Low-alkali cement must have an alkali content of less than what percentage?

Low-alkali cement is specifically defined by its alkali content, which is an important consideration in preventing alkali-silica reactions (ASR) that can cause expansions and cracking in concrete structures. For cement to be classified as low-alkali, it must have an alkali content of less than 0.6 percent. This threshold is critical in ensuring that the cement does not contain excessive reactive alkali levels, which could potentially interact with reactive silica in aggregates and lead to detrimental effects over time.

The selection of 0.6 percent is based on industry standards and guidelines that have been established to mitigate these risks. Utilizing cement that meets this criteria can help ensure the longevity and structural integrity of concrete applications, particularly in environments where moisture and reactive aggregates are present.

In this context, percentages lower than the threshold indicate a lower risk of ASR-related damage, thereby enhancing the suitability of such cements for various construction projects.