Earth is considered as the cheapest material readily available for construction in rural areas of Asia, South America to Africa. The main reasons for the popularity of adobe can be summarized as follows: (a) local material is available everywhere; (b) a high level of skill and technology is not required for the production of adobe bricks and constructions; (c) repair and maintenance of adobe structures do not require specialized labor; and (d) inherent properties of earth make it an efficient heat and sound insulating material. Despite these numerous merits, adobe houses are prone to damage under seismic vibrations and they are susceptible to water.

In this study, the solutions for seismic performance improvement of new adobe walls have been examined. To improve the performance of walls, two resolutions have been tested to improve properties of the block and mortar. For this purpose, blocks have been enhanced by natural additives (such as palm fiber, rice husk, wood chips and straw) with various percentages 0/3%, 0/6% and 0/9% in weight. The bricks were made in size of 22 × 22 × 7 cm (face × bed × end), and their mechanical properties have been examined. The best reinforced block, by best compressive strength and its durability against water is selected. Natural fibers have been used for a long time in many developing countries in cement composites and earth blocks because of their availability and low cost. However, the use of mud bricks for structural elements of buildings is the subject to an assessment of its mechanical properties, the investigation of which constitutes the aim of this paper.

This study presents an experimental investigation on mud brick wall under axial compression. The average compressive strength of bricks is 4.73 MPa. To determine the performance of straw additives in mortar, mortar used to build walls is considered in two forms: non-reinforced mortar and reinforced with straw fibers and their mechanical properties have been measured. Then six walls in sizes 120 × 22 × 22 cm were made ​​with two different kinds of mortar and bricks (simple wall and reinforced wall). Walls were put under diagonal compressive axial load in order to evaluate type of cracks, ultimate load capacities, deformability, and energy absorption characteristics. Cracks and their depth in samples with reinforced mortar were reduced. The ultimate strength of conventional walls and the walls with reinforced mortar were 16.6 and 22.77 kN that shows an increase of 37% in the ultimate load level. The energy absorbed by the typical walls and reinforced walls were respectively, 268.16 and 573.02 Joules, which shows an increase of 1.14 percent in energy absorption. Final displacement for ordinary walls and reinforced walls were respectively 23.1 and 32.96 mm that shows a final increase of 43 percent. Test results showed that straw additives can be used as reinforcing material in mortar of mud brick walls with better economical and the structural efficiency.