Plant fibers (especially, wheat straw) are available surplus to requirements in sub-tropical regions. Many researchers have studied these fibers for non-structural applications. However, for civil engineering structural applications, in depth behavior of wheat straw reinforced concrete (WSRC) with steel rebars is not known. For this purpose, WSRC needs to be explored in detail for load bearing structures. This paper presents the contribution of plant fibers (i.e. wheat straw) in improving the behavior and capacity of reinforced concrete for structural applications. Reinforced concrete beam-lets with varying flexure and shear rebars, without and with inclusion of wheat straw, are experimentally investigated for studying the altered behavior due to fibers. In addition, to start with the practical implications, concrete pavements are considered. The study is concluded with an increase in flexural strength (up to 7.5%), energy absorption (up to 30.4%), and toughness indices (up to 11.1%) along with better crack arresting mechanism by incorporation of wheat straw in reinforced concrete. Also, concrete pavement containing wheat straw has comparable design with likely more durable and sustainable structure.
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Introduction

Concrete is a most widely used construction material all over the world. It is basically very strong in compression however it is brittle in nature. Brittleness of concrete results in low strain capacity in tension and thus ultimately have low toughness. Many researchers have been working on increasing the toughness of concrete with the addition of dispersed fibres. So, it has been long recognized as a solution for enhancing the energy absorption capacity, toughness and crack resistance or crack arresting [1–۵]. This technique had been used since biblical times for strengthening the brittle matrices. The development of cracks and increase in width of already developed cracks can be prevented using dispersed fibres as crack arresters [6,7]. Biryukovichs used glass as dispersed fibre for the reinforcement of cement paste and mortar in early 1900 [8]. The application of dispersed fibres in the concrete as a building material for different purposes resulted in improved properties [9]. However, the incorporation of fibres in steel reinforced concrete has also been studied by various researchers [7,10–۱۴]. Shear behavior of fibre reinforced concrete (FRC) beams was studied by [11]. Polypropylene fibres with 0.5% and steel fibres with 0.5%, 1%, and 2% content, by volume of wet concrete, were used. The compressive strength and tensile strength were increased up to 54.8 MPa and 4.3 MPa, respectively. High strength fibre reinforced concrete beams with steel rebars were also studied by [13]. The steel ratio used were 0.0017, 0.0064, 0.0075, 0.012, 0.015, and 0.022 for tensile reinforcement. And for compression reinforcement, 0.0045 and 0.0047 steel ratios were used. The percentages content for the steel fibres used were 0.5%, 1%, and 2%, by volume of wet concrete. The study resulted in significant increase of flexural strength. The above-mentioned studies concluded that the fibre reinforced concrete with steel bars showed improved results in crack and deflection resistivity, toughness, and energy absorption.