Constituent and Composition of Ordinary Portland Cement
|Lime (CaO)||60 – 65%|
|Silica (SiO_2 )||17-25%|
|Alumina (Al_2 O_3 )||3-8%|
|Iron oxide (Fe_2 O_3)||0.5-6%|
|Soda or Potash (Na_2 O & K_2 O)||0.5-1%|
|Sulphur Tri-oxide (SO_3)||1-2%|
Function of Constituents of cement
• It imparts strength and Soundness to cement. If it is in excess, makes a cement unsound.
• If in deficiency, reduces the strength and setting time.
• It imparts strength to the cement. If in excess, strength of the cement is increase but also increases the setting time of cement.
• It imparts quick setting property to cement.
• It acts as a flux and helps in reducing the clinkering temperature.
• If in excess, weakens the cement.
• It helps in increasing the initial setting time of the cement.
• It is generally added in the form of gypsum to cement clinker.
• It imparts strength, hardness and Reddish-brown tin (shade) to the cement.
• It imparts strength, hardness, yellowish tin (shade) to the cement.
• If in excess makes the cement unsound.
• It is responsible for volumetric changes in the cement-hence leads to unsoundness to cement.
Alkalies (Soda & Potash)
• These are present in form of soda (Na_2 O) and potash (k_2 O), which are responsible for staining and efflorescence.
Boost your preparation with the all-new Concept Booster Series by Adda247 Engineering Jobs, this series aims to target all the important engineering exams such as SSC Je 2022, GATE 2022, ESE 2022, and many more. Please reach out to us with your feedback in the comment section.