DOI: 10.14489/td.2020.05.pp.046-050

Bulatov A. S., Popov A. A.
MEASUREMENT THICKNESS OF PROTECTIVE-DECORATIVE COATINGS ON CONCRETE BASES
(pp. 46-50)

Abstract. The factors affecting to the ultrasonic testing of the coating thickness on concrete are considered. The structure and design of the transducer used to solve this problem. Features of the organization of the measurement process are described. Options for creating reference samples for tuning and testing ultrasonic thickness gauges used to solve this problem. The results of measuring the thickness of the polyurethane coating on concrete obtained on the Bulat 3 device using a specialized transducer are presented. The characteristics of concrete, which necessitate the use of special protective and decorative materials (surface abrasion, insufficient density, low hydrophobicity, etc.), and the characteristics of organic polymer coatings (adhesion, elasticity, wear resistance, chemical resistance, and hardness), which depend significantly on dry film thickness (protective layer). It is indicated that in order for the coating to ensure the fulfillment of the declared parameters taking into account economic feasibility, it is necessary to fulfill the requirements for a given minimum coating thickness, and that the use of the ultrasonic testing method seems to be the optimal method for measuring the coating thickness. Factors affecting the measurement process (the ratio of acoustic impedances, reflection coefficient and its variation range for various types of concrete and the most common coatings) are also considered. It is indicated that, based on a number of experiments with different types of transducers (dual element, single element and single element with the delay line), the maximum sensitivity and measurement range are ensured by using a direct single element transducer with a delay line. The data on the choice of the operating frequency of the transducer is given, depending on the range of measured coating thicknesses. The design and construction of the transducer, the features of the construction of its elements and their influence on the transducer characteristics, the principle of measuring the coating thickness and its implementation on the Bulat 3 ultrasonic thickness gauge are described. The char-acteristics of the device that allowed it to be used for such measurements are indicated. Information is provided on various options for the implementation of reference samples of the coating, on the methodology for their testing and the measurement results.

Keywords: measurement of coating thickness on concrete, ultrasonic testing, standards of coating on concrete.