Building Materials

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Portland cement is an inorganic material made by heating limestone and clay in a kiln. When mixed with water, it sets into a hard mass and is used to bind construction materials like bricks and stones…

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The main raw materials are: - Calcareous materials: limestone (CaCO₃), chalk (rich in CaO) - Argillaceous materials: clay, shale (rich in SiO₂ and Al₂O₃) Additionally, gypsum (CaSO₄·2H₂O) is added dur…

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Gypsum (CaSO₄·2H₂O) is added to cement in small amounts (2–3%) to slow down the setting process. Without gypsum, cement would set too quickly due to rapid hydration of tricalcium aluminate (C₃A). Exce…

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In the **wet process**, raw materials are mixed with water (35–40%) and ground into a slurry before being fed into the rotary kiln. In the **dry process**, raw materials are dried and ground into powd…

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Bogue's compounds are the major chemical phases in Portland cement: - Tricalcium silicate (C₃S) – 54.1% - Dicalcium silicate (C₂S) – 16.6% - Tricalcium aluminate (C₃A) – 10.8% - Tetracalcium aluminofe…

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$$\mathrm{C_3A} + 6\mathrm{H_2O} \longrightarrow \mathrm{C_3A \cdot 6H_2O}$$ This reaction occurs rapidly and releases a large amount of heat. It contributes to the initial setting of cement but can c…

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Setting is the initial stiffening of cement paste when mixed with water, occurring within 25 hours. Hardening is the gradual development of strength over time (up to a year or more). Both involve hydr…

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Tricalcium silicate (C₃S) hydrates relatively quickly and is responsible for early strength development in cement. It reacts with water to form calcium silicate hydrate (C-S-H) and calcium hydroxide, …