Polymer-Cement Coating

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

Plan of experiment. The statistical material model of polymer-cement coating was defined as the relation between components and properties [2-3]. The laboratory tests were based on the statistical planning of experiments, which was needed by economics of tests (obtaining the maximum information with minimum number of performed laboratory tests) and the fact, that the results of the laboratory tests based on the statistic planning are more predestined to statistical analysis. 

There is no possibility to present the relation of three variables at the same time that is why the graphic presentation of the model is a set of three figures - each figure presents the relation between the value of one property and two variables. The results for technical properties were surfaces with various character. Fig. 1 shows an example. This graph shows the water penetration depth for polymer-cement coating in function of coded values polymer to fillers ratio (P/F) and hydrophobic agent to Portland cement ratio (H/C). The graph character is an elliptic paraboloid. Another example is presented in Fig. 2 (water-vapor transmission rate in function of coded values X2 and xs). 

Table 4. Material model of polymer-cement coating - three variants of overall desirability in...

Fig. 4. Overall material model of polymer-cement coating - overall desirability (D) vs. material variables (xi, X2, X3) - fragments of graphs adequate to the satisfactory range <0.37 0.69> a -...

The important matter is the fact that when values of function of two variables are analyzed, the range of material variables (coded values) is narrowed to <-l, 1>. The analysis of graphs (especially in case of hyperbolic paraboloid) shows pairs of maxima and minima (or very clear tendency to the pair of extrema. Considering the mathematics - such result is correct but considering the technical properties - it is necessary to find the extremum that would be correct and rational in an engineering sense. Some of the extrema need to be rejected as they are reached with combinations of material variable values for the polymer-cement coating which are not relevant. Such result was reached in case of the flexibility index in function of coded values polymer to Portland cement ratio (P/C) and hydrophobic agent to Portland cement ratio (H/C). The shape of surface described by this relation was a hyperbolic paraboloid (refer with Fig. 5). 

In case of the flexibility index the desired value was the maximal value. The graph shows a very clear tendency of flexibility index value to the pair of maxima. First of these maxima (in considered area for variables narrowed to range <-l, 1>) was placed near the point of the maximal (= 1.0) value of P/C and minimal (= -1.0) value of H/C and the second maximum is placed near point of minimal (= -1.0) value of P/C and maximal (= 1.0) value of H/C. From the mathematical point of view two maxima in case of hyperbolic paraboloid is a correct result but from the practical point of view in case of flexibility index the second maximum has no sense as the increase of flexibility is proportional to the increase of polymer content. It is hard to expect that the polymer-cement coating containing less polymer is more elastic than coating containing more polymer. 

The models for each property showed that the relations between the property and composition and that the relations between the properties themselves are complicated and sometimes even mutually exclusive increasing the amount of polymer increases the flexibility and waterproofness but decreases vapor permeability, increase of waterproofness by adding more fillers does not causes the increase of flexibility, the vapor permeability is not clearly disproportional to waterproofness. It was shown that some relations which had seemed to be obvious when considering the composite material such as polymer-cement coating have not worked. That is why the specific definition of the expectations is so necessary and why the desirable material properties, their importance and weights of empiric data must be defined precisely. Using elaborated material models is very helpful in designing materials. 

Recent information suggests that such coatings operate by increasing the electrical resistance between the steel and the concrete both epoxy and polymer-cement-based materials seem to have this effect, reducing local corrosion current exchange [9]. 

Figure 4. PJ gives the polymer-cement ratio vs. water retention of latex-modified mortars, measured according to JIS A 6908 (Finish Coatings and Wall Coverings for Decorative Use) and ASTM C 91 (Standard Specification for Masonry Cement). The water retention nerally increases with rising polymer-cement ratio, and becomes nearly constant at a polymer-cement ratio of 5 to 10%. Such excellent water retention of the latex-modified mortars is most helpful or effective to inhibit dry-out phenomena (the lack of cement hydration due to water loss in the mortar or concrete) in thin layer linings or coatings on highly water-absorbable substrates such as dried cement mortars and ceramic tiles.

Figure 4.51 Effect of polymer-cement ratio on adhesion in tension of bonded ordinary cement mortar to latex-modified paste-coated mortar substrates.

The investigation proved that material models based on statistical methods are efficient tools for designing polymer-cement protective coatings. 

There are other properties which polymer-cement protective coatings obtain thanks to the presence of polymers, but relations between the three mentioned above and the amounts of main components are the bases of the material model [1,2], for the considered coating. The relations are difficult to define as they are not linear and the properties are contradictory to each other (e.g. waterproofness and vapor permeability). Besides the presence of particular components, such as cements, mineral fillers, polymer and hydrophobic agent significantly (positively or negatively) affects each property. 

The material model for the considered polymer-cement protective coating determined according to the above principles is presented below (refer with Table 2). 

Table 2 Model of elastic polymer-cement sealing coating.

An additional verification confirmed the conformity of evaluated model with data from additional laboratory tests carried out for different polymer-cement protective coatings designed using the material model. 

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

Chem. Descrip. Proprietary BIT CAS 2634-33-5 EINECS/ELINCS 220-120-9 Uses Presen/ative for indoor, emission-free paints/coatings rec. for polymer emulsions, adhesives, caulks, sealants, cement coatings, and plasters food pkg. adhesives food-contact paper/paperboard slimicide in food-contact paper/paperboard... 

Uses Monomer for UV-cured inks and coatings, glass coating, vise, index improver for functional oils, polymer cements and sealants polymer modifier... 

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... 

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