Review of the mechanical and durability properties of natural fibre laminate-strengthened reinforced concrete beams

Abstract

The brittle nature of concrete has always necessitated the need for various forms of reinforcement that will absorb the tensile stress that is responsible for cracking. Conventionally, steel rebar embedded in concrete, giving rise to reinforced concrete structures has turned out to be a composite material that has been most used for infrastructural development around the world. The ductility impacted on concrete by steel rebar has been very efficient, though reinforced concrete structures are prone to durability challenges when exposed to adverse environmental conditions. Most times, repairing deficient concrete structures is more economical and sustainable than total replacement. Various approaches have been successfully implemented around the world in strengthening weakening reinforced concrete structures, nevertheless, bonding of fiber reinforced polymer (FRP) composites to the soffit of weak beams is turning out to be a viable option. Of particular interest is the adoption of naturally occurring fibers for laminates used for beam strengthening. In this era of Sustainable Development Goals (SDGs), in which the world is striving to reduce the effects industrial productions on the environment, advances in adopting renewable materials is highly welcomed. This research reviews the past works on the use of natural fibre-based composites in strengthening deficient reinforced concrete beams. The outcome of this research will go a long way in contributing towards the achievement of the SDGs.

Experimental Investigation on the Strengthening of Reinforced Concrete Beams Using Externally Bonded and Near-Surface Mounted Natural Fibre Reinforced Polymer Composites—A Review

“…To build a laminate that is effective at reinforcing a concrete beam, it is crucial to comprehend the characteristics, strengths, and limitations of the specific fibre functioning as reinforcement [ 41 ]. This knowledge can only be gained by studying the characteristics of natural fibre reinforced polymer laminates.…”

“…Leaves, bark, stems, husks, seeds, and grass are all sources of plant fibres, as are a variety of other plant parts. The skin and fur of many animals are used to make animal fibres [ 41 , 43 ].…”

“…Reinforced concrete members using NFRP laminates were shown to be more resistant to cyclic stress and to fail at greater displacement values than CFRP laminates. NFRP laminate strengthening of concrete has a bright future thanks to the elimination of most of the objections to the external bonding technique using the near surface mounting method (NSM) [ 41 ]. However, durability performance in terms of water penetration, alternate wetting and drying, ultrasonic velocity, temperature resistance, abrasion resistance, and effect of saline environment on concrete members with NFRP is yet to be extensively explored using both strengthening systems.…”