A study on mechanical behavior of structural composites reinforced with wheat straw fibers and their use as building materials

The purpose of this feasibility study was to examine the experimental behavior, environmental performance of oriented straw cable composites, and begin to develop a model of the composite. The material is made of wheat straws bound in cables of 50.8 mm (2 in.) diameter which were then used to reinforce a low strength cementititous matrix.; Several different components of the material were tested in a series of compression, tension, and bending tests. Tension test were performed on individual wheat straws and straw cables. Behavior of the straw cables, cable bundles, and oriented straw composite short columns were examined in compression. Larger scale experiments were conducted for oriented straw cable beams; they were tested in four point bending tests. Parameters such as length and straw type were examined in these tests. Comparing the compression tests performed on these low strength cementitious matrix samples with oriented straw cable reinforced cementitious matrices it was shown that the load carrying capacity was increased by more than 200%. A total of 65 different specimens were tested and the number of specimens was limited by the delivery of the production company.; A finite element modeling program ABAQUS was used to conduct finite element analysis (FEA) of the wheat straw and straw cables in tension and compression. The material properties for the model were obtained from both measured properties and literature sources available. The results obtained from experiments were in good agreement with the finite element models.; The environmental impacts of production and construction of the material was investigated by means of life cycle assessment (LCA) technique. A simple wall system was selected as the unit for the analysis and the life cycle impact assessment results were compared with a timber wall system. The comparisons showed production, construction, and disposal of an oriented straw cable composite wall system had larger environmental impact scores than a system constructed with timber in most of the impact categories mostly due to the cementitious matrix component of the composite.; The feasibility study showed that the material can be a good candidate for structural construction. The composite can offer an inexpensive, locally available, and environmentally friendly construction material that can be used in regions where these criteria are critical for housing needs.