A study on industrial-scale waste utilization in construction material production: the use of fly ash in GRP composite pipe

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.