For centuries, historians and materials scientists have marveled at the longevity of ancient Roman concrete structures, which have survived for millennia under harsh marine environments. While modern concrete degrades within decades, Roman concrete, particularly marine mortar, grows stronger over time. A team of geologists analyzed the mortar and found that the crystallization of a rare mineral, aluminous tobermorite, occurs when seawater penetrates the concrete. Rather than eroding the material, the seawater initiates a chemical reaction with the volcanic ash and slaked lime, filling microscopic cracks and structurally reinforcing the concrete matrix.
Which choice best states the main idea of the text?
- Seawater initiates a chemical reaction within ancient Roman marine concrete that reinforces the material rather than eroding it.Answer
- BAncient Roman engineering techniques were superior in every respect to modern methods of concrete production.
- CRoman marine concrete degrades rapidly when exposed to seawater, prompting geologists to search for ways to protect ancient ruins.
- DStudying Roman marine mortar will allow modern engineers to construct coastal structures that never require maintenance.
Answer
Seawater initiates a chemical reaction within ancient Roman marine concrete that reinforces the material rather than eroding it.
The correct answer accurately summarizes the passage by highlighting that seawater triggers a chemical process (the crystallization of aluminous tobermorite) that reinforces Roman concrete rather than eroding it. This captures the central mechanism explained in the text.
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