Concrete polymer based admixtures

Y. Ohama. Polymer-based admixtures. Cement and Concrete Composites, v. 20 (1998), p. 189-... 

The synthetic polymers and resins considered here are those that are used for polymer cement concretes (PCC). Properties of ordinary cement mortars and concretes are significantly improved by polymer-based admixtures, which are classified into four main types (Ohama 1998) ... 

Figure 13.4 Simplified images of stnicture of a polymer cement concrete consecutive stages of formation of a polymer cement co-matrix. Reprinted from Cement and Concrete Composites, Vol 20, Ohama, Y., Polymer-based admixtures , pp. 24., Copyright (1998), with permission from Elsevier.

Polymer-based admixtures, Cement and Concrete Composites,... 

With the advent of high-performance concrete and the development of third-generation (mostly acrylic polymer-based) superplasticizers which provide significantly higher water reduction at flowable consistencies, this demarcation has blurred. Through the use of a mixture of admixtures it is now possible to obtain highly durable low water-cement ratio concretes that are nearly self-leveling and yet quite cohesive. 

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. 

Construction Ceramic tile Decorative brick Concrete Cellulose insulation Carpeting Core base Asphalt roofing Studs and framing Wall covering Glass fiber and rockwool insulation Ceiling tiles Installation Installation Polymer cements, bond coats, and admixture to concrete Binder for fibers and adhesive to substrate Installation Installation Additive to urea-formaldehyde resin Interior Installation Lamination Installation... 

A variety of materials, ranging from mineral binders to polymers, can be used as binder. However, materials based on polymers, such as epoxy or polyester resins, which are often used for concrete structures, should undergo careful assessment before use in historical masonry, due to possible issues regarding the mechanical and physical compatibility. Much more common for the repair of historical buildings are mineral binder systems based on cement or hydraulic lime with the addition of admixtures and fillers or aggregate. To inject bore holes, usually pure water/binder systems are used with typical w/b values of 0.8-1.0. However, the w/b ratio has to be adjusted according to the volume to be injected and to the moisture content of the substrate. 

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