DECORATIVE SANDWICH CONCRETES WITH A PROTECTIVE POLYMER LAYER ENSURING IMPROVED FRACTURE STRENGTH
Pages 96 - 99
This paper covers the integrity of decorative sandwich materials; relations between relative deformations of the sandwich system and the length of contact between layers; thicknesses of the surface layer and relative deformations of the concrete base. Principles of the proposed technology are also provided in the article.
The field study of the behaviour of decorative sandwich concrete products exposed to severe conditions of operation have proven that products collapse due to cracking and peeling of the polymer concrete layer in particular cases.
Deformations of sandwich materials caused by temperature and humidity fluctuations were analyzed by strain-gauge resistance sensors placed onto the surface polymer concrete layer of a product fragment and on the concrete base in the course of their freezing. Deformations were measured at the temperature intervals of 4 to 5 degrees Celsius. Freezing represents the most severe condition.
Mathematical method of experimental planning was employed to identify the dependence between relative deformations of sandwich system Исс and length of layer-to-layer contact L, thickness of surface layer h and relative deformations of the concrete base ɛ 105.
As a result of the probabilistic and statistical processing of the experimental data a three-factor quadratic model of relative deformations of a sandwich system was generated.
This equation is used to identify the most favourable conditions to assure the integrity of a sandwich product under the combined impact of the aforementioned factors. The analysis has proven that the surface layer made of polymer concrete does not crack irrespective of the contact length if deformations of the concrete base do not exceed the limit tensibility of the surface layer. In the event of substantial deformations of the concrete base, integrity of the sandwich system is to be assured by means of the right choice of thickness and length of the surface layer.
Based on the dependence of relative deformations of the sandwich composite, made of a concrete matrix and a polymer concrete decorative and protective layer, analysis of their integrity was performed with the account for the thickness of the surface layer, contact length and relative deformations of the water saturated concrete base in the course of freezing.
Pre-set theoretical provisions were applied to develop recommendations aimed at the optimization of the composition and characteristics of the technology of production of double-layer decorative and protective products based on polymer and mineral binders.
DOI: 10.22227/1997-0935.2012.3.96 - 99
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