How does wrought iron resist alkali-silica reaction?

Wrought iron, a highly durable and corrosion-resistant material, has long been favored in construction for its ability to withstand harsh environmental conditions. One of its lesser-known but critical advantages is its resistance to alkali-silica reaction (ASR), a common cause of deterioration in concrete and other materials.

Unlike steel or other metals, wrought iron contains very low levels of reactive silica, which minimizes its susceptibility to ASR. This reaction typically occurs when alkalis in cement react with silica in aggregates, leading to expansion and cracking. However, wrought iron's unique composition—primarily iron with small amounts of slag—prevents this chemical interaction.

Additionally, wrought iron forms a stable oxide layer when exposed to moisture, further protecting it from alkali attacks. This passive layer acts as a barrier, reducing the penetration of harmful ions that could trigger ASR. Its fibrous slag inclusions also enhance its mechanical resilience, making it less prone to stress-induced damage.

In summary, wrought iron's low silica content, natural corrosion resistance, and robust structural integrity make it an excellent choice for environments where alkali-silica reaction is a concern, ensuring longevity and reliability in construction projects.