Discrete Optimization of Software-Controlled Modes of Heat Treatment of Concrete Products in Heat-Technological Facilities

In the article the technique of an assessment of modes of operation of the heat engineering equipment used for heat treatment of concrete products in the conditions of programcontrolled heat supply according to the pattern of “heating – isothermal influence – cooling” has been developed. The method is based on the numerical solution of a non-stationary heat equation supplemented by equations describing the hydration process of a concrete product; also, it includes a system of initial and boundary conditions for its spatial structure. The method makes it possible to create tabulated functions of temperature and the degree of hydration of the time of heat treatment in any point of a 3D-product. The mathematical tools for calculating the functional dependencies of concrete hydration equipment with software-heated environment are presented. Numerical calculations of the concrete hydration process in the formwork are performed with respect to the symmetrical object. Based on the calculation of the temperature gradient across the minimal cross section of the product, a numerical analysis of the functions modeling heat supply mode depending on the processing time of a concrete product has been fulfilled. It is demonstrated that the maximum speed of the hydration process in a concrete product hardening is achieved at the maximum of time lag of isothermal cure. Additionally, with an increase in the duration of the product heating, the value of the maximum hydration rate decreases. It is concluded that the method of assessing the mode of heat treatment of concrete products being developed makes it possible to determine parameters for the calculation of the minimal useful heat required for the heat treatment of concrete products with spatially distributed parameters. The proposed method is applicable to calculate the temperature fields and the extent of hydration in the products of any geometric shape and volume in a software-controlled heating environment of industrial facilities for the accelerated hydration of concrete, and also affords the possibility of preliminary calibration prior to the assignment of relevant heat supply modes to the products being processed.

1. Khr?ustalev B. M., Romaniuk V. N., Sednin V. A., Bobich A. A., Muslina D. B., Bubyr T. V. (2014) To the Subject of Development of Power Supply Process for Industrial Heat Technologies and Heat Supply Systems in Belarus. Energetika. Izvestiya Vysshikh Uchebnykh Zavedenii i Energeticheskikh Ob’edenenii SNG = Energetika. Proceedings of the CIS Higher Educational Institutions and Power Engineering Associations, (6), 31-47 (in Russian).

2. Romanyuk V. N, Radkevich V. N., Kovalyov Ya. N. (2001) Fundamentals of Efficient Energy Use at the Production Enterprises of the Road Industry. Minsk, Tekhnoprint Publ. 292 (in Russian).

3. Bibik M. S., Babitskii V. V. (2010) On the Energy Saving Modes of Heat Treatment of Concrete and Reinforced Concrete Products. Stroitel`naya nauka i texnika [Construction Science and Technique], (4), 55 –59 (in Russian).

4. Fedosov S. V., Ibragimov A. M., Gushhin A. V. (2008) Application of Methods of Mathematical Physics for Modeling of Mass and Energy Transfer in Technological Processes of the Construction Industry. Stroitel`ny`e materialy = Construction Materials, (4), 65–67 (in Russian).

5. Kuriakose B., Rao B. N., Dodagoudar G. R., Venkatachalapathy V. (2015) Modelling of heat of hydration for thick concrete constructions – a note. Journal of Structural Engineering, 42 (4), 348 – 357.

6. Fedosov S. V., Bobylev V. I., Ibragimov A. M., Kozlov V. K., Sokolov A. M. (2011) Modeling of Concrete Strength Gain During Cement Hydration. Stroitel`ny`e materialy = Construction Materials, (11), 38–41 (in Russian).

7. Usherov-Marshak A. V., Sinyakin A. G. (1994) Information Technology of Accelerated Hardening Concrete. Beton i zhelezobeton [Concrete and Reinforced Concrete], (6), 2–4 (in Russian).

8. Nixon J. M., Schindler A. K., Barnes R. W., Wade S. A. (2008) Evaluation of the Maturity Method to Estimate Concrete Strength in Field Applications: Research Report. Highway Research Center and Department of Civil Engineering at Auburn University. Available at: http://www.eng.auburn.edu/files/centers/hrc/930-590-2.pdf. (accessed 14 December 2018).

9. Sorogovetc I. B., Goncharov É. I., Artem`ev V. B. (2000) Polynomial Solutions in Problems of Controlling the Heating of Solids. Journal of Engineering Physics and Thermophysics, 73 (5), 889–893. https://doi.org/10.1007/bf02681575

10. Babitskii V. V. Sukhodeev N. V. (2008) The Elements of Projecting of the Regime of Thermal and Moisture Treatment of Concrete. Perspektivy razvitiya novykh tekhnologii v stroitel'stve i podgotovke inzhenernykh kadrov Respubliki Belarus': sb. tr. XV Mezhdunar. nauch.-metod. sem. [Prospects of Development of New Technologies in Construction and Training of Engineering Personnel of the Republic of Belarus: Proceedings of XVth International Scientific-and-Methodic Seminar]. Novopolotsk, 139–143 (in Russian).

11. Babitskii V. V., Semenyuk S. D., Bibik M. S. (2009) Forecasting of Characteristics of the Hardened Heavy Concrete. Resursoekonomnii materiali, konstruktsii, budivli ta sporudi: zbir. nauk. prats' [Resource-Efficient Materials, Constructions, Buildings and Structures. Collected Research Works]. Rivno, 18, 3–12 (in Ukrainian).

12. Usherov-Marshak A. V., Gil` Yu. B., Sinyakin A. G. (2000) "Thermobet-M" Information Technology of the Monolithic Concrete. Beton i zhelezobeton [Concrete and Reinforced Concrete], (4), 2–5 (in Russian).

13. Aksenchik K. V. (2014) Improvement of the Thermal Operation of Curing Chambers for Curing of Concrete Products. Ivanovo. 20 (in Russian).

14. Podgornov N. I., Koroteev D. D. (2014) Mathematical Formulation of the Problem of Determining the Temperature of the Concrete During Heat Treatment in Solar Cells of a “Hot Box” Type. Vestnik Rossiiskogo universiteta druzhby narodov. Seriya: Inzhenernye issledovaniya = RUDN Journal of Engineering Researches, (1), 131–135 (in Russian).

15. Batyanovskii E. I., Ivanova E. I., Osos R. F. (2006) Efficiency and Problems of Energy-Saving Technologies of Cement Concrete. Stroitel`naya nauka i texnika [Construction Science and Technique], (3), 7–17 (in Russian).

16. Mar`yamov N. B. (970) Heat Treatment of Products at the Plant of Precast Concrete (Processes and Facilities). ?oscow, Stroiizdat Publ. 272 (in Russian).

17. Aleksandrovskii S. V. (2004) Calculation of Concrete and Reinforced Concrete Structures for Changes in Temperature and Humidity, Taking into Account the Creep of Concrete. ?oscow, RICRC. 712 (in Russian).

18. Krasulina L.V. (2012) Structural and Thermophysical Properties of Hardening Concrete. Nauka i tekhnika = Science & Technique, (2), 29-34 (in Russian).