KR-20260063180-A - An eco-friendly cement replacement using precipitated calcium carbonate and an eco-friendly cement composite composition including the same

Abstract

The present invention relates to an eco-friendly cement substitute using precipitated calcium carbonate and an eco-friendly cement composite composition containing the same. By replacing cement with an eco-friendly material, carbon dioxide emissions are reduced, and through the improvement of physical and chemical properties, it can be used in various applications in diverse fields, such as new construction and remodeling. An eco-friendly cement composite composition comprising an eco-friendly cement substitute using precipitated calcium carbonate according to the present invention is composed of a mixture of 75-85% by weight of cement, 3-7% by weight of precipitated calcium carbonate, 3-7% by weight of nano silica, and 7-13% by weight of waste glass, or a mixture of 80-90% by weight of cement, 5-10% by weight of precipitated calcium carbonate, and 5-10% by weight of nano silica based on 100% by weight of the total.

Inventors

• 이희영
• 이재곤
• 차인영

Assignees

• 조선대학교산학협력단

Dates

Publication Date

20260507

Application Date

20241030

Claims (6)

1. An eco-friendly cement substitute using precipitated calcium carbonate, characterized by being composed of precipitated calcium carbonate, nano silica, and waste glass powder mixed in a ratio of 1:0.9~1.1:1.8~2.2 by weight.
2. An eco-friendly cement substitute using precipitated calcium carbonate, characterized by being composed of precipitated calcium carbonate and nano silica mixed in a ratio of 1:0.9 to 1.1 by weight.
3. An eco-friendly cement substitute using precipitated calcium carbonate according to claim 1 or claim 2, wherein the precipitated calcium carbonate has a particle size of 1.8㎛ ±10%.
4. An eco-friendly cement substitute using precipitated calcium carbonate according to claim 1 or claim 2, wherein the precipitated calcium carbonate is manufactured through a manufacturing process comprising: a first step of preparing limestone as a starting material; a second step of crushing the limestone and calcining it at 900°C to 1000°C to produce calcium oxide (CaO); a third step of reacting the calcium oxide with water to produce calcium hydroxide (Ca(OH) ₂ ); a fourth step of injecting carbon dioxide ( CO₂ ) gas into the calcium hydroxide to produce precipitated calcium carbonate (PCC); and a fifth step of controlling the particle size of the precipitated calcium carbonate produced in the fourth step to 1.8㎛ ±10%.
5. An eco-friendly cement composite composition comprising an eco-friendly cement substitute using precipitated calcium carbonate, characterized by comprising, based on 100% by weight of the total, 75-85% by weight of cement and 15-25% by weight of an eco-friendly cement substitute using precipitated calcium carbonate according to Claim 1 or Claim 2.
6. An eco-friendly cement composite composition comprising an eco-friendly cement substitute using precipitated calcium carbonate, characterized in that, in claim 5, the composition comprises a mixture of 75-85% by weight of cement, 3-7% by weight of precipitated calcium carbonate, 3-7% by weight of nano silica, and 7-13% by weight of waste glass, based on 100% by weight of the total, or a mixture of 80-90% by weight of cement, 5-10% by weight of precipitated calcium carbonate, and 5-10% by weight of nano silica, based on 100% by weight of the total.

Description

An eco-friendly cement replacement using precipitated calcium carbonate and an eco-friendly cement composite composition including the same The present invention relates to an eco-friendly cement composite composition, and more specifically, to an eco-friendly cement substitute using precipitated calcium carbonate that reduces cement usage by replacing cement with an eco-friendly material, and an eco-friendly cement composite composition containing the same. Concrete is a vital material in the global construction industry, with billions of tons produced annually. However, cement, the main component of concrete, is recognized as a major contributor to greenhouse gases due to the massive amount of carbon dioxide ( CO2 ) emitted during its production process. Consequently, efforts to reduce cement usage and research eco-friendly alternatives are becoming increasingly important. Registered Patent No. 10-0999534 comprises 55-70% by weight of blast furnace slag fine powder with a fineness of 4,000-6,000 cm²/g; 2-5% by weight of Na₂SO₄ powder with a diameter of 50-300 μm as an alkali stimulant; and 25-40% by weight of limestone coarse fine powder with a fineness of 6,000-12,000 cm²/g; The composition is an eco-additive for cement substitution composed of the following: Registered Patent No. 10-2549198 shortens the steam curing period and, for the development of initial and long-term strength, comprises 50 to 75 parts by weight of clinker powder with 4CaO·3Al2O3·SO3 as the main component, 10 to 20 parts by weight of ordinary Portland cement clinker powder, 5 to 20 parts by weight of blast furnace slag powder, 5 to 15 parts by weight of crack-reinforcing mixed powder in which silica fume and nano-calcium carbonate are mixed in a 1:1 weight ratio, and 5 to 15 parts by weight of petrocoke desulfurization gypsum powder; wherein, for 100 parts by weight of a rapid-hardening cement binder, the composition comprises 45 to 60 parts by weight of natural fine aggregate with a particle size of silica sand No. 6 to No. 8, 40 to 55 parts by weight of coarse aggregate with a particle size of 5 to 15 mm, and waste glass or broken glass used as a substitute for 5 to 15% of the natural fine aggregate. It is a high-strength cement concrete mortar composition using waste glass or broken glass, composed of fine aggregate and water. In the following description of the present invention, specific descriptions of related known functions or configurations will be omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these definitions may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The eco-friendly cement substitute using precipitated calcium carbonate according to the present invention comprises a mixture of precipitated calcium carbonate, nano silica, and waste glass powder, or a mixture of precipitated calcium carbonate and nano silica. 1. Precipitated calcium carbonate. Precipitated calcium carbonate (PCC) is a type of calcium carbonate produced through a chemical precipitation process. It is known to have fine and consistent particle size, high brightness, and purity, and is relatively inexpensive compared to other forms of calcium carbonate. Additionally, as a cement substitute, it offers the advantage of precisely controlling particle size and shape. The method for manufacturing precipitated calcium carbonate according to the present invention is as follows. A. Preparation of limestone. Limestone is primarily composed of calcium carbonate (CaCO3) and is prepared as a starting material for precipitated calcium carbonate; thus, limestone containing high-purity calcium carbonate is prepared. B. Formation of calcium oxide. Limestone is crushed (the crushed particle size is approximately 1.8㎛ ±10%, which is the final particle size) and calcined at 900℃ to 1000℃ to produce calcium oxide (CaO). C. Formation of calcium hydroxide. Calcium oxide is reacted with water ( H₂O ) to produce calcium hydroxide (Ca(OH) ₂ ). D. Formation of precipitated calcium carbonate. Precipitated calcium carbonate (PCC) is produced by injecting carbon dioxide ( CO2 ) gas into calcium hydroxide. E. Control of precipitated calcium carbonate particle size. The particle size of the precipitated calcium carbonate produced through the entire process is controlled to be used as a cement substitute, and the particle size is 1.8㎛ ±10%. A ball mill or similar equipment is used to grind the dried calcium carbonate to the desired particle size. A ball mill is equipment that performs grinding by placing steel balls of various sizes into a rotating drum; the particle size can be controlled by adjusting the rotation speed and grinding time. The rotation speed used here is 70% of the critica