No abstract

In this study, hybrid matrix mixtures with different matrix phase resin types were prepared and 5%, 10% and 20% chopped E type glass fibers were added to these mixtures. The orthophthalic, isophthalic and terephthalic polyester resins were each mixed with each other and epoxy-based vinyl ester resin in different combinations as double and triple hybrid matrix mixtures. The tensile properties of the composites produced were determined. As a result of the study, as the fiber ratio increased, the hybrid matrix composites were seen to turn into a more rigid structure and the highest tensile mechanical properties were obtained in the blends containing 20% fiber and vinyl ester resin. It was determined that orthophthalic + vinyl ester (OV) mixture has the highest rigidity in all mixtures prepared with two types of hybrid resin matrix. When the tensile properties of the composites with two types and three types of hybrid resin matrix were compared with each other, it was seen that there were no significant differences.

It was aimed to produce glass fiber reinforced pipes (GRP), having less resin consumption and higher mechanical properties by changing the grain distribution of fillers used in the core region. American Foundry Society (AFS) grain fineness number currently used in GRP pipe production, and the grain distribution determined to the Fuller equation, the exponent of which is 0.8 (F 0.8), were used in the study. Chopped glass fibers, unsaturated polyester resin, and silica filler were used. It was manufactured three GRP pipes having 6 m length and nominal diameter (DN) of 350 mm by centrifugal casting technique. Initial specific ring stiffness and longitudinal tensile strength (LTS) tests were conducted on GRP pipes. After the longitudinal tensile tests of the produced GRP pipes, SEM images were taken from the core region and the morphological analyzes of the images were made. As a result of the study, when GRP pipes are produced incorporating 14 % less body resin in F 0.8 grain distribution, 44.11 % higher stiffness and 50.4 % higher LTS was obtained than the minimum value required in the standard.

This study presents a new approach to the utilization of industrial by-products in construction materials by using fly ash (FA) in the production of glass fiber-reinforced polyester (GRP) pipe. The FA was substituted by 10% and 20% (by weight of sand) in the mixtures to produce GRP pipes of 350 mm in diameter and 6 m in length for testing. Stiffness modulus (SM), axial tensile strength (ATS), and hoop tensile strength (HTS) tests were conducted on the produced GRP pipes and their elasticity modulus (EM) values were also calculated. To observe the microstructure of the GRP pipes and the interfacial transition zone of the layers, SEM and microscopic analyses were performed. Furthermore, a strain-corrosion test was conducted to obtain information about long term-performance of samples. The results showed that the FA-filled GRP pipes were found to meet the requirements of the related standards, and that the use of FA in the GRP pipe industry may be an important alternative approach to the utilization of industrial wastes via effective recycling mechanisms.