization has led to nonuniform approval practices. In most countries, environmental standards are mainly based on health risks related to contaminant leachability. Leaching tests and solubility standards vary. Standards on waste composition and mix proportions have also been adopted in many countries. Based on a survey of practices in various countries, a hierarchical procedure is presented for the environmental assessments relevant to the utilization of by-products. In this model, the verification of environmental suitability can be based on a composition analysis, studies on leaching of contaminants, or a risk assessment procedure. In the next stage, composition and solubility standards (MPE values) need to be issued. Despite some identified drawbacks and data gaps, the Dutch methodology proved to be the most appropriate with respect to the derivation of substance-specific MPEs.     

Risk-Based Framework for Safety Investment in Construction Organizations

The costs of construction injuries can have a substantial impact on the financial success of construction organizations and increase the overall costs of construction up to 15%. Following the Occupational Safety and Health Act of 1970, construction firms began to implement a variety of management techniques to reduce the frequency of injuries. Although these strategies decrease the cost of injuries, they consume time and other significant resources. Thus, it is imperative for construction organizations to objectively evaluate the cost-benefit of investments in injury prevention through formal and robust processes. This paper presents a risk-based framework that can be used to evaluate the incremental return on investment of a series of investments in highly effective injury prevention strategies. The framework was developed using foundational risk quantification and analysis techniques and is illustrated using a hypothetical case study that is based on archival data published by United States government agencies. The conclusion of this study is that the optimal investment strategy can be identified through a formal analysis and that optimization depends on the frequency and cost of injuries, the sequence in which the specific injury prevention techniques are implemented, the risk mitigated by each strategy, and the organization’s attitude toward acceptable risk.     

Use of Residential Construction Waste and Residues from Red Ceramic Industry in Alternative Mortars

The use of residential construction wastes and residues from the red ceramic industry in alternative mortars was studied. Specifically, the influence of the surface area of these residues, determined by the Blaine method, and the mechanical behavior of those mortars were investigated. The materials are two hydrated limes and four pozzolanas (a red ceramic residue from bricks and tiles, two residential construction wastes, and one artificial pozzolana). These materials were characterized using studies of chemical composition, thermal differential analysis, and x-ray diffraction. The wastes were ground to obtain a distribution of surface areas and pozzolanic activities (determined by consumption of lime). Alternative mortars were prepared in the ratio of 1:3 by weight (cement/aggregate). For lime pozzolana cement, compositions of 30–70, 40–60, and 50–50% of lime and pozzolana were used. The specimens were cured for periods of 7, 28, and 60 days and the unconfined compression strength (UCS) was determined. The results showed high recycling viability of solid residues and a significant increase in UCS of the mortars with increasing surface area of the residue samples.     

Developing a Resource Supply Chain Planning System for Construction Projects

The high variability of construction environments results in high construction-cost variation, especially in material costs. Inadequate planning may cause material shortages that delay the project schedule or, alternatively, a substantial increase in inventory costs by producing or supplying materials earlier than they are needed at the construction site. In order to solve these problems, this paper studies steel rebar production and supply operations and establishes an optimal model that minimizes the integrated inventory cost of the supply chain. Based on the optimal model, this paper develops a decision-support system to generate a production and supply plan for a supplier and buyers of steel rebar. After utilizing the decision-support system to create the supply and production plan, this paper analyzes the results to study the influence of transaction constraints on inventory cost. This paper also discusses cases of global optimization of the inventory cost for the entire supply chain and compares them with cases of local optimization for individual members.     

Tracking the Location of Materials on Construction Job Sites

Automated tracking of materials on construction projects has the potential to both improve project performance and enable effortless derivation of project performance indicators. This paper presents an approach by which materials tagged with radio frequency identification (RFID) tags can be automatically identified and tracked on construction sites, without adding to regular site operations. Essentially, this approach leverages automatic reading of tagged materials by field supervisors or materials handling equipment that are equipped with a RFID reader and a global positioning system receiver. To assess the technical feasibility of this approach, a mathematical model has been formulated such that the job site is represented as a grid and the location of materials within the grid is determined by combining proximity reads from a discrete range. Field experiments were conducted using an off-the-shelf RFID technology, and several metrics were developed to quantify the field performance and compare it with the theoretical positional accuracy derived from the discrete formulation.     

Multi-Agent Framework for General-Purpose Situational Simulations in the Construction Management Domain

The need for contextually rich education environments in construction management suggests the development of a general-purpose situational simulation framework that can be used by independent developers to build effective training environments. Design and implementation of such a framework involves an understanding of the reasoning processes underlying the construction management domain. These reasoning processes can be isolated using a conceptual classification of problems in the construction management domain into constraint satisfaction and planning. Such a classification allows us to distribute the different reasoning processes to autonomous agents that comprise the foundations of a multi-agent framework for building general-purpose situational simulations. The Virtual Coach is an implementation of the proposed framework. Experimental results from preliminary studies have shown the efficacy of the Virtual Coach as an educational tool.     

Contributors to Construction Debris from Electrical and Mechanical Work in Hong Kong Infrastructure Projects

The crucial problem of construction debris is of increasing concern in Hong Kong. In the construction industry, the electrical and mechanical (E&M) installations in the infrastructure, for example, buildings, tunnels, or dams, are some of the major and usually complex components. Difficulty in coordinating the various trades affects productivity in general, and has a major impact on the quantity of construction debris. By identifying the sources of waste at each stage of E&M engineering work, some of the construction debris can be eliminated at the source during production. This paper investigates the critical production shortcomings in the E&M sector in Hong Kong. The study is based on a survey that includes a preliminary questionnaire survey, brainstorming exercises with a focus group, structured interviews with experienced frontline supervisors, and a second focus group exercise to test findings and proposed measures. The principal findings are that “poor coordination” and “design changes and/or errors” are major contributors to variations or change orders and rework, which in turn result in a high volume of construction debris. The results also indicate that construction debris can be minimized in the E&M sector of the construction industry, if the material wastes from incidental work are reduced and also controlled better in a new work process flow pattern through recommended construction project management improvements for reducing critical production shortcomings.     

Component-Based Framework for Implementing Integrated Architectural/Engineering/Construction Project Systems

Current practices and integration trends in the architectural/engineering/construction (A/E/C) industry are increasing the demands for the implementation and deployment of integrated project systems. Much of the research throughout the last decade was driven by the need to develop integrated project systems and standard industry-wide data models to support their development. This paper presents a multitier component-based framework that aims to facilitate the implementation of modular and distributed integrated project systems that would support multidisciplinary project processes throughout the project life cycle. The framework addresses the specific requirements of A/E/C projects, and highlights the required functionality and approach to develop integrated project systems. The framework defines a three-tier architecture: Applications tier, common domain-services tier, and project data-repository tier. The applications tier includes a set of function-specific software tools that interact with the domain-services-tier components via a set of adapters. Adapters map the applications’ internal proprietary-data models to and from a standard integrated data model. The domain-services-tier components implement a number of generic services, such as data management, transactions management, document management, and workflow management. The data-repository tier represents a centralized shared storage of all relevant project information. The paper also discusses the implementation of a prototype software system that demonstrates the use of the framework’s reusable components and the industry foundation classes data model in typical building projects.     

Parallel Computing Framework for Optimizing Construction Planning in Large-Scale Projects

Available construction optimization models can be used to generate optimal tradeoffs between construction time and cost, however their application in optimizing large-scale projects is limited due to their extensive and impractical computational time requirements. This paper presents the development of a parallel computing framework in order to circumvent this limitation. The framework incorporates a multi-objective genetic algorithm module that identifies optimal trade-offs between construction time and cost; and a parallel computing module that distributes genetic algorithm computations over a network of processors. The performance of the framework is evaluated using 150 experiments that represent various combinations of project sizes and numbers of processors. The results of this analysis illustrate the robust capabilities of the developed parallel computing framework in terms of its efficiency in reducing the computational time requirements for large-scale construction optimization problems, and its effectiveness in obtaining high quality solutions identical to those generated by a single processor.     

Framework for Providing Customized Data Representations for Effective and Efficient Interaction with Mobile Computing Solutions on Construction Sites

Conceptual representations of information contained in product and process models are often difficult to use for accessing data when performing engineering tasks. This is especially true if project-management information contained in product and process models needs to be made accessible on a mobile computer on construction sites. To make this information accessible, customized conceptual and visual information representations are needed. For the project-management tasks of progress monitoring and creating and administering punch lists, existing approaches that provide access to relevant project information are ineffective and inefficient in transforming information from product and process models into usable representations. As a result, these applications do not always provide information representations that are of the required structure, granularity, and type. In this paper, we describe a navigational model framework, which is an approach that effectively and efficiently creates and manages different views of information contained in product and process models. We validated this framework by implementing a prototype system and testing it through a designed set of experiments. The use cases for these experiments were established in an extensive study on the information and data collection needs on construction sites.     

Identifying and Assessing Influence Factors on Improving Waste Management Performance for Building Construction Projects

Environmental sustainability has become one of the key drivers for continuous growth in the construction industry. Many project practitioners face challenging circumstances in finding an effective way to prevent pollution and minimize wastes by making the best use of the increasingly scarce natural resources. However, most of these efforts are focused on planning and/or design strategies; therefore, they fail to thoroughly cover the environmental issues based on the construction execution level. Further, there is a lack of quantitative measurement system and management-level guidance. To overcome these limitations, this paper proposes a new methodology that assists project managers to assess the performance level of a project in terms of waste management practice. This study is based on a two-pronged approach. One is the identification of the waste management influence factors that play an important role in decreasing waste and increasing recycled materials on construction sites. The other is the development of an assessment tool to measure the level of waste management performance for a particular project. As a result of this work, 59 factors were identified and an assessment tool was developed based on quantification of these factors. The tool has been proved to effectively measure waste management performance throughout four real-case validity tests. From the industry perspective, this paper contributes to establishing the environmentally sustainable production systems by providing the project stakeholders with an established set of influence factors and with a diagnosis tool for measuring their current performance. Additionally, project owners can use the output of the tool, especially the total index score, as a measure to benchmark the level of waste management for continuous improvement.     

Leachate from Land Disposed Residential Construction Waste

Solid waste from construction and demolition (C&D) activities is often disposed in unlined landfills. Leachate from unlined landfills poses a potential risk to groundwater quality. An understanding of the types of chemical constituents likely to be encountered in C&D waste landfill leachate and the concentrations at which they occur help assess this risk. An experiment was performed to characterize leachate from land-disposed residential construction waste. Four 54 m2 (580 ft2) test cells were excavated, lined, and filled with waste. Leachate samples were collected and analyzed for a number of water quality parameters over a 6 month period. No volatile or semivolatile organic compounds were detected at elevated constituent levels in the leachate. Inorganic ions were found to account for the bulk of the pollutant mass leached. Calcium and sulfate were the predominant ions in the leachate, resulting from the dissolution of gypsum drywall. The concentrations of several leachate constituents were found to exceed water quality standards. These constituents included aluminum, arsenic, copper, manganese, iron, sulfate, and total dissolved solids. Arsenic was the only primary water quality standard exceeded. The arsenic was concluded to result from chromated copper arsenate (CCA)-treated wood. The potential risk of impacting groundwater was examined by comparing the measured constituent concentrations with the water quality standards to assess the amount of dilution and attenuation needed in the groundwater so that a water quality standard would not be exceeded. The water quality standard exceeded by the greatest magnitude was manganese, followed by iron.     

Cost-Benefit Analysis of Embedded Sensor System for Construction Materials Tracking

Tracking and monitoring the location of materials on a construction job site is an important, yet commonly overlooked aspect of field data acquisition because timely information about the status of materials, equipment, tools, and labor resources are directly related to the successful completion of a project. With the advanced technologies and innovations in the construction industry, it has become technically viable to implement automated tracking for construction materials. Through the development of an embedded sensor system, this paper illustrates the implementation of pilot experiments examining the accuracy of a system’s performance. A cost-benefit analysis is conducted to illustrate labor savings associated with construction materials handling by comparison between manual and sensor-based materials tracking. The presented embedded sensor system can be extended into diverse application areas in tracking and monitoring framework by providing improved method of field data acquisition and information management.     

PDM++: Planning Framework from a Construction Requirements Perspective

Construction requirements represent the key preconditions for construction. These include topological precedence, key resources, space requirements, etc. Consequently, identifying them is necessary for feasible construction planning to be achieved. Despite this, little attention has been given to the impact of construction requirements on a project schedule, possibly because of the lack of a good tool for representing these requirements. This paper distinguishes construction requirements into static and dynamic types, according to changes in the need of the requirement during its life cycle. A modeling framework, PDM++, is then proposed. The framework deals with schedule constraints arising from both static and dynamic construction requirements, provides greater semantic expression to capture schedule constraints unambiguously, and facilitates the representation of interdependent conditional relationships. The concept of meta-intervals is also devised to represent complex requirements involving several activities and schedule constraints, and it facilitates modeling at higher levels of plan abstractions. Finally, an illustrative case study is presented to show the applicability of PDM++ in representing schedule constraints and alternative scheduling from a construction requirements perspective.     

Empiricist Framework for TQM Implementation in Construction Companies

As a management philosophy, total quality management (TQM) is implemented differently in firms. This study investigates the implementation level and the types of TQM practices adopted in construction companies. Eight elements had been identified from both organizational-/management- and construction-related studies to represent the TQM spirit. These elements are top management leadership, customer management, people management, supplier management, quality information management, process management, organizational learning, and continual improvement. A questionnaire survey was conducted to solicit the implementation level of the identified TQM elements. The survey findings indicate that customer, process management, and top management leadership were implemented at a higher level than the remaining elements with quality information management implemented at the lowest level. Important practices that constitute each element were also identified. Based on the findings, we propose a TQM implementation framework for construction companies.