Carpet industrial waste

Keywords Carpet industrial waste, fiber reinforced concrete, field study. 

Although FRC has become widely available from concrete suppliers, its use has been limited primarily due to cost considerations. Effort to reduce the cost includes limiting the fiber dosage and developing inexpensive fibers. A very attractive alternative, however, would be to use suitable recycled fibers from industrial waste which otherwise would be discarded, the carpet industrial waste being an example. 

This paper summarizes the results of an experimental program to evaluate the effectiveness of using recycled fibers from carpet waste for concrete reinforcement. It also discusses issues that need to be addressed for the application of such FRC in large scale construction projects. It then reports on a building construction project using carpet waste fiber reinforced concrete. The results suggest that using carpet industrial waste fibers in construction would not only improve the reliability and life of the concrete structure, it but also could reduce the landfill spaces needed to dispose the waste material. 

The carpet industrial waste generated each year and that accumulated in landfills represent an abundance of useful resources, as they can provide effective reinforcement for concrete. As to be discussed in the following sections, concrete reinforced with recycled fibers from hard carpet waste is indeed a suitable material for construction. It suggests that using carpet waste in construction could be a very cost-effective way to improve the durability and performance of the concrete structure, and to reduce the needs for landfill spaces. 

The laboratory study described above demonstrated that recycled fibers from carpet industrial waste can provide effective reinforcement for concrete. However, concerns do exist that must be addressed before such FRC can be widely accepted for construction. 

Wang, Y., Zureick, A.H., Cho, B.S., and Scott, D.E. (1994) Properties of fiber reinforced concrete using recycled fibers from carpet industrial waste. Journal of Materials Science, Vol. 29, No. 16, pp. 4191—4199. 

YoujiangW (1993) Fiber reinforced concrete using recycled carpet industrial waste and its potential use in highway construction. Symp Proc on Recovery and effective reuse of discarded materials and by-products for construction of highway facdities, October 1993, Denver, CO... 

The U.S. carpet industry produces about 1 billion m2 of carpet and consumes about 1 million tons of synthetic fibers per year. About 70% of the carpet produced is for replacement of used carpet, which translates into about 2 million tons of used carpet for disposal. In the Dalton, Georgia area where many carpet manufacturers are located, over 40, 000 tons of carpet waste has to be disposed of each year. Significant amount of carpet trim waste is also being disposed of by other industries such as the automobile manufacturers. Because of the high cost of developing and managing landfills, waste disposal in landfills has become increasingly difficult. 

The carpet industry in the United States produces about 1 billion square meters of carpet per year. Of this, approximately 70% is used to replace existing carpet this translates into 1.2 million t (1.32 million T) of carpet waste produced annually [49]. Additional wastes produced by the carpet making industry increase the total amount of waste fibers to an estimated 2 million t (2.2 million T). Several research efforts are addressing ways to include these waste fibers in both asphalt pavements and Portland cement concrete. 

Carpet is a complex, multicomponent system. The tufted carpet, the most common type (90%) as shown in Figure 16.1, typically consists of two layers of backing (mostly polypropylene fabrics), joined by CaCOs-filled styrene-butadiene latex mbber (SBR), and face fibers (majority being nylon 6 and nylon 6,6 textured yams) tufted into the primary backing. The SBR adhesive is a thermoset material, which cannot be remelted or reshaped. The waste containing the SBR (postconsumer and some industrial waste) has not found suitable uses, and it forms the major part of the carpet waste going into the landfills. Figure 16.2 shows the typical masses for the various components [13]. 

Kip B. J., Peters E. A. T., Happel J., Huth-Fehre T. and Kowol F. (1999), Method of identifying post consumer or post industrial waste carpet utilizing a hand-held infrared spectrometer , US Patent 5 952 660. 

Uses Industrial defoamer formulated with low vise, for ease of handling and pumping for leather finishing, metalworking, carpet cleaning, waste treatment Properties Sp.gr. 1.00 flash pt. (PMCC) none pH 7.0 5% silicone Mazu DF 206 [Emerald Foam Control]... 

In an industrial application dissolution/reprecipitation technology is used to separate and recover nylon from carpet waste [636]. Carpets are generally composed of three primary polymer components, namely polypropylene (backing), SBR latex (binding) and nylon (face fibres), and calcium carbonate filler. The process involves selective dissolution of nylon (typically constituting more than 50wt% of carpet polymer mass) with an 88 wt % liquid formic acid solution and recovery of nylon powder with scCC>2 antisolvent precipitation at high pressure. Papaspyrides and Kartalis [637] used dimethylsulfoxide as a solvent for PA6 and formic acid for PA6.6, and methylethylketone as the nonsolvent for both polymers. 

A large amount of carpet waste is disposed of in landfills each year. This not only poses economical and environmental problems to the industry, it also represents a severe waste of resources because the waste material can prove to be valuable for construction applications. This study focused on the use of carpet waste fibers in fiber reinforced concrete and demonstrated that such reinforcement can effectively improve the shatter resistance, toughness, and ductility of concrete. Performance enhancement has also been observed in the drying shrinkage test. Such improvements in concrete performance is especially beneficial for concrete structures in seismic zones as the increased toughness could improve the reliability and shock resistance of the structures. 

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