## 1 Introduction
Figure 1: The increasing trend among researchers of studying the impact of using agricultural wastes in construction (data obtained from Web of Science using the following keywords: agricultural waste AND concrete AND cement). different uses of agricultural waste materials, including applications such as their use as organic fertilizer or animal bedding in areas where animal husbandry is more common, or their use as a source of energy. In addition, some developing applications include producing biochar, biochemical, and pharmaceutical materials with a focus on extracts from certain agro-waste materials for pharmaceutical applications. Recently, the focus on the use of disposable agricultural materials for water treatment has also been considered. The competition between the superiority of each of these applications is based on the volume of available materials and the added value that they bring. Firstly, many researchers have focused on developing the strength of oil palm shells, and lately, the compressive strength of these lightweight shells as concrete aggregate was developed to be greater than 40 MPa [7]. As a next step, some researchers explored the application of oil palm shells as aggregate in concrete for structural objectives to analyze the bending and shear stress-induced behaviors of reinforced concrete (RC) beams when using the shells and concrete slabs, as well as conducting structural analyses of palm oil clinker and coconut shells as aggregate in concrete regarding the flexural and shear behavior of RC beams [8; 9; 10; 11; 12]. Agricultural waste materials have also attracted a lot of attention as useful building materials to produce insulation materials from a thermal and acoustic point of view [13; 14]. For this aim, several different agro-wastes have been evaluated as raw resources to build lightweight panels, bricks, blocks, etc. [15; 16; 17]. For this purpose, waste agricultural materials must be pretreated or processed: for instance, making composite board materials using compression molding, hot pressing, or extrusion techniques; extracting cellulose from agricultural residue and processing it with insulating foam and pretreatment using additives; removing impurities from rice husk ash; weaving coconut fibers into mats or blankets for insulation; etc. This review presents a response to the following question: what are the very recent advances in the application of agricultural wastes in construction, and how do these innovations contribute to sustainable and environmentally friendly building construction? Therefore, this review focuses on providing a general idea to analyze the application and the performance of different materials used in concrete as aggregate and as supplementary materials for cement, as well as in building insulation. The findings reported by recently published studies (over almost five years) are summarized and evaluated in this review. The next important objective of this review is to provide useful information among researchers and engineers to generate interest for using waste agro-materials in lightweight construction, as well as for protecting the environment from the current concerns. This research contributes to the growing body of knowledge on sustainable construction practices and underscores the importance of exploring alternative materials to address environmental concerns on a global scale.