『新东方在线托福听力』为托福考生准备了ETS托福TPO/【学术讲座】#46听力练习：What does the speaker say about chunks of calcium carbonate in concrete?原文题目答案解析，TPO/【学术讲座】#46听力原文范文音频翻译。

托福TPO/【学术讲座】#46听力原文What does the speaker say about chunks of calcium carbonate in concrete?【新东方在线】

Listen to a talk in an architecture class.

男：你有没有想过，为什么像罗马竞技场和渡槽这样的古代混凝土结构能持续数千年，而现代混凝土建筑仅仅几十年后就开始破损、需要更换？

Man: Have you ever thought about how ancient concrete structures like Roman amphitheatres and aqueducts have managed to last for thousands of years, while modern concrete buildings seem to fall apart and need replacing after just a few decades?

长期以来，研究人员认为罗马混凝土耐久的秘密在于火山灰。

For a long time, researchers thought the secret to Roman concrete's durability was volcanic ash.

这说得通，因为火山灰是主要成分，而且当时的建筑师和历史学家在写作中也明确这样描述过。

That makes sense, since volcanic ash was a major ingredient, and it was explicitly described as such by architects and historians who were writing at the time.

但事实证明，真正的秘密其实是微小的碳酸钙块。

But it turns out the real secret was actually tiny chunks of calcium carbonate.

这些碳酸钙块的形成是因为罗马人在混合料中使用了干燥的生石灰，而不是我们今天制造波特兰水泥的方法——后者先把石灰与水混合，再与其他材料搅拌。

These formed because the Romans used dry, quick lime in their mix instead of the way we make concrete today called Portland cement, where lime gets mixed with water first, then blended with everything else.

当罗马混凝土出现裂缝、水渗入时，这些碳酸钙块会与水反应，把裂缝封住。

When cracks show up in Roman concrete and water gets in, those calcium carbonate bits react with the water and seal up the cracks.

所以混凝土基本上能够自我修复，裂缝被修复后，随着时间的推移反而变得更加坚固。

So the concrete basically heals itself, fixes the cracks, and gets stronger over time.

有趣的是，研究人员早就注意到罗马混凝土中有这些小块，但他们一直认为那是生产缺陷——比如有人配料时没搅拌均匀。

Funny thing is, researchers have noticed these chunks in Roman concrete for ages, but they just figured they were a production flaw, like someone didn't mix the ingredients well enough.

总之，考虑到现代混凝土寿命短，而且生产它对环境有害，想到我们或许能在未来的建筑中使用一些古罗马的技巧，这还是挺令人兴奋的。

Anyway, considering how short lived modern concrete is, and the fact that making it is bad for the environment, it's pretty exciting to think we might be able to use some of these ancient Roman tricks in future construction.

What does the speaker imply about volcanic ash?

What does the speaker say about chunks of calcium carbonate in concrete?

What is the speaker's attitude toward modern concrete?

Listen to a talk in an architecture class.<br />Man: Have you ever thought about how ancient concrete structures like Roman amphitheatres and aqueducts have managed to last for thousands of years, while modern concrete buildings seem to fall apart and need replacing after just a few decades? For a long time, researchers thought the secret to Roman concrete's durability was volcanic ash. That makes sense, since volcanic ash was a major ingredient, and it was explicitly described as such by architects and historians who were writing at the time.<br />But it turns out the real secret was actually tiny chunks of calcium carbonate. These formed because the Romans used dry, quick lime in their mix instead of the way we make concrete today called Portland cement, where lime gets mixed with water first, then blended with everything else. When cracks show up in Roman concrete and water gets in, those calcium carbonate bits react with the water and seal up the cracks. So the concrete basically heals itself, fixes the cracks, and gets stronger over time.<br />Funny thing is, researchers have noticed these chunks in Roman concrete for ages, but they just figured they were a production flaw, like someone didn't mix the ingredients well enough. Anyway, considering how short lived modern concrete is,and the fact that making it is bad for the environment, it's pretty exciting to think we might be able to use some of these ancient Roman tricks in future construction.

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