STUDY OF THE PHYSICAL PROPERTIES OF CEMENT OBTAINED BASED ON ASPHALT PLANT FILTER WASTE

ABSTRACT

This study investigates the physical properties of a cement sample obtained using waste from the filter section of an asphalt plant at the Sherobod Cement Plant. Within the scope of the research, the physical and mineralogical composition of the asphalt plant waste was analyzed, and its effects on the properties of cement were evaluated. The cement samples were tested for key physical parameters such as density, bulk weight, and Blaine fineness. The results showed that using asphalt plant waste as an additional component can improve cement quality and offer an environmentally efficient solution in the production process. The findings of this research contribute to identifying the prospects for implementing this innovative approach in practice.

АННОТАЦИЯ

В данном исследовании рассматриваются физические свойства цементного образца, полученного с использованием отходов из фильтрационной секции асфальтового завода при Шерабадском цементном заводе. В рамках исследования был проведён анализ физического и минералогического состава отходов асфальтового завода, а также оценено их влияние на свойства цемента. Образцы цемента были испытаны на основные физические параметры, такие как плотность, насыпной вес и тонкость по Блейну. Результаты показали, что использование отходов асфальтового завода в качестве добавочного компонента может улучшить качество цемента и предложить экологически эффективное решение в производственном процессе. Полученные данные способствуют выявлению перспектив практического внедрения данного инновационного подхода.

Ключевые слова: Шеребадский цементный завод, отходы фильтров асфальтобетонного завода, клинкер, цемент, физические свойства, экономическая эффективность, экологическая эффективность.

Keywords: Sherobod Cement Plant, asphalt plant filter waste, clinker, cement, physical properties, economic efficiency, environmental efficiency.

Introduction. The waste generated from the operation of asphalt plants is considered one of the significant environmental issues. Recycling and effectively utilizing these wastes not only helps protect the environment but also makes it possible to create economically beneficial materials for the construction industry. One such waste is the material collected from the filter section of asphalt plants: during asphalt production, gravel, sand, and other minerals are heated in a drying          drum at temperatures between 450–600°C. As a result, fine mineral dust particles are released. These dust and particles are captured by filtration systems to prevent them from being emitted into the environment. One of the main challenges in Portland cement production is the high energy consumption. To reduce energy use, cement manufacturers are working on implementing energy-efficient technologies and utilizing renewable energy sources. In recent years, many scientific studies have focused on the use of industrial waste as additives in Portland cement production. These additives aim to improve cement quality while reducing production costs and environmental impact. In our research, we aimed to reduce clinker consumption by directly adding 7% of the asphalt plant filter waste to the clinker component during cement production at the Sherobod Cement Plant. For the production of D20 400 grade cement at the Sherobod Cement Plant, the clinker is usually mixed with 13.2% limestone, 3.5% gypsum, and 3.8% blast furnace slag, and then ground in a ball mill. In our experiment, the clinker component was blended with 13.2% limestone, 3.5% gypsum, and 7% asphalt plant filter waste, and the mixture was ground in a ball mill. The obtained cement sample was thoroughly analyzed and found to potentially improve economic efficiency by reducing clinker consumption at the plant scale. Notably, the presence of silica (SiO₂), aluminum oxide (Al₂O₃), and lime (CaO) in appropriate proportions was confirmed, which plays a crucial role in enhancing the strength of cement.

The aim of this study is to examine the physical properties of cement produced using asphalt plant waste and to evaluate its impact on cement quality and strength.

Methods: The cement sample obtained based on waste from the filter section of the asphalt plant was prepared through the following stages:

Raw Material Analysis: The chemical composition of the waste from the asphalt plant’s filter section was studied using X-ray analysis, focusing on the quantity of oxides obtained. The amount of oxides identified through the X-ray analysis of the filter waste product is presented in Table 1.

Table 1.

 Oxide content of the filter waste product

Material Preparation: To incorporate asphalt plant filter waste into D20 cement production, it is essential to properly organize the processes of raw material preparation, mixing, and grinding. The ratio of the main materials used for producing D20 cement based on asphalt plant filter waste is presented in Table 2.

Table 2.

Ratio of primary materials

Evaluation of Physical Properties: In cement production, physical parameters such as density, bulk weight, and Blaine index play a significant role. The obtained cement sample was tested under laboratory conditions based on these key parameters.

Density: Density indicates the degree of compactness of the binding material. It was determined using a Micrometrics device.

Bulk Weight: Bulk weight refers to the volumetric mass of cement, which plays an important role in packaging and storage processes.

Blaine Index: The Blaine surface area represents the total surface area of the cement particles. It influences the hydration rate and ultimately affects the strength of the cement.

Results. The physical properties of the cement sample obtained during the research were tested and evaluated through laboratory procedures as follows:

Density Measurement: To determine the density, 65 grams of the cement sample was weighed using an analytical balance. The sample was then placed into the Micromeritics device, and the lid was tightly sealed. After entering the measured mass into the device, the density of the sample was automatically calculated and displayed on the screen. The result showed that the density of the cement, measured using the Micromeritics device in the plant’s physical laboratory, was 3.08 g/cm³.

Bulk Weight Measurement: To measure the bulk weight, a clean and dry cylindrical container with a volume of 1 liter was used. Cement was gradually poured into the cylinder while applying gentle vibration to ensure uniform filling. Once the cement reached the rim of the container, it was leveled off with a spatula. The filled container was then weighed, and the mass of the empty container was subtracted from the total. As a result, the bulk weight of the cement sample was determined to be 1287 grams.

Blaine Fineness Determination: The cement sample, with added asphalt plant filter waste, was analyzed using a Blaine apparatus. To perform this, the density of the cement sample (3.08 g/cm³) was multiplied by two constants: 73.652 and 0.5. The result was: m = 3.08 × 73.652 × 0.5 = 113.79 grams. This calculated mass was weighed and placed into the Blaine tube-shaped device with filter paper at the bottom. The setup was then installed into the apparatus. The next step involved inputting the determined density into the device, after which the number of particles was displayed on the screen within a short time. The specific surface area of the cement sample prepared using asphalt plant filter waste was found to be 3200 cm²/g, which is consistent with the requirements for CEM II/A-I 32.5N grade cement.

Discussion: This research focused on the possibility of producing D20 400 grade cement by adding 7% asphalt plant filter waste to the clinker component at the Sherobod Cement Plant. The results showed that the addition of waste material had no negative impact on the cement’s Blaine surface area, density, and bulk weight parameters, which complied with GOST and O‘zDST standards.

Specifically, the Blaine surface area of the cement produced was almost identical to that of CEM II/A-I 32.5N grade cement. The bulk weight and density indicators improved the cement's ability to retain liquid, without negatively affecting its strength.

The asphalt plant filter waste contains inorganic particles, metal oxides, and heat-resistant minerals, which influence the phase composition of the clinker. As a result, the C₃S and C₂S phases are fully synthesized, maintaining the strength of the cement.

From both an ecological and economic perspective, the approach is positive, as clinker consumption was reduced by 7%, leading to savings in fuel energy and raw material usage. The reduction in CO₂ emissions released into the atmosphere aligns with the principles of ‘green technology.’

Conclusion: This study explored the possibility of producing D20 400 grade cement by adding 7% asphalt plant filter waste to the clinker component. The following key conclusions were drawn:

• Clinker consumption was reduced by 7%, which allowed for a decrease in fuel, raw material, and energy consumption during production.
• The physical and technical parameters of the cement samples with added waste, such as Blaine surface area, density, and bulk weight, fully complied with normative requirements, and the cement quality did not decline.
• Environmentally, the use of waste led to a reduction in CO₂ emissions, a decrease in atmospheric dust, and successful utilization of the filter waste.

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