Cements polymer fiber-reinforced

While these attempts to optimize the strength and durability of cement were more or less unsystematic and empirical, the exact details of the chemistry of cement were first elucidated by Le ChateHer (1904). Later developments included the invention of reinforced concrete by Wilkinson and Lambot in 1855, and of blast furnace cement by Emil Langen in 1862. Thereafter, the twentieth century witnessed the invention and optimization of sulfate-resistant alumina cements (1908), the addition of plasticizers such as Hgnosulfonic acid or hydroxylated polysaccharides and superplasticizers such as sulfonated naphthalene-formaldehyde condensate, and the advent of macro-defect-free (MDF) and polymer fiber-reinforced cements, to name only a few. 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Figure 4.39 Steel fiber content and polymer-cement ratio vs. 84-day drying shrinkage of steel fiber reinforced latex-modified mortars.

Carbon fiber has been found to be an effective thermistor [192-194], such as a cement paste reinforced with chopped carbon fiber (about 5 mm long) with silica fume (15 wt% cement). Its electrical resistivity decreased reversibly with increasing temperature (1-45°C), with activation energy of electrical conduction (electron hopping) of 0.4 eV. This value is comparable to semiconductors (typical thermistor materials) and is higher than that of carbon fiber polymer matrix composites. The current-voltage characteristics of carbon fiber reinforced silica fume cement paste were linear up to 8 V at 20°C. 

Other tertiary recycling processes that have been developed include a Freeman Chemical Corp. process to convert PET bottles and film to aromatic polyols used for manufacture of urethane and isocyanurates. Glycolized PET, preferably from film, since it is often lower in cost than bottles, can be reacted with unsaturated dibasic acids or anhydrides to form unsaturated polyesters. These can then be used in applications such as glass-fiber-reinforced bath tubs, shower stalls, and boat huUs. United States companies that have been involved include Ashland Chemical, Alpha Corp., Ruco Polymer Corp., and Plexmar. Unsaturated polyesters have also been used in polymer concrete, where the very fast cure times facilitate repair of concrete structures. Basing polymer concrete materials, for repair or precast applications, on recycled PET reportedly leads to 5 to 10 percent cost savings and comparable properties to polymer concrete based on virgin materials. However, they are still approximately 10 times the cost of portland cement concrete. There appears to be little commercial application of these processes at present. 

Khazanchi AC et al (1990) Material science of natural organic fiber reinforced composites in polymer/cement/mud matrix for construction engineering. In Hamelin P, Verchery G (eds) A book on textile composites in building construction. Pluralis, France, pp 69-76... 

The structural reinforcement of floors in brick and cement is one of the most common applications of using pulbuded sheets or carbon fiber-reinforced polymer (CFRP) fabrics, thanks to the rapidity of application and the many advantages they offer. The reinforcement may be deemed necessary on several different occasions. 

Bijen, J., van den Plas, C. (1992) Polymer modified glass fibre reinforced g5 sum, in Proc. Int. Workshop High Performance Fiber Reinforced Cement Composites, RILEM/ACI, W. H. Reinhardt and A. E. Naaman eds, London Spon/Chapman and Hall pp. 271-87. 

Kelly, A. and C. Zweben, eds. 2000. Comprehensive Composite Materials. (6 vols.) Amsterdam/New York Elsevier available online. Topics covered in the six volumes are fiber reinforcements and general theory of composites, polymer matrix composites, metal matrix composites, carbon/carbon, cement, and ceramic matrix composites, test methods, nondestructive evaluation, smart materials, and design and applications. 

This chapter presents the materials used for the seismic retrofit of structures covered by modem retrofit design codes and recommendations such as reinforced concrete, steel, and composite stmetures as well as masonry stmetures (EC8-3 2005 FEMA 547 2006 Fardis 2009 CNR-DT 200/2004). It discusses materials for both repair and strengthening of contemporary stmetures with special focus on reinforced concrete buildings and bridges (Priestley et al. 1996 Fardis 2009) as well as on advanced materials (high-performance cement-based materials, shape-memory alloys, fiber-reinforced polymers, textile-reinforced mortars, etc.). 

J. Bijen, Improved Mechanical Properties of Glass Fiber Reinforced Cement by Polymer Modification , Cem. Conor. Compos. 12,1990, 95-101. 

A. Sugiura and M. Vtfekasuti, Durability and Fire Resistance of Polymer Modified Glass Fiber Reinforced Cement , in S. Nagataki, T. Nireki, and T. Tomosawa (eds) Durability of Building Materials and Components 6, Proc. Int. Conf. (Japan), E FN Spon, London, 1993, pp. 139-146. 

J.l. Daniel and M.E. Pecoraro, Effect of Forton Polymer on Curing Requirements of AR-Giass Fiber Reinforced Cement Composites, Research Report (Sponsored by Forton Inc., Sewickley, Pennsylvania), Construction Technology Laboratories, Division of Portland Cement Association, Skokie, IL, October, 1982. 

When the coloring of latex-modified mortar and concrete is required, alkali-resistant, weatherproof pigments are used. Furthermore, it is important that the pigments do not obstruct the stability of polymer latexes and the hydration of cements. Alkali-resistant glass, steel, polyamide, polypropylene, polyvinyl alcohol (poval), aramid and carbon fibers are employed as mixable reinforcements. Reinforcing bars for ordinary cement concrete are also used for the reinforcement of the latex-modified concrete. 

As shown in Fig. 4.56,the reinforcement of latex-modifled concretes with steel fibers causes a pronounced improvement in the impact strength with increased polymer-cement ratio and steel Gber content... 

Figure 4 6 Relation between fiber content and polymer-cement ratio and relative impact strength of steel IQber reinforced PAE-modified concretes.

Many carpet manufacturers, fiber and chemical suppliers, recycling companies, and academic institutions are actively pursuing various methods to recycle fibrous waste. The approaches include chemical processes to depolymerize nylon and other polymers, recovery of plastic resins from carpet fibers, direct extrusion of mixed carpet waste, composites as wood substitutes, fibers for concrete and soil reinforcement, waste-to-energy conversion, and carpet as feedstock for cement kilns. 

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