Erosion Control Treatment Using Geocell and Wheat Straw for Slope Protection

Slope failure triggered by soil erosion under rainfall remains one of the most difficult problems in geotechnical engineering. Slope protection with planting vegetation can be used to reinforce the soil and stabilize the slope, but the early collapse of the planting soil before the complete growth of plants becomes a major issue for this method. This paper has proposed a composite soil treatment and slope protection method using the geocell structures and the wheat straw reinforcement. The geocell structures improve the stability of the planting soil and provide a stable and fixed environment for the vegetation, while the wheat straw reinforces the soil and also increases the fertility. The authors have performed a total of 9 experiments in this work that are classified into three groups, i.e., the unsupported slopes, the geocell reinforced, and the geocell and wheat straw composite reinforced with a consideration of three different rainfall intensities. The progressive slope failure development during the rainfall was assessed, as well as the soil erosion, the slope displacement, and the water content. The results show that the slope failure increases as the rainfall continues, and the soil degradation increases with the intensity of rainfall. The soil treatment using geocell improves the slope stability, but the geocell and wheat straw composite reinforcement has the best erosion control and slope protection.

Prediction of the Elastic Properties of the Clay-Rice Straw Composite by Numerical Homogenization Technique using Digimat

This paper deals with numerical modelling of the elastic properties of the rice straw-clay composite. This composite material is currently attracting interest because of its low impact on the environment but also for economic reasons. Benefiting from the advantages of a promising building material, straw reinforced composites attract more attention. This work allowed to model the effect of the straw inclusions on the elastic properties of the composite by a numerical approach considering the aspect ratio, the volume fraction, the orientation and the distribution of the straw inclusions. The Mori-Tanaka homogenization scheme for the RVEs is done using Digimat-MF software and the 3D composite microstructure models are generated by the Digimat-FE software. This made it possible to calculate the effective elastic properties of the clay-rice straw composites by numerical simulation. An empirical linear correlation between the volume fraction of the inclusions and the Young's modulus has been proposed. The results obtained can help to better control the formulation of the composite in developing countries.

Preparation of insulating material based on rice straw and inexpensive polymers for different roofs

Fossil fuel saving is part of the 21th century goal. One of the largest sectors that consumes energy is the building sector since it consumes 40% of the total energy in Europe through heating and cooling. Thus, the need of minimizing the energy consumption played an important role in the development of building insulation materials. Selection of a proper material for building insulation differs according to the building surrounding climate and the properties required in the material. Building climate determines the insulating material location whether its internal or external while properties can differ according to many parameters that affect the material quality such as thermal insulation, acoustic insulation, waterproofing, resistance to fire and mechanical properties. Another factor is newly considered which doesn’t affect the product quality but has an influence in the energy consumption is the environmental impact. The aim of the research is considering most of the above factors through making a composite of rice straw particles bounded by a polymer to produce roof insulations. The utilization of wastes such as rice straw to produce a high quality product with the least price is the research main objective. The polymers selected for research are the unsaturated polyester resin and the polyurethane foam polymers. The polyester is not recently applied for insulation on comparison with the polyurethane foam which is dominant through the global market. At the end of the research, satisfying results have been achieved to nominate the 80% polyurethane foam and 20% rice straw composite as the best sample among all of the prepared samples. The other samples include polyester and rice straw composite with different compositions. The foam and straw sample have the best insulation with value of 0.1627 W/m oC. The compression strength has also been improved on addition of rice straw to the polyurethane foam by three times the initial value. Also, the density measurement revealed a very light composite which is suitable for the construction field requirements. This results in reducing the cost by 28.35%. On contrast, polyester samples which have very high density and higher K factor are not so efficient, so it is suggested that they can be applied at rural regions due to their low cost.