Open Access Dissertation
Concrete--Additives; Recycling (Waste, etc);
The problem of disposing and managing solid waste materials in the United Slates and other industrial countries has become one of the major environmental, economical, and social issues. A complete waste management system including source reduction, reuse, recycling, landfilling, and incineration needs to be implemented to control the increasing waste disposal problems. Of the above options, recycling is the most promising waste management process to the disposal of materials in the waste stream. One of the most promising markets to utilize recycled waste materials successfully on an open-loop basis is the construction industry.
The purpose of this research study was to evaluate the possibility of using different granulated solid waste materials (plastics, fiberglass, and glass) from different sources as partial aggregate substitutes to the fine aggregate (sand) in a portland cement concrete mixture to produce new concrete composites. Three different types of concrete composites containing one of these aggregate waste materials were prepared. Four different volume percentages of aggregate substitute (5, 10, 15, and 20%) were utilized for each additive. A control cementitious concrete composite was also prepared as a reference for the new concrete composites. Three different test methods were conducted on these cementitious concrete composites: compression strength test, splitting tensile strength test, and flexure test. Standard ASTM procedures were followed in casting of and testing all the flexural beams and concrete cylinders and the curing of 28-day concrete samples.
Statistical procedures of the data obtained were used to determine any significant differences among the values of the mechanical properties of the tested concrete composites. Graphical representation and analysis of the calculated results were also performed to compare the developed cementitious concrete composites with the control specimens. Furthermore, a scanning electron microscope (SEM) was used to study the relationship between these mechanical properties and the microstructure and interfacial features of the new concrete composites. Optical photographs were also obtained to show the general fracture behaviors of these composites.
The main findings of this investigation revealed that increasing the volume percentage of plastics aggregate substitute to the cementitious concrete composite led, in general, to a slight reduction of the compressive, splitting tensile, and flexural strengths. On the other hand, the stiffness of these plastics-containing concrete composites was almost the same as that of the control one. In case of glass-containing concrete composites, the average values of compressive and splitting tensile strengths of these composites were comparable to those of the control one. On the other hand, the values of the modulus of rupture and elasticity of all the tested glass-containing concrete composites were almost the same as (and in some cases especially at 20% glass aggregate substitute higher than) those of the control one. In case of fiberglass-containing concrete composites, adding more volume percentages of this aggregate substitute to the cementitious concrete composite led to reducing the compressive, splitting tensile, and flexural strengths of the cementitious concrete composite. On the other hand, adding more volume percentage of fiberglass aggregate substitute to the cementitious concrete composite led to an increase in the stiffness of this composite. Based on the present research study, it is believed that the visual analysis technique should be strongly recommended to compare the properties of different types of concrete composites qualitatively. This technique may also be used to predict whether different concrete composites have the same brittle or ductile fracture modes under different loading systems.
Year of Submission
Doctor of Industrial Technology
Department of Industrial Technology
Mohammad F. Fahmy, Advisor
Ahmed ElSawy, Co-Advisor
1 PDF file (xvii, 241 pages)
©1996 Ibrahim Hussein Shehata
Shehata, Ibrahim Hussein, "An investigation on using solid waste materials as aggregate substitute in cementitious concrete composites" (1996). Dissertations and Theses @ UNI. 911.