Investigation of the effectiveness of CFRP strengthening of concrete made with recycled waste PET fine plastic aggregate

Abstract

In recent decades, several studies have considered the use of plastic waste as a partial substitute for aggregate in green concrete. Such concrete has been limited to non-structural applications due to its low strength. This raises whether such concrete can be enhanced for use in some structural applications. This paper reports an attempt to develop a structural-grade concrete containing plastic waste aggregate with high proportions of substitution and confined with carbon fiber reinforced polymer (CFRP) fabrics. Experimental research was conducted involving the casting and testing 54 plain and confined concrete cylinders. A concrete mixture was designed in which the fine aggregate was partially replaced by polyethylene terephthalate (PET) waste plastic at ratios of 0%, 25%, and 50%, and with different w/c ratios of 0.40, 0.45, and 0.55. The results show that confinement has a substantial positive effect on the compressive behavior of PET concrete. The enhancement efficiency increases by 8–190%, with higher enhancement levels for higher substitution ratios. Adding one layer of CFRP fabric raises the ultimate strength of samples that have lost compressive strength to a level close to that of unconfined samples not containing PET. This confinement is accompanied by an increase in the slope of the stress-strain curve and greater axial and lateral strain values at failure. For the specimens confined by CFRP fabric, PET aggregate can be used as a partial substitute for sand at a replacement ratio of up to 50% by volume for structural applications. This paper also considers the ability of existing models to predict the strength of confined-PET concrete circular cross-sections by comparing model predictions with experimental results. The strength of confined PET concrete elements can’t be accurately predicted by any of the models that are already out there. It’s important to come up with a new model for these elements.

Investigation of the physical-mechanical properties and durability of high-strength concrete with recycled PET as a partial replacement for fine aggregates

“…The properties of the PET waste bottles are presented in Table 3. After receiving the PET waste bottles, they were processed as follows: (i) removal of Frontiers in Materials frontiersin.org bottle caps followed by the washing and drying of the bottles, (ii) shredding and grinding of the PET waste bottles using a plastic granulator machine, and (iii) sieving the grinded PET waste bottles to obtain PET aggregate with a maximum aggregate size of 4.75 mm" (Qaidi et al, 2022a). Figure 3 shows the processed PET used as aggregates.…”

“…This management of waste is unfavorable because most wastes are nonbiodegradable and stay in the natural environment for hundreds and thousands of centuries (Rahmani et al, 2013;Barreto et al, 2021;de Azevedo et al, 2021;Room et al, 2021;Fediuk and Ali, 2022;Lesovik et al, 2022). Accordingly, the environmental friendliness of this process decreases" (Qaidi et al, 2022a).…”

Ultra-High-Performance Fiber-Reinforced Concrete: Applications

“…ˑThis ˑreview ˑincludes ˑfive ˑparts. ˑThe ˑpurpose ˑof this report is to summarize previous research and to suggest some needs for future" research [39][40][41][42][43][44][45].…”

The Effects of Eccentric Web Openings on the Compressive Performance of Pultruded GFRP Boxes Wrapped with GFRP and CFRP Sheets

“…Most of the existing studies on the behavior of reinforced concrete (RC) beams with a web opening chose to use the FRP reinforcement for the strengthening of the opening region [ 29 , 30 ]. FRP was found to be effective for strengthening RC members in structures because of its excellent mechanical properties [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. FRP reinforcement schemes can be implemented in different ways.…”