Han-Yong Jeon

By Han-Yong Jeon

First, the general concept of nanotechnology formulations used to manufacture geotextiles (GT) is introduced. Separation and filtration functions using geotextiles from nanoclay formulations are introduced as important concepts. Yellow clay was added as nanoparticles to make a polyester formulation in turn to make nonwoven geotextiles to improve the removal effects of toxic and organic components of leachate solutions. Engineering behavior was evaluated to confirm the effects of adding yellow clay. There is a possibility of nanocomposite formulations for geosynthetics in the future. Second, sustainable laminar geotextile composites with different fiber-packing densities were made, and the effects of laminar structures were examined on water permeability. To fabricate these materials, the fiber-packing densities of laminar geotextile composites were discriminated correspondingly. The experimental values of water permeability by permittivity test were smaller than those of the theoretical values due to the loss of hydraulic pressure at the interface between geotextiles. To interpret the water permeability behaviors, structural model of tubes with different fiber-packing densities was applied. Finally, the inlet forms – bell mouth and soft tube structures – of laminar geotextile composite pores were estimated from the loss rates of hydraulic pressure.

Part of the book: Non-woven Fabrics

By Han-Yong Jeon

In an elastic solid the strain stays constant with time and is constant and the stress decays slowly with time. The increase in strain is not linear, and the curve becomes steeper with time and also as the stress-rate is increased. The slope of the curve tends to decrease with time, but it is steeper for higher strain rates. The variation of both strain and stress with time is linear for constant stress- and strain-rate tests upon elastic materials. The final comment about the compressive creep test and data interpretation is as follows: (1) Description of the creep mechanism of the geosynthetics (exactly not compression but perpendicular compression) is very important because the creep mechanism of tension and compression is quite deferent. (2) To reduce the specimen-to-specimen, many ramp-and-hold (in the case of tension creep: 1 h) tests are recommended. (3) Loading rate is also important because it make initial strain value. To check the nonaffected loading rate, prior to the main creep test, some kind of short-term test is needed. (4) The method to assess the reduction factor by creep also will be reviewed because the value will be changed according to the applied load.

Part of the book: Creep

By Han-Yong Jeon

Polymeric synthetic fabrics are continuous sheets of woven, nonwoven, knitted, or stitch-bonded fibers and yarns. The sheets are flexible and permeable and generally have the appearance of a fabric. Among polymeric synthetic fabrics, geosynthetics including geotextiles have special functions of separation, filtration, drainage, reinforcement, and erosion control in civil engineering applications. Also, geosynthetics such as geotextiles and geogrids are used in asphalt pavement reinforcement. An important function of these geotextiles is as cushion layers to prevent puncture of geomembranes (by reducing point contact stresses) from stones in the adjacent soil, waste, or drainage aggregate. Geotextiles, however, are made from a combination of two or more polymeric synthetic fabrics. In this chapter, geotextiles as polymeric synthetic fabrics are introduced not only for improvement but also maintaining stability of ground structure in civil engineering circumstance with their related technologies.

Part of the book: Engineered Fabrics

By Han-Yong Jeon

The relationship of compressive behavior according to manufacturing process parameters of geonet was investigated. We analyzed the drainage behavior of the bi- and tri-plane geonet used for the planar drainage and investigated the changes of the drainage behavior due to the restraining load. The data showed that there is no critical manufacturing factor to affect the compressive strength of the bi-planar geonet. All of these parameters can affect in a very complicated way. And the strand inclination can mainly affect to the after compressive strength, i.e., roll-over behavior. The results considering site-specific conditions of the landfill system explained the temperature has influence on the compressive behavior of the geonet. The compressive strength was reduced and the strain at yield increase gradually with the temperature for both of bi- and tri-planar geonet. Significant reductions in flow capacity were observed for the traditional bi-planar and cylindrical type geonet and this value was consistent to the compressive strength. These decreases were anticipated due to the abrupt thickness decrease of the geonet caused by roll-over. In the other hand, there was no significant decrease of transmissivity for the tri-planar geonet which has no roll-over phenomena.

Part of the book: Fluid Flow Problems

By Han-Yong Jeon

Most of the geosynthetics contribute to the long-term stability of the soil structure, so products with little change in long-term performance are mainly used. To this end, demand for biodegradable products emphasizing planting and environmental compatibility is increasing. Sustainable geosynthetics can be categorized as “Usual Geosynthetics” and “Green Geosynthetics” on the basis of required performance, and it can be said that it is meaning to expand the use of geosynthetics in the fusion level. In here, “Usual Geosynthetics” refer to functional long-term maintenance and environmental adaptive products, and “Green Geosynthetics” refer to eco-environmental products that are decomposable geosynthetic fibers whose functions are extinguished after a required period of time. In this paper, we introduce sustainable geosynthetics, which are differentiated from raw materials to applicability.

Part of the book: Geopolymers and Other Geosynthetics