Reducing the carbon footprint of the concrete production is a complex task that many have failed to achieve so far. What makes it so difficult though?

Steffi Pawlik
11 Jan 2022

Short answer: Producing concrete is a highly complex process.

You might be thinking: “But it’s just mixing sand, cement and water, what’s so complex about that?”

Well, it’s not quiet that easy….

Concrete is a composite material which is made up of aggregates and a binder. The binder (cement paste) "glues" the aggregates together. The binder consists of cement, filler and water, while the aggregates can be fine or coarse like sand, gravel, or crushed stone. In many cases a plasticizer is used as well, for example to produce flowable concrete.

Sounds pretty straight forward so far. The right composition of the ingredients is where it gets tricky.

The right composition of the ingredients is where it gets tricky.

All components of concrete differ in their compositions. Just as an example: There are 27 types of cement currently used in the German building industry. They all have diverse characteristics and react differently to the other components in the concrete mixture. Even the same type of cement can differ in its mineralogical composition depending on where it’s from. There are many different chemical reactions taking place when cement is mixed with water. These reactions depend on different factors. Some of these dependencies are not yet fully understood so a simple one size fits all solution is not possible.

Usually, each concrete plant has their own set of recipes which are specialized for a specific purpose. Obviously, the different concrete mixes also react differently to the Sonocrete-treatment. For this reason, extensive research is needed to reach optimal outcomes for a broad set of concrete compositions.
Another reason, why it’s not an easy task to reduce the CO2 emissions of concrete is due to the norms and standards of the building industry. Of all the concrete components cement has the highest CO2-emissions which owes itself to the chemically bound CO2 released during production and the thermal and electrical energy necessary for its production. Using as little cement as possible would just make sense however this is only possible to a limited extent, depending on local standards.

And here’s where Sonocrete can make a real contribution. The precast concrete industry often relies on using their molds as many times as possible. Therefore, their concrete compositions are designed to achieve high compressive strength in only a few hours. This usually is reached with a higher cement content and/or heating of the concrete. With the help of the Sonocrete activation the needed compressive strength can be reached while cement is reduced by up to 30%.

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