Influence of Recycled Aggregate Composites on the Factor of Safety of Earthen Structures

In this study, six composite reinforcements such as cement composite made of Abandoned Cell Husks (ASH), Stones, Wood chips, Concrete and Bricks have been used along with control specimen. It is known that the material used in earth reinforcement applications must be safe against tension failure and adhesion failure for its effective utilization in the field and reliable design of earth structures. Single type of material can provide limited reinforcement capability in reinforced earth structures due to its low frictional resistance and poor cohesion. For an optimal response, therefore, composite reinforcement, that fulfils both the requirements such as possess adequate tensile strength and adequate frictional resistance, is getting considerable attention. Slope stability analyses containing six types of reinforcement have been performed. Stability of the slope has been quantified using minimum factor of safety corresponding to critical slip surface. It was observed that the composite reinforcement whose surface treated by brick aggregate enhanced the factor of safety significantly. The paper also depicted the design aids of reinforced slope in terms of embedding lengths and spacing of reinforcements.

Interaction Properties of Geosynthetic with Different Backfill Soils

Characterization of a geosynthetic is necessary for its effective use in various field application of reinforced soil structure. In this paper, a new type of geosynthetic has been evaluated for its interaction properties for different backfill soils using direct shear device. The test results are compared based on the type of soils, inclusions, and interface mechanical properties. Three backfills soils (sandy, clayey, and pure sand) in combination with four different geosynthetics (one geotextile and three geogrids) were tested at various loading conditions in direct shear. Test results reveal that the stress-deformation behaviour of the geotextile and geogrid interfaces with sandy and clayey backfills can be defined as hyperbolic. For the pure sand-geogrid interfaces, the relationship is followed by displacement hardening and softening behaviour. The dilatancy behaviour of a particular soil-geosynthetic interface is found similar at all normal stresses. Both contractive and dilative nature is observed for the interfaces with pure sand. On the contrary, only negative dilatancy or contractive behaviour is observed for sandy and clayey backfills with the same geosynthetics. The test results reveal that the relationship of the interface shear strength with the normal stress is not linear in most cases. Based on the test results, a simplified nonlinear equation is proposed for the soil-geosynthetic interface shear strength envelops which was in good agreement with the experimental data.

Waste Shell Husks Concrete: Durability, Permeability and Mechanical Properties

Shell husk is annually produced as a byproduct of shell production in Japan. According to Japanese Ministry of Forestry, Fisheries and Agriculture, the amount of the abandoned shell husk is about 151,000 tons per year. This huge amount of abandoned shell husk is not only thrown away without any commercial return but also causing pollution and environmental problems. To mitigate the pollution and environmental problems, possible utilization of abandoned shell husk is thoroughly observed in concrete construction. Overall response of the mechanical properties of concrete specimens containing different percentage of abandoned shell husk aggregates such as 0, 10%, 0, 30%, 40% and 50% in the ratio of mass is demonstrated. Results of engineering properties such as compressive strength,Young’s modulus, tensile strength, unit weight, water absorption capacity and coefficient of hydraulic conductivity are depicted. It is observed that the use of shell husk in concrete improves strength and durability performance of concrete treated in aggressive sea environments.