The gas is fed back over the calcium oxide.

气体被氧反作用。

Heating this chemical compound drives off carbon dioxide gas leaving calcium oxide.

加热这种合物会驱除二氧碳气体，留下氧。

The essential ingredient in cement is calcium oxide, CaO.

中基本成分是氧， CaO。

When water enters these tiny cracks, it hydrates the concrete’s calcium oxide.

当进入这些微小裂缝时，它会合混凝土中氧。

The heat is applied to limestone, to break up its principal constituent, calcium carbonate, into calcium oxide (cement's crucial ingredient) and CO2.

对石灰石施加热量，将其主要成分碳酸分解成氧（关键成分）和二氧碳。

The essential ingredient in cement is calcium oxide, CaO. We get that calcium oxide from limestone, which is mostly made of calcium carbonate: CaCO3.

中基本成分是氧，CaO。 我们从石灰石中得到氧， 它主要由碳酸构成：CaCO3。

Over time, some CO2 from the atmosphere drifts into all that cement in buildings and bridges, and reacts with the calcium oxide to form calcium carbonate again.

随着时间推移，大气中一些二氧碳漂移到建筑物和桥梁所有中， 并与氧反应再次形成碳酸。

Limestone is refined to produce calcium oxide, or quicklime, for cement, in a reaction known as calcination, which releases a lot of carbon in the form of CO2.

石灰石被提炼以生产用于氧或生石灰， 在称为煅烧反应中，该反应以 CO2 形式释放大量碳。

The resulting calcium hydroxide reacts with carbon dioxide in the air, starting a process called autogenous healing, where microscopic calcium carbonate crystals form and gradually fill the gap.

生成氢氧与空气中二氧碳发生反应，开始一个称为自生愈合过程，在此过程中会形成微小碳酸晶体并逐渐填充间隙。

But in fact, most of the CO2 emissions come not from the heating, but from the breakdown of limestone, which is calcium carbonate, into calcium oxide and carbon dioxide, or CO2.

但事实上，大部分二氧碳排放不是来自加热，而是来自石灰石， 也就是碳酸， 分解成氧和二氧碳， 即二氧碳。

It wasn't until 2004 that they found the cause of the problem was lime or calcium hydroxide, to give it its proper chemical name, which was being used in the construction of roads.

直到2004年，他们终于找到了这个问题根源是石灰，或者叫一个专有学名词，氢氧，是一直被用来建设公路物质。