Ductility Evaluation of Damaged Recycled Aggregate Concrete Columns Repaired With Carbon Fiber-Reinforced Polymer and Large Rupture Strain FRP

Abstract

The inherent defects of recycled aggregate concrete (RAC) include the complex interfacial transition zone (ITZ) and the many micro-cracks that appear during its producing process, which result in some inferior mechanical properties compared with natural aggregate concrete (NAC). This drawback usually prevents RAC from being selected for structural purposes. Existing research has shown that the strength and ductility of damaged concrete in compression members can be significantly enhanced through external confinement using fiber-reinforced polymer (FRP) wraps. This application has been widely used in concrete structural repair and retrofitting technology. However, research on the effects of RAC damage coupled with different load damage conditions is rare, as is information on the mechanical properties of RAC reinforced with FRP jackets. This paper presents the results of an experimental study on the behavior of pre-damaged recycled aggregate concrete cylinders that were repaired with carbon fiber-reinforced polymer (CFRP) or large rupture strain (LRS)-FRP jackets. Tests were conducted on 58 concrete cylinders with variations in the replacement ratio, damage levels, and FRP properties. Test results demonstrated that the ultimate strain and strength of damaged recycled aggregate concrete could be significantly enhanced by FRP jackets and that aggregate quality plays a vital role in the strength of confined concrete. Also, the energy absorption of CFRP- and LRS-FRP-confined RAC were evaluated. The analysis indicated that, compared with CFRP-confined RAC, LRS-FRP can greatly improve the energy absorption capacity of RAC; thus, LRS-FRP confined concrete has a good potential to achieve a ductile design for concrete columns, especially when used in seismic reinforcement.

Utilization of response surface methodology in optimization of locally sourced aggregates

“…It is a type of environmentally friendly concrete produced by partly or completely replacing natural aggregates with recycled aggregates made from leftover concrete blocks from construction projects after mechanically squashing, grading and cleaning the aggregates. Notably, the use of RAC allows for the recycling of construction waste, which has significant ecological, economic, and social consequences [20,21] in addition to addressing the environmental issues brought on by building waste dumps. Despite having a lower apparent density than natural aggregate, a higher water absorption rate, and a lower crushing value, recycled aggregates can be combined with natural aggregates to satisfy the criteria for the workability and strength of RAC.…”

Sustainable and Low-Cost Hemp FRP Composite Confinement of B-Waste Concrete

“…A prevalent solution to improve substandard compressive strength of concrete fabricated with recycled brick aggregates can be practiced by wrapping it using different synthetic and natural fiber reinforced polymer (FRP) sheets. Although now-a-days, readily available synthetic FRPs are common in structural strengthening works [17][18][19][20][21][22] and improving structural properties of RAC [23][24][25][26][27][28], their expensive cost is a major concern [29][30][31]. Further, these FRPs are synthesized using chemicals that are capable of imparting skin issues such as irritant and allergic contact dermatitis for concerned personnel [32][33][34].…”

Durability and life prediction analysis of recycled aggregate concrete with ceramic waste powder under freeze-thaw conditions based on impact-echo method and Grey-Markov model

“…Recycled aggregate concrete (RAC) is a kind of eco-friendly concrete manufactured by substituting natural aggregates partially or entirely with recycled aggregates which derived from waste concrete blocks in building waste after mechanical crushing, cleaning, and grading. Notably, the use of RAC not only solves the environmental issues produced by construction waste dumps, but also enables the recycling of construction waste, which has significant ecological, economic, and social relevance (Li et al, 2020;Amadi et al, 2022).…”