Applications erosion control

Fabric formed revetments (FFR) can be used as an alternative to rock rip-rap structures, as shown in Fig. 8.43. They are constructed by pumping a very fluid fine-aggregate grout (i.e. cast-in-place concrete) into a woven fabric envelope consisting of two layers connected by tie-chords or by interweaving. FFRs can be engineered to perform as impermeable or permeable wave barriers. 

Inland soil erosion follows a process of detachment and transportation of soil particles by wind and rain water under the influence of gravity. Wind erosion is a problem largely in open areas (lack of shelter) - exposed slopes of non-cohesive (loose and dry) soils, or exposed smooth bare surfaces with 

ECN and ECM are open-weave structures whereas ECB are needle-punched non-wovens. They are the most commonly used temporary, degradable systems. An improvement on these structures is organic fibre-filled blankets (OFB), which are essentially jute or coir fibres sewn into or placed between synthetic nettings. They give increased ground cover and better resistance to rainfall impact. The installation life of OFBs is from 4 to 24 months. Their biodegradabUity depends on the choice of nettings, fibre type, and chemical nature of the rain and soil. 

A further development of the OFB concept is erosion control and re vegetation blankets (ECRB). These are a combination of PA or PP staple fibre bound within two PP or PA nets. They have similar ground cover characteristics to the OFBs. However, the use of ultraviolet stabilised fibres provides for a much longer installation life than the organic blankets. 

TRM structures are composed of fused polymer nettings, made of randomly laid monofilaments, or yarns woven or tufted into an open, 3-dimensionally stable but flexible mat. Soil filling is carried out during installation and the weight of the soil fill ensures the mat conforms to undulations in the soil surface. They are designed to retain seed and soil cover, and therefore to entangle vith the root and stem of the plants as the vegetation becomes established. 

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In more recent applications, several types of ET cover designs also have incorporated synthetic materials, such as geomembranes, which are used to enhance the function of minimizing water into the waste. For example, the Operating Industries Inc. Landfill in California has incorporated a soil layer with a geosynthetic clay liner in the design. The cover system for this site will reduce surface gas emissions, prevent oxygen intrusion and percolation, and provide for erosion control.68... 

Phytoremediation is the use of plants to treat or stabilize contaminated soils, sediments, or water. Plants provide and support remediation processes in many ways. Common applications of phytoremediation-based systems include remediation of contaminated soil and groundwater, reuse of municipal wastewater and biosolids, reuse of industrial wastewater and by-products, alternative landfill capping and erosion control, and landfill leachate reuse. 

Slope stabilization is just one potential application for composites in the broad area of erosion control. Several other related applications are bridge abutments, freeway cuts, storage tank embankments, mine tailings, sand dunes, and areas of turbulent water flow. 

Pesticides have to be developed against pathogens, insects and weeds, which cannot be controlled adequately by the products available today. New demands are created by the acquired resistance of pests to various kinds of pesticides, by changes in the ecosystem arising from pesticide application, and by new agronomic techniques, such as new water management systems, erosion control, and zero tillage. All these demands set new research tasks. 

Brazil accounts for 55% of pesticide sales in Central and South America. Pesticide sales in Brazil were US 1.4 billion in 1994 and an increase in sales was seen for all leading crops between 1993 and 1994 (up 57% for cotton, 44.8% for coffee, 36.3% for maize, 30.2% for soybean, 17.7% for citrus fruits and 11.5% for sugai cane). Herbicide sales dominate the market (50% in 1994) and it was predicted that usage would continue to expand as more farms convert to minimum tillage practices (due to severe problems with soil erosion and deterioration in soil structure) that rely on increased herbicide applications to control weeds,... 

Processing methods include shredding, splitting in halves, cutting sidewall/ beads, and baling. A number of products, in the form of processed tires, can be made from scrap tires that have applications in erosion control, soil conserva-... 

Hydraulic structures using scrap tires for bank protection include tire mats, revetment (retaining walls, seawalls, revet mattresses), and tire-concrete imits. In search for economical bank-protection structures, the use of scarp tires as a less-expensive alternative is desirable, considering the costs of the metal and concrete used in reinforced-concrete construction, especially in developing countries. Whole scrap tires can be utilized for surface erosion control, beach and slope protection, and stream bank stabilization. In these applications, scrap tires are banded together and partially or completely buried on imstable slopes. Tires can be used with other stabilization materials to reinforce an unstable highway shoulder or protect a channel slope remained stable and can provide economical and immediate solutions. In bank protection structures, tires are laced together by steel cables and used as a protective layer or mat over stream banks or soil embankments. The top, toe, upstream and downstream ends of the mattress are tied into the banks. Used tires with metal cords were shown to bean excellent construction material that can partially replace reinforced concrete for protection of river banks and canal walls [19]. 

Erosion control applications of scrap tires, which are banded together and partially or completely buried on unstable slopes, can provide economical and immediate solutions. Construction costs were reduced by 50 to 75% of the lowest cost alternatives such as rock, gabion (wire-mesh/stone matting), or concrete protection. 

Tires with the proper installation technology can serve a variety of applications in the construction industry as marine reefs, energy-efficient house construction, highway bank reinforcement, and erosion control. 

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