多ロミットセメントモルターの老化過程におけるヒドロタルシートのような相の形成と進化
Elena Sutormina1, Marjan Marinšek2, Anton Meden3
1University of Ljubljana, Faculty of Chemistry and Chemical Technology, Slovenia. es2333@student.uni-lj.si.
Acta chimica Slovenica
|August 21, 2025
まとめ
ポートランドセメントのドロミット反応はアルカリ状態で加速し,ヒドロタルシートのような相を形成します. 時間が経つにつれて,炭酸塩は水酸化物によって置き換えられ,セメントの耐久性に影響を与えます.
科学分野:
- 材料科学
- 土木工学
- 地化学
背景:
- ドロマイトは,セメント材料の一般的な鉱物添加物です.
- 様々な条件下でセメントペーストの反応を理解することは,材料の性能にとって極めて重要です.
研究 の 目的:
- ポルトランドセメントにおけるドロマイトの反応メカニズムを加速老化条件下で調査する.
- シメント・ドロミットモルターの相組と微細構造の変化を分析する.
主な方法:
- 段階組成分析のためのX線微分法 (XRD).
- 熱分析 (TGA/DSC) を用いて材料の特徴を決定する.
- 電子顕微鏡でX線微分析 (SEM-EDX) を用いて微細構造と元素分析を行う.
主要な成果:
- 塩基条件はドロミット反応速度を大幅に増加させた.
- 主要な反応産物は,水タルシートのような相 (Mg4Al2(CO3) 1-x(OH) 12+2x·nH2O) であった.
- 3ヶ月後,ヒドロタルシートの中間層の炭酸アニオンは徐々に水酸化アニオンに取って代わられました.
結論:
- 媒体のアルカリ性は,基本的な反応産物を変えないまま,ドロミットの反応性を高めます.
- ハイドロタルシートの形成は,硬化セメントパストのドロミット消費の重要なメカニズムです.
- 水素タルシートの層間のアニオン交換は,セメント系における重要な長期的な変化プロセスである.
さらに関連する動画
07:32Monitoring Pedogenic Inorganic Carbon Accumulation Due to Weathering of Amended Silicate Minerals in Agricultural Soils.
Published on: June 4, 2021
5.3K
06:27Expression of Cementitious Pore Solution and the Analysis of Its Chemical Composition and Resistivity Using X-ray Fluorescence
Published on: September 23, 2018
9.4K
関連する概念動画
Hydration of Cement
380
Hydration of cement is a chemical reaction between cement particles and water. This process occurs primarily through two mechanisms: through-solution and topochemical. In the through-solution process, anhydrous compounds dissolve into their constituents, hydrates form in the solution, and then precipitate from the supersaturated solution. The topochemical process involves solid-state reactions at the cement particle surface. The through-solution process dominates the topochemical process at the...
380
Strength and Heat of Hydration
342
The hydration of cement is an exothermic reaction in which heat is generated as cement hydrates. This heat of hydration is critical to cement's strength development. The rate at which this heat is generated affects the temperature rise, with a majority of the heat being released early in the hydration process, half within the first three days, and about 75% within the first week.
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
The heat of hydration for each cement compound is significant; for instance, tricalcium aluminate (C3A) and...
342
Transition Zone
148
The transition zone in concrete is a critical area where aggregate meets cement paste, marked by a distinct porosity and weakness compared to the surrounding material. The adhesion around the aggregates is primarily due to Van Der Waals forces. The voids within this zone influence its robustness; initially, it is less durable than the surrounding bulk mortar due to larger voids. Initially, when concrete is compacted, a higher water-cement ratio near the aggregates leads to the formation of...
148
Mortar Joint Deterioration in Masonry
165
Mortar joint deterioration is a significant concern in masonry structures, with water accumulation in the joints leading to damage from freeze-thaw cycles. The repeated expansion of water during freezing and its melting during thawing develop and propagate cracks in the masonry joints. Eventually, this leads to the spalling of mortar from the joints, loosening masonry units and weakening the structure. The deteriorated mortar joints are also vulnerable to moisture intrusion into the walls.
The...
The...
165
Sulfate Attack on Concrete
291
Sulfate attack on concrete is a deterioration process characterized by a whitish discoloration beginning at the edges and corners, accompanied by cracking and spalling. This phenomenon occurs when sulfates react with the components of hardened concrete, forming compounds like calcium sulfate and calcium sulfoaluminate which occupy more space than the substances they replace, causing the concrete to expand and disrupt.
Sulfates from sources like soil, groundwater, or industrial effluents...
Sulfates from sources like soil, groundwater, or industrial effluents...
291
Soundness of Cement
234
The soundness of cement refers to the ability of cement paste to retain its volume after setting. Unsound cement can lead to expansion and structural damage due to the presence of free lime, magnesia, and calcium sulfate. Free lime hydrates very slowly, expanding and causing unsoundness, which is difficult to detect because it intercrystallizes with other compounds. Magnesia also reacts with water, forming crystals that can disrupt the cement's structure. Calcium sulfate can create...
234
