MODELING THE EFFECT OF ADDING PLANT AND WOOD SAWDUST TO DRY BUILDING MIXTURES BASED ON PLASTER ON THE STRENGTH OF ADHESION TO THE CONCRETE SURFACE

ABSTRACT

The article explores how plaster-based dry construction affects the strength of a mixture to a concrete surface by the additives and fillers added to it resulting in the development of a mathematical expression.

АННОТАЦИЯ

В статье исследуется, как сухое строительство на основе штукатурки влияет на прочность сцепления смеси с бетонной поверхностью за счет добавляемых в нее добавок и наполнителей, что приводит к разработке математического моделя.

Keywords: dry construction mixtures, plaster, plant and wood sawdust, adgesia, modeling

Ключевые слова: сухие строительные смеси, штукатурка, растительные и древесные опилки, адгезия, моделлаштирш.

Introduction

In the world, special importance is attached to the issues of production of environmentally friendly, durable, long-lasting, inexpensive modern building materials that require low labor costs. Currently, in developed countries, gypsum occupies one of the leading places as a binder in construction and in the production of dry building mixtures, due to the growing need for dry building mixtures based on gypsum worldwide, using domestic raw materials, it is necessary to develop and introduce new compositions into practice. In this regard, including in the world, there is a wide production of types of dry construction mixtures, especially those that are obtained on the basis of modern energy and industrial waste. One of the modern progressive building materials, considered to be dry building mixtures, has a special emphasis on improving their production and efficiency. [3-4]

The relevant tasks of the president of the Republic of Uzbekistan in the decree of the president of the Republic of Uzbekistan No. PF-60 of January 28, 2022 "on the strategy for the development of a new Uzbekistan in 2022-2026", PQ-4335 of May 23, 2019 "on additional measures for the rapid development of the building materials industry"are defined.[1-2]

Method

In our experiments, when determining the ability of gypsum-based dry construction building mixtures to adhere to the surface, samples were made 50x50 mm in diameter, 5 mm thick, based on part 7.1.1 of the standard GOST 31376-2008. The samples were glued to brick, concrete, gasoblock surfaces, and a special metal Bolt was placed in the middle of the samples on the second side of the samples when preparing the samples. To ensure that the force is spread across an equal surface when pulling on the ends of metal bolts, metal shacks are placed, a special mold is made and a Bolt is placed in the shaker to pull it into it, and then a mixture is poured. Samples and plates from their testing, expressed in Figure 1.

After the samples were prepared, the air temperature was kept at 220s and the relative humidity of the air was maintained at 63% of the conditions for 2 days.

a)                                                                   b)

Figure 1. General views of samples prepared for testing:

a-b) the appearance of standard samples of determining the ability of the mixture to stick to the surface

Samples on a special RT-250m-2 weighing equipment GOST 31376-2008. 3.1.3 was pulled in the third speed traction mode shown in Part 1 table, and the results were calculated using the following formula 1:

     Ai=P / F, MPa.                                                             (1)

The limit of the strength of the adhesion of the three samples to the surface was determined and adopted in place of the average arithmetic information.

Main part

A series of experiments on a linear, three-factor mathematical plan was carried out to determine the optimal amount and indicators of the components that make up the plaster-based dry construction plaster mixture and the optimal ranges of technological parameters that alter the indicators. In this case, as a functional result expected from experiments, the force of adgesia was adopted on the various structural surfaces of the dry construction plaster mixture.

The following indicators were adopted as variable input factors:

• dry construction plaster based plaster the organic additive content of the plaster mixture, mass. %;
• the ratio of water and dry mixture, s/qa, to form a mixture with sufficient dispersion; P/ CM
• The degree of softness of the plaster binder, which is estimated by the residual amount in the standard sieve to the size of 0.2 mm,%.

    Table 1.

Variable intervals and levels of variable input factors

According to the selected X1, X2, X3, experimental factors, it is enough to analyze the linear equation formula to characterize the linear correlation dependence and the growth kinetics of the gluing force over time to determine the optimal composition parameters that determine the maximum values of the strength of the gluing dry construction plaster mixture with different structural surfaces.

Based on the conditions presented in Table 1, a plan of experiments was drawn up. According to him, the amount of content components is selected in the range of intended changes. The composition of the dry mixture and the plaster plaster plaster mixture was chosen strictly according to the experimental plan Matrix. With the prepared mixture, various structural surfaces (concrete, brick and gazobeton) are plastered. Subsequently, in these experimental samples, the adhesion resistance forces of the algal crust were determined in the case where they followed the instruction set out in the standard GOST 31376-2008. [5]

A full-factor experiment-test plan for choosing the optimal composition of dry plaster mixture with crushed organic additives is presented in Table 2.

Table 2.

Full-factor pilot-test plan

Data processing and drawing up regression equations based on known correlation coefficients through the analysis of experimental and research results, is presented in Table 3.

Table 3.

Constructing regression equations

As a result of the processing of experimental data, a regression equation was compiled, which adequately describes the kinetics of the adhesion strength of the algae crust to the surface according to the optimal amount of components.

      (2)

The degree of influence and optimality criteria of the variable factors considered in this series of experiments are reflected in the following sequence.

                                          (3)

Figure 2. Plaster-based dry construction mathematical models of isoparametric diagrams of the strength of gluing with a concrete base in a three-dimensional system, the result of the regression equation

Mathematical processing of data on the result of experiments carried out on a full-factor plan, as well as analysis of isoparametric diagrams, it was found that the most active effect on the adhesion strength of the recommended system is influenced by the factor x1x3, since it has the highest correlation coefficient.

Conclusion

First of all, the main influence on the strength of plaster-based drywall construction mixtures on concrete surfaces is the increased permeability of the mixture to increase the amount of water to the precipitation reducing the strength of the mixture to the Surface, see Tables 2 and 3. Secondly, it can be seen that the amount of sand in the mixture is also affected.

References:

1. Ўзбекистон Республикаси Президентининг "Қурилиш ашёлари саноатини жадал ривожлантириш учун қўшимча чора-тадбирлар тўғрисида" ги 2019 йил 23 майдаги ПҚ-4335-сонли қарори.
2. Республикаси Президентининг "Ўзбекистон Республикасини янада ривожлантириш бўйича ҳаракатлар стратегияси тўғрисида" ги 2017 йил 7 февралдаги 4947-сонли қарори.
3. Файзиллаев З.Б., Файзиев З.Х. Техническая и экономическая эффективность добавления многофункциональных органических целлюлозо-волокнистие материалы (моцвм), применяется для улучшения качества строительных смесей и штукатурки на основе гипса // Universum: технические науки : электрон. научн. журн. 2021. 2(83). URL: https://7universum.com/ru/tech/archive/item/11327 (дата обращения: 19.04.2023
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