Is Portland cement acidic?

• A. No
• B. Yes
• C. It depends
• D. Not defined

Answer: (A)

Portland cement is not acidic. When it hydrates, it forms calcium hydroxide and other alkalis, creating a highly alkaline paste with a pH typically around 12 to 13. This strong alkalinity is important because it passivates embedded steel and influences how the concrete behaves in different environments. In acidic conditions, the alkalinity can be neutralized, which is when problems like corrosion or deterioration can start; but the cement itself is inherently alkaline, not acidic.