Karim S. Rebeiz

PLASTIC WASTE MANAGEMENT IN CONSTRUCTION: TECHNOLOGICAL AND INSTITUTIONAL ISSUES

Abstract The main objective of a solid waste management system is to effectively safeguard the public health, safety, and welfare. The various options involved in a waste management process are landfilling, incineration, and recycling wastes into useful products. Plastics recycling, in particular, would not be successful unless the proper infrastructure to collect the waste is being set, the technology to economically reprocess the waste into new products is available, and the establishment of markets for the cost-effective use of recycled products are developed. The development of new construction materials using recycled plastics is important to both the construction and the plastics recycling industries. Extensive research investigated the use of resins based on recycled poly (ethylene terephthalate) (PET) plastic waste for the production of a high performance composite material, namely polyester concrete (PC). Resins using recycled PET offer the possibility of a lower source cost of materials for forming good quality PC. PC products also allow the long-term disposal of PET waste, an important advantage in recycling applications.

Flexural strength of reinforced polymer concrete made with recycled plastic waste

Investigators evaluated the flexural behavior and strength prediction of steel-reinforced polymer concrete (PC) using unsaturated polyester resins based on recycled polyethylene terephthalate (PET) plastic waste. Most beams were singly reinforced with steel bars in the tensile zone. Some beams used double reinforcement with steel bars in the tensile and compression zones. Test results revealed that very good flexural strength can be obtained with reinforced PC using unsaturated polyester resins based on recycled PET. Researchers first investigated prediction of the ultimate flexural strength of steel-reinforced PC beams by using the traditional American Concrete Institute (ACI) approach developed specifically for steel-reinforced portland cement concrete. The findings of this analysis revealed that the ACI method produces conservative results when applied to reinforced PC. An alternative method of predicting the ultimate flexural strength of PC is introduced using multiple regression analysis on the experimental data.

Public–Private Partnership Risk Factors in Emerging Countries: BOOT Illustrative Case Study

AbstractA public–private partnership (PPP) is an agreement between a host government and a private entity in which the private sector supplies infrastructure assets and services that are traditionally provided by the government. The popularity of PPP projects has been steadily on the rise over the past few years. This upward trend is in large part driven by governmental fiscal austerity, particularly in the aftermath of a prolonged global economic recession. The perceived attractiveness of PPP projects is particularly acute in emerging countries because of population growth and increased urbanization. PPP projects are usually highly complex in nature. They require large capital expenditure, they have long durations, and they usually utilize sophisticated technology. For a construction firm willing to expand its services internationally, a PPP project represents a unique opportunity to leverage its core competency and achieve competitive advantage in both domestic and foreign markets. Risk, however, increa...

Mechanical Properties of Polymer Concrete Systems Made With Recycled Plastic

The mechanical properties of various polymer concrete (PC) systems using unsaturated polyester resins based on recycled polyethylene terephthalate (PET) plastic waste were evaluated. Resins using recycled PET offer the possibility of a lower source cost of materials for making useful PC products. Also, the recycling of PET in PC would help solve some of the solid waste problems posed by plastics and save energy.

POLYMER MORTAR COMPOSITES MADE WITH RECYCLED PLASTICS

Polymer mortar (PM) is a composite material formed from a resin binder and fine inorganic aggregates, such as sand or fly ash. The resulting product is a strong, durable material typically used as a protective coating in various portland cement concrete structures. This paper describes the important properties and behavior of PM materials made with unsaturated polyester resins based on recycled poly(ethylene terephthalate) (PET), a plastic waste, and reports on the advantages of PM in structural use.

Boardroom’s independence and corporate performance: the ever-elusive conundrum

Purpose – The purpose of this paper is to unravel the root causes as to why the boardroom independence–corporate performance linkage remains an elusive conundrum in the academic literature, and to propose practical recommendations for future research endeavors. Design/methodology/approach – The probing of the underlying issues is made via an extensive review of the existing literature. A thoughtful analysis is conducted from a multi-disciplinary perspective by soliciting feedback from academics with corporate governance expertise in finance, accounting, economy, strategy, management and organizational behavior. Findings – The lack of consensus on the economic value of an independent boardroom is attributed to three reasons. The first reason is ontological complexities inherent to the very nature of the corporation. The second reason is methodological complexities intrinsic to normative research with large archival data. The third reason is self-serving behavioral motive that cannot be factored in archival...

Flexural Properties of Reinforced Polyester Concrete Made with Recycled PET

The flexural strength of steel-reinforced polymer concrete (PC) beams us ing unsaturated polyester resins based on recycled poly(ethylene terephthalate), PET, is reported in this paper. Investigation included mode of failure, moment-curvature response, variation of neutral axis depth with moments and the effect of tensile and compression steel reinforcement on the strength and ductility of the beams. This evaluation is not only important from the standpoint that resins based on recycled PET were used, but also because very few investigations have been done in this area with steel-reinforced PC using virgin resins.

SHEAR BEHAVIOR OF STEEL REINFORCED POLYMER CONCRETE USING RECYCLED PLASTIC

The shear behavior of steel reinforced polymer concrete using resins based on recycled polyethylene terephthalate (PET) plastic waste was analyzed. Testing was done on 25 beams that were reinforced in tension with longitudinal steel bars. Steel fibers were also used in some of the beams. Analyses included modes of failure and the effects of the shear span-to-depth ratio, reinforcement ratio, compressive and flexural strength, and steel fibers on the shear strength of the beams.

Recommended Design Procedure in Shear for Steel-Reinforced Polymer Concrete

The conventional ACI-ASCE design approach to shear developed for reinforced portland cement concrete does not yield very good results when applied to reinforced polymer concrete (PC). A new procedure that combines the techniques of dimensional analysis and statistical regression analysis is therefore recommended for steel-reinforced PC beams without web reinforcement. The PC beams were made using unsaturated polyester resins and were designed in such a way to achieve a wide range of values in the variables affecting the shear strength of reinforced PC. The new procedure gives excellent results for both short beams and long beams.

Strategies for corporate governance in engineering corporations

Although corporate governance plays a crucial role in shaping the vision, image and reputation of a corporation, this subject has been largely ignored in the prevailing engineering and technology management literature. In the wake of scandals like Enron and WorldCom, the call for effective corporate governance echoes across the boardrooms of many corporations. It is the intent of this paper to close the gap between the myth and the reality of US corporate governance effectiveness in engineering companies and to suggest some improvement strategies regarding the modus operandi and optimum structure of this entity. This study would benefit the board of directors of engineering companies that are already in existence or those that are in the process of being formed. It relies on survey results with individuals who, by virtue of their significant experience in the boardroom of engineering corporations, can offer unique insight and provide valuable data to the topic of corporate governance.