The name of the person who first recorded the composition of Roman concrete.
16
The main environmental advantage of adopting the Roman concrete-making method today.
17
The specific location where the research samples were collected.
18
A comparison of how modern and Roman concrete behave in seawater.
19
The two key minerals that contributed to the strength of the Roman concrete.
Questions 20 - 26:
Complete the summary below. Choose NO MORE THAN TWO WORDS from the passage for each answer.
Roman Concrete vs. Modern Concrete
Research into an ancient Roman 20 has provided new insights into concrete. The study, led by Paulo Monteiro, analyzed samples that had been submerged in seawater for two millennia.
The analysis showed that Roman concrete uses a different binding cement. While modern 21 cement is a compound of calcium, silicon, and hydrates, Roman cement includes 22 and less silicon, forming a very stable compound called C-A-S-H.
A key ingredient in the Roman recipe was 23, which provided the aluminum. The Romans made their concrete for coastal structures by mixing this with lime, placing the mixture in 24, and then immersing it in seawater. This immersion caused a hot chemical reaction.
A significant finding was that this process led to the growth of rare minerals within the concrete, which reinforced it. In contrast, seawater 25 modern concrete. Adopting the Roman method today could lead to the creation of more 26 marine structures.
