The Behaviour of Recycled PET Fibres in Cementitious Concrete: A Review

Abstract

Polyethylene Terephthalate (PET) is a commonly used polymer in packaging, food, and beverage containers, and also in the textile industry. Due to the environmental benefits and higher product quality, recycled PET (rPET) is preferred over virgin PET plastic. Moreover, the fibres obtained from rPET have enhanced mechanical properties of concrete such as tensile and flexural strength, and reduced cracking. However, one of the major concerns in using rPET in concrete is the degradation of the fibres due to the high alkalinity of the cement matrix itself. As to alleviate this problem, partial replacement of cement using pozzolans is practiced. Due to the lesser generation of portlandite and hydration products, the degradation of the fibres can be reduced. Nevertheless, the degradation of the rPET fibres depends on the type and the amount of pozzolan used as well together on other factors such as the curing conditions, and the exposure environments. This review paper aims to investigate the degradation of these rPET fibres in Portland cementitious concrete as well as the effect of using pozzolan-blended cement on fibre degradation. The paper encompasses an up-to-date critical evaluation of the so far conducted research works and additional future research requirements in this field. The overall conclusion that can be drawn is related to the fact that, despite the degradation of the added rPET fibres, in most applications properties of the cementitious composites can be enhanced by following proper degradation control measures.