Fibre reinforced soil

Mattone, R. (2005) Sisal fibre reinforced soil with cement or cactus pulp in bahareque technique . Cement and Concrete Composites, 27-. 611-16. 

A futuristic application for fibre-reinforced glass matrix composites is related to the use of lunar materials for future space constmction activities. Glass/glass composites in which both the fibre and the matrix are made of fused lunar soil have been proposed [28]. These materials, obtained so far on a laboratory scale, show great promise for providing large quantities of basic structural materials for cost-effective outer-space constmction. 

The loss of TS observed by Shubhra et al. is shown in Figure 9.8. It was found that TS values of the composites decreased slowly. For silk fibre/PP composites the TS value was 54.7 MPa whereas after 24 weeks of soil burial test it was 49.1 MPa. So, after 24 weeks of soil burial, silk fibre reinforced PP composite lost 10.2% TS, whereas silk-reinforced PP and NR blend (50 50) composite lost 24.3% TS. For silk-reinforced PP and NR blend (50 50) composites the TS value was 39.9 MPa whereas after 24 weeks of soil burial test it was 30.2 MPa. The author mentioned that this 14.1% higher loss of TS is due to incorporation of NR in the PP matrix. The author found that if NR is low (25% instead of 50%), the composite loses less TS value after 24 weeks of degradation test (from 42.4 MPa to 34.3 MPa, which is 19.1%). 

The loss of BS observed by Shubhra et al. is shown in Figure 9.9. It was found that BS values of the composites decreased more rapidly than TS values. For silk fibre/PP composites the BS value was 58.3 MPa whereas after 24 weeks of soil burial test it was 50.7 MPa. So, after 24 weeks of soil burial, silk fibre reinforced PP composite lost 13% BS whereas silk-reinforced PP and NR blend... 

Granular soil with fibre reinforcement is a material composed of granular natural soil (i.e. sand) and thin continuous fibres distributed in the material volume with or without cement or any other binding agent. The synthetic (polyester, polypropylene or polyamide) fibres are very thin and their volume fraction is low starting from 0.1% or 0.3% also natural fibres may be used (e.g. sisal, coir). The fibres are distributed in a uniform and isotropic way (3D) or are parallel to a selected plane (2D). The main influence of the reinforcement is the cohesion of sand, which is enhanced with the fibre content, while the angle of the internal friction remains constant. 

Thomson, J.C., 1988. Role of natural fibres in geotextiles engineering. In First Indian Textile Conference on Reinforced Soil and Geotextiles, Bombay, India, pp. G25—G29. 

Internal At one time open-weave hessian cloth was very largely used as an internal reinforcement material, but experience showed that this is subject to rotting in the soil. Even when the material appears to be covered with enamel, some of the fibres must protrude, and thus moisture is absorbed so that after a period of years the hessian is generally found to be in a waterlogged condition and forming food for bacteria. 

Synthetic fibres take a static charge because they are non-conductive and only absorb small quantities of water. This effect is reinforced by low air humidity, particularly in winter, and soiling may be increased. Antistatic finishings reduce the high electrical resistance of fibres. These consist of hydrophilic surface active polar compounds (tensids), carbon particles, electrically guiding polymers or salts. Textiles may also be made antistatic by incorporating metallic or metallised fibres or conductive carbon fibres which are coated with polyamide. 

Abstract This chapter deals with the structure, properties and applications of natural fibres. Extraction methods of Natural Fibres from different sources have been discussed in detail. Natural fibres have the special advantage of high specific strength and sustainability, which make them ideal candidates for reinforcement in various polymeric matrices. Natural fibres find application in various fields like construction, automobile industry and also in soil conservation. It is the main source of cellulose, an eminent representative of nanomaterial. Extractions of cellulose from plant-based fibres are discussed in detail. Various mediods used for characterization of cellulose nanofibres and advantages of these nanofibres have also been dealt with. 

Reinforcement compacted soils and aggregates have good compressive modulus but poor tensile modulus and consequently can be readily separated when subjected to sizeable tensile loads. Employing fibres of appropriate tensile moduli, geotextiles become effective reinforcing tension elements when embedded in compacted soils and aggregates. 

The use of natural fibre fabric is an alternative method for geo-engineering applications. The biodegradability of natural fibres has led to their use in short-term geotechnical applications to fulfil technical requirements to temporarily protect and enable the natural growth of local foliage in land and waterway reclamation, restoration or development. Natural fibres such as jute, coir, sisal, kenaf, ramie and other low-cost natural materials such as palm leaves, wood and split bamboo are also used in geotechnical applications such as erosion control, soil stabilization and soil reinforcement. 

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