Taher Abu-Lebdeh

Synthesis and Characterization of Biomodified Rubber Asphalt: Sustainable Waste Management Solution for Scrap Tire and Swine Manure

This paper investigates the feasibility of the application of scrap tire and swine manure to produce a sustainable alternative for bituminous asphalt used in pavement construction. Biobinder is produced from swine manure by using a thermochemical conversion process; biobinder is then blended with crumb rubber and asphalt binder (PG 64-22) to produce biomodified rubber (BMR) asphalt. In addition to offering a renewable alternative for petroleum-based binder, BMR can be a hybrid environmental solution for the management of swine manure and scrap tire. To study the merit of application of BMR in the asphalt industry, this paper compares the rheological properties of BMR with a crumb rubber–modified (CRM) binder commonly being used in the United States. The authors found that BMR has comparable properties with the CRM binder. In addition, the authors found that the introduction of the biobinder to the CRM binder was beneficial in improving the low temperature property of the CRM binder while also reducing the CRM binder’s overall viscosity. In turn, this would allow for lower mixing and compaction temperatures of CRM asphalt while alleviating crumb rubber’s stiffening effect and enhancing the CRM asphalt’s pumpability. A lower mixing and compaction temperature will reduce the greenhouse gas emission during application of the CRM binder in pavement construction.

Bio-Modified Rubber: A Sustainable Alternative for Use in Asphalt Pavements

This paper investigates the feasibility of application of scrap tire and swine manure to produce a sustainable alternative for bituminous asphalt used in pavement construction. Bio-binder is produced from swine manure using thermo-chemical conversion processes. Bio-binder is then blended with crumb rubber and asphalt binder to produce bio-modified rubber (BMR) asphalt. In addition to offering a solution for the management of swine manure and scrap tire, BMR can be a renewable alternative for petroleum-based binder used in pavement construction. To study merit of application of BMR in asphalt industry, this paper compares the rheological properties of BMR with a crumb rubber modified binder (CRM) commonly being used in the U.S. It was found that BMR has comparable properties with CRM. In addition, introduction of bio-binder to CRM asphalt binder found to be beneficial because bio-binder reduces asphalt viscosity allowing for lower mixing and compaction temperature and alleviate crumb rubbers stiffening effect.

Effect of introduction of furfural on asphalt binder ageing characteristics

Asphalt oxidative ageing and excessive hardening are known causes of premature pavement cracking. Asphalt ageing occurs mainly due to the oxidation of certain functional groups in asphalt as well as the loss of the maltene phase disturbing colloidal stability and increasing micellisation concentration. This in turn can cause large non-soluble asphaltene aggregates which are typically suspended in the maltene solution and are stabilised by resin molecules to flocculate. Flocculation can cause the asphalt to become stiffer and more brittle. It should be noted that excessive hardening and brittleness of asphalt caused by oxidation during pavement production and service life increase the susceptibility of asphalt pavements to cracking. Therefore, reducing the extent of asphalt oxidation could increase pavement service life. Therefore, it is imperative to reduce/delay asphalt oxidation in asphalt binder. There have been several studies on delaying asphalt oxidation by introducing modifiers and anti-ageing additives. Furfural, an organic compound derived from a variety of agricultural by-products, has been shown to be a promising modifier for petroleum asphalt binders used in asphalt pavement. Accordingly, this paper investigates the effect of introducing furfural as an antioxidant for asphalt by evaluating the extent of oxidation ageing in asphalt specimens modified by 1%, 2% and 5% furfural. To do so, furfural was introduced to asphalt and the level of change in physiochemical and rheological properties of asphalt after specimens were exposed to short- and long-term ageing was examined. Accordingly, performance characteristics of the base asphalt were compared with those of furfural-modified asphalts using a rotational viscometer, Fourier transform infrared spectroscopy and a dynamic shear rheometer to evaluate the rheological properties of asphalt modified with furfural at different percentages. The study results showed that the addition of furfural helped reduce the extent of oxidative ageing while enhancing high-temperature performance of asphalt binder. Specifically, it was found that the 2% furfural modification had the lowest ageing index after ageing, indicating an improvement in binder oxidative ageing.

The Impact of Project-Based Learning on Improving Student Learning Outcomes of Sustainability Concepts in Transportation Engineering Courses.

ABSTRACT This paper describes an intervention to enhance students’ learning by involving students in brainstorming activities about sustainability concepts and their implications in transportation engineering. The paper discusses the process of incorporating the intervention into a transportation course, as well as the impact of this intervention on students’ learning outcomes. To evaluate and compare students’ learning as a result of the intervention, the Laboratory for Innovative Technology and Engineering Education survey instrument was used. The survey instrument includes five constructs: higher-order cognitive skills, self-efficacy, ease of learning subject matter, teamwork, and communication skills. Pre- and post-intervention surveys of student learning outcomes were conducted to determine the effectiveness of the intervention on enhancing students’ learning outcomes. The results show that the implementation of the intervention significantly improved higher-order cognitive skills, self-efficacy, teamwork, and communication skills. Involving students in brainstorming activities related to sustainability concepts and their implications in transportation proved to be an effective teaching and learning strategy.

Analytical Formulation of the Biaxial Behavior of Concrete Repair Material

An analytical investigation into the behavior of concrete under tension-compression stress states is described. Analytical expressions are developed to predict the ultimate strength envelope as well as the peak stress and the corresponding strain. Analytical stress-strain relations for repaired system under biaxial loading are derived. The proposed analytical expression provides good agreement between the available experimental and analytical stress-strain curves.

Presentation of a Mechanism with a Maltese Cross (Geneva Driver)

The paper presents briefly a mechanism with a cross of Malta. The mechanisms with a Maltese cross (Geneva driver) are present in automation, robotics, mechanical transmissions, continuous variable transmissions, old clocks, especially when it comes to transmitting forces and high moments, being used instead of or with the gears. The geometry of the mechanism consisting of two elements, the kinematics and the forces appearing in this mechanism with a fourth-class upper coupler, are studied very briefly. By studying the forces that appear within the mechanism couple, a dynamic study is also carried out.

Presentation of the Mechanism in the Cross

The cross-machine has frequent uses in mechanical assemblies, automation, robotics and mechanisms with various uses. In the present paper we want to present this type of mechanism with its main, geometric, cinematic, strengths and propose its study in its possible use as an internal combustion engine. In this novelty, the mechanism will have two types of operation, one when operated from the crank (a compressor operation) and another when actuated from the piston (a motor operation). The forces will be presented along with their distribution (how the forces are distributed from one element to the other) in both modes of operation, compressor and engine.

Kinematics of a Mechanism with a Triad

The Assuric Structural Groups are the most well-known classification and modulation used in machine and machine theory, and even though other modular classifications adapted to robots have emerged today, they still remain a reference classification in industrial mechanics and engineering. Diada in the mechanics can be studied similarly to the diode in the electronics, the triad is studied in the theory of machine and robot mechanisms similar to triode (or transistor) study in electronics. Further, the theory of the mechanisms is studying: tetrad, pentad ... but it cannot go further than for a 12th-order structural group because the efficiency of mechanisms using such very large groups is very small and such a mechanism can be blocked in operation. If the similarity between the mechanisms and the electronics is correct up to the 5-6th class, the larger ones are of no use, the advantages of the electronics being that it can also function in the large or very large group with high yields, without blockages, which is why the integrated circuits and electronic chips were born. The present work is intended presenting a triad kinematics general used only with the kinematic couplings rotational (C5), because such approaches are rare in the area, although triad is a structured group Assuric often used. The calculation method presented is an analytical one.

Analytical Study of Reinforced Concrete Beams Strengthened by FRP Bars Subjected to Impact Loading Conditions

Civil engineers have considered Fiber Reinforced Polymer (FRP) materials to enhance the performance of structural members subjected to static and dynamic loading conditions. However, there are some design limitations due to uncertainty in the behavior of such strengthened members. This fact is particularly important when considering the complex nature of the nonlinear behavior of materials, the impact loading conditions and geometry of the members having FRP systems. In this research, a new analytical model is developed to analyze structural members strengthened with FRP systems and subjected to impact loading conditions. ABAQUS based finite element code was used to develop the proposed model. The model was validated against nine beams built and tested with various configurations and loading conditions. Three sets of beams were prepared and tested under quasistatic and impact loadings by applying various impact height and Dynamic Explicit loading conditions. The first set consisted of two beams, where one of the beams was reinforced with steel bars and the other was externally reinforced with GFRP sheet. The second set consisted of six beams, with five of the beams were reinforced with steel bars and one of them wrapped by GFRP sheet. The last set was tested to validate the response of concrete beams reinforced by FRP bar. In addition, beams were reinforced with glass and carbon fiber composite bars tested under Quasi-Static and Impact loading conditions. The impact load was simulated by the concept of a drop of a solid hammer from various heights. The numerical results showed that the developed model can be an effective tool to predict the performance of retrofitted beams under dynamic loading condition. Furthermore, the model showed that FRP retrofitting of RC beams subjected to repetitive impact loads can effectively improve their dynamic performance and can slow the progress of damage.

Geometry and Determining the Positions of a Plan Transporter Manipulator

The conveyor mechanism (working in a plan) to be presented in this study is a classic case of manipulating conveyor, simply with a single degree of mobility. It is a very common mechanism used in classical mechanics, being encountered at lifting platforms, at handicapped chairs, at cranes, forklifts, automatic machines and machines, or at older steam locomotives where it having the role of reversing the rotation-translation movement. Being a simple, common manipulator, he is also a good teaching example, much used in the student courses of mechanics, mechanisms, robotics-mechatronics. That is why we want to present in this study in a concise way the geometry and the kinematics of this mechanism. There will be a constructive and one kinematic scheme. The mechanism consists of a crank (a motor element 1), an RRR dyad composed of elements 2 and 3 and an RRT dyad formed by kinematic elements 4 and 5. The motor element 1 has a complete rotation (360 degrees) being the single driving feature of the entire mechanism. The element 3 is a bar that links the engine element 1 to the rocker element 2. From the rocker element 2, the movement is forwarded through the rod 4 to the final execution member 5, which is a slider (patina), having the role of oscillating linearly (it can also be a piston in a cylinder). The mechanism can also be used by changing the driving element to the driven one so as to become a motor mechanism with the leading element 5 and when the rotation element 1 to become a final driven element. Thus it can be used as a mechanism for producing the movement and transmitting it with the conversion from the rotation to translation movement. We intend to present this mechanism, in the present paper, when it functions as a manipulator, having the motor element 1 and the final element, the execution element, the patina 5. Special emphasis will be placed on the kinematics of the mechanism, studied on elements, but also on structural groups. Obviously there will be presented and some applications of the mechanism.