Polymer-Cement Composite

Effect of Epoxy Resin Addition on the Moisture Sensitivity of Macro Defect Free Polymer-Cement Composites... 

Keywords optimization, material model, polymer-cement composite, polymer-cement coating, insulation. 

Figure 1. Damages of concrete floors covered with surface coating made of polymer-cement composites and epoxy resin, caused by high deformations...

Fig. 10.5 Model of polymer-cement composite microstructure formation for the pre-mix polymer addition, (according to [5])...

Hasegawa, M. etal. (1995) A new class of high strength, water and heat resistant polymer-cement composite solidified by an essentially anhydrous phenol resin precursor. Cement and Concrete Research 25,1191-1198. 

McHugh, A.J. etal. (1996) Processing-stracture-properties interaction in polymer-cement composites, in Proceedings MAETA Workshop on High Flexural Polymer-cement Composites, Sakata, pp.59-67. 

E.I. Du Pont de Nemours, Colloidal stable solvent cement compositions comprising chloro-prene polymers, phenolic resins and polyisocyanate, U.S. Patent 3,318,834, 9 May, 1967. 

The last stage in the development of the EBA cement is represented by the polymer cements. Brauer Stansbury (1984b), taking advantage of the fact that the EBA-HV liquid does not inhibit vinyl polymerization, included methacrylates into the cement composition. The object was to produce a material that set after mixing, both by polymerization and by salt or chelate formation. 

Similar copolymers with N-vinyl-N-methylacetamide as a comonomer have been proposed for hydraulic cement compositions [669]. The polymers consist of AMPS in an amount of 5% to 95%, vinylacrylamide in an amount of 5% to 95%, and acrylamide in an amount of 0% to 80%, all by weight. The polymers are effective at well bottom-hole temperatures ranging from 200° to 500° F and are not adversely affected by brine. Terpolymers of 30 to 90 mole-percent AMPS, 5 to 60 mole-percent of styrene, and residual acrylic acid are also suitable for well cementing operations [253]. 

Acrylic latices have been used successfully for more than 35 years to modify portland cement composites. The use of solid grade acrylic cement modifiers has become common during the past few years. Both of these types will be discussed later in this section. The level of polymer modification is measured as a ratio of polymer solids by weight of cement. A 15%-20% modification represents the range for optimum performance lower modification levels may prove acceptable for certain product applications (Rohm Haas, 1989). 

Soh, Y.S. (1992), Development of Lightweight Polymer Cement Concrete, Korea-Japan Symposium on Development and Application of Concrete-Polymer composits, Chonbuk National Univ., pp. 172-159. 

Major polymer applications optical fibers, dials, optical components, household items, car rear lights, artificial stones (filled products) for injection molded bath sinks, and kitchen worktops, bone cement, composites, medical applications (e.g. bone cement)... 

The last method to be discussed, which is used to form polymer/ceramic composites by electrospinning, is extremely different to the methods previously described, but worth mentioning. Zuo et al. [129] used a method to create a composite scaffold that is actually the reverse of what most people are doing. Instead of mineralizing the nanofibers, Zuo et al. actually incorporated electrospun polymer nanofibers into a ceramic bone cement in order to form a composite scaffold. It was found that by incorporating electrospun nanofibers into the cement, the scaffold became less brittle and actually behaved similarly to that of a ductile material because of the fibers. Composite scaffolds with different polymers and fiber diameters were then tested in order to determine which scaffold demonstrated the most ideal mechanical properties. However, no cell studies were conducted and this method would most likely be used for a bone substitute instead of for bone regeneration applications. 

Cement is a binder that sets and hardens by itself or binds other materials together. The most widely known application of cements is in construction a second one is the area of bone cements. Cements used in construction are characterized as hydraulic or nonhydraulic and mostly for the production of mortars and concrete. Hydraulic cements set and harden after combining with water. Most construction cements are hydraulic and based on Portland cement, which consists of calcium silicates (at least 2/3 by weight). Nonhydraulic cements include the use of nonhydraulic materials such as lime and gypsum plasters. Bone cements and bone cement composites refer to compounds that have a polymer matrix with a dispersed phase of particles. For instance, polymethylmethacrylate (PMMA) is reinforced with barium sulphate crystals (for radio-opacity) or with hydroxyapatite... 

Although polymers and monomers in any form such as latexes, water-soluble polymers, liquid resins, and monomers are used in cement composites such as mortar and concrete, it is very important that both cement hydration and polymer phase formation (coalescence of polymer particles and the polymerization of monomers) proceed well to yidd a monolithic matrix phase widi a network structure in which the hydrated cement phase and polymer phase interpenetrate. In the polymer-modified mortar and concrete structures, aggregates are bound by such a co-matrbc phase, resulting in the superior properties of polymer-modified mortar and conoete compared to conventional. 

Latex-modified mortar and concrete are made by using a composite binder of inorganic cements and organic polymer latexes, and have a network structure which consists of cement gels and microfilms of polymers. Consequently, the properties of the latex-modified mortar and concrete are markedly improved over conventional cement mortar and concrete. The properties of the fresh and hardened mortar and concrete are affected by a multiplicity of factors such as polymer type, polymer-cement ratio, water-cement ratio, air content, and curing conditions. 

Polymer-modified or polymer cement mortar (PCM) and concrete (PCC) are a category of concrete-polymer composites which are made by partially replacing the cement hydrate binders of conventional cement mortar or concrete with polymers, i.e., polymeric admixtures or cement modifiers, thereby strengthening the binders with the polymers. Polymer-modified or polymer cement paste, which is prepared widiout any aggregate, is sometimes used. 

The mechanical properties, the corrosion stability, and some useful properties are the reasons for the continuous interest shown in polymer-concrete composites by various design, research, and production organizations. The most important types of polymer-concrete composites are polymer-impregnated concrete (PIC), polymer-cement concrete (PCC), and polymer concrete (PC). 

PIC is a precast and cured portland cement concrete that has been impregnated with a monomer that is subsequently polymerized in situ. This type of cement composite is the most developed of polymer-concrete products. PCC, on the other hand, is a modified concrete in which a part (10%-15% by weight) of the cement binder is replaced by a synthetic organic polymer. It is produced by incorporating a monomer, prepolymer-monomer mixture, or a dispersed polymer (latex) into a cement-concrete mix. To effect the polymerization of the monomer or prepolymer-monomer, a catalyst (initiator) is added to the mixture. The process technology used is very similar to that of conventional concrete. So, unlike PIC which has to be used as a precast structure, PCC can be cast-in-place in field applications. PC can be described as a composite that contains polymer as a binder instead of the conventional portland cement. 

The particular characteristics of compatihiHty of poly(vinyl acetate) with cement have led to wide use of this latex as a main component in polymer-mortar and polymer-concrete composites. 

FIGURE6.10 Chloride penetration profiles in beams containing HPFRCC repair layer (a) and polymer cement mortar (b). (After Kobayashi, K. et al. Cement and Concrete Composites, 32 411-420. With permission.)... 

M. Neelamegam, Y. Ohama, K. Demura, S. Suzuki and A. Shirai Flexural behavior of poly-mer-ferrocements with various polymer mortars as matrices. The International Journal of Cement Composites and Lightweight Concrete Vol.6, No.3 (1984), pp.151-157. 

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