まとめ
水解産物は,無水セメントの粒内に形成され,シドモルフを形成する. 穀間の隙間にある水酸化カルシウムの結晶は,セメントペーストの強さの鍵です.
科学分野:
- マテリアルサイエンス 材料科学
- 土木工学 土木工学とは
- ケミストリー 化学
背景:
- セメントの水分化を理解することは,建設に不可欠です.
- シメントペーストの微細構造的発展は,その機械的性質に影響する.
研究 の 目的:
- シメントの水分化の過程における微細構造の変化を調査するために.
- シメントペーストの強度に関与する成分を特定する.
主な方法:
- 電子顕微鏡 (SEM) を用いて微細構造を分析した.
- 水無性および水性セメントの粒子の微細構造分析.
主要な成果:
- 水分化製品は,無水セメント粒子の内部で形成され,シドモルフを生み出します.
- 水酸化カルシウムの結晶は,セメント粒子の間の空間に沈殿します.
- これらのカルシウム水酸化物結晶は,セメントペーストの強度に責任があるようです.
結論:
- セメントの水分化には,内部産物形成と穀物間空間の埋め込みが含まれます.
- 水酸化カルシウムは,セメントペーストの機械的完全性において重要な役割を果たします.
関連する概念動画
01:21Portland Cement
Portland cement is the essential binding ingredient in concrete, made from finely ground materials including lime, iron, silica, and alumina. Lime is derived primarily from limestone, marble, marl, seashells, and clays, which also supply iron and alumina, while silica is sourced from sand, chalk, and bauxite. Contemporary manufacturing of Portland cement is a significant source of carbon dioxide emissions, prompting research into reducing its content in concrete through alternative...
01:22Types of Cement II
Portland blast-furnace cement is made by blending Portland cement clinker with granulated blast-furnace slag, which accounts for 25 to 65 percent of the cement's weight. Despite its similarities to ordinary Portland (Type I) cement in terms of fineness and setting times, its early strength is lower, though it achieves comparable strength later on. It's particularly suited for mass concrete structures and marine environments due to its lower heat of hydration and superior sulfate resistance.
01:18Porosity in Cement Paste
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is critical—it...
The balance of water to cement in the mix is critical—it...
01:21Pozzolans
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is a...
Fly ash is a...
01:23Pore Size Distribution
In concrete, the pore size distribution significantly influences the material's properties. Capillary pores, markedly larger than gel pores, form a vast network within partially hydrated cement paste, reducing the concrete's strength and increasing its permeability. This heightened permeability leads to a greater risk of damage from environmental factors like freeze-thaw cycles and chemical attacks, with the extent of vulnerability also being tied to the water-to-cement ratio.
Adequate...
Adequate...
01:21Types of Cement I
Portland cement comes in several types, each with distinct properties and applications based on their chemical composition and hydration characteristics:
Type I (Ordinary Portland Cement) is widely used for general construction where special properties are not required. It has moderate sulfate resistance and heat of hydration.
Type II (Modified Cement) offers moderate resistance to sulfate attack and a lower rate of heat development compared to Type I. It is suitable for structures in...
Type I (Ordinary Portland Cement) is widely used for general construction where special properties are not required. It has moderate sulfate resistance and heat of hydration.
Type II (Modified Cement) offers moderate resistance to sulfate attack and a lower rate of heat development compared to Type I. It is suitable for structures in...