Polymer concrete characteristics

Polymer concrete, as highly filled polymer compositions, can be prepared on any synthetic binding. However, due to the requirements for density, strength, deform-ability, chemical resistance, and other characteristics, about 10 different types of monomers or oligomers are used in practice. In combination with modifying additives, they provide more than 30 varieties of polymer concrete. 

Following are the results of long-term experimental research on the effect of a water environment on the physical and mechanical characteristics of polymer concretes [14],... 

Characteristics of Polymer Concretes Depend on Time of Exposure in Water Environment... 

FIGURE 2.8 Influence of negative temperatures on the ratio of the module of elasticity (1), ultimate compression strength (2), and ultimate deformations at compression (3) to the similar values obtained at test of control RubCon samples at room temperature. (Reprinted from Yu. Potapov, O. Figovsky, Yu. Borisov, V. Chmyhov, and D. Beilin, Influence of Temperature on Physical-Mechanical Characteristics of Polymer Concrete, J. Scientific Israel Technological Advantages 5, nos. 1-2 (2003) 11-13.)... 

Potapov, Yu., Figovsky, O., Borisov, Yu., Chmyhov, V., and Beilin, D. Influence of Temperature on Physical-Mechanical Characteristics of Polymer Concrete, J. Scientific Israel Technological Advantages 5, no. 1-2 (2003) 11-13. 

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. 

VE polyurethane resins have mechanical properties similar or superior to those of conventional VE and epoxies. Characteristics include a heat distortion temperature of 120C (248F). Ultimate elongation of an unreinforced molding compound without fillers is 5.5% tensile strength is 80 MPa and flexural strength 150 MPa. The resins can be custom-formulated. Applications include customized automobile parts, recreational vehicles, outdoor equipment, tubs/showers and electrical parts. The resins are suitable for standard molding processes some were specifically developed for pultrusion, RIM, foam, adhesive, and polymer concrete applications. 

Polymers. The purpose of adding polymers to the concrete matrix is to improve the characteristics of the fresh concrete (such as workability) and also to enhance the hardened properties such as flexural strength, modulus of elasticity and adhesive performance [8]. The incorporation of polymers into concrete may be in the form of polymer modified concrete (PMC), polymer impregnated concrete (PIC) or as polymer concrete (PC) [9], For this project, the objective was to develop an ultra-lightweight concrete material using Portland cement as the main binder modified with a suitable polymer - thus a PMC application. The polymer modifiers selected for the development of the ultra-lightweight thin filmed material were a commercially available SBR latex as well as a readily available acrylic polymer. 

B) Polymer-cement concrete is a modified concrete in which a part of the cement binder is replaced by organic polymer. It is produced by incorporating a monomer, prepolymer, or dispersed polymer latex into a cement-concrete mixture. The process technology used is similar to that of conventional concrete and has the advantage that it can be cast in place for field applications. Most of the polymer-cement-concrete composites are based on different kinds of lattices obtained especially by emulsion polymerization. The lattices are aqueous emulsions containing polymer particles such as SBR, NBR, PVAc, copolyesters of AA-MAA, and PAA-PMAA-SBR. The compatibility of SBR, PVAc, and acrylic lattices with Portland cement produces particular characteristics that led to wide use of this component as polymer-concrete composites. 

The properties of polymer concrete depend on the characteristics of the polymer and the aggregate used and the formulation [12, 13]. Broadly speaking, the unique properties of polymer concrete are [13] ... 

Overlays polymer concrete overlays are used to get a durable, almost impervious and wear-resistant surfaces on Portland cement concretes. Suitable surface texture may be obtained for appropriate skid resistance and hydroplaning characteristics. The surfaces on which overlay will be applied must be prepared to ensure good adhesion. The surface must be strong, sound, dry and clean. The monomer and aggregate systems used for polymer concrete overlays are similar to those of polymer concrete repairing materials. 

Any of these components of tear or fatigue can play a main role or a secondary one, in function of the polymer concrete structure and the ingredients it contains, the medium nature, mechanical regime, the characteristics of the surfaces in contact with the polymer during friction. 

Reis, J.M.L. (2006) Fracture and flexural characteristics of natural fiber reinforced polymer concrete. Constr. 

LMC is used in underwater concrete for both new construction and repair. The important requirements to obtain antiwashout capability, such as segregation resistance, flowability, self-leveling characteristics and lower bleeding are provided by the addition of viscosity-enhancing polymeric admixtures at polymer-cement ratios of 0.2-2.0%. These admixtures are water-soluble polymers, and classified under two groups, viz., cellulose types such as methyl cellulose and hydroxy ethyl cellulose and polyacrylamide types such as polyacrylamide and polyacrylamide-sodium acrylate [101]. 

One of the significant limitations of the use of first- and second-generation superplasticizers in ready-mixed flowing concrete is the rapid decrease in the initially achieved high workability and this constitutes one of the chief constraints to their wider acceptance. Therefore, a number of major producers of admixtures have sponsored active research to improve the workability retention characteristics of their superplasticizers. Some recent developments [48] have shown promise, among these are materials based on acrylate polymers (AP). The AP-based materials are reported to be more effective than SNF- or SMF-based surplasticizers in terms of water reduction, slump increase and slump retention. Figure 7.19 shows the remarkable improvement in the retention of workability produced by the AP type superplasticizer compared to an SNF type. 

Oligophenylethoxysiloxanes are used as modifiers for various polymers to improve their weather resistance and other technical characteristics, as well as to increase the heat resistance of coatings. E.g., PES-50 is used to modify polyethers, aciylic and epoxy polymers PES-80 is used to modify alkyd and urea-formaldehyde resins. Besides, PES-80 is used as an additive in paints and enamels (to improve their flow properties, gloss and colour), as well as in concrete mixes (to improve the water resistance and durability of concrete works). 

To date, to materialize these characteristic features in the concrete or the abstract, many nucleophile-containing polymers have been synthesized and studied. In particular, the abstract materialization is as innumerable as the functional polymers, taking account of polymers other than the nucleophile-containing polymers. The polymers resulting from the abstract materialization have been occupying their particular fields. 

It is noteworthy that for investigation of properties of real polymer systems with topological constraints it is not enough to be able to calculate the statistical characteristics of chains in the lattice of obstacles. It is also necessary to be able to compare any concrete physical system with the unique lattice of obstacles, which is a much more complicated problem than the first task. In this way, the model polymer chain in an array of obstacles is an intermediate between the microscopical and phenomenological approaches. The direct investigation of the PCAO-model was fulfilled in Refs. [16-25]. 

Sulfur Concrete Modified with Styrene. If styrene is added to sulfur melts, the viscosity rises to a maximum within a few minutes irrespective of the styrene concentration (Figure 9). After reaching the maximum value, the viscosity decreases steadily to a constant final value which depends on the amount of styrene added. This characteristic behavior may be caused by thermal polymerization of the styrene followed by degradation of the polymer by reaction with sulfur. 

Dispersions of gas in solids are also called foams but the foam cells (bubbles) formed are isolated from one another. An example of such foams are the natural porous materials, cellular concrete, cellular glass and polymer foams. However, if in such disperse systems both phases are continuous (such as in many foamed polymers), they are called sponges. Many porous materials are partially sponge and partially solid foam. The properties of solid foams differ drastically from those of foams with liquid dispersion medium. At the same time the strength and other physical and mechanical characteristics of solid foams depend significantly... 

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