Assessment of Altawseea Ordinary Portland Cement Northern Iraq: Mineralogy, Microstructure, and Hydration

Abstract

The current study is an assessment of the Al-Tawsseea Cement Plant, located in the northwest of Iraq, Nineveh. This plant produces Ordinary Portland Cement grade 42.5R according to the I.Q.S No(5)/2019. Ordinary Portland Cement was chosen to determine the mineralogy using X-Ray Diffraction and Scanning Electron Microscope before and after hydration. Physical tests were carried out such as the Fineness Test (Blain) (331.4) M2/Kg, Soundness Test (Autoclave) 0.1% Compressive Strength Test (2 Days 22.35 N/mm2 and after 28 Days 47.81 N/mm2) and Setting Time Test (Initial 150 Min and Final 3:10 Hours) and all the physical tests are within the requirements of limits according to I.Q.S No(5)/2019. XRD analyses revealed that the studied cement is composed of alite, belite, ferrite, and aluminate which indicate good burning and cooling processes, while after hydration the paste is composed of CSH, CH, and Ettringite. The Scaning Electron Microscope showed that the studied Ordinary Portland Cement microstructure, characterized by an intensive intergrowth of hypidiomorphic crystals and belite (spherical to oval shape) is less but bigger than alite. After hydration, the microstructure became dense and calcium-silicate hydrate (C-S-H) formed a lathe-like shape fill the pores of the cement paste and gave the paste hardness and good compressive strength. The pore diameters in studied Ordinary Portland Cement are ranging from 9.9 to more than 15.9 µm. They look like circular or irregular shape and are randomly distributed which decrease the density, and compressive strength of the paste. According to the results of the physical test and mineralogy microstructure, we can say that it is possible to raise the grade of Ordinary Portland Cement of the Al-Tawseea Cement Plant (42.5R) by increasing the proportion of calcium in the raw materials mixture within the specification. This will lead to an increase in the value of LSF and the C3S which is responsible for increasing hardness or compressive strength.