How we could make carbon-negative concrete | Tom Schuler

Transcriber: TED Translators Admin Reviewer: Rhonda Jacobs

翻译人员: TED Translators Admin 校对人员: Yolanda Zhang

Concrete is all around us,

我们身边处处是混凝土，

but most of us don't even notice that it's there.

不过多数人不会注意到它的存在。

We use concrete to build our roads, buildings, bridges, airports;

我们使用混凝土来建造道路、 建筑物、桥、机场；

it's everywhere.

可以说， 混凝土无处不在。

水是唯一比混凝土更常用的资源。

The only resource we use more than concrete is water.

And with population growth and urbanization,

随着人口增长和城市化的发展，

we're going to need concrete more than ever.

我们比以往更需要混凝土。

But there's a problem.

但这里有一个问题：

水泥是一种把混凝土 粘合在一起的胶浆。

Cement's the glue that holds concrete together.

And to make cement,

要制造水泥，

you burn limestone with other ingredients in a kiln at very high temperatures.

需要将石灰石和其他材料 放入窑炉内进行高温烧制。

One of the byproducts of that process is carbon dioxide, or CO2.

这一过程产生的副产品之一 就是二氧化碳，即 CO2。

For every ton of cement that's manufactured,

每制造一吨水泥，

almost a ton of CO2 is emitted into the atmosphere.

就有约一吨二氧化碳 释放到大气中。

As a result,

结果就是，

水泥工业成为了 第二大工业二氧化碳排放源，

the cement industry is the second-largest industrial emitter of CO2,

responsible for almost eight percent of total global emissions.

约占全球二氧化碳排放量的 8%。

If we're going to solve global warming,

如果要解决全球变暖问题，

innovation in both cement production and carbon utilization

我们就必须在水泥制造 和碳利用方面

is absolutely necessary.

进行创新。

Now, to make concrete, you mix cement with stone, sand, and other ingredients,

要制造混凝土，需要将水泥 与石头、沙土和其他材料混合，

throw in a bunch of water, and then wait for it to harden or cure.

加入大量的水， 然后等待它固化。

With precast products like pavers and blocks,

使用像路砖或砌块 这样的预制产品，

you might shoot steam into the curing chamber

可以将蒸汽喷进凝固室里，

to try to accelerate the curing process.

以加快混凝土凝固。

For buildings, roads, and bridges,

对于建筑物、道路和桥梁，

we pour what's called ready-mix concrete into a mold on the job site

我们会在施工现场 将预搅拌混凝土倒入模具，

and wait for it to cure over time.

然后等待它固化。

Now, for over 50 years, scientists believed

50 多年来，科学家始终相信，

如果用二氧化碳，而不是水， 来固化混凝土，

that if they cured concrete with CO2 instead of water,

混凝土就会更耐用，

it would be more durable,

but they were hamstrung by Portland cement's chemistry.

但这一想法受制于生产 波特兰水泥时的化学反应。

You see, it likes to react with both water and CO2,

水泥与水和二氧化碳 都能产生反应，

and those conflicting chemistries just don't make for very good concrete.

这些相互竞争的化学反应 并不能制作出优质的混凝土。

So we came up with a new cement chemistry.

于是，我们设计了 一种新的水泥化学反应。

We use the same equipment and raw materials,

我们使用相同的设备和原料，

but we use less limestone,

但减少了石灰石的用量，

and we fire the kiln at a lower temperature,

并降低了窑炉的烧制温度，

resulting in up to a 30 percent reduction in CO2 emissions.

结果，二氧化碳的排放量 减少了 30%。

Our cement doesn't react with water.

我们的水泥不会与水产生反应。

We cure our concrete with CO2,

我们用二氧化碳固化这种混凝土，

and we get that CO2 by capturing waste gas

而这些二氧化碳来自工业设施， 比如合成氨厂或乙醇厂

from industrial facilities like ammonia plants or ethanol plants

所排出的废气，

that otherwise would've been released into the atmosphere.

从而避免了这些废气 被排放到大气中。

During curing, the chemical reaction with our cement breaks apart the CO2,

在固化期间，我们的水泥 所产生的化学反应会分解二氧化碳，

capturing the carbon to make limestone,

并利用捕捉到的碳制造石灰石，

and that limestone's used to bind the concrete together.

将混凝土粘合在一起。

Now, if a bridge made out of our concrete were ever demolished,

如果使用我们的混凝土 搭建的桥被摧毁了，

there's no fear of the CO2 being emitted because it doesn't exist any longer.

也不用担心它会释放二氧化碳， 因为二氧化碳早就不见踪影了。

When you combine the emissions reduction during cement production

如果将水泥生产过程中 减少的碳排放

with the CO2 consumption during concrete curing,

与混凝土固化过程中消耗的 二氧化碳结合起来，

we reduce cement's carbon footprint by up to 70 percent.

水泥的碳足迹最多可降低 70%。

And because we don't consume water, we also save trillions of liters of water.

而且这个过程不消耗水源， 所以还能节省上万亿升的水。

Now, convincing a 2,000-year-old industry

不过，要说服 一个拥有 2000 年历史，

that hasn't evolved much over the last 200 years,

但在过去的 200 年里 没有多大发展的行业进行变革

is not easy;

并不容易，

but there are lots of new and existing industry players

好在目前有许多新的 和现有的业内机构

that are attacking that challenge.

正在努力应对这一挑战。

Our strategy is to ease adoption

我们的策略是简化方案，

by seeking solutions that go beyond just sustainability.

寻找超越可持续性的解决方案。

We use the same processes, raw material, and equipment

我们采用了传统水泥的

that's used to make traditional concrete,

制作过程、原料和设备，

but our new cement makes concrete cured with CO2

我们的新型水泥使用二氧化碳 进行固化，得到的混凝土

that is stronger, more durable, lighter in color,

更坚固耐用，颜色也更淡，

and it cures in 24 hours instead of 28 days.

能在 24 小时内凝固， 而不再需要 28 天。

Our new technology for ready-mix

我们用于制作 预搅拌混凝土的新技术

is in testing and infrastructure applications,

尚处于测试和基础设施应用阶段，

and we've pushed our research even further

而且我们进一步推动了相关研究，

to develop a concrete that may become a carbon sink.

希望能开发出 一种可以用作碳汇的混凝土。

That means that we will consume more CO2 than is emitted during cement production.

这意味着，我们在制作水泥期间， 消耗的二氧化碳会比排放的更多。

Since we can't use CO2 gas at a construction site,

鉴于我们无法在施工地 使用二氧化碳，

we knew we had to deliver it to our concrete

所以必须将二氧化碳以固态 或液态形式

in either a solid or liquid form.

注入混凝土中。

So we've been partnering with companies that are taking waste CO2

我们一直在与一些公司合作，

把二氧化碳废料转化成 一系列有用的化学物质，

and transforming it into a useful family of chemicals

like oxalic acid or citric acid,

比如草酸或柠檬酸，

the same one you use in orange juice.

跟我们在橙汁里添加的一样。

When that acid reacts with our cement,

当这种酸性物质 与我们的水泥产生反应，

we can pack in as much as four times more carbon into the concrete,

我们能将相当于 四倍的二氧化碳注入混凝土，

使它变成碳负性。

making it carbon negative.

That means that for a one-kilometer road section, we would consume more CO2

这就意味着， 对于一个一公里的路段，

我们所消耗的二氧化碳比 10 万棵树 在一年内消耗的还要多。

than almost a 100,000 trees do during one year.

So thanks to chemistry and waste CO2,

利用化学反应和二氧化碳废气，

we're trying to convert the concrete industry,

我们正试图将混凝土，

the second-most-used material on the planet,

这个地球上用量第二大的材料，

into a carbon sink for the planet.

转变为地球的碳汇。

Thank you.

谢谢。